RELIEVING INTERNAL PRESSURE

All internal pressure must be relieved to zero pressure before disassembly or inspection of the strainer, vapor eliminator, any valves in the system, the packing gland, and the front or rear covers.

Serious injury or death from fire or explosion could result in performing maintenance on an improperly depressurized and evacuated system.

Strictly follow this procedure Relieving Internal Pressure Procedure for LPG and NH3 Meters:

1.Close the belly valve of the supply tank.

2.Close the valve on the vapor return line.

3.Close the manual valve in the supply line on the inlet side of the meter. If no manual valve exists on the inlet side, consult the truck manufacturer for procedures to depressurize the system.

4.Slowly open the valve/nozzle at the end of the supply line.

5.After product has bled off, close the valve/nozzle at the end of the supply line.

6.Slowly crack the fitting on top of the differential valve to relieve product pressure in the system. Product will drain from the meter system.

7.As product is bleeding from the differential valve, slowly reopen and close the valve/nozzle on the discharge line. Repeat this step until the product stops draining from the differential valve and discharge line valve/nozzle.

8.Leave the discharge line valve/nozzle open while working on the system.

The most common indication of mechanical air and vapor eliminator failure is leakage in and around the cover and valve plate area. Common causes of air eliminator failure are valve plate wear, a broken reed strip, a damaged cover gasket, and a punctured float filled with product.

Relieving Internal Pressure

Be sure to relieve internal pressure and remove all product from the system before disassembling the mechanical air eliminator. See the warning above.

Follow these steps:

1.Remove the 4 screws and washers at the base of the air eliminator. Pull the air eliminator off the strainer.

2.Remove the baffle plate and the baffle cup (aluminum air eliminators only) from the housing. If the air eliminator has a lock nut and a bushing on the bottom of the guide post, remove them.

3.Remove the cover screws from the air eliminator cover with a 1/2-inch wrench or socket, Then pull the cover, vent plate and seal ring from the housing.

4.To remove a reed strip that is still intact, hold down the reed strip and unscrew the reed screw (shown on the top right). Gently allow the reed strip to straighten. Reed strips violently snap back if they are not held down while removing the reed screw. Failure to hold down the reed strip could result in injury and is the cause of many lost screws.

5.Pull the float, along with the attached reed strips, out from the bottom of the air eliminator (shown on the right). If the float is heavy and full of product, replace it with a new float assembly.

6.If one of the reed strips is broken, remove it and replace with a new reed strip.

7.Begin reassembly. Push the float, along with the attached reed strips, up into the air eliminator cavity. Pull the reed strips out of the side slots (shown on the right). Hold the reed strips down and screw them down with the reed screws. If the air eliminator had a lock nut and a bushing on the bottom of the guide post, replace them.

8.Replace the valve plate, cover gasket, and cover. Tighten the cover screws to a torque of 17.5 - 20.5 ft-lbs.