2. Why Monitor?
As one of the oldest compressor designs, recips enjoy unique
capabilities and are quite flexible with features such as broad capacity
control ranges and the ability to compress gas regardless of mole
weight or k value. Add mutiple stages and they can compress a gas
to extremely high compression ratios. Consequently, they’re an ideal
fit for selected applications—such as hydrogen compression in the
de-sulfurization process of many refineries—and as part of the
low-density polyethylene production process in chemical plants,
to name just a few.
However, reciprocating compressors suffer from one very serious
drawback: high maintenance costs. In fact, compared to similarly
sized centrifugals, recips can consume as much as five times the
amount of maintenance dollars.
That’s why a continuous monitoring system is so important. Specifically
designed to meet the unique machinery protection and condition
monitoring needs of recips, our solutions can help close the gap,
bringing your recip maintenance costs closer to the levels associated
with centrifugals while simultaneously improving reliability, availability,
and safety. And, with patented* technology, comprehensive services,
and over 25 years experience monitoring reciprocating compressors,
no one is better equipped to help you.
* United States Patents 4,987,774; 6,421,571; 6,826,490; 6,937,941; 6,934,696
Great Britain Patent 2,408,338
1
3. HYDROGEN RECYCLE COMPRESSOR
Cumulative Unplanned Repair Costs
Maintenance Dollars per HP
8
DOLLARS (IN MILLIONS) 7
6
5
4
3
Centrifugals Recips
2
Recips can consume five times as many 1
maintenance dollars as an equivalently
sized centrifugal compressor!
1 2 3 4
YEARS
Without monitoring With monitoring
A monitoring system from GE will often more
than pay for itself in the first year, and can save
millions of dollars over the life of the compressor.
2
4. Recip Monitoring In Detail.
MULTI-EVENT WHEEL
Frame Vibration PRIME
3500 Monitor: 3500/70M 4-Channel MOVER
Increases in frame vibration can indicate problems
Impulse/ Velocity monitor
such as imbalance due to unusual pressure
Transducer: 330500 Velomitor®
differential or inertial unbalance, looseness in
or 190501 Velomitor CT
the foundation attachment (such as deteriorating
Piezo-Velocity Transducer
grout or shims), and high moments caused
by excessive rod load.
Piston Rod/Plunger Position
X-Y proximity probes observing the piston rod 3500 Monitor: 3500/72M 4-Channel
provide information on rod bow and rider band wear. Rod Position Monitor
Continuous monitoring gives maximum magnitude Transducer: 3300XL Series
and direction of rod movement along with the crank Proximity Transducer
angle at which the maximum occurs. The source of
movement can be identified, enabling the proactive scheduling
of maintenance for rider band replacement or crosshead repair.
Monitoring plunger position in hyper compressors provides
protection against detoriating plungers.
Suction/Discharge
Valve Temperature 3500 Monitor: 3500/61 6-Channel or
Suction and discharge valves are typically the 3500/65 16-Channel Temperature Monitor
highest maintenance items on recips. Faulty Transducer: RTD or Thermocouple
valves can significantly reduce the compressor’s
efficiency as well as increase combined rod load.
By recompressing the same gas, a leaky valve
becomes hotter than normal, causing the valve cover plate
temperature to increase. By monitoring both absolute valve
temperature, and differential temperature between a group of
valves, valve problems can be spotted early and repaired before
efficiency losses mount.
Main Bearing Temperature 3500 Monitor: 3500/61 6-Channel or
This measurement indicates problems related to fluid-
3500/65 16-Channel Temperature Monitor
film bearings, including overload, bearing fatigue,
or insufficient lubrication. Transducer: RTD or Thermocouple
3500 Monitor: 3500/77M 4-Channel Continuous Rod Load
Cylinder Pressure Monitor Combined (inertia and gas) rod loads
Crosshead Acceleration Discharge Gas Temperature Transducer: 165855 Cylinder calculated at the crosshead provides
Crosshead-mounted accelerometers can detect 3500 Monitor: 3500/61 6-Channel or Continuous monitoring of discharge gas information about the lubrication condition
3500 Monitor: 3500/70M Pressure Transducer
machinery problems due to impact-type events 3500/65 16-Channel Temperature Monitor temperature can give an indication of worn of the crosshead pin. Insufficient reversal or
Transducer: 330400 or
such as crosshead looseness, liquid ingestion Transducer: RTD or Thermocouple valves, unloaders, excessive compression ratio, excessive rod load can be identified and
330425 Accelerometer corrected before costly running gear
into the cylinder, or excessive clearance in the or insufficient cooling water.
wrist pin bushing. damage occurs.
3
5. Malfunction/Measurement In Detail.
Multi-Event Keyphasor ® Signal See Note2 MALFUNCTION1
3500 Monitor: 3500/25
A proximity probe observing a multi-toothed wheel on
Excessive Main Bearing Temperature
Keyphasor Module
Excessive Clearance in Crosshead
Faulty Cylinder Discharge Valves
the crankshaft provides a precise reference timing signal
Transducer: 3300XL Series
(including reversal, excessive loading, etc.)
Faulty Cylinder Suction Valves
every 30 degrees of rotation in addition to a once-per-
Proximity Transducer
Pressure Packing Case Leaks
turn reference point. This allows measurements such
as rod position and cylinder pressure to be correlated
Excessive Crankcase and
Leaking Pressure Rings
with a highly accurate crank angle measurement. Rod
Mechanical Looseness
Management Solution
Excessive Crosshead
position can be captured at the same point in the piston
API-618 (Fourth Ed.)
Protection Solution
rod stroke, and cylinder volume can be computed
Worn Rider Bands
Cylinder Vibration
(piston, liner, piston rod)
Slipper Clearance
Liquid Ingestion
precisely at each point in the stroke for highly accurate
Rod Load Faults
(loss of lubrication)
P-V curves.
Bushing/Pin
& Seizures
3500 Monitor: 3500/61 6-Channel
Crosshead Shoe Temperature
Continuous monitoring of crosshead shoe (slipper)
or 3500/65 16-Channel
temperature provides useful information on developing
Temperature Monitor Frame Vibration
slipper problems such as overload, fatigue, and
Transducer: RTD or Thermocouple
insufficient lubrication.
Main Bearing Temperature
Crosshead Acceleration
3500 Monitor: 3500/61 6-Channel
Pressure Packing Case Temperature
Continuous monitoring of pressure packing
or 3500/65 16-Channel
temperature provides useful information on
Multi-Event-Per-Revolution Keyphasor® Signal
Temperature Monitor
Transducer: RTD or Thermocouple developing problems related to the packing,
including excessive wear, insufficient cooling, Cylinder Pressure
and inadequate lubrication.
Combined Rod Load3
Cylinder Pressure Profile MEASUREMENT Piston Rod Position
3500 Monitor: 3500/77M 4-Channel
The single most effective way of determining the
Cylinder Pressure Monitor overall health of a reciprocating gas compressor is Hyper Plunger Position
Transducer: 165855 Cylinder by examining the cylinder pressure profile. Online
Pressure Transducer access to the internal pressure for each compressor
Suction Valve Temperature
cylinder enables continuous monitoring of cylinder
pressures, compression ratios, peak rod loads, and
rod reversal. This provides valuable information on the Discharge Valve Temperature
condition of suction valves, discharge valves, piston
rings, packing glands, and crosshead pin. And,
Pressure Packing Case Temperature
interfacing the 3500 System with System 1 ® software
provides valuable diagnostic plots such as Pressure
versus Volume (P-V), Log P versus Log V, and pressure Crosshead Shoe Temperature
versus crank angle.
Suction Gas Temperature
Discharge Gas Temperature
3500 Monitor: 3500/61 6-Channel
Suction Gas Temperature
Continuous monitoring of suction gas temperature
or 3500/65 16-Channel Online Gas Analyser Data Input
provides a useful baseline against which to compare
Temperature Monitor
Transducer: RTD or Thermocouple suction valve temperature. Relative changes in the
temperature between suction valves and suction gas Trending & Analysis Software
can give an indication of the worn suction valves.
In addition, suction gas temperature, combined with
the integrated equation of state engine in System 1 ® 1 All of the measurements marked in each column are highly recommended to detect the malfunction.
The red-marked I measurements are recommended for auto-shutdown machinery protection.
software, provides the information necessary to
2
calculate capacity at suction conditions and cylinder
flow balance numbers. 3 Combined rod load shares the sensors of cylinder pressure but is used for specific malfunction and protection functions.
4
6. At the heart of our Recip Monitoring Solution is the Bently Nevada™
3500 Series Machinery Protection System...
Integrated Machinery All monitor modules are New capabilities for assessing 6- or 16-channel temperature mon
Protection and totally software configurable piston rod vibration and position variety of RTDs or thermocouples.
via the 3500’s Rack Interface at precisely defined crank angles differential alarming capabilities allo
Machinery Management Module—key lockable to for repeatable, useful information to be used for valve temperatures,
prevent unauthorized on rider band wear, rod bow, process temperatures, bearing tem
Our powerful 3500/22M TDI Rack Interface • Fully compliant with the requirements of tampering. and other conditions. Also crosshead shoe (slipper) temperatu
Module eliminates the need for bulky external American Petroleum Institute (API) Standard applicable to hypercompressors packing case temperatures, and a
using plungers instead of other machinery or process tempe
data acquisition hardware or special interface 670 for Machinery Protection Systems and
conventional pistons. measurements.
modules between the monitor rack and Standard 618 for Reciprocating Compressors.
software. Simply plug an Ethernet cable
• Available in 19” 14-slot EIA rack or space-
into the 3500/22M and you’re ready to Keyphasor® module accepts
saving 12” 7-slot mini-rack. multi-event-per-turn signals for
communicate with our powerful System 1®
greater accuracy—required
software for advanced diagnostics, condition • Available with a variety of high-quality display for reciprocating compressor
options ranging from self-configuring VGA applications where crank angle
monitoring, and other plant asset management
must be precisely determined.
functionality. The result is a zero-footprint touch screens to remote workstations to LCD
solution requiring absolutely no additional panels that mount directly on the rack face.
rack or cabinet space when augmenting • Monitor modules available with 4-20 mA Highly reliable power supplies
your basic machinery protection system recorder output signals for interfacing with accept worldwide AC/DC
with System 1® connectivity. voltages/frequencies and can
strip chart recorders and other analog based be ordered as fully redundant
control and automation equipment. to assure uninterrupted
And, the enhanced data collection technology performance.
of our 3500/22M TDI allows earlier and
improved diagnosis of previously difficult-to-
ascertain transient events (such as cylinder
liquid ingestion). Single-cable Ethernet
connectivity to our System 1®
software for advanced
diagnostics and condition
monitoring functionality.
Powerful cylinder pressure A variety of relay modules are avai
measurements now available for actuation upon user-configura
for the most complete picture alarm and status events. Relays are
of reciprocating compressor reliable and intended for connectin
health. Dynamic P-V curves, monitoring system to external annun
rod reversal measurements, and machinery control systems fo
and much more. auto-shutdown.
5
7. Cylinder Pressure
Where the Action Is.
The single most important measurement for condition monitoring of reciprocating compressors
nitors accept a Special-purpose 4-channel vibration modules are
is cylinder pressure. Armed with accurate cylinder pressure at each point in the piston’s stroke, a
Absolute and designed to address the casing vibration and
w the monitors crosshead acceleration measurement requirements Pressure-Volume (PV) curve can be constructed that provides indispensable information on your
gas or other unique to reciprocating compressors by providing machine’s health.
mperatures, reliable machinery protection without false or
ures, pressure missed alarms. Filtering, alarm delay, full-scale
variety of range, transducer input type, and a host of other That’s why we’ve given particular attention to this vital measurement. With a robust sensor,
rature options are fully software configurable on a advanced signal processing functionality in our 3500/77M Recip Cylinder Pressure Monitor, and a
per-channel basis.
suite of graphical plots in System 1® software specifically for analyzing cylinder conditions, there’s
simply no better way to get inside your cylinders—where the action is.
Generic 4-channel vibration modules Historically, measuring these conditions meant temporarily attaching transducers to indicator
accept velocity, acceleration, and valves on each cylinder. Although cumbersome, this practice was necessary because pressure
proximity transducers. Filtering, alarm
delay, full-scale range, transducer transducers simply couldn’t survive under long-term exposure to the harsh environment of cylinder
input type, and a host of other options chambers. We knew that the key to reliable and effective assessment of machinery health—not
are fully software configurable on a
per-channel basis. Used for a variety
to mention convenience—was to design a sensor that could endure 24/7 exposure to such an
of measurements on the recip’s environment, eliminating the burden of constantly connecting and disconnecting every time you
prime mover.
wanted data. With our all-new Bently NevadaTM 165855 Cylinder Pressure Transducer, we’ve done
just that. It provides continuous static and dynamic pressure data and is specifically designed for
use with our 3500/77M Recip Cylinder Pressure Monitor. Innovative materials and construction
techniques† allow it to deliver reliable measurements in the extreme temperatures, pressure
cycling, and harsh chemical environments (such as H2S) inherent in reciprocating compressor
cylinder applications.
Available in a variety of pressure ranges from 100
psia to 10,000 psia, the 165855 has undergone
extensive testing. In fact, we’re so confident of its
performance that we offer something unique to
ilable the industry: a 3-year warranty.
Fully digital communications of all monitored
able parameters and statuses using a variety of
highly industry-standard protocols—ideal for
ng the connection to process and machine control
nciators systems rather than using analog (4-20
or mA) outputs. Supports time-stamping of
alarms and clock synchronization.
†
U.S. Patent 6,955,090
6