Liquid Controls Optical Air Eliminator

How the Optical Air Eliminator Works

A solenoid valve, located at the top of the air eliminator, is either open or closed. When the liquid level is below the optical sensor, and a delivery is initiated, the solenoid valve opens and vents air and vapor to atmospheric pressure. Simultaneously, a solenoid-actuated control valve (e.g., A2982-11 or A2848-11) closes at the meter outlet.

When liquid rises to the optical sensor level as air is exhausted, the optical air eliminator solenoid valve closes, preventing further venting. At the same instant, the control valve at the meter outlet opens, allowing delivery to begin or continue. This ensures only liquid passes through the meter for measurement.

As long as a delivery is active and the liquid level remains at or above the optical sensor, the air eliminator solenoid valve stays closed and the control valve remains open. If the liquid level drops below the optical sensor, the air eliminator solenoid valve opens and the control valve closes. When the delivery is complete, the control valve closes, and a delivery ticket is printed. The air eliminator solenoid valve is inactive between deliveries, remaining closed.

Figure 1: Liquid Level below Optical Sensor. Shows the solenoid valve open, venting air/vapor, while the control valve is closed.

Figure 2: Liquid Level at or above Optical Sensor. Shows the solenoid valve closed, and the control valve open, allowing liquid flow.

Cutaway views show the vent port through the solenoid valve, designed to optimize air and vapor venting. When liquid is below the sensor, the S3 solenoid valve is open (Figure 4). When liquid is at or above the sensor, the S3 solenoid valve closes the vent path (Figure 5).

The diagram in Figure 6 illustrates the LectroCount register logic for a preset delivery. Proper function requires the optical air eliminator to be used with a solenoid-actuated control valve at the meter outlet (e.g., A2982-11 or A2848-11).

Figure 6: Optical Air Eliminator operating sequence. Depicts the timing of solenoid valve states (Solenoid 3 for air eliminator, Solenoid 1 & 2 for control valve) relative to optical sensor level and product flow (No Flow, Full Flow, Dwell Flow) during delivery initiation, active delivery, and end of delivery.

General

• Environmental Rating: NEMA 4X
• Safety: Designed to meet Class I, Division 2 requirements
• Temperature Rating: -40° to 160°F (-40° to 71°C)

Materials of Construction

• Class 1: Body: Aluminum, Solenoid: Brass
• Class 2: Body: Anodized Aluminum, Solenoid: Stainless Steel

Pressure Rating

• Maximum non-shock working pressure: 150 PSI (10.3 BAR)
• Maximum differential pressure: 100 PSI (6.9 BAR)

Products

• Class 1 Refined Fuels: Gasoline, Gasohol, Diesel fuel, and Fuel Oil
• Class 2 Aviation: Av-Gas and Jet Fuel

Solenoid (S3)

• Voltage: +12 (± 2)VDC
• Optional Voltage: +24 (± 4)VDC
• Current: 1A maximum

Optical Sensor

• Voltage: +10 to +28VDC
• Current: 0.5A maximum

General Information

The Liquid Controls Optical Air Eliminator is designed for use with LectroCount® Electronic Registers. An optical sensor, installed in the wall of the air eliminator housing, monitors the liquid level. The presence or absence of liquid at the sensor level activates or deactivates a solenoid valve at the top of the air eliminator to vent air or vapor from the system.

It is designed to work with Liquid Controls M5, M7, M10, M15, and M25 meters for measuring refined petroleum products. It shares mounting dimensions with mechanical air eliminators, requiring no plumbing changes for retrofits. However, electronic registers require CPU board part number 81920 for LCR and LCR-II, or part number 81924 for LC³. A solenoid-operated control valve (e.g., E-7 or A2848-11) on the meter's outlet side is also required.

Class 2

The Class 2 optical air eliminator (Part #A8981A) is manufactured for aviation applications and features an anodized aluminum housing and a stainless steel solenoid valve.

New Installations

When ordered with a new meter, the optical air eliminator is mounted atop a strainer on the meter's inlet side. An example configuration includes a high-capacity strainer, two-stage valve, and LectroCount LCR-II® Electronic Register.

A vent line must be connected from the optical air eliminator's output port. This connection is 1/2" NPT and must lead to an appropriate receptacle, such as an overflow tank on a truck.

The optical air eliminator solenoid valve and optical sensor are supplied pre-wired to the LectroCount Electronic Register.

Figure 7: New Assembly. Shows the optical air eliminator mounted on a meter assembly with a LectroCount LCR-II register and a 1/2" NPT vent port.

Retrofit Installations

Adding an optical air eliminator to an existing configuration may require modifications to vent piping, the outlet valve, or the register.

Required components for operation include:

• LectroCount LCR/LCR-II Electronic Register with internal CPU board Part Number 81920, or LC³ with CPU board Part Number 81924.
• Electronically-controlled outlet valve such as the A2982-11 or A2848-11.

Refer to the accompanying manuals for proper installation and configuration of these items.

[Warning] Before disassembly of any meter or accessory component, ALL INTERNAL PRESSURES MUST BE RELIEVED AND ALL LIQUID DRAINED FROM THE SYSTEM IN ACCORDANCE WITH ALL APPLICABLE PROCEDURES. Pressure must be 0 (zero) psi. Close all liquid and vapor lines between the meter and liquid source. Failure to follow this warning could result in property damage, personal injury, or death from fire and/or explosion, or other hazards that may be associated with this type of equipment.

Steps for Retrofit Installation (using Hi-Cap strainer/air eliminator):

1. Step 1 - Remove Old Air Eliminator and Baffle Cup: After relieving internal pressure and draining liquid, remove the four bolts and washers securing the old air eliminator to the strainer. Inspect and replace the O-ring if necessary. Figure 8: Shows removal of the old air eliminator.
2. Step 2 - Mount the Optical Air Eliminator: Fasten the optical air eliminator to the strainer/air eliminator in one of four 90° rotational increments, selecting the best orientation for wiring and vent piping. Use the four bolts and washers provided. Tighten bolts to a torque of 27 lbf-ft (37 Nm). Figure 9: Shows orienting the optical air eliminator.
3. Step 3 - Connect the Vent Piping/Tubing: This connection uses a 1/2" NPT port. Remove the pipe thread protector and connect the piping/tubing to the vent port. This typically connects directly to an overflow tank on a truck. Figure 10: Shows fastening the optical air eliminator.
4. Step 4 - Wire the Solenoid and Sensor to the Register: Wiring instructions begin on Page 9.

Dimensions

Front View: Overall dimensions shown, including 8.97" width and 8.75" height. Features three 1/4"-18 NPT pressure gauge ports.

Side View: Overall dimensions shown, including 1" depth and 9.5" height. Features a 1/2"-14 NPT exhaust port.

Bottom View: Overall dimensions shown, including 3.94" diameter. Shows mounting bolt pattern.

Optical Air Eliminator with High Capacity Strainer: Shows combined unit dimensions, approximately 23.7" height and 23.3" depth.

Dimensions shown are not for construction use. Consult the factory for certified Engineering Drawings.

Wiring

The optical air eliminator requires a LectroCount LCR/LCR-II Electronic Register with CPU board part number 81920, or LC³ with part number 81924. If the register does not have the correct CPU board, it must be ordered as a replacement.

The 81920 CPU board uses connector J15; the LC³ 81924 CPU board uses connector J11.

The optical sensor comes with a 24" cable, potted at one end. A threaded cord grip fastens the other end into the register. The solenoid requires a 12 AWG, two-wire, braided cable, approximately 24 to 36" long.

Steps for Wiring:

1. Step 1 - Remove Cable Plug: Loosen and remove the screw from the S3 solenoid valve cable plug cover. Remove the plug from the solenoid coil. Remove the cover from the cable plug housing and then the terminal block. Note its orientation. Leave the gasket on the coil.
2. Step 2 - Connect Cable to Cable Plug: Route one end of the cable through the conduit fitting into the cable plug housing. Connect wires to the terminal block: BLACK wire to Terminal 2, RED wire to Terminal 1 (indicators are marked).

[Caution] Incorrect wiring can damage the optical sensor.

[Warning] For North American Installations, installation must comply with the National Electrical Code (US) or Canadian Electrical Code to maintain hazardous location ratings. This may involve using rigid conduit.

3. Step 3 - Reassemble Cable Plug: Reinstall the terminal block into the cable plug housing in its original orientation. Tighten the strain relief strap with two screws. Tighten the cable gland to seal around the cable. Reconnect the cable plug to the coil. Fasten the cover with the screw to a torque of 8.8 in-lbs (1 Nm).
4. Step 4 - Connect to LectroCount Electronic Register: Route cables from the optical sensor and solenoid valve to the back of the register. Connect them to two open ports using the appropriate connectors.

LCR-II Connections:

Connect wires to terminal block J15 on the LectroCount CPU board. Refer to Figure 11a for clarification.

Figure 11a: LCR-II to Optical Air Eliminator Wiring. Shows connections to the internal LCR-II 81920 Board, Optical Sensor, and Solenoid Connector Block via J15.

LC³ Connections:

Connect wires to terminal block J11 on the LectroCount CPU board. Refer to Figure 11b for clarification.

Figure 11b: LC³ to Optical Air Eliminator Wiring. Shows connections to the internal LC³ 81924 Board, Optical Sensor, and Solenoid Connector Block via J11.

Tools Required:

• Flat blade screwdriver
• 14mm box end or open end wrench

Disassembling

The optical air eliminator consists of a housing, optical sensor, and control solenoid valve. Only the solenoid valve is serviceable. If any part of the solenoid is damaged, a new solenoid assembly (Part Number 502011) must be ordered. The optical sensor has no serviceable parts as its internal components are potted; if it fails, the complete assembly (Part Number 81947) must be replaced.

1. Step 1: Loosen the thin hex nut holding the solenoid in place using a 14mm wrench. Remove the nut and coil from the armature guide post.
2. Step 2: Remove the plastic bonnet from the armature guide post. This should be easy to remove without tools.
3. Step 3: Using a screwdriver, loosen the upper left and lower right screws of the valve body. These two screws hold the valve body in place. The upper right and lower left screws fasten the armature guide post and valve body together. Remove the valve body from the optical air eliminator housing.
4. Step 4: Place the valve body on a flat surface. Using a flat blade screwdriver, remove the two screws holding the armature guide post and valve body together. Lift the armature guide post off the valve body. The internal components are a plunger and a spring. Inspect the spring for damage.
5. Step 5: The armature guide post is composed of four components: two O-rings, the guide post, and the flange. Inspect these components for damage. Image shows an armature guide post with O-rings highlighted.
6. Step 6: The valve body has two O-rings on the face that mates with the housing. These O-rings are identical. Inspect them for damage. Inspect the ports for blockage. Image shows the valve body face with O-rings highlighted.

Reassembling

1. Step 1: Place the spring inside the plunger and insert the plunger, spring end first, into the armature guide post. Place the armature guide post assembly onto the valve body. Fasten the armature guide post to the valve body using the two screws removed earlier. Ensure screws are inserted into the threaded holes. Note the number stamped on the valve body; this is crucial for proper orientation.
2. Step 2: Align the solenoid valve body so the stamped number faces the housing assembly. The valve body can be fastened in two orientations, but only one is correct.

   [Important] If the stamped numbers face away from the housing, the optical air eliminator will not function properly, the port will be blocked, and the air eliminator will fail.

   With the correct orientation, fasten the valve body to the housing using the two screws. Tighten to a torque of 15 to 18 in-lbs (1.7 to 2.0 Nm).
3. Step 3: Place the plastic bonnet over the valve body and snap it into place.
4. Step 4: Place the coil over the armature guide post and fasten with the thin hex nut. Tighten the nut with a 14mm wrench to a torque of 4.5 in-lbs (0.5 Nm).

Optical Sensor Replacement

If the optical sensor needs replacement, use a 1" open end wrench to remove it from the housing. When installing a new sensor, do not exceed a torque of 75 in-lbs (8.5 Nm) to avoid damage.

A light coating of grease or anti-seize lubricant should be applied to the sensor's threads before assembly.

Troubleshooting

PROBLEM: Excessive liquid flowing out of vent to spit tank.

Scenario 1: Solenoid not closing.

• Check S3 solenoid wiring.
• Measure resistance across S3 solenoid. Value should be approximately 15 Ω. If not, replace S3 solenoid.
• Inspect S3 solenoid for blockage. Refer to disassembly instructions.
• LectroCount CPU failure. Replace CPU board.

Scenario 2: Optical Sensor not functioning.

• Check optical sensor wiring.
• Measure resistance between the RED and WHITE wires. Value should be approximately 10kΩ. If not, replace optical sensor.
• LectroCount CPU failure. Replace CPU board.

PROBLEM: No liquid flowing through meter during delivery.

Scenario 1: Liquid level not rising in optical air eliminator.

• Check S3 solenoid. It may not be opening to allow air/vapor to vent.
• Check S3 solenoid wiring.
• Measure resistance across S3 solenoid. Value should be approximately 15 Ω. If not, replace S3 solenoid.
• Inspect S3 solenoid for blockage. Refer to disassembly instructions.
• LectroCount CPU failure. Replace CPU board.

Scenario 2: Meter outlet valve not opening.

• Check wiring of the outlet valve S1 solenoid.
• Measure resistance across S1 solenoid. Value should be approximately 15 Ω. If not, replace S1 solenoid.
• Inspect S1 solenoid for blockage. Refer to the manual which accompanies the valve.
• LectroCount CPU failure. Replace CPU board.