prognost ® -nt module capabilities

PROGNOST®-NT

Contents

Introduction ......................................................................................................................................................................................................................................................... 4

Proven by experience ...................................................................................................................................................................................................................................... 5

PROGNOST®-NT system overview and capabilities .................................................................................................................. 6

Asset Performance Management ........................................................................................................................................................................................................... 6

PROGNOST®-NT .................................................................................................................................................................................................................................................. 6

PROGNOST®-NT modules profiles ........................................................................................................................................................................................................... 7

System scaleability ........................................................................................................................................................................................................................................... 8

Diagnostic capabilities ................................................................................................................................................................................................................................... 9

PROGNOST®-SILver ........................................................................................................................................................................................................................................ 10

Machine condition visualization (VISU) ............................................................................................................................................................................................ 11

Safety Analyses ................................................................................................................................................................................................................................................. 12

Early Failure Detection ................................................................................................................................................................................................................................. 13

Wear Monitoring ............................................................................................................................................................................................................................................. 14

Performance Optimization ........................................................................................................................................................................................................................ 14

Lubrication Monitoring ............................................................................................................................................................................................................................... 14

Process Data Analyses .................................................................................................................................................................................................................................. 15

Component Tracking .................................................................................................................................................................................................................................... 15

Tech Corner – Advanced technologies ....................................................................................................................................... 16

Why vibration monitoring? ....................................................................................................................................................................................................................... 16

Automated p-V diagnoses ......................................................................................................................................................................................................................... 17

Monitoring of compressor components ................................................................................................................................... 18

Piston rod and Plunger ................................................................................................................................................................................................................................ 19

Crosshead ........................................................................................................................................................................................................................................................... 20

Crankshaft bearings ...................................................................................................................................................................................................................................... 20

Cylinder and Packing lubrication ......................................................................................................................................................................................................... 20

Crankshaft ........................................................................................................................................................................................................................................................... 20

Process problems ............................................................................................................................................................................................................................................ 21

Rider rings and Piston sealing rings .................................................................................................................................................................................................... 21

Discharge and Suction valves ................................................................................................................................................................................................................. 21

Packing .................................................................................................................................................................................................................................................................. 22

Cylinder liner and Compression chamber ....................................................................................................................................................................................... 22

3

PROGNOST Systems started monitoring reciprocating

compressors more than 20 years ago. The first commercial

installation was realized in 1992. Today, PROGNOST®-NT is

monitoring more than 600 rotating machines all over the

world – what makes us the unquestioned marketleader for

online compressor diagnoses.

Over the years, PROGNOST Systems has developed an exces-

sive customer orientation that is reflected in our continuous

dialog with our customers and their influence in our R&D

Introduction

efforts. Furthermore, our Customer Support repeatedly gets

very good marks for compentence, responsiveness and sup-

portiveness within our annually conducted Customer Satis-

faction Survey in conformety with our ISO 9001 certification.

We will continue to strengthen our market position and

maintain our brand to be the No. 1 supplier for Asset

Performance Management systems for all critical rotating

equipment.

4

A reliable, full-featured monitoring system requires a solid

number of installations and many years of field experience.

No amount of “laboratory” testing can reflect the condi-

tions of the actual operating environment – much less the

characteristics of many different operating environments

over extended periods of time. What assurance do you have

that your monitoring system will perform as promised? How

much confidence do you have in the accuracy of the diag-

noses your system generates?

Insist that your vendor documents the amount of time their

system has been in actual use in operating locations. Deter-

Proven by experience

mine the amount of time in which the vendor has resolved

problems and implemented user suggestions from the field

in order to refine the performance of their monitoring sys-

tem. Ask for references. Contact as many of them as possible.

Better still, visit user sites whose environments most closely

match your own. Input from vendor representatives is useful.

However, uncensored comments from genuine users are

invaluable in deciding whether a prospective system will

meet your expectations.

5

PROGNOST®-NT System overview and capabilities

PROGNOST®-NT

PROGNOST®-NT is an automated machinery diagnostic

system incorporating safety protection and online condi-

tion monitoring. It is developed specifi cally for reciprocating

machinery but is also used for diff erent kinds of rotating

equipment. It detects impending failures at an early stage

and assigns the aff ected components. Operation-critical

damages are avoided and maintenance measures can be

performed effi ciently.

A full Asset Performance Management system owns a holistic

approach in terms of machine condition monitoring with

emphasis on safety protection and early failure detection.

Accurate anomaly detection is accomplished by capturing a

complex combination of signals and analyzing them in a way

that allows even minor changes to be recognized. By detec-

ting slight changes and understanding their consequences,

early failures are detected – and false alarms are avoided. This

type of in-depth intelligence demands a monitoring system

that has been perfected through 20 years of fi eld experience.

Additional features like permanent monitoring of wear

parts, such as piston rider rings or the integration of DCS

values, e.g. temperatures, help to maximize machinery up-

time and minimize maintenance eff orts.

Asset Performance Management

6

PROGNOST®-NT modules profi les

Data Acquisition & Safety Protection PROGNOST®-SILver – SIL 2-certifi ed protection hardware

Safety Analyses Recording and visualization of online signals and trends

Early Failure Detection Monitoring of critical components, automatic pattern recognition

Wear Monitoring Trend based monitoring of wear parts

Performance Optimization Automated p-V diagram analyses

Lubrication Monitoring Continuous monitoring of lubrication fl ow quantities

Process Data Analyses DCS data analyses and trending, P&I diagram

Component Tracking Maintenance planning tool, component lifetime registry

Visualization Signal visualization, machine status, online and trend data, logbook

7

System scaleability

PROGNOST®-NT is scalable in two ways: First, it is function-

ally scalable, allowing new or additional capabilities such as

measuring loops or diagnostic modules to be added to an

installed system without inordinate cost or diffi culty. Second,

PROGNOST®-NT is scalable in magnitude. In other words,

this system off ers the expansion of monitoring to additional

machines. As your needs change and your experience with

this system grows, it is likely that you wish to extend cover-

age to other machines. This allows a simple, cost-sensitive

pathway for growth.

Turn key PROGNOST®-NT system – completely assembled,

confi gured, tested and ready for shipping

8

Diagnostic capabilities

Detecting an anomaly is one thing. Defi ning and pinpointing

it is another. PROGNOST®-NT does not solely indicate prob-

lems but also provides an accurate diagnosis with specifi c

component identifi cation, location and indication of the

extent of damage. Equipped with this information, you can

make well-founded decisions about the maintenance proce-

dures you need to take and the time you need to take them.

PROGNOST®-NT Swift for temporary use, e.g. initial machine

start-up or after compressor overhauls

9

Data acquistion and SIL 2-certifi ed safety protection

The vital role of a protection system to mitigate the risk

of serious damages is covered by PROGNOST®-SILver. This

hardware has proven its eff ectiveness and reliability on a

daily basis, worldwide and in diff erent process environments.

PROGNOST®-SILver is the only machinery protection system

for reciprocating machinery with a SIL 2 certifi cate for all

shutdown loops connected (max. 68 loops). The intelligent

combination of vibration, dynamic rod position, dynamic

cylinder pressure and temperatures analyses provides the

most reliable shutdown parameters in the industry. The

PROGNOST Systems invention of “Segmented Vibration

Analy sis” and a unique algorithm ensure fast, reliable ma-

chine shutdown and no false alarms.

PROGNOST®-SILver gives you a stand-alone safety protec-

tion system but also convenient wiring options for the data

acquisition of PROGNOST®-NT.

Signal Plausibility Check

PROGNOST® uses specialized signal processing to avoid false

alarms caused by electrical or hardware failures such as bro-

ken or loose wires, short circuits or broken terminals. Even

out-of-range signals are identifi ed and indicated as “UNSAFE“.

Users are informed about any “UNSAFE” loop immediately.

PROGNOST®-SILver

PROGNOST®-SILver, 19” hardware with sensor cable mounting either on the front- or backside

for various installation options, e.g. cabinet frame mounting, wall mounting, housings

PROGNOST®-SILver in Ex-housing (without cover) for fi eld

installation (Ex-zone)

10

Signal visualization: machine status, online and trend

data, logbook

PROGNOST®-NT Visualization is much more than a “data

display” software. It allows active access to all kinds of signals,

analyses and logbook entries. User-friendly design of func-

tions, views and data access allows even untrained users to re-

ceive status information of the machine with just a few clicks.

All of our customers enjoy the logical and easy way to investi-

gate waterfall diagrams, alarm logbooks and trend views. Sup-

ported with audio replay functions for vibration measurement

and easy data export to standard Offi ce software, you fi nd the

most comprehensive tool set for diagnosis.

Machine Condition Visualization (VISU)

Vibration signal segmentation

3D trend p-V diagram with automated effi ciency analysis

Machine status view in the “OneClick Cockpit”

Logbook with all alarms, machine starts and stops

11

Visualizes the Safety Protection analyses performed

by PROGNOST®-SILver, e.g. online signals, trends and

safety limit violations.

Reliable safety protection hardware is only one side of the

story. Answers as to “why” a safety incident occured is the

next step further. PROGNOST®-NT Safety Analyses is a mod-

ule to visualize and save online and trend data to provide all

information required for precise root cause analysis.

Ringbuff er

Transient data recording allows maintenance technicians

to replay a safety shutdown, alert, or machine start-up by

examining a gapless recording of all signals in an uncom-

pressed format – revolution by revolution. The ringbuff er

off ers the possibility of subsequent analyses; the time frame

of seven minutes before and three minutes after the ALERT,

SHUTDOWN or UNSAFE alarm can be closely evaluated us-

ing all recorded time signals from all dynamic sensors and

process values in the PROGNOST®-NT system.

Safety Analyses

Peak-to-Peak analysis of the piston rod position (Operational run out)

Monitoring the following components (Legend: see page 19 and following)

0 15 30 45 60

m il

0 15 30 45 60 75 90 10 5 12 0 13 5 15 0 16 5 18 0 19 5 21 0 22 5 24 0 25 5 27 0 28 5 30 0 31 5 33 0 34 5 36 0

T D C B D C T D C

0 10 20 30 40 m il

0 15 30 45 60 75 90 10 5 12 0 13 5 15 0 16 5 18 0 19 5 21 0 22 5 24 0 25 5 27 0 28 5 30 0 31 5 33 0 34 5 36 0 1 2 3 4 5 6 7 8

R D S tage 1, P eak-P eak over 8 S eg. .. 45 d egrees degree crank angle

degree crank angle

12

mechanical defects at an early stage

local and functional clarity

With its dedicated analyses for reciprocating machinery,

PROGNOST®-NT detects developing damages at an early

stage, providing users with valuable lead time for proactive

compressor operation management and effi cient mainte-

nance planning.

Automatic detection of operating conditions

PROGNOST®-NT recognizes changing machine operating

conditions and automatically switches to corresponding,

pre-defi ned threshold sets to avoid false warnings caused by

changing load conditions.

Automated threshold setting

Using the automated threshold setting, the system can easily

be confi gured for new operating conditions to guarantee

high quality of warnings.

Early Failure Detection

Pattern recognition with fully integrated

diagnostic database

All PROGNOST®-NT users benefi t from experiences of more

than 4.25 million recip operating hours annually and more

than 20 years of diagnostic experience. All major failure

modes are integrated within a failure pattern database

and can be diagnosed automatically providing clear text

messages including failure type and location of the failing

component. The diagnostic capabilities are a blend of the

most reliable and useful soft computing disciplines – from

Fuzzy Logic to Rule Based.

Online vibration signal and segmented analysis for one crank revolution

-4,0

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-1,0

0

1,0

2,0

3,0

4,0g

0 15 30 45 60 75 90 105 120 135 150 165 180 195 210 225 240 255 270 285 300 315 330 345 360° CA

0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

5,0

5,5g

0 15 30 45 60 75 90 105 120 135 150 165 180 195 210 225 240 255 270 285 300 315 330 345 360° CA

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

TDC BDC TDC

CHS 1, RMS values via 36 Seg. .. 10 degrees

Monitoring the following components

13

supported and eased

PROGNOST®-NT Wear Monitoring provides wear trend plots

of critical components. Thus development from normal wear

to threatening damage becomes recognizable. The operator

is advised by threshold violations and therefore wear-based

damages become predictable and avoidable. As a result, the

number of machine stops decreases as well as the number

of replaced components because components can be oper-

ated over their full wear potential.

Machine outages to perform periodic manual inspections

can be avoided when an accurate means to quantify remai-

ning rider band potential is continuously available.

Reliable and meaningful piston rod position

PROGNOST®-NT uses the full revolution of the piston rod

position signal to provide a precise piston rider ring wear

calculation. The dynamic rod position signal is also used to

monitor the mechanical condition of the piston rod and its

connections. Used as a protection parameter for automatic

shutdown, it is the only method to detect cracked piston

rods before they fail.

Wear Monitoring

based on fl ow rate

measuring points

With this application, any number of lubrication lines can

be equipped with PROGNOST®-NT Lubrication Monitoring

sensors to monitor the fl ow rate. These sensors are ideally lo-

cated near the injector to get information about lubrication

quantities. The fl ow rate of the individual lubrication points

is monitored by trend analysis and changes become visible

at an early stage. Blockages or leakages are identifi ed before

they cause component failures.

Lubrication Monitoring



energy consumption

condition monitoring

Measuring dynamic cylinder pressures, PROGNOST®-NT

evaluates the effi ciency and condition of a compressor and

its sealing elements. The continuous and automated p-V dia-

gram analyses detects impending valve failures most reliably.

Apart from p-V diagram analyses, the following additional key

values are calculated, monitored and recorded in the logbook:

Performance Optimization


These data analyses provides operators and maintenance

personnel with all information that is required for an opti-

mized operation of reciprocating machinery.

See also page 17.

14

for data exchange

DCS values as trends

DCS parameters avoiding false warnings

This module establishes a direct communication between

DCS and PROGNOST®-NT. When operating conditions of

the compressor are changing, e.g. speed or pressure, these

changes are refl ected within the PROGNOST®-NT analyses to

avoid false warnings. Conversely, status messages from Safety

Protection or Early Failure Detection modules are forwarded

to the control room personnel for further actions. Information

exchange is realized with standard interfaces Modbus RTU,

OPC or Profi bus. The module also off ers the possibility of dis-

playing DCS data as graphic trends and continuously compar-

ing these trends with warning threshold values.

Process Data Analyses

of all maintenance activities

for a comparison of spare part lifetimes

This module supports predictive maintenance strategies

with an effi cient tool for planning and tracking mainte-

nance activities along with real-time component lifetime

information. Users receive all information required: running

time of individual components (based on actual machine

run-time, not on installation date) and a timeline, displaying

all planned and realized maintenance activities. Further-

more, expected dates for replacement of wear parts can be

confi gured.

Component Tracking

Component history: installation date and operating hours


15

The most important and well established technique for

machine monitoring is vibration analyses. However, not all

vibration analyses are the same. Seemingly minor differ-

ences in data acquisition and evaluation strategies have

dramatic impact on the quality of signal diagnoses. Choos-

ing the proper mathematical evaluation method is the key

to reliable Early Failure Detection and Safety Protection. Re-

ciprocating machinery has specific vibration characteristics,

e.g. vibration peaks during valve opening and closing, which

must be taken into consideration to avoid false alarms.

Segmentation

Monitoring systems should continuously acquire and

diagnose machine vibrations for each revolution and then

segment signals into crank angle-related portions. This al-

lows harmless but sometimes erratic machine behavior to

be rightly identified as a “good condition” – thereby avoiding

false alarms.

PROGNOST Systems invented the “Segmented Vibration

Analysis“ and thus determined that it is the best approach

to subdivide the 360° of one revolution into 36 segments of

10° crank angle each. This is the most accurate proportion of

an average impact width related to one revolution. Vibration

signals must be evaluated using the most accurate mathe-

matical analysis. For reciprocating machinery, only RMS (Root

Mean Square) analysis has proven reliable. RMS analysis is

superior because it considers not only amplitude but also

the energy content of an impact.

Why vibration monitoring?

Tech Corner Advanced technologies

-20 -10

0 10 20

g

0 15 30 45 60 75 90 10 5 12 0 13 5 15 0 16 5 18 0 19 5 21 0 22 5 24 0 25 5 27 0 28 5 30 0 31 5 33 0 34 5 36 0

T D C B D C T D C

0 5

10

15 g

0 15 30 45 60 75 90 10 5 12 0 13 5 15 0 16 5 18 0 19 5 21 0 22 5 24 0 25 5 27 0 28 5 30 0 31 5 33 0 34 5 36 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

crosshead guide Cyl.1 , R M S valu es via 36 S eg. .. 10 d egrees degree crank angle

degree crank angle

Crosshead vibration signal and segmented analysis

16

The benefi ts of optimal equipment performance are clear:

reduced energy consumption and increased productivity.

Tracking performance can also provide other benefi ts, such

as early warning of impending gas leakages. Unfortunately,

Automated p-V diagnoses

losses in effi ciency often go undetected by many monitor-

ing systems that focus on vibration, piston position and tem-

perature only. Machine effi ciency – like other key parameters

– should be monitored continuously.

PROGNOST®-NT checks machine effi ciency and provides

comprehensive analyses that identify how to restore opti-

mum operation. Analyses begin by detecting any changes

in dynamic pressure during operation and performing

automated, specialized p-V analyses to identify components

causing effi ciency reductions. They also incorporate infl u-

ences resulting from today’s compressor regulations. Finally,

they analyze other key values such as compression cycle,

piston rod load and piston rod reversal. Monitoring systems

should compile all this information to give a comprehensive

view of machine effi ciency.

Pressure curve with piston rod load

17

Valve Failures 29%

Piston Rod 7%

Misc 7%

Sensor Failure 6%

Crosshead 5%

Flow control caused problems 4%

Piston Rings 3%

Plunger 3%

Rider Rings 3%

Piston 2%

Bearing 2%

Leackage 2%

Liquid slug 2%

Process 2%

Pulsations 2%

Packing 1%

Cylinder 1%

5% 10% 15% 20%

Monitoring of compressor components

18

As for double-acting compressors, alternating tensile and

compressive forces on the piston rod are the result of gas

compression on the crank end side (CE) or head end side

(HE) of the compression chamber. These forces from two op-

posing directions act alternately upon the piston rod.

Loosened connections

The integrity of motion works is ensured via vibration analy-

ses and rod position monitoring. Accelerations on the cross-

head slide gaplessly record vibration arising as the result of

increasing clearances. Subsequent diagnosis identifi es actual

deviations in the vibration pattern.

Piston rod position analyses reveal connections that are in

the process of detaching at an early stage, e.g. cracks. By

permanent rod position measurement even weakened con-

nections (e.g. low contact pressure between piston nut and

piston) are detectable.

Overload/excessive piston rod load

(compressive and tensile forces)

The compressive and tensile forces aff ecting the piston

rod can be calculated continuously.

Plunger monitoring (Hyper compressor)

For Hyper compressors, orbit monitoring (horizontal/vertical

displacement of the plunger, “plunger run-out”) is recom-

mended to detect excessive wear of the packing. Increased

vibration is detected at an early stage to prevent damaging

of the brittle hard metal plunger. An automatic shutdown is

crucial to avoid costly consequential damages. Additionally,

gap protection can also be used for safety shutdown.

PROGNOST®-NT monitoring modules recommended

Piston rod and Plunger

19

Crosshead

Cylinder and Packing lubrication

Crankshaft bearings

Crankshaft

Segmented vibration analysis (see page 16) allows the early

detection of mechanical damages within motion works,

from the connecting rod to the piston. Loosened con-

nections, e.g. between connecting rod and crosshead, are

detectable at an early stage as they create characteristic

vibration peaks at rod load reversal points.

Wrist pin

Wrist pin failures are usually consequential damages caused

by loss of lubrication. Using p-V monitoring, dynamic rod

load changes periods can be calculated. If these periods are

too short, a loss of lubrication of the wrist pin is creating a

critical situation.


Vibration analysis assists in the early detection of mechani-

cal damages within motion works, e.g. the connecting rod.

temperature monitoring of bearings is not always distinct.

The friction heat, generated by a damaged bearing, often

is insuffi cient to produce a signifi cant rise in temperature.

In contrast, vibration allows sleeve bearing damages to be

recognized immediately. Unlike temperature instrumenta-

tion, vibration measurement can be installed even if no

borehole at the bearing cap is designed for the sensor by

the manufacturer.


ages often are not recognized by the customary method of

installed at each lube oil line, precisely record lubrication

quantity and trigger an alarm in case of excessive or insuffi -

measurements, making the reading of sight glasses obsolete

and thus reducing the time spent by maintenance person-

nel in hazardous areas at the machine.


to continuous torsional vibration. When the machine was

designed, a defi nite vibration behaviour was calculated and

the shaft was sized correspondingly. However, the use of

load controls such as stepless valve unloaders generates

operating conditions which may not have been taken into

resonances can be excited which result in unplanned

loads for the crankshaft and its drive connection. To enable

nuous monitoring of torsional vibration is recommended.


20

Process problems

Discharge and Suction valves

Rider rings and Piston sealing rings

Liquids in the compression chamber cause a short term rise

of the piston. It can be detected with a peak-to-peak analysis

of piston rod position using a displacement sensor. Another

way to detect liquid carryover is provided by a crosshead

slide acceleration sensor when incompressible liquid is

pressed through discharge valves. This often results in high

vibration around TDC and BDC.

Both analyses are highly recommended as shutdown signals

to prevent severe consequential damages such as piston rod

failures or broken cylinder head.


Automated p-V diagram analysis is one of the most impor-

tant methods for evaluating the condition of piston sealing

rings. For the detection of leaking piston sealing rings on

a double acting cylinder, the two opposite compression

chambers are analyzed in parallel. If changes appear in both

compression chambers, it can be considered as an indica-

tion of leaking piston sealing rings.

The vertical position of a piston is an important indicator for

wear of piston rider rings. The measured vertical position of

a piston rod can be converted into a lowering in the piston

centre, which corresponds to the wear of the rider rings. To

receive accurate rider ring wear values, only the segmented

monitoring of each complete revolution gives reliable

results.


Automated p-V diagram analysis (pressure/volume diagram)

is one of the most important methods to determine the

condition of valves. Valve leakages cause characteristic

changes in the measured pressure curve which can be

recognized with p-V analyses. The dynamic pressure curve

measured is converted to a p-V diagram for which particu-

lar characteristic values are calculated. These values, e.g.

discharge losses, polytropic exponents or the crank angle of

the suction valve opening, are assigned warning thresholds

which result in warning messages when exceeded.

Acquisition and analysis of the vibration on cylinders assists

the early detection of mechanical damages, e.g. cracks in the

valve body or valve plates. Flow noise of damaged valves as

well as shifted valve opening or closing events are detect-

able through high resolution measurement with accelera-

tion sensors.

Measurement of valve temperature is the traditional method

here. Using a temperature sensor, gas temperature in the

valve chamber is measured. If the temperature at a valve

is clearly increased, a damage, e.g. leak, can be assumed.

However, if there are several valves on the cylinder, costs

have to be taken into consideration as a temperature sensor

is required for each valve.


21

PackingCylinder liner and Compression chamber

Automated p-V diagram analysis: Increased leakages cause

characteristic changes in the indicated pressure curve. Ap-

propriate analyses are capable to diff erentiate between valve,

piston ring and packing leakage. The results are compared

with the pattern recognition database and displayed as clear

text.


The cylinder liner can be damaged by worn-out rider rings

and solid residue in the compression chamber, e.g. caused

by gas impurities. These types of damages are detected

with a peak-to-peak evaluation of piston rod position using

a displacement sensor as well as crosshead vibration. Both

analyses are recommended as shutdown signals.


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PROGNOST Systems GmbH

Birkenallee 177

48432 Rheine

Germany

+49 (0)59 71 - 8 08 19 0

+49 (0)59 71 - 8 08 19 42

[email protected]

PROGNOST Systems, Inc.

1020 Bay Area Blvd. Suite 105

Houston, TX, 77058

USA

+1 - 281 - 480 - 93 00

+1 - 281 - 480 - 93 02

[email protected]

www.prognost.com

prognost ® -nt module capabilities

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