878406A 1 Mercury REPAIR KIT, Check Valve

Nitrogen used in this process exceeds 57° C (135° F) temperature and 6.9 bar (100 psi) pressure. There is a potential for burn hazard if proper procedure is not followed. Gloves and Eye protection are required during this procedure and once the discharge has started do not touch the components with a bare hand.
Do not allow dirt to enter the fuel system. Thoroughly clean the area around a fuel system component that will be disconnected. Fit a suitable cover over any disconnected fuel system components.
Nitrogen from a liquid cylinder or compressed gas cylinder is the recommended purge gas. Use a compressed gas pressure regulator to reduce the pressure from the nitrogen gas source to approximately 345 kPa (50 psi).Specifications
Table 1
Parameter Value
Dew Point −40° C (−40° F)
Level sensor 700+/-50 pF Introduction
This procedure is used for drying moisture/water out of an empty Liquid Natural Gas (LNG) tank. If the plumbing is ever opened to remove or change components, moisture from the atmosphere can enter the tank. Moisture in the LNG tank can cause the level sensor readings to be too high or may freeze and cause blockages or restrictions in LNG flow.This procedure demonstrates how to utilize heated nitrogen at low pressures to dry out the LNG tank. Caution must be used while heating nitrogen so there is no damage to the tank insulation. The dryness of the tank is verified using a dew point meter.Personal Protective Equipment
Leather work gloves
Safety glasses (with side shields)
Steel toe bootsRequired Tools
Table 2
Item Qty Part Number Part Name
T1 1 N/A BAK Type S36 Heater
T2 1 N/A Keysight Technologies U1733C LCR Meter
T3 1 N/A Traceable Hygrometer Thermometer Dew Point Meter Model 4085CC
T4 1 N/A Compressed Nitrogen
T5 1 N/A Vent Nozzle
T6 1 N/A Adapter from heater to 1” JIC Test Preparation
Before starting procedure check valve positions to ensure proper drying:
Valve 1: Closed
Valve 2: Closed
Valve 5: Closed
Valve 6: Closed
Valve 8: Closed
Illustration 1 g06448106
Depressurize/empty LNG tank by slowly opening "Liquid Shutoff" valve. Close valve once the tank has no pressure left.Note: Stand clear of outlet port, tank will depressurize through this valve.
Illustration 2 g06446991
Check capacitance of LNG tank with the LCR meter, before drying process for a baseline reference.
Plug in leads to LCR meter and measure the capacitance of the leads prior to hooking up to tank. Record this value.
Disconnect the level sensor box from the TNC coming out of tank. Connect the LCR meter to the TNC connection on the tank.
Subtract the tank capacitance from the wire capacitance and continue if the reading is greater than 700 +/- 50 pF.
Disconnect the LCR meter.
Remove the hose that connects to the "LNG out" bulkhead on the LNG Tank. Cap the ends of the hose to prevent debris and moisture from getting into this hose.
Illustration 3 g06447132
(1) Heater nozzle (outlet)
Plumb the heater into the "LNG Out" tank bulkhead.
Make sure that the heater is OFF until ready to heat the nitrogen.
Plumb the nitrogen into the back of the heater.
Make sure the valves "1, 2, 5, 6, and 8" are closed.Test Procedure
Illustration 4 g06447129
Open the Liquid shutoff valve in front of the heater.
Turn up the supply nitrogen discharge pressure to 138 to 207 kPa (20 to 30 psi).Note: The drying process may take several days depending on the amount of water in the tank, make sure to have sufficient nitrogen 10.
Attach a vent nozzle to the vent receptacle and slowly open the "Manual Vent Valve" until a steady stream of nitrogen is discharging through the nozzle. The vent nozzle should not be hooked up back to the station.
Turn on heater. Monitor plumbing temperature with a laser temperature reading. Temperature should not exceed 79° C (175° F).
Periodically measure the capacitance and see tread head downward towards