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Steam injectors

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Steam injectors for boiler feedtank, hot waterand other industrial processheating requirements.

Vigorous mixing of steamand water takes placeinside the nozzle ensuringquiet operation.

Steam in

Hot water out

Cold water drawnin through radialports.

IN40M shown

Spirax Sarco steam injectors use steam to raise the temperature of water or other liquids. The injector draws in

cold liquid, mixes it with steam inside the injector and distributes the heated liquid in the tank. In many applications

the circulation induced by the injector is an advantage ensuring thorough mixing and avoiding temperaturestratification.

Boiler feedtank applicationsDissolved oxygen must be removed from boiler feedwater if corrosion is to be prevented in the boiler. Oxygen

can be removed either by chemicals or by heating. The dissolved oxygen content of water at 20C is 9 ppm,

at 60C is 5 ppm and at 90C is just under 2 ppm.

By heating the boiler feedwater to typically 85 - 90C to remove most of the oxygen, and introducing an oxygen

scavenging chemical into the boiler feedline to remove the small quantity of remaining oxygen, chemical usage

can be minimised. Additionally, boiler efficiency may be increased since blowdown requirements may be lowered.

FittingThe injectors can be fitted to the steam supply pipework or installed directly onto the tank wall using a female

threaded connection. For very large installations, multiple injectors may be used.

Range Nominal size End connections

IN40M 40 mm (1") Butt weld, screwed BSP or NPT

IN25M 25 mm (1") Butt weld, screwed BSP or NPT

IN15 15 mm (") Screwed BSP or NPT

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Typical injector systems - examplesA typical electropneumatic system and a self-acting control system are shown below. Self-acting controls offer

an economical solution for boiler feedtank applications. Pneumatic or electric systems can offer close temperature

control for process applications. Pipework can be routed inside or outside the tanks. Your local sales engineer

will be pleased to advise on the most suitable system for your plant requirements.

Steam in

Stop valve

Y-typestrainer

Vacuumbreaker

Controlvalve

Dialthermometer

Controland sensor

Injector

Pocket

Steam in

Stop valve

Y-typestrainer

Vacuum breaker

Control valve

Dialthermometer

Temperaturesensor

Injector

Pocket

O Complete mixing of steam within the injectorprovides quiet, efficient, and economic heating.

User benefits

O Avoids temperature stratification in tanks -maintains efficiency.

O 316 stainless steel injectors for long life andmaintenance free operation.

O Reduced need for oxygen scavenging chemicalsin boiler feedwater applications.

O Flexible control system packages,to suit individual applications.

Self-acting control system

Electropneumatic control system

Controller

Selecting a systemSpirax Sarco offers a wide range of valves,

controllers, sensors and ancillary equipment for

pneumatic, electric and self-acting control systems.

Literature describing these products is available on

request. The optimum choice of an efficient and

economical steam injection system depends on

many factors including temperature, steam flow,heating times and tank volume.

IN25M / IN40Mshown

IN15 shown

Your local Sales Engineer will be pleased to advise

on the most suitable equipment for your plant.

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Some of the products may not be available in certain markets.

Spirax-Sarco Limited, Charlton House,Cheltenham, Gloucestershire, GL53 8ER UK.

Tel: +44 (0)1242 521361 Fax: +44 (0)1242 573342E-mail: Enquiries@SpiraxSarco.com

Internet: www.SpiraxSarco.com

Copyright 2006 Spirax Sarco is a registered trademark of Spirax-Sarco Limited

SB-P401-02 AB Issue 6

CapacitySteam injector capacities when heating tanks of up to 3 metresdeep and vented to atmospheric pressure. The choice of controlvalve can affect the steam capacity:

Injector type A B C Weight

IN15 " 205 28 0.4

IN25M 1" 84 71 0.8

IN40M 1 " 115 88 1.6

Dimensions / weights(approximate) in mm and kg

Limiting conditions

Estimating steamflowrates for water heating

Body design rating PN25Minimum operating pressure 0.5 bar g

Maximum saturated steam conditions 17.0 bar g @ 207 C

Example1. 'My tank size is 1.5 m x 2 m x 1.5 m.

I want to heat it from 20 C to 40 C in one hour'. Assume the tank is full.The tank volume = 4.5 m = 4 500 litre (4 500 kg).From the graph the required injected steam rate = 155 kg/ h.

2. 'My tank is the same as example 1, but I want to heat it in

20 minutes'. Since it is required to heat it up 3 times faster, thenthe injected steam rate will be three time as great i.e. 465 kg/ h.

3. 'I want to heat up my boiler hotwell from 30 C to 90 C, I havetwo boilers steaming all year round. They are each generatinga maximum of 10 000 lb/ h and my blowdown rate is 5 %'.Total steam generation rate = 20 000 lb/ h.Total blowdown rate = 5 % of 20 000 = 1 000 lb / h, hencefeedwater flowrate = 20 000 + 1 000 = 21 000 lb/ h.From the graph the required injected steam rate = 1 000 kg/ h

Injected steam rate lb / h

Injected steam rate kg / h

Tankcontentskg

(litre)

orBoilerfeedwaterflowrate

kg/h

The following chart enables an estimate to be made of the steam flowrate

required to heat up a tank in one hour or to produce a particular temperaturerise in a boiler feedtank.For boiler feedtanks note that feedwater flowrate equals steam generationrate plus blowdown rate.

100 000

70 000

50 000

30 000

20 000

10 000

7 000

5 000

3 000

2 000

1 000

700

500

300

200 300 500 1 000 2 000 5 000 10 000 20 000

50 70 100 200 300 500 1 000 2 000 5 000 10 000

200 000

100 000

70 000

50 000

30 000

20 000

10 000

7 0005 000

3 000

2 000

1 000

700

20C30

C50

C80

C10C

Example1

Example3

Water

temp

eratur

erise

Materials

How to orderExample:1 off Spirax Sarco IN25M steam injector in 316L gradestainless steel having a 1" screwed BSP connection.

SystemsFully engineered systems are available from Spirax Sarcoincluding controllers, valves and other ancillary products.

Austenitic stainless steel 316L

1" BSP Taper or NPT maleIN15

B

A

B

BSP/NPTfemale

IN25MIN40M

Injector type IN15 IN25M IN40M

Steam pressure at Saturated steaminlet of injector (bar g) capacity kg / h

0.5 11 75 222

1 20 135 4002 48 175 580

3 66 280 805

4 84 350 970

5 102 410 1 125

6 120 500 1 295

7 138 580 1 445

8 156 640 1 620

9 174 700 1 820

10 192 765 1 950

11 210 830 2 250

12 228 900 2 37013 246 975 2 595

14 264 1 045 2 710

15 282 1 095 2 815

16 300 1 170 3 065

17 318 1 225 3 200

Intermediate values may be obtained by linear interpolation.For higher capacities use two or more injectors in parallel.The information given is empirical and must not be used forcritical applications.

A

C

C

Tankcontentslb

orBoilerfeedwaterflowrate

lb/h

(Imperialgallon

=10lb)