摘要:
A method and apparatus for detection of clogging of an orifice by measuring the upstream side pressure without breaking up the piping system in a flow rate control unit using an orifice, so as to extend the life of the flow rate control unit and enhance its safety. The apparatus of detecting clogging of an orifice in a pressure-type flow rate controller has a control valve (CV), an orifice (2), a pressure detector (14) for measuring the upstream pressure P1 therebetween, and a flow rate setting circuit (32) wherein, with the upstream pressure P1 maintained about two or more times higher than the downstream pressure P2, the downstream flow rate QC is calculated with the equation QC=KP1 (K=constant) and wherein the control valve (CV) is controlled by the difference signal QY between the calculated flow rate QC and the set flow rate QS. The apparatus comprises: a storage memory M memorizing standard pressure attenuation data Y(t) of the upstream pressure P1 measured with the flow rate switched from the high set flow rate QSH to the low set flow rate QSL with the orifice (2) not clogged, a pressure detector (14) for determination of the pressure attenuation data P(t) of the upstream pressure P1 with the flow rate switched from the high set flow rate QSH to the low set flow rate QSL with the orifice (2) in the actual conditions, a central processing unit CPU for checking the pressure attenuation data P(t) against standard pressure attenuation data Y(t), and an alarm circuit (46) that turns on a clogging alarm when the pressure attenuation data P(t) deviates from standard pressure attenuation data Y(t) to a specific degree or beyond that.
摘要:
An improved and reduced-size and low-cost gas supply system equipped with a pressure-type flow rate control unit, to be used, for instance, in semiconductor manufacturing facilities is disclosed. Transient flow rate characteristics are improved to prevent the gas from overshooting when the gas supply is started, and to raise the flow rate control accuracy and reliability of facilities. That eliminates non-uniformity of products or semiconductors and raises the production efficiency. The gas supply system equipped with a pressure-type flow rate control unit is so configured that with the pressure on the upstream side of the orifice held about twice or more higher than the downstream side pressure, the gas flow rate is controlled to supply the gas to a gas-using process through an orifice-accompanying valve, the gas supply system comprising a control valve to receive gas from the gas supply source, an orifice-accompanying valve provided on the downstream side of the control valve, a pressure detector provided between the control valve and the orifice-accompanying valve, an orifice provided on the downstream side of the valve mechanism of the orifice-accompanying valve and a calculation control unit where on the basis of the pressure P1 detected by the pressure detector, the flow rate Qc is calculated with an equation Qc=KP1 (K: constant) and the difference between the flow-rate specifying signal Qs and the calculated flow rate Qc is then input as control signal Qy in the drive for the control valve, thereby regulating the opening of the control valve for adjusting the pressure P1 so that the flow rate of the gas to supply can be controlled.
摘要:
A fluid supply apparatus with a plurality of flow lines branching out from one pressure regulator with the flow lines arranged in parallel and constructed so that opening or closing one flow passage will have no transient effect on the steady flow of the other flow passages. Each flow passage is provided with a time delay-type mass flow controller MFC so that when one closed fluid passage is opened, the mass flow controller on that flow passage reaches a set flow rate Qs in a specific delay time Δt from the starting point.The invention includes a method and an apparatus in which a plurality of gas types can be controlled in flow rate with high precision by one pressure-type flow control system.
摘要:
A fluid supply apparatus with a plurality of flow lines branching out from one pressure regulator with the flow lines arranged in parallel and constructed so that opening or closing one flow passage will have no transient effect on the steady flow of the other flow passages. Each flow passage is provided with a time delay-type mass flow controller MFC so that when one closed fluid passage is opened, the mass flow controller on that flow passage reaches a set flow rate Qs in a specific delay time At from the starting point. The invention includes a method and an apparatus in which a plurality of gas types can be controlled in flow rate with high precision by one pressure-type flow control system.
摘要:
A fluid supply apparatus with a plurality of flow lines branching out from one pressure regulator with the flow lines arranged in parallel and constructed so that opening or closing one flow passage will have no transient effect on the steady flow of the other flow passages. Each flow passage is provided with a time delay-type mass flow controller MFC so that when one closed fluid passage is opened, the mass flow controller on that flow passage reaches a set flow rate Qs in a specific delay time &Dgr;t from the starting point. The invention includes a method and an apparatus in which a plurality of gas types can be controlled in flow rate with high precision by one pressure-type flow control system.
摘要:
A valve with an integral orifice for use in gas feeding equipment provided with a pressure-type flow volume control device to be employed for manufacturing of semi-conductors and chemical goods. The valve with an integral orifice has the excellent flow rate control characteristics by improving the processing accuracy of the orifice and preventing the distortion of the orifice at the time of assembling. The orifice is formed in a stainless steel made orifice disc. The metal-made orifice disc with the orifice formed by separate processing and the synthetic-resin-made valve seat body are removably assembled, wherein the orifice disc and the synthetic resin made valve seat body are fixed airtight to the valve main body by pressing the valve seat body via a metal inner disc.
摘要:
A valve with an integral orifice for use in gas feeding equipment provided with a pressure-type flow volume control device to be employed for manufacturing of semi-conductors and chemical goods. The valve with an integral orifice has the excellent flow rate control characteristics by improving the processing accuracy of the orifice and preventing the distortion of the orifice at the time of assembling. The orifice is formed in a stainless steel made orifice disc. The metal-made orifice disc with the orifice formed by separate processing and the synthetic-resin-made valve seat body are removably assembled, wherein the orifice disc and the synthetic resin made valve seat body are fixed airtight to the valve main body by pressing the valve seat body via a metal inner disc.
摘要:
A valve with an integral orifice for use in gas feeding equipment provided with a pressure-type flow volume control device to be employed for manufacturing of semi-conductors and chemical goods. The valve with an integral orifice has the excellent flow rate control characteristics by improving the processing accuracy of the orifice and preventing the distortion of the orifice at the time of assembling. The orifice is formed in a stainless steel made orifice disc. The metal-made orifice disc with the orifice formed by separate processing and the synthetic-resin-made valve seat body are removably assembled, wherein the orifice disc and the synthetic resin made valve seat body are fixed airtight to the valve main body by pressing the valve seat body via a metal inner disc.
摘要:
A pressure-type flow rate control apparatus for use especially in the gas supply system in semiconductor manufacturing facilities. The flow control apparatus is provided with a bore-variable orifice, which permits easy switching of the fluid flow rate control range as well as size reduction of the pressure-type flow control apparatus, and offers other advantages including improved gas replaceability, prevention of dust formation, and reduced manufacturing costs of the flow control system. The apparatus comprises an orifice, a control valve provided on the upstream side of the orifice, a pressure detector provided between the control valve and the orifice, and a control unit to calculate a fluid flow rate Q on the basis of a pressure P1 detected by the pressure detector with the equation Q=KP1 (K=constant) and to output in a drive for the control valve the difference between the set flow rate signal Qs and the calculated flow rate signal Q as control signal Qy, wherein the pressure P1 on the upstream side of the orifice is regulated by actuating the control valve for controlling the flow rate of the fluid downstream of the orifice with the ratio P2/P1 between the pressure P1 on the upstream side of the orifice and the downstream pressure P2 maintained at not higher than the ratio of the critical pressure of the controlled fluid, characterized in that a direct touch type metal diaphragm valve unit functions as the orifice and that the ring-shaped gap between the valve seat and the diaphragm serves a variable orifice wherein the gap is adjusted by the orifice drive.
摘要:
An orifice for a pressure-type flow rate controller, which can be produced by a simple method at a low cost, that provides a linearity--between the pressure P1 on the upstream side of the orifice and the flow rate--over a wide range of the pressure ratio P2/P1 of the pressure P2 on the downstream side of the orifice to the upstream pressure P1 and that permits adjustment with ease of flow characteristics among a plurality of orifices. The orifice comprises an inlet taper 1 in the shape of a bugle and a short narrowed straight section 2 adjoining the inlet taper 1, both formed by cutting one opening end of a preliminary hole 6 made in an orifice plate D, and further comprises a short inner taper 3 and an enlarged straight section 4 connecting with the taper 3 which are formed by enlarging the preliminary hole 6 at the other opening end, the short inner taper 3 adjoining the narrowed straight section 2 on one side and neighboring the enlarged straight section 4 on the other side.