Abstract: A flow sensor readily obtains high sensitivity without errors due to tilting. The flow sensor includes a flow channel having a pair of parallel portions and temperature sensing resistors for heating a fluid to a preset temperature. The temperature sensing resistors are disposed on parts of the parallel portions of the flow channel, to detect a fluid flow rate based on a change in temperature distribution of a flow channel due to a change in flow rate of the fluid flowing through the flow channel. The temperature sensing resistors include a first upstream temperature sensing resistor and a first downstream temperature sensing resistor that are disposed in a line on upstream and downstream sides of one of the parallel portions, respectively; and a second upstream temperature sensing resistor and a second downstream temperature sensing resistor that are disposed in a line on upstream and downstream sides of the other parallel portion, respectively.

Abstract: According to the present invention, there is provided a high-precision differential pressure sensor which is not affected by a considerable change in baseline pressure. A differential pressure sensor of the present invention includes: a pair of diaphragms, each including a diaphragm portion capable of being deformed due to application of a pressure and a support portion for holding an outer peripheral edge of the diaphragm portion; a pair of fixed electrodes in disk-like form fixed to the support portions of the diaphragms; and a movable electrode including a disk-like electrode portion and shaft-like projections extending in opposite directions from a central portion of the electrode portion. The shaft-like projections extend at a right angle relative to the electrode portion, and the movable electrode is secured to central portions of the diaphragms through the shaft-like projections so that the electrode portion faces each of the fixed electrodes in a predetermined spaced relationship.

Abstract: An actuator operated by a solenoid and a force amplifying means utilizing hydraulic pressure are used in combination with a diaphragm, to thereby provide a diaphragm valve made of Teflon™, and which is compact in size, has low power consumption, and which is capable of exerting a large force. The force amplifying means mainly comprises a cylinder including cylinder portions having different cross-sectional areas and oil filled in the cylinder. A force amplification ratio is equal to a ratio between the cross-sectional areas of the cylinder portions. A plunger which receives a biasing force of a spring is provided on an upper side of the force amplifying means. The plunger is operated by a solenoid, and a driving force of the plunger is amplified by the force amplifying means and transmitted to the diaphragm, thus adjusting a degree of valve opening.

Abstract: An electromagnetic valve for opening and closing a fluid flow passage by operating a plunger under a magnetic force of a solenoid. The valve comprises a valve head provided at one of opposite ends of the plunger, and a fixed valve seat including an orifice providing a fluid flow passage. The valve head is adapted to abut against the valve seat to close the orifice. A spring resiliently presses the valve head in a direction for abutment of the valve head against the valve seat to close the orifice. Either one of the valve head and the valve seat is formed from a metallic material and the other is formed from a non-metallic material having a greater hardness than the metallic material. It is preferred that the metallic material be a highly corrosion-resistant metal alloy containing Ni in a high amount ratio, and the non-metallic material be of a ceramic type.

Abstract: The present invention provides a high-performance mass flow controller which is compact and lightweight, which has a flow path having a simple structure and which does not have dead space in which a fluid is likely to stagnate and cause the problem of contamination. A cylindrical valve conduit having a hollow structure, a yoke and a sensor conduit are connected in tandem. A fluid inlet portion is connected to an end of the valve conduit and a fluid outlet portion is connected to an end of the sensor conduit. A solenoid valve is provided on a side of the fluid inlet portion and a thermal mass flowmeter is provided on a side of the fluid outlet portion. In the valve conduit, a cylindrical plunger providing a movable portion of the solenoid valve and a valve portion of which a degree of opening is adjusted by moving the plunger are provided on a side of the fluid inlet portion. A bypass for generating a laminar flow is disposed in the sensor conduit so as to effect one-way flow of a fluid.

Abstract: A vaporizer comprises disks each including an aperture at a central portion thereof. A hollow pipe having apertures for permitting radial outflow of a liquid extends through the aperture of each of the discs so as to form a stack of the discs. A resilient member applies a biasing force to the discs, and structure applies a force, via fluid control, against the biasing force to thereby remove the biasing force from the discs. Liquid in the hollow pipe is adapted to be delivered from the apertures to spaces between the discs and vaporized in the spaces between the discs.

Abstract: The liquid supply system comprises a pump for delivering a liquid under high pressure and a vaporizer for vaporizing the liquid delivered from the pump. The liquid vaporized in the vaporizer is supplied to a reaction chamber. A pressure gage is provided in a passage extending from the pump to the vaporizer. A monitor device is provided so as to indicate a pressure, based on an output of the pressure gage.

Abstract: The vaporizing apparatus comprises a disk portion in which a plurality of sheet disks are provided in a stacked configuration, with a top disk being provided on a top of the sheet disks. Each of the sheet disks has a thin sheetlike form and includes a through-hole at a central portion thereof. A shaft extends through these openings and supports the sheet disks and the top disk. The disk portion is accommodated in a chamber formed on a base. A liquid is introduced through a flow passage into the openings of the sheet disks of the disk portion in the chamber. Heaters are provided within the base. A piezoactuator is provided so as to bias the disk portion in the chamber from a side of the top disk. The piezoactuator adjusts the gaps between the disks and opening/closing of the flow passage.

Abstract: There is provided a flow rate sensor comprising: a pair of heating resistors operable to heat a sensor tube; a temperature sensor operable to control respective temperatures of the heating resistors; and a case operable to hold the heating resistors and the temperature sensor. The flow rate sensor is adapted to detect a flow rate of a fluid flowing in the sensor tube based on variations of voltages applied to the heating resistors, wherein the variations occur according to the flow rate of the fluid. The flow rate sensor further comprises a voltage applying device operable to arbitrarily set an increase in temperature of each of the heating resistors. The sensor tube has opposite ends thereof thermally connected to the case. The temperature sensor is positioned to be equidistant from the opposite ends of the sensor.

Abstract: An actuator utilizing the pressure of a gas is used to operate a diaphragm-operated control valve. An operating force generated by the actuator is varied by feeding and discharging a gas such as N2 through a narrow metallic tube. This is conducted by remote control, by means of electromagnetic valves provided in an environment at room temperature. The state of the control valve is monitored by a flow rate sensor which detects an actual flow rate of a fluid being controlled. Based on a signal representative of the detected actual flow rate, the electromagnetic valves for the actuator are controlled so that the fluid always flows at a desired flow rate. The gas such as N2 is heated by a heat exchanger in a high-temperature atmosphere in the vicinity of the actuator, to thereby prevent cooling of the fluid being controlled.

Abstract: A valve body includes: a main body having a recess formed in a surface thereof facing a valve seat. A sealing member fills the recess of the main body. The sealing member is made of annealed nickel. The annealed nickel has a low hardness, so that the sealing member is slightly depressed by abutment thereof against the valve seat. The sealing member is then hardened by further application of stresses. Therefore, complete sealing between the sealing member and the valve seat can be achieved.

Abstract: A flow control valve includes a valve member mounted in a valve chamber having an inlet port, through which a fluid flows into the valve chamber, and an outlet port through which the fluid flows out of the valve chamber. The valve member is slidable in the valve chamber in response to a driving force applied from an actuator. Valve seat member is mounted in the valve chamber in opposed relation to the valve member, the valve seat member cooperating with the valve member to control a rate of flow of the fluid. The valve seat member has at least a first hole formed therein and extending in a direction of driving of the valve member, a second hole formed therein and extending from an outer peripheral surface thereof and a third hole which is separated from the first hole and extends from its surface facing the valve member to the second hole in a direction of driving of the valve member, the second hole extending in a direction substantially perpendicular to the direction of driving of the valve member.

Abstract: Elastic members are retained in respective recesses of open boxes. Heating (cooling) temperature sensing elements are held on the elastic member. A pipe which has already been laid is sandwiched between the open boxes such that the heating (cooling) temperature sensing elements join to desired positions, respectively, of the existing pipe. The pipe is subjected to a temperature change by the heating (cooling) temperature sensing elements, and hence the fluid therein is subjected to a temperature change, causing a temperature gradient to occur between the upper and lower streams of the fluid flow. The temperature gradient is detected by the heating (cooling) temperature sensing elements, and a flow rate of the fluid flowing through the pipe is obtained on the basis of the outputs of the sensing elements.

Abstract: A solenoid valve is disclosed and includes a solenoid, a plunger made of a magnetic material, and a yoke receiving the plunger therein such that the plunger may be moved by the magnetic field produced by the solenoid. A valve element is connected to the plunger for controlling the rate of flow through the solenoid valve. A permanent magnet is disposed in a desired position outside the yoke. The magnetic flux of the magnetic field of the permanent magnet is effectively used for damping the oscillation of the plunger to thereby achieve excellent controllability of the valve.

Abstract: A laminar flow device includes a plurality of disks and a plurality of spacers alternately stacked together. The plurality of disks are defined by first disks and second disks, each of the first disks having a hole formed through a central portion thereof, and each of the second disks having a plurality of holes formed through an outer peripheral portion thereof. The first disks and the second disks are alternately arranged with the spacer interposed between any two adjacent ones of the disks.

Abstract: A mass flow controller includes a photoelectric transducer for receiving information through an optical fiber and an electro-optical transducer for transmitting the result of detection of the mass flow through the optical fiber, thereby transmitting and receiving information through the optical fiber. Accordingly, the transmission and reception of data between the host computer and the mass flow controller performed through the optical fiber are not affected by electro-magnetic noise. Further, the mass flow controller can include a correction device responsive to a command from the host computer for correcting the result of a detection, to thereby accurately process the result of the detection because the result of the detection is corrected as required and then transmitted to the host computer as the correct data.

Abstract: A flow control valve of the present invention includes a valve member mounted in a valve chamber having an inlet port, through which a fluid flows into the valve chamber, and an outlet port through which the fluid flows out of the valve chamber, the valve member being slidable in the valve chamber in response to a driving force applied from an actuator, and a valve seat member mounted in the valve chamber in opposed relation to the valve member, the valve seat member cooperating with the valve member to control a rate of flow of the fluid.

Abstract: A mass flow sensor is capable of accurately measuring a mass flow irrespective of changes in the ambient temperature. The mass flow sensor includes at least one heating resistor disposed on a portion of a sensor pipe through which a fluid to be measured flows and a housing for the sensor pipe. The heating resistor and a temperature sensitive resistance constitute a bridge circuit. The temperature sensitive resistance is disposed in the housing. The resistance of the sensor changes in accordance with the change in the temperature of the housing to thereby adjust the change in the resistance of the heating resistor. Further, an improved temperature sensitive matching resistor is suitably used in the mass flow sensor, in which a plurality of temperature sensitive resistances having equal characteristics are integrated.

Abstract: A flowmeter sensor includes a sensor tube, and a heater/resistor through which the sensor tube passes. The heater/resistor includes a substantially cylindrical sleeve fitted around the sensor tube and made of ceramic. A thin film of platinum is deposited on the sleeve and is then partially removed by a laser to provide a helical resistance pattern. A pair of electrically conductive rings are tightly fitted around opposite ends of the ceramic sleeve and serve as bases to be connected with a corresponding pair of leads.

Abstract: A bypass unit of a flowmeter sensor includes a chamber, inlet and outlet paths through which a fluid flows into and out of the chamber, an upstream bypass path through which a portion of the fluid is diverted from the chamber to a sensor tube, and a downstream bypass path through which the portion of the fluid is returned from the sensor tube to the chamber. A bypass member is arranged within the chamber and a space is defined between the peripheral wall of the housing and the bypass member. The bypass member includes inlet and outlet ports formed in coaxial relation to the inlet and outlet paths, respectively, and a plurality of radial ports. A substantially cylindrical partition is disposed between the peripheral wall of the housing and the bypass member to define a space between the peripheral wall of the housing and the partition and between the partition and the bypass member.