Subsections

• Pump Failure

Manual Door Operation

In the event that electrical power is lost (and thus hydraulic control) the door can be opened manually. There are five manual popet valves, that are to be opened in a certain sequence, that will allow hydraulic fluid to slowly drain from the cylinders thus opening the doors.

1. Open the popet valve at the top of each door cylinder (valves SV-C-9 & SV-C-10) by pressing the switch on the valve. The valve is located on the downstream side at the top of each cylinder.
2. Open the popet valve at the bottom of each cylinder (valves SV-C-11 & SV-C-12) in the same way. The valve is located on the upstream side at the bottom of each cylinder.
3. Finally open the valve (valve SV-C-13) located on the rear wall of the spectrometer, above the electronics hut.

The fluid drains from the cylinders slowly. Opening the door this way may take more than several minutes. The five solenoid valves will need to be reset before electronic operation can resume.

Pump Failure

The hydraulic pump has two motors that are independently switched. Either will provide adequate power to operate the SOS door hydraulics. It is recommended that both pumps be used or alternated so that both are kept lubricated.

The motion of the door is monitored by the control system. Linear displacement encoders on each cylinder provide analog signals to the controls. The two cylinders must move at the same rate or the control system will stop the door progress. The doors will stop if the difference between the cylinders becomes more than 0.020". The control system will attempt to level the door and continue, massive skewing of the door will cause the door to wedge in the track. If the door wedges in the track crane support may be necessary to correct the problem.

Figure 2.34: Explanation of Symbols used in Door/Jack Hydraulic Diagram.

Figure 2.35: The SOS Door/Jack Hydraulic Diagram.