Abstract: Embodiments of the present invention are directed toward pressure controllers and calibrators for setting or measuring pressures in test devices. In one embodiment, the pressure controller contains a dual reference pressure controller. The dual reference pressure controller is operable to maintain two different pressures relative to a reference pressure. The first pressure being a relatively fixed amount greater than the reference pressure and the second pressure being a relatively fixed amount less than the reference pressure.

Abstract: Embodiments of the present invention are directed toward pressure controllers and calibrators for setting or measuring pressures in test devices. In one embodiment, the pressure controller contains a dual reference pressure controller. The dual reference pressure controller is operable to maintain two different pressures relative to a reference pressure. The first pressure being a relatively fixed amount greater than the reference pressure and the second pressure being a relatively fixed amount less than the reference pressure.

Abstract: Embodiments of the present invention are directed toward pressure controllers and calibrators for setting or measuring pressures in test devices. In one embodiment, the pressure controller contains a dual reference pressure controller. The dual reference pressure controller is operable to maintain two different pressures relative to a reference pressure. The first pressure being a relatively fixed amount greater than the reference pressure and the second pressure being a relatively fixed amount less than the reference pressure.

Abstract: Embodiments of the present invention are directed toward pressure controllers and calibrators for setting or measuring pressures in test devices. In one embodiment, the pressure controller contains a dual reference pressure controller. The dual reference pressure controller is operable to maintain two different pressures relative to a reference pressure. The first pressure being a relatively fixed amount greater than the reference pressure and the second pressure being a relatively fixed amount less than the reference pressure.

Abstract: A gas mass flow meter includes an elongated channel extending through a high thermal mass body and a critical flow nozzle in a downstream portion of the channel. A heat exchanger is provided upstream in the channel. Gas is forced through the heat exchanger and the critical flow nozzle at a flow rate of up to 5000 slm and at sufficiently high-pressure to ensure critical flow of the gas through the critical flow nozzle. The heat exchanger brings the gas close to the temperature of the high thermal mass body. The pressure of the gas is measured upstream and downstream from the nozzle and the temperature of the gas emerging from the heat exchanger is measured. The mass flow rate of gas through critical flow nozzle is computed from the upstream pressure, downstream pressure, temperature of the high thermal mass body, density of the gas, and a dimensional characteristic of the critical flow nozzle.

Abstract: A device for accurately measuring the pressure (Pg) of very highly pressurized gas includes a cylinder (16) having a cylindrical outer surface (16A) and a bore extending through the cylinder and an elongated piston (23) rotatable and vertically movable in the bore, and supporting calibration weights by means of the piston. An internal reservoir (32) is formed by providing a housing (31) to support the cylinder, the housing including a lower portion engaging a bottom portion of the cylinder and a lower peripheral portion of the cylinder and an upper portion engaging an upper peripheral portion of the cylinder, an inner portion of the housing (31) and a portion of the outer surface (16A). An interior of the reservoir (32) is pressurized through a passage (30A) extending from the reservoir to pressurize gas inlet. A passage (34) conducts pressurized oil from the reservoir into a gap between the piston (23) and the bore.

Abstract: A gas mass flow meter includes an elongated channel extending through a high thermal mass body and a critical flow nozzle in a downstream portion of the channel. A heat exchanger is provided upstream in the channel. Gas is forced through the heat exchanger and the critical flow nozzle at a flow rate of up to 5000 slm and at sufficiently high-pressure to ensure critical flow of the gas through the critical flow nozzle. The heat exchanger brings the gas close to the temperature of the high thermal mass body. The pressure of the gas is measured upstream and downstream from the nozzle and the temperature of the gas emerging from the heat exchanger is measured. The mass flow rate of gas through critical flow nozzle is computed from the upstream pressure, downstream pressure, temperature of the high thermal mass body, density of the gas, and a dimensional characteristic of the critical flow nozzle.

Abstract: A device for accurately measuring the pressure (Pg) of very highly pressurized gas includes a cylinder (16) having a cylindrical outer surface (16A) and a bore extending through the cylinder and an elongated piston (23) rotatable and vertically movable in the bore, and supporting calibration weights by means of the piston. An internal reservoir (32) is formed by providing a housing (31) to support the cylinder, the housing including a lower portion engaging a bottom portion of the cylinder and a lower peripheral portion of the cylinder and an upper portion engaging an upper peripheral portion of the cylinder, an inner portion of the housing (31) and a portion of the outer surface (16A). An interior of the reservoir (32) is pressurized through a passage (30A) extending from the reservoir to pressurize gas inlet. A passage (34) conducts pressurized oil from the reservoir into a gap between the piston (23) and the bore.

Abstract: A mass flow meter includes a body having a cylindrical bore and an elongated cylindrical piston positioned in the bore concentrically therewith. An elongated annular fluid flow channel of uniform depth is bounded by a cylindrical surface of the piston and a surface of the bore. Fluid flows laminafly through the channel. First and second concentric ferrules are located at first and second end portions of the piston to precisely position and hold the piston concentrically in the bore, by elastically expanding in response to longitudinal forces on the first and second end portions of the piston to symmetrically engage a wall of the bore. A first pressure measuring probe in fluid communication with an upstream equalization chamber measure fluid pressure in the upstream equalization chamber, and a second differential pressure transducer in fluid communication between the upstream equalization chamber and a downstream equalization chamber measures differential fluid pressure between the two equalization chambers.

Abstract: An improved dead weight piston pressure measurement/calibration device includes a cylinder and a dead weight piston assembly that includes a piston rotatable and vertically in the cylinder, bell housing supported by the piston and carrying a number of calibration weights. The weight of the dead weight piston assembly initially is supported by an elastic stop device. Gas from an external source is rapidly forced into the cylinder until the dead weight piston assembly rises in an "elastic" zone defined by the elastic stop device. Such movement is sensed to "proportionally" reduce the rate of flow of gas and stabilize the position of the piston in the second element in a free-floating equilibrium condition, and actuate a drive mechanism that rotates the dead weight piston assembly and maintains the rotation rate in a defined range without producing any sustained vertical or radial displacement forces on the dead weight piston assembly, and thereby avoiding pressure overshoot.

Abstract: A system for precisely controlling gas under high pressure produces an initial gas pressure in a pressure chamber while applying a predetermined amount of power to a heating element located in the pressure chamber and then applies a computed change of power to produce an average gas temperature increase or decrease in the pressure chamber and thereby rapidly produce an increase or decrease in gas pressure with resolution limited by the resolution of measurement of gas pressure in the pressure chamber and the application of the computed change of power. The described invention is particularly advantageous at gas pressure above roughly 1000 pounds per square inch.

Abstract: A pressure controller rapidly, precisely sets and stabilizes the pressure in a test volume to a target pressure by opening a fast inlet solenoid valve or a fast outlet solenoid valve, and opening a slow inlet solenoid valve or a slow outlet solenoid valve, to rapidly increase or decrease pressure in the manifold. When the pressure has reached a predetermined level, the fast inlet or fast outlet solenoid valve is closed. Then only the slow inlet or slow outlet solenoid valve remains opened to further increase or decrease the pressure to a second predetermined level. Then, based on the present pressure in the manifold and the test volume, a computation is made of the amount of gas needed to be injected into the manifold to increase the pressure to the target pressure. A computation is made of the time duration during which the slow inlet valve and the slow outlet valve must be differentially opened to increase the net amount of gas injected into the manifold and test volume by the computed amount.