Pressure controller

Claim 2

In a pressure controller for use with a manometer having means for generating an error signal varying as a function of the difference between a reference pressure and the pressure in an output line, the improvement comprising: first and second control valves, each of said control valves including throttling means for controlling fluid flow through the valve, each of said throttling means having means defining a valve seat of nonmagnetic material, a poppet carried in the valve for movement toward and away from said seat to close and open the valve, with at least a portion of said poppet being of magnetic material, and a poppet driver mounted in the valve adjacent said poppet for movement toward and away from the poppet and valve seat, with said driver magnetically energized for attracting the poppet; means for connecting a low-pressure source as an input to said first control valve; means for connecting a high-pressure source as an input to said second valve; means for connecting the output of each of said control valves to said output line; and valve actuating means having said error signal as an input for actuating each of said poppet drivers to simultaneously increase flow through one valve and decrease flow through the other valve as said error signal varies, with said valves and actuating means adjusted such that both valves are partially open for the zero difference condition.

Claim 3

A controller as defined in claim 1 in which each of said control valves includes an electrical coil disposed in a magnetic path, with said coil fixed to said poppet driver, and a flexible suspension for said poppet driver urging the driver toward said poppet and valve seat.

Claim 4

A controller as defined in claim 1 including: a first fluid pressure regulator connected between said low-pressure source and said first control valve input; a second fluid pressure regulator connected between said high-pressure source and said second control valve input; and means for connecting said output line as a reference pressure to each of said regulators.

Claim 5

A controller as defined in claim 1 in which said valve actuating means includes an amplifier for amplifying said error signal; and said controller includes means for varying the gain of said amplifier as a function of the pressure in said output line.

Claim 6

A controller as defined in claim 4 in which the amplifier gain is substantially constant in a first lower pressure zone, increases substantially logarithmically in a second intermediate pressure zone, and is substantially constant at a higher value in a third higher pressure zone.

Claim 7

A controller as defined in claim 5 wherein the higher gain of said third zone is in the order of about 10,000 times the gain of said first zone.

Claim 8

In a pressure controller for use with a manometer having interconnected first and second cisterns carrying pools of mercury with one of said cisterns disposed vertically relative to the other, a reference pressure source connected to the upper cistern above the pool, an output line connected to the lower cistern above the pool, a pressure sensor comprising a mercury chamber interconnected with said cisterns, a pressure chamber connected to said output line and a movable wall member between said chambers, means for generating a first signal varying as a function of unbalance at said first and second cisterns, and means for generating a second signal varying as a function of movement of said wall member, the improvement comprising: first and second control valves, each of said control valves including throttling means for controlling fluid flow through the valve, each of said throttling means having means defining a valve seat of nonmagnetic material, a poppet carried in the valve for movement toward and away from said seat to close and open the valve, with at least a portion of said poppet being of magnetic material, and a poppet driver mounted in the valve adjacent said poppet for movement toward and away from the poppet and valve seat, with said driver magnetically energized for attracting the poppet; means for connecting a low-pressure source as an input to said first control valve; means for connecting a high-pressure source as an input to said second control valve; means for connecting the output of each of said control valves to said output line; and valve actuating means having said signals as inputs for actuating each of said poppet drivers to simultaneously increase flow through one valve and decrease flow through the other valve as said signals vary, with said valves and actuating means adjusted such that both valves are partially open for the zero difference condition.

Claim 9

In a pressure controller for use with a manometer having interconnected first and second cisterns carrying pools of mercury with one of said cisterns disposed vertically relative to the other, a reference pressure source connected to the upper cistern above the pool, an output line connected to the lower cistern above the pool, a pressure sensor comprising a mercury chamber interconnected with said cisterns, a pressure chamber connected to said output line and a movable wall member between said chambers, means for generating a first signal varying as a function of unbalance at said first and second cisterns, and means for generating a second signal varying as a function of movement of said wall member, the improvement comprising: first and second control valves, each of said control valves including throttling means for controlling fluid flow through the valve, each of said throttling means having means defining a valve seat of nonmagnetic material, a poppet carried in the valve for movement toward and away from said seat to close and open the valve, with at least a portion of said poppet being of magnetic material, and a poppet driver mounted in the valve adjacent said poppet for movement toward and away from the poppet and valve seat, with said driver magnetically energized for attracting the poppet; means for connecting a low-pressure source as an input to said first control valve; means for connecting a high-pressure source as an input to said second control valve; means for connecting the output of each of said control valves to said output line; and valve actuating means having said signals as inputs for actuating each of said poppet drivers to simultaneously increase flow through one valve and decrease flow through the other valve as said signals vary, with said valves and actuating means adjusted such that both valves are partially open for the zero difference condition.

Claim 10

A controller as defined in claim 7 in which each of said control valves includes an electrical coil disposed in a magnetic path, with said coil fixed to said poppet driver, and a flexible suspension for said poppet driver urging the driver toward said poppet and valve seat.

Claim 11

A controller as defined in claim 8 in which said actuating means includes a first direct coupled amplifier and a second capacitive coupled amplifier, with the amplifier outputs combined to drive the coils of each of said throttling means in parallel, and means for connecting said first signal as an input to said first amplifier and said second signal as an input to said second amplifier.

Claim 12

A controller as defined in claim 7, including a third on-off valve connected between said lower cistern and said mercury chamber for blocking mercury flow therebetween when in the off position, with said actuating means including a first direct coupled amplifier and a second capacitive coupled amplifier with the amplifier outputs combined to drive each of said poppet drivers in parallel, and switch means for connecting said second signal as an input to each of said amplifiers when said third valve is in the off position, and connecting said first signal as an input to said first amplifier and said second signal as an input to said second amplifier when said third valve is in the on position.

Claim 13

A controller as defined in claim 7 including: a first fluid pressure regulator connected between said low-pressure source and said first control valve input; a second fluid pressure regulator connected between said high-pressure source and said second control valve input; and means for connecting said output line as a reference pressure to each of said regulators to provide a substantially constant pressure drop across each of said first and second control valves.

Claim 14

A controller as defined in claim 9 including means for varying the gain of each of said amplifiers as a function of the pressure in said output line.

Claim 15

A controller as defined in claim 12 in which the amplifier gain is substantially constant in a first lower pressure zone, increases substantially logarithmically in a second intermediate pressure zone, and is substantially constant at a higher value in a third higher pressure zone.

Claim 16

A controller as defined in claim 10 including: a first fluid pressure regulator connected between said low pressure source and said first control valve input; a second fluid pressure regulator connected between said high pressure source and saiD second control valve input; means for connecting said output line as a reference pressure to each of said regulators to provide a substantially constant pressure drop across each of said first and second valves; and means for varying the gain of each of said amplifiers as a function of the pressure in said output line.