149625020 Instrumentation Bently Nevada

GE Measurement & Control

Reciprocating Compressor Cylinder Pressure Patterns Instrumentation Layout

Components and Nomenclature

™

Bently Nevada™Asset Condition Monitoring Multi-Event Wheel Timing Details

Cylinder Pressure Installation Details Isolation Valve (should not induce channel resonance reference GER-4273)

Suction Valve Cage 1. Drill and tap three 3/8-24 UNF 2B thread 1.00 in. deep 120 degrees apart on 3.00-inch diameter bolt circle.

Suction Valve

3. Slide the recip multi-event wheel over the guiding stud and align the falling edge of the divided notch with the Keyphasor. The second narrow notch should trail the first one in the direction of rotation. Loosely install 3/8 – 24 bolts to hold the wheel in place. 3

Cooling Water

Main Bearings Crankshaft Crankpin Bearings

Crosshead

Connecting Rod Bearing Temperature

4. You can precisely align the edge by measuring the voltage from the Keyphasor probe-proximitor combination when the probe is located over the notch, and then when it is over the protrusion. Rotate the wheel to obtain the minimum negative Keyphasor voltage over the protrusion and record this value.

5. Rotate the wheel to obtain the maximum negative Keyphasor voltage over the notch and record this value. Average the two voltage values to get the precise edge value.

6. Rotate the wheel back to the edge. When the Keyphasor output equals the calculated halfway value, secure the wheel into place Typical Pressure Versus Displaced Volume

2

Discharge Temperature

A pressure transducer installation suffering from channel resonance will show pressure fluctuations when the suction and discharge valves are closed as well as when the valves are opened. The frequency of this resonance remains nominally constant throughout the cycle.

2

2

Main Bearing Temperature 1

1

1

Single-Event Keyphasor® System

Cylinder Head (Outer End or Head End)

Valve Cover

Crosshead Pin Bushing

Suction Temperature

A

API-618 (Fifth Ed.) Protection Solution

Multi-Event Keyphasor® System

1. 2.

Management Solution

1. 2.

Direction of rotation Minimum negative voltage output

Direction of rotation Maximum negative output voltage

1.

Direction of rotation

2.

Keyphasor output equals halfway value Channel Resonance on Pressure Versus Displaced Volume Curve

Leak to High Pressure Side (discharge valves) Red is Theoretical Pressure Curve Black is Indicated Pressure Curve

Pressure Versus Volume

Log Pressure Versus Log Volume

Pressure Versus Volume

Red is Theoretical Pressure Curve Black is Indicated Pressure Curve

Log Pressure Versus Log Volume

Inter-Chamber Leak (usually piston rings)

Red is Crank End Theoretical Pressure Curve Black is Crank End Indicated Pressure Curve Green is Head End Theoretical Pressure Curve Blue is Head End Indicated Pressure Curve

Pressure Versus Volume

Log Pressure Versus Log Volume

Reciprocating Compressor Operating Cycle Pressure Operated Valves

Mechanically Operated Valves P2

P1

Rounded Heel

2

1

2

1

2

1

2

1

2

1

Stroke

Indicated pressure falls slower than theoretical on expansion stroke (if theoretical curve uses cylinder nameplate clearance).

Indicated pressure compression and expansion strokes not parallel in log-log format.

Indicated pressure rises faster than theoretical on compression stroke.

VOLUME OUTLET

INLET

Indicated pressure compression and expansion strokes not parallel in log-log format.

P2 PRESSURE

Indicated pressure falls faster than theoretical on expansion stroke (if theoretical curve uses cylinder nameplate clearance). Indicated pressure rises slower than theoretical on compression stroke.

CLEARANCE VOLUME

Leak to Low Pressure Side (often suction valves)

Indicated pressure crosses theoretical pressure (both chambers)

Rounded Toe

P1

3

CLEARANCE VOLUME

Crosshead Pin

2. Install the guiding stud of the recip multi-event wheel.

Direction of rotation Falling edge Divided notch Trailing narrow notch

A typical indicated cylinder pressure curve will have some pressure fluctuation when the suction and discharge valves are opened. The areas labelled “A” and indicated by braces show these pressure fluctuations. When the valves are closed, the pressure shows a smooth line.

PRESSURE

Lubricating Passage

Cylinder Valve Temperature

A

A 1. 2. 3. 4.

Recip Mulit-Event Wheel Kit (Part No. 146973-01)

Cylinder Acceleration

Chamber (Frame End or Crank End) Piston Piston Rings Wear Bands (Rider Rings) Chamber (Outer End or Head End) Discharge Valve Discharge Valve Cage

120°

1

Cylinder Pressure

Piston Rod Distance Piece Intermediate Partition Packing Pressure Packing Case Cylinder Head (Frame End or Crank End)

4

Mechanical Bracing To Protect Cylinder Pressure Transducer

Recip Multi-Event Wheel (Part No. 145732-01) Recip Multi-Event Stud and Pilot (Part No. 146622-01)

Packing Vent Temperature

2

3/8-24 UNF 2B 25.4mm (1.00 in.) deep 3 places 120°

Crosshead Vibration

Piston Rod Locknut Oil Wiper Packing

Crosshead Shoe

Frame Vibration

Packing Case Temperature

Connecting Rod Crosshead Pin

Crosshead Assembly Nomenclature Connecting Rod

Rod Position

Cylinder

Frame

38.1 mm (1.500 in.) radius

Cylinder Pressure Transducer (-/+ 0.5% accuracy for 1+ billion cycles)

Stroke VOLUME OUTLET

Inter-Chamber Leak

P2

P1

Supporting Evidence

Supporting Evidence

Supporting Evidence

• Is flow balance greater than 1.05? • Does the trend of a particular suction valve temperature indicate a rise compared to the other suction valve covers? • Does valve cover acceleration/ultrasonic show high amplitude when suction valves are closed?

• Is flow balance less than 0.95? • Does the trend of a discharge valve temperature indicate a rise compared to the other discharge valve covers? • Does valve cover acceleration/ultrasonic show high amplitude when discharge vavles are closed?

• Is flow balance on both chambers greater than 1.05? • Is discharge temperature elevated compared to adiabatic discharge temperature? • Does acceleration/ultrasonic show high amplitudes when chamber pressures different and low amplitudes when chamber pressures are equal?

Historical Historical

440

The shortest distance, measured in degrees of crank revolution, between each change in sign of force in the combined rod-loading curve.

10k lbf/div

Maximum Allowable Continuous Gas Load (MACGL)

Rod Reversal

Cylinder pressure when the piston is at bottom-dead-center for head-end chamber or at top-dead-center for crank-end chamber.

-61794.3 lbf (-274875 N) 0 Degrees

100

A value determined by the OEM based on the design limits of the static components (frame, distance piece, cylinder, and bolting).

VOLUME

220

50

0

0

-50

-220

Rod Reversal

-440

-100

Minimum Pressure Smallest indicated pressure value that occurs over the entire pressure-volume cycle.

Indicated Discharge Pressure (Heel Pressure)

Maximum Pressure

Cylinder pressure when the piston is at top-dead-center for head-end chamber or at bottom-dead-center for crank-end chamber.

Largest indicated pressure value that occurs over the entire pressure-volume curve cycle.

Compression Ratio Indicated discharge pressure divided by the indicated suction pressure.

Maximum Pressure

P1

CLEARANCE VOLUME

INLET

PRESSURE

Indicated Suction Pressure (Toe Pressure)

-105746.2 lbf (-470382.5 N) 0 Degrees MACHINE SPEED: 276 rpm 43951.9 lbf (195508 N) 0 Degrees

3

OUTLET

4

3

5 Stroke VOLUME

Indicated Discharge Pressure

OUTLET

INLET

P2 PRESSURE

Historical

TDC

INDICATED PRESSURE

Synch From 29APR2003 12:36:39 To 29APR2003 12:36:39

10k N/div

A value determined by the Original Equipment Manufacturer (OEM) based on design limits of the various components in the compressor frame and the running gear (bearings, crankshaft, connecting rod, crosshead assembly, zpiston rod, piston assembly).

Gas Force Crank Angle Compressor Train Inertial Load Crank Angle Compressor Train Combined Force Crank Angle Compressor Train TDC

4

Stroke

P2

Maximum Allowable Continuous Combined Rod Load (MACCRL)

CLEARANCE VOLUME

INLET

Minimum Pressure Indicated Suction Pressure

P1

CLEARANCE VOLUME

Leak from High Pressure Reservoir (crank end shown, head end similar)

PRESSURE

Leak to Low Pressure Reservoir (crank end shown, head end similar)

4

3

5 Stroke VOLUME

OUTLET

INLET 0

100

200 20 Degrees/div Crank Angle

300

5 %/div Displaced Volume

For more information visit www.bentlyrecip.com or www.bntechsupport.com or call (775) 215-1818 Bently Nevada, Keyphasor and System 1 are trademarks of General Electric Company. Copyright © 2012 General Electric Company. All rights reserved.