-
the spring seat
-
the spring pin
-
the bleed screw.
The slide valve has drilled ports to let the hydraulic fluid move through the valve. The wire installed on the spring pin goes through the jet to prevent it from being blocked. The spring pushes against the spring seat to keep the valve in the open position.
The valve seat is installed at the lower end of the valve body and is held in position by a screwed ring sealed by packing rings.
(2) Hydraulic Fluid
In normal operation, the hydraulic fluid goes into port B, passes through the slot in the slide valve and goes out through port C.
When a leak occurs downstream of the safety valve (with a flow rate greater than 11 litre/minute) the slot in the slide valve stops the increase of flow. This causes the valve to begin to close. At the same time the spring is compressed and cavitation is formed in chamber A, which slows the movement of the slide valve.
The hydraulic fluid passes through the small hole in the slide valve and fills chamber A. When the chamber A is full the effect of the cavitation is removed and the valve closes. The speed at which chamber A fills controls the speed at which the valve will operate.
When the NLG door-actuator is operates it momentarily increases the hydraulic flow rate and causes cavitation in chamber A. When this happens, the spring returns the slide valve to the open position.
The safety valve will stay in the closed position even when the supply pressure decreases to that of the Green system reservoir.
1EFF : ALL 1 32-31-00Page 43 1 1 May 01/05R 1 1 1CES 1
To reset the safety valve it is necessary to depressurize the Green system reservoir or to open the bleed screw installed on the end of the safety valve.
E. MLG Actuating Cylinder (2503GM,2504GM)
**ON A/C 001-003, 051-052, 301-399,
(Ref. Fig. 022)
R **ON A/C 004-049, 053-099, 101-149, 151-199, 201-299, 401-499,
(Ref. Fig. 022A)
R **ON A/C 001-049, 051-099, 101-149, 151-199, 201-299, 401-499,
(Ref. Fig. 023)
**ON A/C 301-399,
(Ref. Fig. 024)
**ON A/C ALL
(1) Description
The MLG actuating cylinder is installed on the main fitting at the piston rod end. Two lugs attach the body of the actuating cylinder to the wing rear spar.
The actuator is operated hydraulically and has rate control devices. The primary components of the unit are:
-
a cylinder
-
a piston rod
-two valve housings.
The cylinder contains the piston rod and a sealed piston head. Each valve housing contains a restrictor and a restrictor valve. The restrictor decreases the flow of fluid in each direction and the restrictor valve decreases the flow of fluid out of the cylinder.
1EFF : ALL 1 32-31-00Page 44 1 1 Aug 01/05 1 1 1CES 1
MLG Actuating Cylinder (2503GM,2504GM)
Figure 022
R 1EFF : 001-003, 051-052, 301-399, 1 32-31-00Page 45 1 1 May 01/05 1 1 1CES 1
MLG Actuating Cylinder (2503GM,2504GM)
Figure 022A
R 1EFF : 004-049, 053-099, 101-149, 151-199, 1 32-31-00Page 46 1201-299, 401-499, 1Aug 01/05 1 1 1CES 1
MLG Actuating Cylinder - Schematic
Figure 023
R 1EFF : 001-049, 051-099, 101-149, 151-199, 1 32-31-00Page 47 1201-299, 401-499, 1Aug 01/05 1 1 1CES 1
MLG Actuating Cylinder - Schematic
Figure 024
R 1EFF : 301-399, 1 32-31-00 Page 48
1 1 May 01/05
1 1
1CES 1
(a) Actuating Cylinder
The body of the actuating cylinder has a housing bolted to each end that are connected by an external pipe. Each housing contains a restrictor and a restrictor valve. These components control:
-
the speed at which the actuating cylinder operates
-
the end of travel damping, which occurs in each direction of travel.
To give protection against the high fluid pressures (caused during end of travel damping) the walls of the actuating cylinder are thicker at the piston rod end.
(b) Piston Rod
The piston rod moves in the cylinder assembly and has:
-a plug at the internal end
-an integral eye-end (with a spherical bearing) at the external end
-a vent valve.
If pressurized fluid gets into the piston rod, the vent valve blows out and prevents an increase in pressure in the piston rod. To prevent corrosion a small quantity of hydraulic fluid is put into the piston rod during assembly.
With hydraulic pressure supplied to:
-
the full area side of the piston, the piston rod extends and retracts the MLG
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