ER-56.

07 ECN: 201800258 VER: 18 - 4-2-18

Instrumentation
Packagers must provide safety shutdowns, controls, and instrumentation to ensure the compressor system
operates within published Ariel limits. The use of “alarm” instead of “shutdown” for any minimum
instrumentation requirement may result in equipment damage. Additional information for control and
instrumentation may be found in the appropriate Ariel Maintenance and Repair Manual.
NOTE: Ariel recommends the use of shipboard or armored cabling as opposed to wiring in
conduit to minimize nuisance shutdowns due to wire chafing and shorts. Cable in cable trays
also facilitates maintenance access.

CAUTION: DO NOT drill holes in cylinders or other pressure containing components for any
purpose. Epoxy-mounted clamps (to bare metal) for wiring and tubing are a suitable
alternative. See Ariel ER-89.10.

TABLE  1 Required Instrumentation Summary

INSTRUMENT SUPPLIER SETTING/REQUIREMENT

Frame Oil System (see ER-56.06)

Oil Pressure Packager

l Start Permissive with Prelube Pump 30 psig (2.1 barg) for 2 minutes

l Run Permissive 45 psig (3.1 barg) within 10 seconds of start

l Alarm 50 psig (3.4 barg)

l Shutdown 45 psig (3.1 barg)

Oil Filter Differential Ariel

l JG:A:M:P:N:Q:R:J:H: E, KB100, Change at 10 psi (0.7 bar) or 4000 hours, whichever occurs first.
JGK:T/2/4, KBK:T/2/4, JGC:D:F/2
l JGC:D:F/4/6, JGK:T/6, KBK:T/6, Change at 15 psi (1.0 bar) or 4000 hours, whichever occurs first.
KBB:V:Z:U

Oil Temperature Packager

l Minimum, to start up or to load See ER-56.06 for max. oil viscosity based on frame size.

l Minimum, operating 150°F (66°C)

l Maximum, shutdown 190°F (88°C)

Crankcase Level Packager 1/2 to 2/3 sight glass level

l Low Level Shutdown 1/4 sight glass level

Main Bearing Temp. Ariel Standard on B:V:Z:U. Recommended, but optional on

JG:A:R:J:H:E:K:T:C:D:F & KBK:T.

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 INSTRUMENT SUPPLIER SETTING/REQUIREMENT

Thrust Bearing Temp. Ariel Standard on B:V, optional on JGC:D:F:Z:U and KBZ:U.

l Alarm +20°F (11°C) above normal not to exceed 220°F (104°C)

l Shutdown +30°F (17°C) above normal not to exceed 230°F (110°C)

l Differential Alarm 20°F (11°C)

l Differential Shutdown 30°F (17°C)

Packing Case Temp. Ariel Optional

l Alarm +20°F (11°C) above normal

l Shutdown +30°F (17°C) above normal

Packing Case Vent Packager Optional

l Vent Flow Alarm 2 - 4 scfm (per throw)

l Vent Flow Shutdown > 4 scfm (per throw)

Scrubber Liquid Level Packager

l High Liquid Level Control

l High Liquid Level Shutdown

Gas Conditions Packager

l Inlet Temperature Indicator, each cylinder

l Inlet Pressure Indicator, each stage

l Discharge Pressure Indicator, each stage

l Discharge Temperature Indicator, each cylinder, each nozzle on dual nozzle cylinders

l High Discharge Temperature 10% above normala

Shutdown, each cylinder (Not to exceed the maximum temperatures below)

l Lubricated Cylinders 350°F (177°C)

l Non-Lube/PRC Cylinders 325°F (163°C)

l Hydrogen Rich > 50% < 0.41 Specific 300°F (149°C)

Gravity

l Air Not to exceed autoignition temperature of cylinder lubricant at

discharge pressure

l Relief Valve Setting above normal operating Up to 150: 15 to 2500: to 3500: to 5000: Over 5000:
pressure (not to exceed MAWP) psig (1.0 barg) 10% 8% 6% As agreed

See ER-56.04.

Cyl. Rod Load Protection Packager

High Vibration Shutdown Packager As close to normal level as practical. See TABLE 3.

Over Speed Packager 10% over rated speed for shutdown

a. Example: Normal Discharge Temp. = 270°F; Shutdown Setting = 270 x 1.1 = 297°F.

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Notes
1. Install the compressor frame low lube oil pressure shutdown set to stop the unit if oil pressure
downstream of the filter falls below 45 psig (3.1 barg). Compressor operation for only a few seconds
without oil pressure causes major damage. Normal oil pressure is about 60 psig (4.1 barg) at full rated
speed and normal operating temperature. The low oil pressure shutdown must activate after oil pressure
exceeds 45 psig (3.1 barg) at start-up. Ariel provides a 1/4 inch tubing fitting to connect the low lube oil
pressure shutdown and ties a tag to this connection before each compressor ships. Do not operate the
compressor for prolonged periods at less than 50 psig (3.4 barg) oil pressure.
2. Automated pre-lube systems require a start permissive to sense minimum required pressure/time at oil
gallery inlet. See ER-56.06. Unit must shut down if the system fails to achieve 45 psig (3.1 barg) oil
pressure within 10 seconds after crankshaft starts to turn.
3. Mount overhead lube oil supply tanks high enough to provide oil flow to the level control at all ambient
temperatures.
4. On multi-nozzle cylinders, Ariel strongly recommends a temperature device in both discharge nozzles.
5. Install the high lube oil inlet temperature shutdown at the filter inlet connection.
6. At a minimum, install one vibration shutdown for two and four throw frames and two for six throw frames.
Mount vibration device near the top of the frame with the sensitive axis parallel to the piston rod axis.
7. Install all safety shutdowns, controls, instrumentation, ignition systems, electrical devices, and high
temperature piping (gas discharge and engine exhaust) in accordance with good engineering practice
and applicable codes for the area classification at the end user location. Ensure compatibility of all
systems for area classification.
8. If packing vent temperature is monitored, alarm and shutdown set points should be confirmed through
vent flow rates.

Ariel Supplied End Devices

CAUTION: Any arc welding on the skid and/or associated equipment and piping can
permanently damage solid-state electronic equipment. Welding can cause immediate failure
or reduce electronic equipment life and void the warranty.

To protect electronic equipment prior to any arc welding (including repair welding),
disconnect all electrical connections including ground, and remove batteries, or completely
remove the electronic equipment from the compressor.

It is good practice to attach the welding ground clamp as close as possible to the area
where the welding will occur and to use the lowest practical welder output setting. Welding
must not cause a current flow across any compressor bearing surface, including but not
limited to crankshaft and crosshead bearing surfaces.

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Main Bearing, Thrust Bearing, and Packing Case Temperature
Sensors
Thermocouples, Type J (Iron-Constantan) or K (Chromel-Alumel) - A thermocouple is two dissimilar
conductors joined together at one end to form a sensor that produces a thermoelectric voltage as an
accurate function of temperature. Appropriate controls interpret the thermocouple voltage as temperature.

Resistance Temperature Devices (RTD) - An RTD is a sensor that

produces electrical resistance as an accurate function of temperature.
Appropriate controls interpret the electrical resistance as temperature. A
typical measurement technique sends a small constant current through
the sensor and measures voltage across the sensor with a digital
voltmeter to indicate resistance by a computer and wave-fitting
equations.
For main or thrust bearing temperature sensing, Ariel supplies dual
element, six-wire, 100 Ohm (at 0°C) RTD’s. Dual element RTD’s allow
rewiring instead of sensor replacement if an element fails. Insulate
unused wire ends from each other and conduit ground.
To simplify wiring, RTD's come with two green wires and one black for
one element, and two red wires and one white for the other. See
FIGURE 1.
A Zone 1 environment may require the installation of proper, intrinsically
FIGURE 1 Typical Dual
safe or equivalent protection to fulfill electrical requirements. Element RTD Wiring Diagram

Force Feed Lubrication System Monitoring

Ariel requires the control panel to shut down the unit if a lube distribution block stops cycling during
compressor operation. Set the shutdown to a maximum of 3 minutes. This is a class B shutdown, defined as
a shutdown unarmed until a short time (typically 2 minutes) after the compressor starts. This allows divider
blocks time to cycle the first time before the shutdown activates.
Ariel requires all force feed lubrication monitoring devices to be grounded back to the control panel earth
ground, and all unused wires to be individually isolated so they cannot contact each other or external
sources. Improper grounding and wiring can result in unreliable monitor operation, phantom shutdowns,
and premature device failure.
Ariel offers several lube system shutdown devices. See TABLE 2 for specifications on available types. For
detailed information about each device, visit the vendor literature section of www.arielcorp.com.

Shutdown Switch
The shutdown switch monitors divider block pin position and supplies a shutdown contact. If the divider block
stops cycling for a given time, the switch sends a shutdown signal to the control system.
For no flow shutdown devices, Normally Open (NO) refers to the switch state while the divider block cycles
or the unit runs. An NO switch means when the unit runs, the shutdown switch is open or non-failsafe; the
control system cannot detect damaged devices or loose or cut wires at startup and will never stop the unit. A
Normally Closed (NC) switch means when the unit runs, the shutdown switch is closed or failsafe; the
control system will detect a loose or cut wire and shutdown the unit.
Ariel recommends NC (failsafe) switches. However, when a NO (non-failsafe) switch is used, Ariel
recommends testing shutdown circuits at least once a month.

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Proximity Switch
The proximity switch senses divider block piston position and changes switch state or pulses with every
position change. This device must work with a PLC or some other counter/timer device to produce a
shutdown. Some devices open the switch when the pin is in and close when the pin is out. Others produce a
0.5 second pulse when the pin moves in and out. With pulses, the control system must sense switch cycling
and stop the unit if a block stops cycling.
When using a proximity switch, a local cycle indicator is required for local monitoring of lube cycle times.
Ariel recommends a control system set to find the time between triggered cycles when the switch transitions
from off to on. See FIGURE 2.
1. Shutdown Time with No Lubrication - Distribution block cycle times vary slightly from cycle to cycle;
12 seconds for one cycle, then 15, then 14 is normal. The recommended shutdown time is double the
design cycle time + 30 seconds, limited between 30 seconds and 3 minutes.
l Shutdown Time = (2 x design cycle time + 30 seconds)
l Find design cycle time on the compressor lube sheets or the compressor tag.
2. DE-BOUNCE and Latching Circuits - The device and control system scan time may necessitate de-
bounce hardware and/or software. Some devices include no built-in de-bounce circuits and can cause a
fast control system to double or triple count. Other times, it may be necessary to latch input to allow the
control system to detect only the first transition from low to high. This becomes significant when
displaying the cycle time for the operator to set pump flow rates and when calculating total oil through the
divider block.
3. Suggested Operator Displays
l Divider Block Cycle Time - Set lube system pumps according to recommended divider block cycle
times. A display of divider block cycle time in seconds is helpful to adjust lube pumps as they wear out,
or to set divider block cycle times at pump replacement.
l Time Since Last Pulse - It is helpful to display the timer so the operator sees it actively timing.
l Average Cycle Time - Cycle time varies a few seconds from cycle to cycle. It is sometimes helpful to
display a cycle time averaged over 5 to 10 cycles.
l Total Oil Consumed - Displays how much oil the lube system uses for accurate oil orders.
4. Sample Flow Diagram to Create Shutdown - FIGURE 2 shows one method to create a shutdown
within the PLC from a cycling digital input.

FIGURE 2 Suggested Force Feed Lube System Proximity Switch Shutdown Logic Diagram

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TABLE  2 Force Feed Lube System Monitors - Specifications

Specification Proximity Switch DNFT Programmable DNFT

Shutdown Signal NO YES YES

Proximity Signal YES YES YES

Local Data Storage NO NO Count Display

Infrared Port NO NO NO

Remote Mounting NO NO NO

Local Cycle Indicator Separate Indicator YES - LED YES - LCD & LED

De-bounce Included NO YES YES

Power N/A Battery: A-10807 Battery: A-10807

or 24 VDC or 24 VDC

Shutdown Time PLC 180 seconds Programmable

20 to 255 seconds

Area Classification CSA, IECEX, ATEX

CSA CSA 186200 (Canada): Ex d m IIC T5

CSA 186200 (US): Ex d m IIC T5, Class I, Zone 1, AEx d mb IIC T5 Gb

IECEX IECEx CSA 12.0020, Ex d mb IIC T5 Gb

ATEX II 2G SIRA 12ATEX1357, Ex d mb IIC T5 Gb

Temperature -40°F to +131°F (-40°C to +55°C)

Max. Switch Voltage 240 VDC

Max. Switch Current 10.4 mA

Max. Switch Power 2.5 VA

Vibration Protection (Packager Supplied)

Ariel requires sensors, such as a vibration switch or transmitter, to protect the equipment in the event of
excessive vibration. Adjust alarm and shutdown levels on site under normal running conditions. Below are
typical vibration levels established from field experience:
TABLE  3 Typical Vibration Levels for Ariel Reciprocating Compressors, inch/sec (mm/s)

Package JG:A:M:P:N:Q:R:W, JGJ:H:E:K:T, JGC:D:F:B:V:Z:U,

Components KB100 KBK:T KBB:V:Z:U

Skid <0.10 (<2.5) <0.15 (<3.8) <0.20 (<5.1)

Compressor Frame <0.20 (<5.1) <0.40 (<10) <0.50 (<13)

Compressor Cylinder <0.45 (<11) <0.80 (<20) <1.0 (<25)

Tandem Cylinder <0.70 (<18) <1.0 (<25) <1.0 (<25)

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1. Ariel does not provide vibration limits for skid piping, bottles, or scrubbers.
2. Table does not apply to JGI - vertical non-balanced compressors.
3. These figures apply to balanced opposed reciprocating compressors. They are measured in terms of
velocity, inches per second (mm/s), in zero to peak values, band filtered from 10 to 250 Hz. The values
are guidelines only. In general, if vibration levels fall below those in TABLE 3, stress levels are well below
equipment fatigue stress limit.
4. Analyze levels exceeding TABLE 3 values to determine the cause. A spectral vibration analysis should
be performed by a qualified vibration specialist.

The following devices are acceptable for use on Ariel equipment.

Vibration Switch
Ariel requires installation of an inertial or electronic vibration switch with the sensitive axis in the piston rod
direction. A minimum of 2 switches are recommended for six throw machines. Switches are not required if
transducers are utilized.

Velocity Transducers
For frames over 500 HP, Ariel recommends velocity transducers (or accelerometer transducers integrated
to a velocity measure) from a 10-250 Hz bandwidth, measured in peak or RMS converted to peak levels.
Mount velocity transducers perpendicular to the crankshaft at the crankshaft centerline elevation. A single
transducer on the drive end is adequate on 2-throw and 4-throw machines. Six-throw frames require one
transducer on the drive end and one on the auxiliary end. Many Ariel frames now have machined bosses for
easy and solid connection. TABLE 3 guidelines can be applied to these readings. The packager may set
these levels as initial alarms in the shop, but must reduce them to more conservative protection levels after
achieving normal operation.
Load changes from pneumatic clearance pockets or HE unloader actuation may cause intermittent high
vibration levels that can cause nuisance shutdowns. If this is problematic, a 1-second delay to ensure the
vibration is not a transient condition is acceptable. Other more complicated methods in control logic can
prevent these nuisance shutdowns as well.

Accelerometer Transducers
Acceleration measurement on the frame or crosshead guides is sometimes a preferred method and
acceptable as a secondary method of protection. Typically, acceleration is measured with a high sample rate
over a wide bandwidth to quantify impact levels for protection. The many factors associated with this
measurement (sensor resonance, sample rate, mounting, structure resonance), prohibit Ariel from
providing predetermined amplitude limits. Set shutdown and alarms for these devices to a practical level
above normal after normal operation is achieved. Given the variability of acceleration responses, shutdown
and alarms (as a percentage of normal operation) may vary with application. These measurements can also
be sensitive to unloader and pocket activation.

Impact Sensors
Use of crosshead guide impact sensors or accelerometers is optional. Impact sensors monitor and count
peak G levels over a set threshold for a certain number of revolutions, and report the count to the panel,
usually in a 4-20mA current loop. They are typically mounted in the vertical direction on the crosshead guide
or in the horizontal direction on the frame and are acceptable as a second level of protection.
On high speed separable compressors, crosshead guides have a fairly high impact response in the vertical
direction due to normal rod reversals. Sometimes a normal machine response can saturate impact sensor

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electronics and cause nuisance alarms and shutdowns. Mount impact sensors on a machined surface. If a
mounting location is not already available, these sensors can be mounted on the lifting eye machined
surface. If a different location is preferred, drill, tap, and spot face the mounting hole. It is critical to drill the
hole straight so the sensor sits flat on the machine.
Mounting sensors on the frame in the horizontal direction at centerline elevation is also acceptable as a
second level of protection. Impact responses from looseness and debris transmit to the sensor effectively in
this location. For frame mounting, use the machined frame bosses if possible. One impact sensor per each
pair of throws or in between throws offers adequate protection. Drill, tap, and spot face mounting hole. It is
critical to drill the hole straight so the sensor sits flat on the machine.
Impact sensors must be selected based on the intended operating speed of the compressor. Impact sensors
require field tuning with a calibration tool. Consult manufacturer instructions for adjustment. Typical settings:
time the reset level to capture approximately 16 revolutions at normal operating speed. Set the threshold to
1.25 to 3 times the normal baseline level depending on how unit load changes affect sensor response.

The contents of this document are proprietary and confidential. They are the property of Ariel Corporation and may
not be disclosed, reproduced, or used for manufacture in part or in whole without written permission from Ariel
Corporation.

DATE: VER: ECN: DESCRIPTION:

4-2-18 18 201800258 Page 1, Table 1: “JG:A:M:P:N:Q:R:J:H: E, KB100, JGK:T/2/4, KBK:T/2/4,

JGC:D:F/2” was “JG:A:M:P:N:Q:R:J:H: E:K:T & JGC:D:F/2”, “JGC:D:F/4/6,
JGK:T/6, KBK:T/6, KBB:V:Z:U” was “JGC:D:F/4/6, JGK:T/6, & KBB:V:Z:U”,
“Minimum, to start up or to load” was “Minimum, start up”, deleted row
“Minimum, to load”, “JG:A:R:J:H:E:K:T:C:D:F & KBK:T” was
“JG:A:R:J:H:E:K:T:C:D:F”. Page 6, Table 3: “JG:A:M:P:N:Q:R:W, KB100”
was “JG:A:M:P:N:Q:R:W“, “JGJ:H:E:K:T, KBK:T” was “JGJ:H:E:K:T”.

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