Combined sensor and control

A combined flow sensor and control comprising:

• a hydraulic circuit adapted to be connected between a working hydraulic pressure fluid source and a load;
• a flow sensor connected in the circuit so that working hydraulic fluid flow in the circuit is constrained to pass through the sensor;
• orifice means in said sensor operative to produce pressure differentials in the working hydraulic fluid flowing through the sensor analogous to variations in the rate of flow of said hydraulic fluid through said orifice means;
• said sensor including an element arranged to be subjected to said pressure differentials and to be driven in one direction by said differentials in pressure;
• resilient means biasing the element in the opposite direction;
• a control fluid circuit isolated from the hydraulic circuit and adapted to be connected to a control fluid pressure source and having an outlet port;
• a pressure regulator in said control fluid circuit and movable to different positions for controlling the pressure of the control fluid delivered to said port;
• and
• means drivingly interconnecting the element and regulator so as to vary the control pressure delivered to said port in an analogous relation to changes in the rate of flow of said working hydraulic fluid through said orifice means.

A hydraulic fluid flow sensor and control comprising;

• a first means having a cavity with an inlet, an outlet, and a wall therebetween with a flow orifice therein connecting the inlet and outlet;
• first and second conduits, the first conduit being connected at one of its ends to said cavity at the inlet side of the orifice, and the second conduit being connected at one of its ends to the cavity at the outlet side of the orifice;
• a second means having a first bore and a second bore coaxial therewith;
• the other ends of the conduits being connected to said first bore at axially spaced positions, respectively;
• a piston reciprocable in said first bore and disposed between said other ends of the ducts;
• a diaphragm closing the end of the second bore which is more remote from the first bore, and having an inner face facing toward the piston;
• an axial passage between and connecting the bores;
• a rod reciprocable in the passage and connected to the piston and to the diaphragm;
• means blocking passage of fluid from the first bore to the second bore through said passage around the rod;
• resilient means biasing the piston, rod, and diaphragm concurrently in one direction axially of the bores, which direction is the direction of movement of the piston toward the connection of the end of the first conduit with said first bore;
• said second means having a chamber at the outer end of the second bore and said diaphragm being connected between the outer end of the second bore and the chamber and forming a common wall therebetween;
• said second means having a discharge passage leading from the chamber to the exterior of the second means at the outer side of the diaphragm, and having a vent duct at the inner side of the diaphragm and leading from said second bore to the atmosphere;
• said disphragm having a by-pass passage therethrough which, when open, connects said second bore and chamber;
• said second means having a chamber inlet passage coaxial with said second bore;
• a valve reciprocable therein and operable to open and close said chamber inlet passage, respectively;
• a spring biasing the valve in a direction toward the diaphragm to closed position;
• said valve having a stem with a plug portion thereon which, in the closed position of the valve and intermediate position of the diaphragm, closes said by-pass passage through the diaphragm;
• and
• said diaphragm being movable, upon predetermined pressure in said first conduit, so as to cause said by-pass passage to be moved away from said plug to open condition, against the biasing force of said resilient means.

A combined sensor and control comprising:

• sensing means through which working hydraulic pressure fluid can flow from a source to a hydraulically operable power mechanism through a restrictive orifice, and which senses changes in the rate of flow of the hydraulic fluid as a function of the changes in the differential in hydraulic pressure across said orifice;
• a pneumatic pressure varying device connectable to a pneumatic pressure fluid source and operative to vary the pneumatic pressure from the source delivered to a device to be operated;
• and
• means interconnecting the sensing means and pneumatic pressure varying device so as to maintain the magnitude of said pneumatic pressure in an analogous relation to the magnitude of said differential in hydraulic pressure.