tcvn 6101 - 1996 he thong chua chay cacbon dioxit t.ke va lap dat.doc
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Microsoft Word - 6101
VIETNAM STANDARD
TCVN 6101:1990 ISO 6183:1990
10
typed by thangnc
FIRE PROTECTION EQUIPMENT CARBON DIOXIDE EXTINGUISHING SYSTEMS FOR USE ON PREMISES DESIGN AND INSTALLATION
1. The scope of application:
This standard specifies the requirements for the design and installation of fixed carbon dioxide fire extinguishing system in the house. These requirements do not apply to fire extinguishing systems on ships, aircraft, fire engines, or underground systems in the mining industry, as well as for inert system by using carbon dioxide.
This standard does not specify the design of the system in which the clearances aren't closed and exceed the prescribed area and in place wherethe clearances can be influenced by the effects of wind. General guidelines on the procedures must comply in such cases presented in 15.6.
2. QUOTE STANDARD
ISO 1182:1983 - Testing the fire - Building materials - Testing the non-combustible capability.
ISO 4200:1985 - Normally pipes and steel tubes, welding and weldless - General tables of dimensions and mass per length unit.
ISO 834:1975 - Testing the fire-resistant - Strutural component of building materials.
TCVN 6100:1996 (ISO 5923:1984) - Fire protection and fire fighting - Extinguishant - Carbon dioxide.
3. DEFINITIONS
This standard uses the following definitions:
3.1. Cacbon dioxit fire extinguishing system
Carbon dioxide supply source is regularly connected with fixed navigation system with nozzles arranged to discharge carbon dioxide into the protected area so as to achieve the firre extinguishing concentration according to the design.
3.2. Volume fire extinguishing system
Carbon dioxide supply source is regularly connected with fixed navigation system with nozzles arranged to discharge carbon dioxide into the space surrounding the fire hazard zone so as to maintain concentration to extinguish the fire.
3.3. Local fire extinguishing system
The fixed carbon dioxide supply source is regularly connected with fixed navigation system with nozzles arranged to discharge carbon dioxide directly into inflammable materials or where the fire occurs.
3.4. Automatic control
Perform functions without human intervention.
3.5. Driver Device
Equipment to control the sequence of events leading to the discharge of carbon dioxide.
3.6. Manual control
Perform a functional with human intervention.
3.7. Control Structure
A component involved in the element between the startup of the system and the carbon dioxide discharge.
3.8. Discharging cacbon dioxit
Opening the container and the selector valve leads to discharge carbon dioxide into the protected area.
3.9. Maintain time
The time that carbon dioxide exists at concentrations according to the design covering fire hazard area.
3.10. Organizations and individuals authorized
Organizations, agencies or individuals is responsible for device approval, installation, construction method or system design.
3.11. Selector valve
Equipment to control flow of carbon dioxide through the gas distribution piping directly to the pre-selected protection area.
4. CACBON DIOXIT
Extinguishant used is carbon dioxide in accordance with the requirements of TCVN 6100:1996 (ISO 5923:1984).
Other information about carbon dioxide and application of carbon dioxide are outlined in appendix c.
5. SAFETY REQUIREMENTS
In all cases, use of carbon dioxide fire extinguishing system, while people can get stuck inside or go into protected areas, must have the appropriate protection measures to ensure the evacuation quickly from the area, limiting to enter the area after degassing, except when necessary to facilitate emergency rapidly for people trapped. The safety requirements such as staff training, warning signs, warning the gas discharge and demolition tools must be taken into consideration. Pay attention to the following requirements:
a) The exit routes are kept clear at all times and must adequately have the appropriate instruction signage;
b) Alarm sound in the gas discharge area and the other alarm signals are not the same and must work immediately after discovering the fire and discharging carbon dioxide (see Article 6);
c) Must have the automatically self-closing door with one side out, these doors can be opened from the inside even when locked outside;
d) Must have the visual alarm device or heard at the access door until the air becames safety;
e) Must add the odor additive into CO2 to detect the dangerous air;
f) There must be a warning sign and guide in the entrance;
g) There must be a means of ventilation in the areas after the fire is extinguished;
h) There must be other protective means when necessary for each individual situation.
6. WARNING ALARM
Must have the audible alarm equipment on the volume fire protection system and on the local fire-fighting system, while the diffusion of carbon dioxide from system entering the room with concentrations greater than 5%. Alarm sound must be sounded continuously during the time period from detecting the fire to discharging gas and during the gas discharge time. Alarm sound intensity is described in 5.b must be heard in comparision with the medium noise level where the fire alarm occurs. In some place with particular high noise, must have the visible warning signs.
The alarm device must be provided enough power to allow continuous alarm at least 30 minutes.
Note: No need for alarm to the local fire system unless the discharge of carbon dioxide occurs corresponding to the volume of the room can create concentration exceeds 5%.
7. Automatically interruption for equipment
Prior to or simultaneously with the discharge of carbon dioxide system, all devices is capable of ignition of combustible materials such as heating equipment, gas stoves, infrared light ... must be automatically disconnected.
8. REDUCING AUTOMATIC PRESSURE
The automatic pressure reduction should be made in areas where the highest pressure of a room can be closed and may cause the increase of pressure when the carbon dioxide pours in.
Note: The leakage around the access doors, windows, pipes and smoke exhaust valves, Although not obvious or easy to identify, can create a natural ventilation for carbon dioxide system.
For other airtight spaces, the area needed to vent freely X (in square millimeters) can be calculated by the following formula:
X = 23, 9 Q P
Where:
Q: the flow of carbon dioxide, measured in kilograms per minute (kg/min)
P: allowed intensity (internal pressure) of enclosed space, (bar)
In many cases, particularly with hazardous materials, the pressure reduction can be done by explosion to open vents. These openings and the other way are usually to ensure the proper vents.
9. EARTHING
The carbon dioxide fire extinguishing system must be grounded appropriately.
Note: The proper grounding of the system will reduce to a minimum the risk of electrostatic discharge. When the system protecting the electrical equipments is put closely or within a building with electrical equipment, metal parts of the system need to be connected definitely with the earthing output of the electrical equipment.
10. BEWARE THE LOWER PROTECTED AREA.
Where carbon dioxide can concentrate in the cracks, well, the bottom of the basement or other underground space, must add to the flavor substances into carbon dioxide and installating the secondary ventilation systems to drain carbon dioxide after discharge.
Note: Carbon dioxide must be consistent with the requirements of TCVN 6100:1996 (ISO 5923) after adding any flavor substances (see Article 4).
11. SAFETY SIGNS
For all the volume fire extinguishing system and local fire extinguishing system can cause the critical concentrations, notices must be written inside and outside each access door leading to the protected areas.
Notices must be informed that in case of alarm or carbon dioxide discharge, the employee must leave the room immediately and not return before the room is fully ventilated because of the risk of choking.
12. BEWARE IN THE MAINTENANCE WORK
For automatically volume fire protection system is protecting the rooms without people, must prevent the automatic discharge when employees come in and can not leave the room for a period of time.
Note: The precaution is usually unnecessary for local fire protection system, but must note the possibility of dangerous concentrations arising in any area, including the presence of human.
13. TESTING THE DISCHARGE IN PLACE WHERE MAY HAVE EXPLOSION MIXTURE.
In the case of the air/vapor mixture of explosive danger, the distress area must be carefully checked before the test can be discharged because it can cause the fire and explosion by static discharge.
14. BASIS FOR DESIGNING CARBON DIOXIDE SYSTEMS
The construction of the enclosed space must be protected by the volume carbon dioxide fire extinguishing system must perform so that carbon dioxide can not drain immediately. The walls and access doors must be able to withstand the effects of fire for a time sufficient to allow the
discharge of carbon dioxide maintained at design concentration during maintenance time.
Note: ISO 834:1975 is used to evaluate the fire resistance of building structures. Where possible, the clearances must be closed automatically and the ventilation systems must be automatically closed before or at least at the start of discharge carbon dioxide and should be sealed.
Where the clearance can not be closed and where no walls or overlapping, must add to carbon dioxide as set out in 15.6.
Especially pay attention when these openings outward the atmosphere and wind conditions can influence the carbon dioxide loss. These cases must be treated as a special application and can be the discharge test to determine the appropriate design concentration.
15. DESIGNING THE VOLUME FIRE EXTINGUISHING SYSTEMS
15.1. Considered factors
To determine the amount of carbon dioxide according to the requirement, the volume of a room or of enclosed space protected shall be taken as the basis. This volume must minus the volume of the solid structural elements such as foundations, columns, beams, girders, and similar materials.
The following factors must be considered:
- Room size;
- Materials must be protected;
- The special risks;
- The clearances can not be closed;
- The ventilation system can not be closed. There should be no holes in the floor.
15.2. Determine the amount of carbon dioxide design
The amount of carbon dioxide design, m, in kilogram calculated by the following formula:
m = K B (0, 2 A + 0, 7V )
Where:
A = AV + 30 AOV
V = VV + VZ VG
AV the total area of all the floors and ceilings (including clearances AO V) of the enclosed space to protect, in square meters;AOV
the total area of all clearances is assumed to be open when the fire occurs, in square meters (see 15.6);
VV l th tch ca khng gian bao kn c bo v, tnh bng mt khi (xem 15.1);
VZ Additional volume due to the loss in time sustained by the ventilation system (see Table 1) can not be closed, measured in cubic meters (see 15.5);
VG the volume of structural elements must subtract, in cubic meters (see 15.1);
K B the coefficient for the protected material, greater than or equal to 1 (see 15.3 and Table 1);
0,2 The part of carbon dioxide can be loss, measured in kilograms per square meter;
0,7 Minimum amount of carbon dioxide is used as the basis for the formula, measured in kilogram per cubic meter.
About the calculation examples, see Appendix D.
Note: 0.2 and 0.7 consider the effects of room size, ie the ratio of room volume (VV) and room area (AV).
15.3. Coefficient K B
Material factor KB for table 1 must be considered when designing flammable material and hazard specially requires a concentration higher than normal concentration.
Coefficient KB for risk not given in Part A of Table 1 is defined by using a crucible instruments described in Annex C or other testing methods equivalence.
15.4. Affect the material forming the glowing embers.
For materials with the formation of glowing embers, must consider the special conditions. Table 1 shows examples of these materials.
15.5. nh hng ca h thng thng gi khng ng li c
To determine the amount of carbon dioxide used, the volume of the room (Vv) must be increased by the volume of air (VZ) is put into or ejected from the chamber when the chamber is flooded with carbon dioxide and in maintain time given in Table 1.
15.6. The effects of the clearances (see introduction)
The impact of all openings, including explosion-proof holes and wall and ceiling not be closed while the fire occurs, which is included in the formula in 15.2 by AOV.
Porosity of cover materials, or leakages around the access doors, windows, shutters ... not be considered as the clearances, as they are formulated.
The clearances are not permitted until it requires maintenance time, unless the amount of the extra carbon dioxide to maintain the concentration required for a time maintained.
When ratio R = AOV/AV > 0,03, the system must be designed as a local fire extinguishing system (see article 16). This does not exclude the use of a local fire extinguishing system when R< 0.03.
When R> 0.03 and where clearances may be affected by the wind, when it must perform the practical test in the most unfavorable conditions to meet the requirements of the competent authority.
15.7. Volume fire extinguishing with interconnected volume
In two or more interconnected volume that there is "free flow" of carbon dioxide or cable of spreading the fire from this location to another location, or the amount of carbon dioxide will be the sum of the calculated quantities for each volume. If a volume requires the concentration greater than standard concentration, the higher concentration should be used in all the interconnected volumes.
15.8. Gas Discharge Time
Time to discharge carbon dioxide in the design calculations, minutes (see 15.2) basically have to match the table 2. For fires with solid materials, such as the materials listed in Table 1, the time is required to maintain a gas discharge must be designed in 7 minutes, but the flow should not be less than necessary flow to increase the concentration to 30% for 2 minutes.
Table 1: Coefficient of materials, design concentration and maintain time
Flammable Material
Coefficient of material ( KS )
CO2 design concentration (%)
Maintain time (minutes)
A- The gas and liquid
Axtn
1
34
-
Axtylen
2,57
66
-
Jet fuel
1,06
36
-
Benzol, Benzel
1,1
37
-
Flammable Material
Coefficient of material ( KS )
CO2 design concentration (%)
Maintain time (minutes)
Butaien
1,26
41
-
Butan
1
34
-
Buten-1
1,1
37
-
isulfua cacbon
3,03
72
-
Monoxit cacbon
2,43
64
-
Coal or natural gas
1,1
37
-
Propan
1,1
37
-
Diesel Fuel
1
34
-
imetyl te
1,22
40
-
Dowtherm
1,47
46
-
Etal
1,22
40
-
Ethyl alcohol
1,34
43
-
Etylen
1,6
49
-
te tyl
1,47
46
-
Diclorua ethylene
1
34
-
Oxyt tylen
1,8
53
-
Gasolin
1
34
-
Hexan
1,03
35
-
Heptan-n
1,03
35
-
Hydro
3,3
75
-
Hydro sulfua
1,06
36
-
Izobutan
1,06
36
-
Izobutylen
1
34
-
Izobutyl format
1
34
-
JP-4
1,06
36
-
Kerosene
1
34
-
Mtan
1
34
-
Axtat mtyl
1,03
35
-
Ethyl alcohol
1,22
40
-
Butal-1 mtyl
1,06
36
-
Mtyl-tyl xton
1,22
40
-
Mtyl format
1,18
39
-
Octan-n
1,03
35
-
Pentan
1,03
35
-
Propan
1,06
36
-
Propylen
1,06
36
-
Lubricant, fire-resistence oil
1
34
-
B- The solid material 1
Cellulosic materials
2,25
62
20
Cotton
2
58
20
Paper, corrugated paper
2,25
62
20
Plastic materials (seeds)
2
58
20
Polystyren
1
34
-
Polyurethane, when vulcanized
1
34
-
C- The case of special applications
The cable chambers
1,4
47
10
Data processing area
2,25
62
20
Computer Space
1,5
47
10
1 The solid materials usually have organic, when burning often formed aglow embers..
Flammable Material
Coefficient of material ( KS )
CO2 design concentration (%)
Maintain time (minutes)
Distribution angular
1,2
40
10
Generators, including cooling system
2
58
Until stopping
Oil Transformer
2
58
-
Ni in u ra
2,25
62
20
Spray and drying paint establishments
1,2
40
-
Spinning machines
2
58
-
15.9. Storage temperature
Storage temperature with high pressure can be from -20C to +50C not require special compensation methods for changing the flow.
16. DESIGNING THE LOCAL FIRE EXTINGUISHING SYSTEM
Note: The local fire extinguishing systems use appropriately to extinguish surface fires of the gaseous combustible substance, liquid and solid where the fire hazard is not enclosed or when enclosed space is not inconsistent with the requirements of volume fire extinguishing.
16.1. Requirement of carbon dioxide
16.1.1. General provision
Original concentration coefficient of carbon dioxide is the coefficient corresponding to KB = 1, ie 34%.
For materials that require a design concentration greater than 34%, the amount of original carbon dioxide increased by multiplying this amount with an appropriate material coefficients in table 1. The coefficients KB for the fire hazards are not listed in section A of table 1 must be specified by using a bowl-type instruments described in Appendix A, or by any other method known equivalent results.
The amount of carbon dioxide design calculations required for a local fire extinguishing system must be based on the total discharge flow needed to cover the area or volume to be protected and discharge time should be maintained to ensure to extinguish completely.
For storage systems with high pressure, the amount of carbon dioxide design calculation must be increased by 40% to determine the nominal capacity of a cylindrical tank with only part of the liquid discharge is effective. The increased capacity of a cylindrical tank is not required for the volume fire fighting system combines local firefighting, volume fire extinguishing.
Where there are long pipes or where the equipments are exposed at temperatures higher than normal temperatures, the amount of design calculation must increase sufficiently enough to compensate for vaporized liquid due to the pipe cooling.
16.1.2. Gaseous discharge flow
Discharge flow of nozzle is calculated by the area method or by volumetric methods such as 16.2 and 16.3.
Total discharge flow for the system is the sum of the particular flows of all the nozzles or discharge structure used in the system.
16.1.3. Gas Discharge Time
The time required to discharge carbon dioxide in the design calculation, m, must be consistent with Table 2. Minimum time should be increased to compensate for any unforeseen conditions require a longer cooling time to ensure to extinguish completely.
Where there is the possibility of the condition of metal or other materials can be
heated higher than the ignition temperature of fuel, manually ignite the gas and effectively discharge time should be increased to allow for proper cooling time.
16.2. Flow calculated according to the area method
16.2.1. General provision
The system design according to area method is used in the fire hazard area where is mainly flat surfaces or objects at a low level compared to the horizontal surface.
The system design should be based on the approved data of the particular nozzles. Extrapolation for values greater than the upper limit or smaller than the lower limit will not be valid.
Example calculation: see Appendix D, Article D3.
16.2.2. Discharge flow of nozzle.
- Designed discharge flow through the particular nozzles must be separately identified on the basis of the distance from the protected surface to each nozzle.
- Gas discharge flow for the nozzles on high must be separately identified on the basis of distance from the protected surface to each nozzle.
-Discharge flow for nozzles fitted with separated tanks must be determined on the basis of distance from the nozzle or effectively spray radius to cover an area protected by each nozzle.
Table 2: discharge time for surface burning
The value in seconds
System
Equipment of high pressure carbon dioxide. Liquid discharge time
Equipment of high pressure carbon dioxide
Volume fire fighting system
Local fire fighting system
Max 60
Min 30
Max 60
Max 60
Max 60
Min 30
16.2.3. Protected area of a nozzle
Largest area protected by each nozzle must be determined on the basis of location or injection radius and design discharge flow in accordance with the specifications approved.
These factors are used to determine the design discharge flow is also used to determine
the largest area covered by each nozzle.
Surface area convention of fire hazard are protected by each nozzle with square type on high.
The surface area of fire danger are protected by nozzle having the separate container or spray nozzles are a rectangular or square in accordance with the distance and the gas discharge limits specified in the technical requirements approved.
When using carbon dioxide to extinguish the liquid fire beneath the tank, in calculating the minimum distance between the nozzle and the surface of the liquid must take down 150mm compared with the mouth of the tank to prevent splash and keep carbon dioxide concentrations on the surface of liquid.
16.2.4. Location and number of nozzles
Must use a sufficient number of nozzles to cover the entire fires area, based on the area of each nozzle protected.
The nozzles with type of particular containers or nozzles are placed directly in the appropriate location with distance and limitation of the discharge flow specified in the
technical requirements approved.
The overhead sprinklers must be installed perpendicular to the fire hazard and the center of the area covered by nozzle. The other must be installed incline with the angle between 45 and 90 compared with the plane of the area to be protected. Height / distance is used when determining the necessary flow and cover area must be the distance from the target point on the protected surface the nozzle surface measured along the axis of the nozzle.
When installed according to the tilt angle, the nozzle should be aimed at a point is measured from the near edge of the area covered by the nozzle, its location is calculated by multiplying the effective coefficients in Table 3 with width of the area to be protected by sprinklers.
The nozzles must be put in place so that the barrier can not affect the release of carbon dioxide.
Table 3: Efficiency coefficient for angle mounting the nozzle based on gap 150mm.
Angle of discharge (1)
Effective coefficient (2)
45 to 60
60 to 75
70 to 90
90 (vertical)
1/4
1/4 to 3/8
3/8 to 1/2
1/2 (center)
(1) Degree from the surface of break-down
(2) Ratio of the area covered by the nozzle
Regarding more information, see Figure 1.
Dimensions in mm.
The discharge of nozzle in flow and pressure selected.
Note:
Firuge 1: Location of nozzle1) The figure represents the nozzles: a) 90 , with the target point in the center of protected area, and at 45 , b) with target point at the width 0.25 of protection surface, into the fuel tray with a gap 150mm;
2) X is pre-selected height used to determine flow requirements.
16.3. Flow calculated by volumetric method
16.3.1. General provisions
System design by volumetric methods are used in place of the fire hazard including the objects with of irregular three-dimensional size, can not be easily provided in the equivalent area of the surface.
Example of calculation: see Appendix D in D1 and D2.
16.3.2. Assumption enclosed space
The overall discharge flow must be based on the volume of a assumption space covering entirely around the fire incident.
Nu dng kh khng hon ton c gi li trong khng gian gi nh th phi c nhng bin php c bit m bo nhng iu kin c bn.
Cc tng v trn gi nh ca khng gian kn ny phi cc ni x ra nguy him chy t nht 0,6m tr khi nhng tng thc c kh nng bao kn cc din tch c th r r, bn te hay chy trn.
Khng c ly i bt c vt g trong th tch ny. Kch thc ti thiu 1,2m c dng
tnh ton th tch ca khng gian kn gi nh ny.
16.3.3. Lu lng x ca h thng
Lu lng x tng i vi h thng chnh khng c nh hn 16kg/ph cho mt mt khi ca th tch gi nh, tr khi khng gian bao kn gi nh c sn kn v c nh hnh bi tng bao lin tc c nh ko di t nht l 0,6m bn trn ni xy ra nguy him chy ( cc tng ngn thng khng phi l mt phn ca nguy him chy), th lu lng x c th gim theo t l nhng khng nh hn 4kg/ph cho mt mt khi i vi cc tng ngn thc bao hon ton khng gian bao kn.
16.3.4. V tr v s lng u phun
Phi s dng s lng u phun ph hon ton th tch nguy him chy trn c s
xc nh lu lng x ca h thng theo th tch gi nh.
Cc u phun phi c t v tr v hng v cc vt th bo v trong khng gian bao kn gi lng cacbon dioxit c x vo th tch c nguy him chy.
Lu lng x thit k qua cc u phun ring bit phi c xc nh trn c s ca v tr hay khong cch phun ph hp vi cc yu cu k thut c duyt i vi cc m chy b mt.
16.3.5. Nhit kho cha
Phi p dng cc phng php c bit b tr cho nhng thay i lu lng, nu nh
nhit kho cha cc bnh p sut cao nh hn 0C hoc ln hn 49C.
16.3.6. u phun
Cc u phun c a vo s dng phi do cc t chc c thm quyn lit k hoc xt duyt v lu lng x, phm vi bo v c hiu qu v mu m hay din tch ph.
Ch thch: Nhng s liu h tr cho cc yu cu v cc phng php th i vi cc
u phun ang c son tho v s c trnh by trong mt tiu chun sp ti.
17. LNG CACBON DIOXIT D TR
Phi d tr lng cacbon dioxit c xc nh vi yu cu l c th s dng c bt k thi im no v khng th s dng cho cc mc ch khc. Phi d phng lng d d phng cacbon dioxit ph thm c s dng cho cc thit b cacbon dioxit p sut thp theo cc yu cu sau:
a) cn bng cc sai lch np hoc x v kh d, lng cacbon dioxit c d tr cho h
thng p sut thp dng cho vng dp chy rng nht phi tng ln t nht 10%.
b) Nu x ra kh nng cacbon dioxit lng c th tn ng trong ng ng gia bnh cha d tr v h thng u phun kh, lng cacbon dioxit d tr b tng ln do s tn ng ny, phi thm vo lng tng 10% quy nh trong im a.
18. LNG CACBON DIOXIT D TR CA H THNG
Trong mt s trng hp khi cc h thng cacbon dioxit bo v mt hay nhiu a im, cn phi c mt lng d tr 100%. Vic cung cp lng d tr cho cc h thng ny phi thng xuyn.
Thi gian cn thit to ra lng cacbon dioxit b sung thm a cc h thng t c cc
iu kin vn hnh phi c xem l yu t ch yu trong vic xc nh cung cp d tr cn thit.
19. THIT B CH YU CA KT CU
H thng cha chy cacbon dioxit ch yu gm kho cha cacbon dioxit hoc mt hay nhiu bnh cha, cc van la chn, cc c cu x, cc ng dn phn phi v cc u phun.
20. KHU KHO CHA CACBON DIOXIT
20.1. Quy nh chung
Ch thch: cha cacbon dioxit phi tun theo cc quy nh thch hp.
Kho cha cacbon dioxit cng vi cc van, cc c cu x v cc thit b khc; nu c th c b tr trong mt bung khng c nguy him v chy, nhng li gn cc phng v cc i tng bo v v d dng lui ti c. Khu vc cha phi c bo v khng cho ngi khng c phn s vo.
Trong mt s trng hp, khi c c quan c thm quyn cho php, kho cha cacbon dioxit c th b tr bn trong cc phng bo v.
20.2. H thng p sut cao
Ni cc bnh cha cacbon dioxit cho h thng p sut cao phi c thit k sao cho nhit
khng kh xung quanh khng c vt qu nhit thch hp trong Bng 4
Bng 4: Nhit ln nht kho
T s np y, kg/lt
Nhit ln nht ca khng kh xung quanh, 0C
0,75
40
0,68
49
0,55
65
Ch thch: Nu nhit khng kh xung quanh ni bnh cha cacbon dioxit xung di
0C th phi c cc bin php c bit tun th cc thi gian x cho trong Bng 3.
20.3. H thng p sut thp
Cc h thng p sut thp phi c thit k sao cho nhit ca cacbon dioxit trong bnh cha lun c gi khong -18C.
Ch thch: Nn s dng cc bin php thch hp duy tr nhit ny. iu c ngha l vic cch nhit lm mt hay t nng, ph thuc v nhit xung quanh vng lu tr. Phi loi tr nhit sinh ra bi h thng lm lnh.
21. BNH CHA CACBON DIOXIT
21.1. Quy nh chung
Ch thch: Ngoi cc yu cu sau y v cc yu cu i vi cc bnh cha p sut thp (xem 21.2) khng c cc yu cu no khc vi cc yu cu cho trong cc tiu chun tng ng v bnh cha kh.
Khi kt cu ca bnh cha khng c c cu an ton p sut th c cu ny phi c t trong van ca bnh cha.
21.2. Bnh cha p sut thp
Kt cu phi m bo nhit ca cacbon dioxit trong bnh cha phi lun c gi -18C
v p sut gn 20bar1. Phi c cc phng tin lin tc ch th lng cacbon dioxit.
Mt h thng lm mt t ng m bo cho nhit v p sut ca cacbon dioxit c gi
trong gii hn yu cu.
Trn cc bnh cha p sut thp phi lp mt b bo ng qu p v c cu ny phi hot
ng trc khi cc van an ton lm vic.
1 1 bar = 0,1MPa
B cha c cch ly y gii hn lng tht thot cacbon dioxit khng ln hn 1,5% (i vi lng cha t 3 n 6 tn), khng ln hn 0,8% (i vi lng cha ln hn 6 n
10 tn) v khng qu 0,5% (lng cha ln hn 10 tn) trong 24 gi trong trng hp h
thng lm mt b hng v nhit xung quanh c coi l cao nht.
Vt liu cch ly phi c bo v bng cc l kim loi trnh nhng h hng c kh. B cha phi c lp ng h p sut v van an ton.
Ch thch: i vi h thng p sut thp, cn m bo sao cho nhit ca cacbon dioxit trong khi np kh cho bnh cha ph hp vi gi tr cn thit cho hot ng ca h thng.
21.3. B bnh cha cacbon dioxit p sut cao
Thng thng lng cacbon dioxit cn thit c cha trong b bnh cha. Vic cung cp cho tng s c chy khc nhau c th c tin hnh t mt b phn ring l ni khng th c s lan truyn la t s c ny sang s c khc. Lng cacbon dioxit tng ca mt b s tng ng vi lng cacbon dioxit ln nht yu cu bo v mt phng hay mt i tng no .
Ch thch: Cc h thng x kh ca b bnh cha v ca cc ng c b tr sao cho mi vng c bo v ring r c th b trn ngp bi cacbon dioxit.
Cc bnh cha ca b phi c kp cht mt v tr c nh sao cho khng b x dch khi h
thng ang x.
Mi bnh cha phi thay th c, c lp vi cc bnh khc. mi mt ng ng ni van bnh cha ti ng nhnh phi lp van mt chiu. Vic tho d bt k mt trong cc bnh cha s khng gy nh hng ti hot ng bnh thng ca cc bnh cn li trong b.
Phi c cc phng tin o lng cacbon dioxit ca mi bnh cha.
22. VAN LA CHN
Nu c nhiu vng phi cha chy t mt b hoc mt h thng bnh cha cacbon dioxit, phi lp van la chn cho mi vng cn cha chy.
Cc van la chn cho h thng bnh cha phi c m t ng trc hay vo cng mt lc vi cc van ca bnh cha hot ng.
Trong cc h thng p sut thp, cc van la chn phi c m t ng v ng t ng
sau khi x lng cacbon dioxit theo yu cu.
Cc van la chn phi c lp t sao cho c th chng c chy. bt k lc no cng c th kim tra c s hot ng chnh xc ca cc van la chn v cc c cu iu khin.
23. H THNG PHN PHI
23.1. H thng ng dn phi lm bng cc vt liu thuc dng khng chy c nu th nghim theo ISO 1182 v c nhng c tnh ha l sao cho khng b bin dng v h hng khi chu ng sut.
Ch thch:
1) C th dng cc vt liu chu n mn c bit hay cc lp ph ngoi khi mi trng khng kh c tnh n mn cao;
2) Cc ng ng v ng mm (bao gm c cc ni ng) l i tng ca tiu chun s c bin son.
23.2. Cc ng v cc ni ng dng cho h thng p sut thp phi c thit k vi p sut th
40bar.
Ch thch:
1) Cc h thng p sut cao l i tng ca tiu chun s c bin son. Cc ph tng ng ng cn ph hp vi cc tiu chun tng ng. Thng thng cc ph tng ng ng hay dng ghp ni bng ren hoc mt bch. Khi thc hin ghp ni bng p cn c bit ch n vic m bo lp rp chnh xc.
2) Cc ng s c la chn theo ISO 4200.
23.3. Cc on ng c th b bt kn mi u, ngha l on ng gia b bnh cha v mt van la chn thng ng c lm bng ng khng hn.
23.4. Cc on ng lp vo mt u m khng chu p sut lin tc, c th l ng hn, tr cc ng c ng knh danh ngha ln hn 40mm c ni t mt b cha p sut thp.
23.5. Cc ng c ng knh danh ngha nh hn 50mm khng c ni bng hn ti hin
trng.
Ch thch: Tuy nhin, cc ng trn c th c gia cng ti x nghip hn no .
23.6. Khng c dng cc ng ng bng gan xm, v chng d b h hng cc iu kin nhit v p sut trong cc h thng cacbon dioxit.
23.7. H thng ng ng phi c g mt cch chc chn, c s co gin cho php v c t ni chu nh hng t nht ca la, cc tc ng c kh, ha cht hay cc h hi khc. ni c kh nng gy n, h thng ng ng phi c treo trn cc gi trnh nhng tc ng va p.
23.8. Khi b tr cc van trong cc h thng c th to ra cc on ng ng kn, th nhng on
ng ng ny phi c trang b cc van an ton p sut.
Vic chnh p sut cho van an ton phi m bo sao cho p sut ln nht c th t c khng vt qu ch tiu nu trong 23.2 nhng c th vt qu p sut yu cu duy tr cc p sut x bnh thng trong ng ng vi lu lng quy nh.
Cc van an ton p sut phi c thit k v lp t v tr sao cho s x t s khng lm nh hng ti ngi hay gy ra thit hi, h hng.
Ch thch: p sut lm vic ca van an ton khng nu trong tiu chun ny.
23.9. Khi c s ngng ng nc trong cc ng, phi c cc phng tin thch hp tiu nc.
Ngi khng c phn s khng c n gn cc im tiu nc ny.
23.10. Cc ng khng c c bavia, g v cc vt cn khc. Phi bo dng chng li s n mn. Trc khi t ng, phi ra, lm sch bn trong ng. Sau khi lp t v trc khi lp cc u phun, phi thi ng cho sch.
23.11. Cng thc sau y v th, hay bt c mt phng php bo c c quan c thm quyn chp nhn phi c s dng xc nh s gim p trong ng ng.
5 5,25
Q2 = 0, 8725 10 D Y L + (0, 04319 D1,25 Z )
Trong :
D l ng knh trong (thc) ca ng, tnh bng mm;
L l di tng ng ca ng, tnh bng m;
Y, Z l nhng yu t ph thuc vo p sut bo qun v p sut ng ng v c th c
nh gi t cc phng trnh sau:
p
Y = pdp
P1
p dp P
Z = = ln 1
p p
P
1
Trong :
P1 l p sut tng tr, tnh bng bar (tuyt i);
p l p sut cui cng ng ng, tnh bng bar (tuyt i)
r1 l khi lng ring p sut P1, tnh bng kilogam trn mt khi (kg/m3)
r l khi lng ring p sut p, tnh bng kilogam trn mt khi (kg/m3)
Trong vic thit k cc h thng dn, c th thu c cc gi tr gim p t cc ng cong p sut chiu di tng i vi cc lu lng v c kch thc ng khc nhau (xem Ph lc B).
23.12. C cu x phi m tt c cc van bnh cha ni lin vi ng phn phi cho ton b vng dp tt. C cu x phi c tin cy v s hot ng ca n c th kim tra c.
24. U PHUN
Mt ct ngang ca l m cc u phun phi c tnh ton theo Ph lc B, vi p sut nh nht ming vo cc u phun l 14bar i vi h thng p sut cao v 10bar i vi h thng p sut thp.
Cc u phun x cacbon dioxit phi c kch thc sao cho khng b tc nghn bi cacbon dioxit rn.
H thng cha chy th tch phi c thit k v lp t sao cho c th thc hin mt nng ng u ca cacbon dioxit tt c cc phn ca khng gian bao quanh vng nguy him chy. Phi lp cc u x gn trn nh.
Ch thch: i vi cc phng c chiu cao t 5m n 10m, phi c cc u phun chiu cao gn bng mt phn ba chiu cao ca phng. i vi cc phng c chiu cao vt qu 10m nn lp cc u phun ph chiu cao bng mt phn ba hay hai phn ba chiu cao ca phng.
Cc u phun ca h thng cha chy cc b phi c thit k v lp t sao cho c th hng trc tip cacbon dioxit vo i tng bo v m khng phn tn cc vt liu chy.
Khi cn thit, phi bo v cc u phun trnh s nhim bn t bn ngoi c th nh hng n cht lng ca chng.
25. C CU TC NG X
25.1. Cc loi c cu tc ng x
Cc h thng x t ng hoc bng tay, hoc:
a) Tc ng x t ng hoc bng tay, hoc
b) Ch tc ng x bng tay ty thuc vo nhng yu cu ca c quan c thm quyn.
S hot ng ca cc c cu x phi lm cho ton b h thng tc ng n cc chc nng ph thuc km theo nh ch th cc thit b bo ng, ng cc h thng thng gi, cc qut ht, bm, bng ti, b t nng, van iu tit v ca chn...
Tt c cc thit b phi c b tr v lp t hoc c bo v thch hp sao cho khng b nhng h hng c kh, ha hc hay nhng h hng khc c th lm cho chng khng hot ng c.
25.2. Tc ng x t ng
Cc h thng tc ng t ng phi c iu khin bng thit b pht hin chy t ng
c xt duyt1 v c chn la theo nhng yu cu ca tng s c ring bit.
ni c thit b pht hin chy sm nh nhng thit b pht hin khi hoc ngn la, h
thng phi c thit k ch hot ng sau khi c hai tn hiu pht hin ring r.
25.3. Tc ng x bng tay
25.3.1. Tc ng x bng tay i vi cc h thng cha chy th tch phi c b tr bn ngoi phng c bo v, v tr gn cc ca ra ca phng. Tc ng x bng tay i vi cc h thng cha chy cc b phi c t v tr va tin li va an ton cho ngi thao tc.
25.3.2. Cc thit b tc ng x bng tay phi c bo v chng nhng tc ng v bng cc dy kp ch hay knh chn hoc mt v che c th m nhanh v phi c ghi nhn
r rng ch r mc ch ca chng.
1 Nhng ni dung chi tit c bit khng c quy nh trong tiu chun ny nhng c quy nh trong tiu chun tng ng khc khi p dng tiu chun ny.
Ch thch: Nu hp cha c bo v bi mt mt knh d v pha trc, th mt knh phi l loi v ra khng to thnh cc mnh nhn hay rng ca c th gy thng tch khi thc hin vic tc ng x bng tay.
25.3.3. Vng cn cha chy c iu khin bng nt n bng tay phi c k hiu r rng
khng c s nhm ln.
25.4. Loi iu khin
Tt c cc c cu tc ng x phi c iu khin bng in, bng kh nn hay c kh.
25.4.1. Bng in
25.4.1.1.Phi cung cp nng lng cho mch pht hin bng in ca cc c cu ngt t hai ngun in c lp, ngha l mt ngun cung cp chnh, vi b chuyn i t ng v bo ng chuyn sang ngun c quy d phng khi ngun cung cp chnh b hng.
25.4.1.2.Cc thit b pht hin v ngt phi c kim sot t ng v cc tn hiu bo ng c s c mi c cu hoc ng dy, cc tn hiu s c ny phi khc vi cc tn hiu bo ng ch th hot ng ca h thng.
25.4.2. Bng kh nn
25.4.2.1.Cacbon dioxit t h thng cha chy c th c s dng nh mt ngun nng lng. Nu la chn mt ngun kh nn khc th ngun ch c dng ring cho mc ch ny, v phi m bo c chc nng vn hnh.
25.4.2.2.Khi dng p sut t bnh cha iu khin lm phng tin v m cc bnh cha cn li, th lu lng cung cp v x phi c thit k tc ng x ng thi tt c cc bnh cn li, s cung cp kh iu khin phi c kim sot lin tc v s c tn hiu bo h hng trong trng hp c s c mt hoc p sut qu mc.
25.4.2.3. Cc thit b pht hin iu khin t ng v h thng ng phi c kim tra
nh k v mc chnh xc trong vn hnh.
25.4.3. Bng c kh
Ch thch: Cc h thng tc ng x c th hot ng bng c kh bi cc cp v ba ri.
Dy no cp iu khin c lng trong cc ng bo v c cc rng rc quay t do
cc gc i hng.
Cc dy no cp iu khin phi c kim tra nh k m bo cho vn hnh c
ng n.
26. THANH TRA V A VO VN HNH
Sau khi lp t, ngi sn xut hoc i l ca ngi sn xut phi kim tra tng h thng cha chy cacbon dioxit m bo cho h thng vn hnh c chnh xc (xem iu 27). Giy chng nhn kim tra i vi php th ny phi giao li cho ngi mua.
Sau khi lp t, phi cung cp nhng hng dn chi tit cho nhn vin chu trch nhim v thanh tra v bo dng h thng.
27. TH NGHIM VN HNH
kim tra vic lp t v vn hnh ng n ca h thng theo yu cu quy nh, phi tin hnh th tnh lin tc ca ng ng dn vi s lu thng t do, khng b tc ca dng kh, nh th thi bng khng kh nn hay cacbon dioxit nn. Ngoi ra, nu c yu cu ca c quan c thm quyn, c th tin hnh th x hon ton. Trong php th ny, phi o thi gian x v xc nh nng ca cacbon dioxit, s phn phi kh cacbon dioxit trn vng b s c chy v thi gian duy tr.
28. HNG DN VN HNH V BO DNG
Phi t c nh v tr d nhn thy bng hay bin bo bng vt liu bn vng hng dn s dng h thng cha chy. Nhng ch dn ny phi cung cp thng tin y v vn hnh ca h thng v thng tin ngn gn v bo dng hng ngy v vic b sung thm kh cho h thng sau khi x. Phi cung cp h s vn hnh v bo dng cho ngi mua.
Ch thch: Khi tho bnh cha cacbon dioxit ra khi h thng sa cha, phi bo m an ton
y cho bnh cha trc khi bt u mt cng vic no v cc van hay cc c cu tc ng x.
Ph lc A (quy nh)
TRNH T TH XC NH NNG CACBON DIOXIT I VI CC CHT LNG V CHT KH CHY (XEM 15.3)
Ch thch: iu cn ch l cng vic c tin hnh i vi dng c ny c th dn n
mt s iu chnh ca cc s liu trong Bng 1.
A.1. Nguyn l
Dng c kiu chn nung c dng xc nh nng cha chy i vi cc cht lng v cht kh.
Kt qu thu c l nng l thuyt nh nht ca cacbon dioxit cha chy. Nng thit k c xc nh t hnh ny (xem iu A.5). Nng thit k nh nht c s dng l 34% c biu din bi h s KB l 1.
i vi cc vt liu chy i hi mt h s ln hn 1, th h s vt liu c p dng nh trnh by trong Bng 1 v c s dng trong cng thc tnh m 15.2.
chuyn i nng thit k c tnh ton (thu c bng cch s dng dng c th) sang mt h s vt liu KB, s dng cng thc sau:
ln (1 C )
B
K =
Trong
ln (1 Cs )
%
A.2. Dng c
100
%
0,34
100
Dng c th l mt chn nung c th hin nh trong Hnh A.1.
A.3. Trnh t th i vi cc cht lng chy
A.3.1. Cho mt mu cht lng chy vo trong bnh cha cht t.
A.3.2. iu khin thit b iu chnh mc t di bnh cha cht t a cht t vo trong chn ti mc cch ming chn 1mm.
A.3.3. ng in cho b phn nung nng chn a nhit cht t ln ti 25C, hay cao hn nhit bc chy ca cht t c xc nh bng chn h l 5C, chu nhit no cao hn.
A.3.4. t chy cht t bng phng tin thch hp, thng dng in, v n khng lm bn cht t c th.
A.3.5. iu chnh lu lng khng kh t ti 40lt/pht.
A.3.6. Bt u m lung cacbon dioxit v tng n t t cho ti khi ng la b dp tt. Ghi li lu lng cacbon dioxit.
A.3.7. Rt khong 10ml n 20ml cht t t pha trn b mt chn bng ng ht c chia . A.3.8. Lp li cc bc A.3.4 ti A.3.6 v tnh gi tr trung bnh ca cc kt qu.
A.3.9. Tnh nng dp ngn la, TC, bng phn trm theo cng thc:
TC = VF 100
40 + VF
Trong :
VF l lu lng cacbon dioxit, tnh bng lt trn pht (l/ph).
A.3.10. Tng nhit cht t ln n nhit thp hn im si ca cht t l 5C hoc ti
200C, chn nhit no thp hn.
A.3.11. Lp li cc bc A.3.2 v A.3.4 cho ti A.3.9.
A.3.12. Ly nng dp ngn la l gi tr cao hn c tnh t hai nhit cht t.
A.4. Trnh t th i vi cc cht kh chy
A.4.1. Dng c c sa i bng cch nhi y chn bng bng thy tinh v lp mt lu lng k kiu phao hiu chnh, cho cht t vo ch bnh ng cht t ca Hnh A1. Lu lng k c ni vi mt ngun cht t qua mt b iu chnh p sut thch hp.
A.4.2. iu chnh lu lng cht t sinh ra mt tc tuyn tnh trong chn l 130mm/s. A.4.3. Hon thnh cc bc t A.3.3 ti A.3.9.
A.4.4. Tng nhit cht t ln ti 150C.
A.4.5. Lp li cc bc t A.3.4 ti A.3.9.
A.4.6. Ly nng cht dp tt ngn la l gi tr cao hn c tnh t hai nhit cht t. A.4.7. Nu yu cu nng nhit cao hn, vt qu nng nhit thp hn mt
lng ng k th cht t c xp loi l nhy cm nhit . Nng dp ngn la i vi cc
cht t nhy cm nhit phi c xc nh nhit ln nht trong khu vc bo v.
A.5. Tnh ton nng thit k
Ly nng thit k l gi tr ca nng dp tt ngn la nhn vi 1,7.
Kch thc tnh bng milimt.
Hnh A1: Dng c kiu chn nung
Ph lc B (quy nh)
XC NH KCH THC NG V MING PHUN CA H THNG CACBON DIOXIT
B.1. p sut lu tr l mt yu t quan trng i vi lu lng cacbon dioxit. Trong lu tr p thp th p sut khi ng trong bnh cha s gim mt lng ty thuc v iu kin tt c hay ch mt phn ca lng cung cp b x. Do , p sut lu tr s khong 19,7bar. Cng thc tnh lu lng c da trn p sut tuyt i, do , 20,7bar c dng cho cc tnh ton cn thit i vi h thng p sut thp.
Trong h thng p sut cao, p sut lu tr ph thuc vo nhit mi trng xung quanh. Nhit mi trng xung quanh chun c gi nh l 21C. nhit ny, p sut trung bnh
trong bnh trong khi x phn cht lng s vo khong 51,7bar. Do , p sut ny c chn cho cc tnh ton i vi h thng p sut cao.
S dng cc p sut 20,7bar v 51,7bar trn, cc gi tr c xc nh cho cc h s Y v
Z trong cng thc tnh lu lng. Nhng gi tr ny c quy nh trong cc Bng B.1 v B.2.
B.2. p dng trong thc t, nn v cc ng cong biu din cho mi kch thc ng c th c s dng. Tuy nhin, phi ch rng cng thc tnh lu lng c th c trnh by nh sau:
L D1,25
105 0,8725Y
2
= 0, 04319Z
Q
D2
Nh vy, bng cch lp th cho nhng gi tr
L D1,25
v Q , c th dng mt h cc ng
D2
cong biu din cho bt k kch thc ng no. Hnh B.1. cho thng tin v lu lng i vi nhit
lu tr -18C trn c s ny. Hnh B.2. cho thng tin tng t i vi p sut cao 21C.
Nhng ng cong ny c th c s dng thit k cc h thng hay kim tra nhng mc lu lng. Nhng iu kin p sut bt k mt im no trong ng ng c th thu c bng
tnh ton cc gi tr Q
v L . Sau , cc im s c v ln ng cong Q
c cc p sut
D2 D1,25 D2
im u v p sut im cui. V d, bi ton c t ra l xc nh p sut im cui cho mt h thng p sut thp gm c 50mm ng ng c 40 vi mt chiu di tng ng l 152m v lu lng l 454kg/pht.
Trc tin cn tnh ton cc gi tr Q D2
v L D1,25
theo cng thc:
Q = 454 = 0,165 kg/pht trn mm2
D2 2758
L = 152 = 1, 075 m/mm1,25
D1,25
141, 3
p sut im u l 20,7bar v
L bng 0 c biu din trong Hnh B.1 im S1. p
D1,25
dng im cui c tm thy vo khong 15,7bar im T1, trong gi tr
l 0,165 giao nhau vi c
gi tr L D1,25
1,075.
Nu ng ny kt thc mt u phun duy nht, din tch tng ng ming u phun phi
c gn cho p sut im cui kim tra lu lng mc mong mun l 454kg/pht.
Tham kho Bng B.8 s nhn thy rng mc lu lng x s l 0,9913kg/pht.mm2 ca din tch tng ng ca ming u phun khi p sut ming u phun l 15,9bar. Din tch tng ng ca ming u phun bng lu lng tng chia cho lu lng trn mt milimt vung.
Bng B.1 Gi tr Y v Z i vi h thng p sut thp
p sut
Y
Z
Bar
MPa
20,7
2,07
0
0
20
2
665
0,12
19
1,9
1500
0,295
18
1,8
2201
0,470
17
1,7
2790
0,645
16
1,6
3258
0,820
15
1,5
3696
0,994
14
1,4
4045
1,169
13
1,3
4338
1,344
12
1,2
4584
1,519
11
1,1
4789
1,693
10
1,0
4962
1,868
Bng B.2 Gi tr Y v Z i vi h thng p sut cao
p sut
Y
Z
Bar
MPa
51,7
5,17
0
0
51,0
5,10
554
0,0035
50,5
5,05
972
0,0600
50,0
5,00
1325
0,0825
47,5
4,75
3037
0,2100
45,0
4,50
4616
0,3300
42,5
4,25
6129
0,4270
40,0
4,00
7256
0,5700
37,5
3,75
8283
0,7000
35,0
3,50
9277
0,8300
32,5
3,25
10050
0,9500
30,0
3,00
10823
1,0860
p sut
Y
Z
Bar
MPa
27,5
2,75
11507
1,2400
25,0
2,50
12193
1,4300
22,5
2,25
12502
1,6200
20,0
2,00
12855
1,8400
17,5
1,75
12187
2,1400
14,0
1,40
13408
2,5900
Hnh B1: S gim p sut trong ng dn i vi p sut lu tr 20,7bar (2,07MPa)
Din tch tng ng ming u phun
4,54/
0,9913// 458
Trn quan im thc t, ngi thit k s chn mt u phun chun c mt din tch tng ng gn nht vi din tch c tnh ton. Nu din tch ming u phun ln hn mt t, th lu lng thc t s ln hn mt t v cc p sut im cui s phn no thp hn gi tr tnh l
15,7bar.
B.3. Trong v d trn, nu thay mt u ln vo im cui, ng ng bt vo hai ng nh, cn phi xc nh p sut u cui ca mi ng nhnh. minh ha cho trnh t ny, gi thit rng cc ng nhnh bng nhau vo c 40mm ng c 40 vi chiu di tng ng l 60mm v lu lng trong mi mt nhnh l 227kg/pht.
Cc gi tr Q D2
v L D1,25
c tnh ton cho ng nhnh l:
Q = 227
= 0,136 kg/pht/mm2
D2 1673
L = 61 = 0, 59 mm1,25
D1,25
103, 4
T Hnh B.1, p sut im u l 15,7bar (p sut im cui ca ng ng chnh) giao nhau
vi ng
Q = 0,136
D2
im S2
cho mt gi tr ca
L = 1, 6 . p sut im cui c tm thy
D1,25
bng cch di chuyn ng
Q D2
sang phi mt khong cch l 0,59 theo trc honh
L , ngha l
D1,25
L = 1, 60 + 0, 59 = 2,19
D1,25
ti im T2
p sut im cui l 11,4bar. Vi p sut im cui mi
ny v lu lng 227kg/pht, din tch yu cu ca u phun cui mi ng nhnh thu c t Bng
B.7 l xp x 368mm2.
Ta s nhn thy rng n ch hi nh hn mt t so vi v d mt u phun ln duy nht, nhng lu lng x gim i mt na bi p sut gim.
Hnh B2: S gim p trong ng dn i vi p sut lu tr 51,7bar (5,17MPa)
B.4. Trong h thng p sut cao, ng gp c cp kh cacbon dioxit bi mt bnh kh ri. Lu lng tng ny c chia cho s bnh kh c c lu lng t mi bnh kh. Kh nng lu thng van ca bnh kh v ng ni vi ng gp s thay i ty theo kt cu v kch thc vi mi ngi sn xut. i vi bt k mt van no, ng ni v b ghp ni, chiu di tng ng c th c xc nh bng chiu di n v ca kch thc ng tiu chun. Vi thng tin ny, c th s dng cng thc tnh lu lng v mt ng biu din lu lng i vi s gim p. iu ny cho ta mt phng php thun tin xc nh p sut ca ng i vi mt van v t hp cc ng ni.
B.5. Cc Bng B.3 v B.4 quy nh chiu di tng ng ca cc ph tng ng ng xc nh chiu di tng ng cho cc h thng ng ng. Cc bng ny ch a ra cc hng dn c th s dng cc s liu ca ngi sn xut. Bng B.3 quy nh cho cc ph tng ni ng bng ren v Bng B.4 cho cc ph tng ni ng bng hn. C hai bng u cho cc c kch thc ng 40; tuy nhin, i vi tt c cc mc ch thc tin, nhng s liu ny cng c th dng cho cc c kch thc ng 80.
B.6. i vi cc thay i danh ngha v nng ca ng ng, v v p sut u c nng cao l khng ng k. Tuy nhin, nu c mt s thay i ln v nng th phi xt n yu t ny. Vic iu chnh p sut u c nng cao trn mt mt (1m), nng ph thuc vo p sut trung bnh ca ng ng ti ch c nng v mt thay i theo p sut.
Thng s iu chnh c cho trong cc Bng B.5 v B.6 tng ng vi cc h thng p sut thp v p sut cao. p sut im cui phi tr i lng iu chnh khi dng kh i ln cao v c cng vi lng iu chnh khi dng kh i xung. p sut im cui ming x c xc nh c th chn cc u phun c kch c thch hp.
i vi h thng p sut thp, lu lng x qua cc ming u phun tng ng l cc gi tr
cho trong Bng B.8. Cc p sut thit k ca u phun nhit lu tr 21C khng c nh hn
14bar.
Bng B.3 Chiu di tng ng ca cc ph tng ni ng bng ren
Kch thc danh ngha ca ng ng
ng khuu
45
ng khuu
90
ng khuu
90 di v
ng ch T
ng ch T
Khp ni hay van ca
Inch
mm
m
M
m
m
m
3/8
10
0,18
0,4
0,24
0,82
0,09
1/2
15
0,24
0,52
0,3
1
0,12
3/4
20
0,3
0,67
0,43
1,4
0,15
1
25
0,4
0,85
0,55
1,7
0,18
1
32
0,52
1,1
0,7
2,3
0,24
1
40
0,61
1,3
0,82
2,7
0,27
2
50
0,79
1,7
1,1
3,41
0,37
2
65
0,94
2
1,2
4,08
0,43
3
80
1,2
2,5
1,6
5,06
0,55
4
100
1,5
3,26
2
6,64
0,73
5
125
1,9
4,08
2,6
8,35
0,91
6
150
2,3
4,94
3,08
10
1,1
Bng B.4 Chiu di tng ng ca cc ph tng ni ng bng hn
Kch thc danh ngha ca ng ng
ng khuu
45
ng khuu
90
ng khuu
90 di v
ng ch T
ng ch T
Khp ni hay van ca
Inch
mm
m
M
m
m
m
3/8
10
0,06
0,21
0,15
0,49
0,09
1/2
15
0,09
0,24
0,21
0,64
0,12
3/4
20
0,12
0,33
0,27
0,85
0,15
1
25
0,15
0,43
0,33
1,1
0,18
1
32
0,21
0,55
0,46
1,4
0,24
1
40
0,24
0,64
0,52
1,6
0,27
2
50
0,3
0,85
0,67
2,1
0,37
2
65
0,37
1
0,82
2,5
0,43
Kch thc danh ngha ca ng ng
ng khuu
45
ng khuu
90
ng khuu
90 di v
ng ch T
ng ch T
Khp ni hay van ca
Inch
mm
m
M
m
m
m
3
80
0,46
1,2
1
3,11
0,55
4
100
0,61
1,6
1,3
4,08
0,73
6
150
0,91
2,5
2
6,16
1,1
Bng B.5 Lng iu chnh nng i vi cc h thng p sut thp
p sut ng trung bnh
Lng iu chnh nng
bar
MPa
bar/m
MPa/m
20,7
2,07
0,100
0,010
19,3
1,93
0,0776
0,0078
17,9
17,9
0,0599
0,0060
16,5
16,5
0,0468
0,0047
15,2
1,52
0,0378
0,0038
13,8
1,38
0,0303
0,0030
12,4
1,24
0,0242
0,0024
11,0
1,10
0,0192
0,0019
10,0
1,00
0,0162
0,0016
Bng B.6 Lng iu chnh nng i vi cc h thng p sut thp
p sut ng trung bnh
Lng iu chnh nng
bar
MPa
bar/m
MPa/m
51,7
5,17
0,0796
0,0080
48,3
4,83
0,0679
0,0068
44,8
4,48
0,0677
0,0068
41,4
4,14
0,0486
0,0049
37,9
3,79
0,0400
0,0040
34,5
3,45
0,0339
0,0034
31,0
3,10
0,0283
0,0028
27,6
2,76
0,0238
0,0024
24,1
2,41
0,0192
0,0019
20,7
2,07
0,0158
0,0016
17,2
1,72
0,0124
0,0012
14,0
1,40
0,0102
0,0010
thp
Bng B.7 Lu lng x ca din tch tng ng ming u phun (1) i vi h thng p sut
p sut ming u phun
Lng x
kg/pht/mm2
bar
MPa
20,7
2,07
2,967
20,0
2,00
2,039
19,3
1,93
1,670
18,6
1,86
1,441
17,9
17,9
1,283
17,2
1,72
1,164
16,5
16,5
1,072
15,9
1,59
0,9913
15,2
1,52
0,9175
14,5
1,45
0,8507
13,8
1,38
0,791
13,1
1,31
0,7368
12,4
1,24
0,6869
11,7
1,17
0,6412
11,0
1,10
0,599
10,0
1,00
0,54
(1) Da theo u phun n tiu chun c l vo trn vi h s l 0,98
Bng B.8 Lu lng x ca din tch tng ng ming u phun(1) i vi cc h thng p sut thp
p sut ming u phun
Lng x
kg/pht/mm2
bar
MPa
51,7
5,17
3,255
50,0
5,00
2,703
48,3
4,83
2,401
46,5
4,65
2,172
44,8
4,48
1,993
43,1
4,31
1,839
41,4
4,14
1,705
39,6
3,96
1,589
37,9
3,79
1,487
36,2
3,62
1,396
p sut ming u phun
Lng x
kg/pht/mm2
bar
MPa
34,5
3,45
1,308
32,8
3,28
1,223
31,0
3,10
1,139
29,3
2,93
1,062
27,6
2,76
0,9843
25,9
2,59
0,907
24,1
2,41
0,8296
22,4
2,24
0,7593
20,7
2,07
0,689
17,2
1,72
0,5484
14,0
1,40
0,4833
(1) Da theo u phun n tiu chun c l vo trn vi h s l 0,98
B.7. Trong cc h thng p sut cao, thi hn thc hin dng kh cn bng thng l khng ng k. Trong cc h thng p sut thp, thi hn v lng cacbon dioxit ha hi trong vic lm mt ng cn c tnh ton v lu lng dng kh cn bng phi c tng ln cho ph hp c th tnh
c nh sau:
td =
mC p (T1 T 2 )
0, 507Q
+ 16850V Q
Trong :
mv =
mC p (T1 T2 )
H
m l khi lng ng, tnh bng kilogam;
p
C l nhit lng ring ca kim loi lm ng, tnh bng kilojun trn kilogam(1); kJ
kg
T1 l nhit trung bnh ca ng trc khi x, tnh bng C
T2 l nhit trung bnh ca cacbon dioxit, tnh bng C(2)
Q l lu lng thit k, tnh bng kilogam trn pht; kg
ph
V l th tch ng, tnh bng mt khi, m2
H l nhit n ha hi ca cacbon dioxit lng, tnh bng kilojun trn kilogam(3); kJ
kg
1 Cp=0,46kJ/kg.
2 Gi thit T2=15,6C i vi p sut cao v T2=20,6C i vi cc thit b p sut thp trong nhng iu khin
chun.
3 H=150,7kJ/khng gian i vi p sut cao v H=276,3kJ/khng gian i vi cc h thng p sut thp.
Ph lc C (tham kho)
THNG TIN V CACBON DIOXIT V CC NG DNG
Cc cht cha cacbon dioxit l cht khng mu, khng mi v l kh tr khng dn in. Cacbon dioxit nng gn gp mt ln ri khng kh. Mt kilogam cacbon dioxit lng p sut kh
quyn v 0C s to ra gn 0,51m3 kh. Cacbon dioxit c cha thnh bnh chu p lc thng
thng tn ti di dng kh ha lng.
Cacbon dioxit dp tt m chy l do gim hm lng xy trong kh quyn ti im khng h
tr cho s chy.
Cacbon dioxit thch hp cho vic dp tt cc dng chy sau:
- Chy cc cht lng hay cc cht rn ha lng c;
-Chy cc cht kh, tr cc trng hp sau khi dp chy c th pht trin mt mi trng n do kh tip tc thot ra;
Trong mt s iu khin nht nh, chy cc vt liu rn thng c gc l cht hu c trong s chy thng xy ra cng vi cc tn la hng;
- Chy cc dng c in ang hot ng;
Cacbon dioxit khng thch hp trong vic cha chy cc vt liu sau:
- Cc ha cht m bn thn c cha ngun cung cp xy nh xenlul nitrt;
-Cc kim loi c hot tnh ha hc v cc hydroxyt ca chng (nh natri, kali, magi, titan v zincroni). Nng cacbon dioxit m c s dng trong cc h thng cha chy c tc dng gy ngt v phi c coi l nguy him cao. Do , nhng yu cu v an ton trong iu 5 phi c xem xt mt cch nghim tc.
Ph lc D (tham kho)
V D V TNH TON D.1. Lu lng bng phng php th tch V d 1
D.1.1. S c (mi nguy him)
Bung phun sn (nhng yu cu i vi khong cha y v bi s l mt tnh ton ring bit;
KB = 1)
D.1.2. Kch thc thc
Rng 2,44m (mt m); Cao 2,13m;
Su 1,83m;
D.1.3. Th tch gi nh
2,44m 2,13m (1,83m su + 0,6m)(1)=12,63m3
D.1.4. T s phn trm ca chu vi ng kn
2, 44 + 1, 83 + 1, 83 = 6,1 100 = 71%
2, 44 + 2, 44 + 1,83 + 1, 83 8, 54
D.1.5. Lu lng x cho 71% ng kn
4(2) + (1 0,71) (16 4)(2) = 7,48 kg
D.1.6. Lu lng x
12,63(m3) 7,48 kg
ph. m3
=94,47 kg
ph. m3 ph
D.1.7. Yu cu cacbon dioxit
94,47 kg
0,5pht 1,4 (bao gm hi)(3) = 66,13kg
ph
D.2. Lu lng bng phng php th tch V d 2
D.2.1. S c
My in c bn cnh v nh m (khng c vch rn lin tc; KB = 1) D.2.2. Kch thc thc
Rng 2,44m; Cao 2,13m; Su 1,83m;
D.2.3. Th tch gi nh
2,42m 2,72m 1,82 = 11,98m3
D.2.4. T s phn trm ca chu vi ng kn
0%
1 Xem 16.2.2
2 Xem tc x c bit tng cng v ti thiu 16.3.3
3 Xem 16.1.1
D.2.5. Lu lng x cho 0% ng kn
16 kg
ph. m3
(1)
D.2.6. Lu lng x
11,98m3 16 kg
ph. m3
= 191,7 kg
ph
D.2.7. Yu cu cacbon dioxit
191,7 kg
ph
0,5pht 1,4 (bao gm hi)(3) = 134,2kg
D.3. Lu lng bng phng php din tch
D.3.1. S c
B ti (KB = 1)
D.3.2. Cc kch thc b mt
Rng 0,92m; Di 2,13m;
D.3.3. V tr u phun
Gi thit s kho st ch ra rng cc u c th t u , t 0,92m n 1,83m cch xa b
mt cht lng m khng nh hng n s vn hnh.
D.3.4. Th tc
T cc u phun c xc nhn theo danh mc (2) ca ngi sn xut, chn mt s ti thiu cc
u phun s ph mt din tch 2,13 0,92m. Gi thit danh mc c mt u phun vi din tch ph
c lng l 1,08m2 v mc lu lng l 22,3 kg
2,16m v mt chiu rng l 1,08m.
D.3.5. Tng mc lu lng
ph . Nh vy, hai u phun s ph mt chiu di
D.3.6. Yu cu cacbon dioxit
1 22,3 kg
ph
= 44,6 kg
ph
44,6 kg
ph
0,5pht 1,4 (bao gm hi) = 31,2kg
D.4. H thng cha chy th tch
D.4.1. Bun cha
Bung cha i vi ru etylic (KB = 1,34) c mt l h (khng c ng li) l 2m 1m.
D.4.2. Cc kch thc thc
Di 16m; Rng 10m; Cao 3,5m;
D.4.3. Th tch gi nh
1 Xem tc x c bit 16.3.3
2 Danh mc cc u phun ca ngi sn xut l mt bng s cc u phun t l gia din tch ph tng ng
vi chiu cao ca b mt bo v v lu lng cho tnh bng kilogam trn pht ( kg
ph )
VV
D.4.4. Th tch b sung cho thng gi
= 16 10 3, 5 = 560m3
D.4.5. Th tch khu tr
V = 0m3
Z
G
V = 0m3
V = 560 0 0 = 560m3
D.4.6. Tng din tch b mt ca tt c cc cnh
A = (16 10 2) + (16 3, 5 2) + (10 3, 5 2) = 502m2
D.4.7. Tng din tch b mt ca tt c cc khe h
D.4.8. Din tch
AOV
= 2 1 = 2m2
D.4.9. Lng thit k cacbon dioxit
A = 502 + 60 = 562m2
m = 1, 34
(0, 2 kg
2
m2 562m
3
+ 0, 7 kg
m3 560m )
= 675, 9kg .