Leakage detector with back pressure sensor

Claim 2

A hydraulic damper for controlling lag-lead movements of a helicopter rotor blade comprising a cylinder, a piston reciprocable in said cylinder having a piston rod extended through an end wall of said cylinder, primary and secondary seals in said end wall surrounding and engaging said rod, a cavity about said rod between said seals, a fluid leakage line extending from said cavity having a fixed restriction therein, a leakage indicator including a chamber communicating with said leakage line upstream of said restriction and a fluid responsive member in said chamber, and an unobstructed pressure equalization line having a fluid connection at one of its ends to said leakage line downstream from said restriction and having a fluid connection at its other end to the chamber of said leakage indicator above the fluid responsive member therein.

Claim 3

A hydraulic damper for controlling lag-lead movements of a helicopter rotor blade comprising a cylinder, a piston reciprocable in said cylinder having piston rods extended through opposite end walls of said cylinder, primary and secondary seals in each end wall engaging said rods, a cavity about each rod between its primary and secondary seals, a fluid line connecting said cavities, means for collecting leakage fluid including a fluid line extending from said connecting line having a fixed restriction therein, a leakage-fluid operated indicator including a cylinder and a piston therein, said cylinder having a fluid connection beneath said piston with said extended fluid line upstream from said restriction therein, and means for preventing false indications of excessive leakage including an unobstructed pressure equalization line having a fluid connection at one of its ends to said indicator cylinder above its piston and having a fluid connection at its other end to said extended fluid line downstream of said restriction therein.

Claim 4

A hydraulic damper for controlling lag-lead movements of a helicopter rotor blade comprising a cylinder, a piston reciprocable in said cylinder having piston rods extended through opposite end walls of said cylinder, primary and secondary seals in each end wall engaging said rods, a cavity about each rod between its primary and secondary seals, a fluid line connecting said cavities, means for collecting leakage fluid including a fluid line extending from said connecting line having a fixed restriction therein, a leakage-fluid operated indicator including a cylinder and a piston therein, said cylinder having a fluid connection beneath said piston with said extended fluid line upstream from said restriction therein, and means for preventing false indications of excessive leakage including an unobstructed pressure equalization line having a fluid connection at one of its ends to said indicator cylinder above its piston and having a fluid connection at its other end to said extended fluid line downstream of said restriction therein.

Claim 5

A hydraulic damper for controlling the lag-lead movements of helicopter rotor blades comprising a cylinder and a piston, a piston rod extended through a wall of said cylinder, primary and secondary seals in said wall surrounding and engaging said rod, an annular cavity about said rod between said seals for collecting leakage fluid, a fluid passage communicating with said cavity having a fixed restriction therein, a leakage indicator having a chamber and a fluid responsive member therein, a compression spring in said indicator chamber above said fluid responsive member, a fluid connection from said indicator chamber beneath said fluid responsive member to said fluid passage upstream of said restriction, and means for preventing untimely operation due to backup of fluid through said restriction including an unobstructed fluid line having a connection at one of its ends to said fluid passage at a point downstream of said restriction and having a connection at its other end with said indicator chamber above said fluid responsive member in the latter.

Claim 6

A hydraulic damper for controlling the lag-lead movements of helicopter rotor blades comprising a cylinder and a piston, a piston rod extended through a wall of said cylinder, primary and secondary seals in said wall surrounding and engaging said rod, an annular cavity about said rod between said seals for collecting leakage fluid, a fluid passage communicating with said cavity having a fixed restriction therein, a leakage indicator having a chamber and a fluid responsive member therein, a compression spring in said indicator chamber above said fluid responsive member, a fluid connection from said indicator chamber beneath said fluid responsive member to said fluid passage upstream of said restriction, and means for preventing untimely operation due to backup of fluid through said restriction including an unobstructed fluid line having a connection at one of its ends to said fluid passage at a point downstream of said restriction and having a connection at its other end with said indicator chamber above said fluid responsive member in the latter.

Claim 7

A hydraulic damper for controlling the lag-lead movements of helicopter rotor blades comprising a cylinder and a piston reciprocable therein, a piston rod extended through a wall of said cylinder, axially spaced primary and secondary seals between said cylinder wall and said rod, a cavity in said wall surrounding said rod, a leaked-fluid line connected to said cavity for conducting fluid from the latter to the damper fluid system, a fixed restriction in said leaked-fluid line, an indicator responsive to the rate of fluid leaking into said cavity including an indicator chamber connected to said leaked-fluid line upstream of said restriction, a fluid pressure responsive member in said indicator chamber, and means for maintaining the same pressure on the remote side of said indicator member as that prevailing in said leaked-fluid line downstream of said restriction, said means including an unobstructed fluid conduit having a connection at one end to said indicator chamber above said fluid responsive member therein and having a connection at its other end to said leaked-fluid line downstream of said restriction.

Claim 8

A hydraulic damper for controlling the lag-lead movements of helicopter rotor blades comprising a cylinder and a piston reciprocable therein, a piston rod extended through a wall of said cylinder, axially spaced primary and secondary seals between said cylinder wall and said rod, a cavity in said wall surrounding said rod, a leaked-fluid line connected to said cavity for conducting fluid from the latter to the damper fluid system, a fixed restriction in said leaked-fluid line, an indicator responsive to the rate of fluid leaking into said cavity including an indicator chamber connected to said leaked-fluid line upstream of said restriction, a fluid pressure responsive member in said indicator chamber, and means for maintaining the same pressure on the remote side of said indicator member as that prevailing in said leaked-fluid line downstream of said restriction, said means including an unobstructed fluid conduit having a connection at one end to said indicator chamber above said fluid responsive member therein and having a connection at its other end to said leaked-fluid line downstream of said restriction.

Claim 9

In combination, a cylinder, a piston reciprocable in said cylinder having a piston rod extended through an end wall of said cylinder, spaced primary and secondary seals in said end wall surrounding said rod, a cavity in said end wall surrounding said rod in the space between said seals for collecting fluid which leaks past said primary seal, a leaked-fluid line connected to said cavity having a fixed restriction therein, means for indicating rate of fluid leakage past said primary seal including an indicator chamber having a fluid pressure responsive member therein, a fluid connection between said indicator chamber below said fluid pressure responsive member and said leaked-fluid line upstream of said restriction therein, and an unobstructed fluid conduit having a connection at one of its ends to said indicator chamber above said fluid pressure responsive member and having a connection at its other end to said leaked-fluid line downstream of said restriction.

Claim 10

In combination, a cylinder, a piston reciprocable in said cylinder having a piston rod extended through an end wall of said cylinder, spaced primary and secondary seals in said end wall surrounding said rod, a cavity in said end wall surrounding said rod in the space between said seals for collecting fluid which leaks past said primary seal, a leaked-fluid line connected to said cavity having a fixed restriction therein, means for indicating rate of fluid leakage past said primary seal including an indicator chamber having a fluid pressure responsive member therein, a fluid connection between said indicator chamber below said fluid pressure responsive member and said leaked-fluid line upstream of said restriction therein, and an unobstructed fluid conduit having a connection at one of its ends to said indicator chamber above said fluid pressure responsive member and having a connection at its other end to said leaked-fluid line downstream of said restriction.

Claim 11

In combination, a chamber adapted to contain a fluid under pressure, a fluid actuated member in said chamber having a driven member carried thereby and extended through a wall of said chamber, spaced primary and secondary seals in said chamber wall surrounding said driven member, a cavity between said primary and secondary seals for collecting fluid which has leaked past said primary seal, a leaked-fluid line connected to said cavity having a fixed restriction therein, means for indicating rate of fluid leakage past said primary seal including an indicator chamber having a fluid pressure responsive member therein, a fluid connection between said indicator chamber below said fluid pressure responsive member and said leaked-fluid line upstream of said restriction, and an unobstructed fluid conduit having a connection at one of its ends to said indicator chamber above said fluid pressure responsive member and having a connection at its other end to said leaked-fluid line downstream of said restriction.

Claim 12

In combination, a chamber adapted to contain a fluid under pressure, a fluid actuated member in said chamber having a driven member carried thereby and extended through a wall of said chamber, spaced primary and secondary seals in said chamber wall surrounding said driven member, a cavity between said primary and secondary seals for collecting fluid which has leaked past said primary seal, a leaked-fluid line connected to said cavity having a fixed restriction therein, means for indicating rate of fluid leakage past said primary seal including an indicator chamber having a fluid pressure responsive member therein, a fluid connection between said indicator chamber below said fluid pressure responsive member and said leaked-fluid line upstream of said restriction, and an unobstructed fluid conduit having a connection at one of its ends to said indicator chamber above said fluid pressure responsive member and having a connection at its other end to said leaked-fluid line downstream of said restriction.