Abstract: A method for detecting the solid particles contained in a fluid, by the use of a particle sensor having a flow path of a fluid, having a fluid inlet and a fluid outlet, and a sensor element provided in the flow path, which comprises (a) a vibrating section having such a mass that is sensitive to the collision of solid particles contained in the fluid, with the vibrating section and (b) a detecting section for detecting the vibration of the vibrating section caused by the collision and converting the vibration to electric signals.

Abstract: A particle sensor includes a flow path of a fluid, having a fluid inlet and a fluid outlet, and a sensor element provided in said flow path, which comprises (a) a vibrating section having such a mass that is sensitive to the collision of solid particles contained in the fluid, with the vibrating section and (b) a detecting section for detecting the vibration of the vibrating section caused by said collision and converting the vibration to electric signals. The sensor has a means capable of selectively detecting any vibration of the vibrating section having a frequency higher than the primary resonance frequency of the sensor element. This particle sensor has improved sensitivity to solid particles and can distinguish the signals generated by collision of solid particles, from the signals generated by collision of bubbles, at a high accuracy.

Abstract: A resistor element has a ceramic substrate and a metallic resistor coated onto the substrate. The metallic resistor has varied electrical resistance depending on temperature. A pair of leads are electrically connected to the metallic resistor. A plurality of glass layers having different compositions are coated onto the metallic resistor. The second glass layer fills a hole formed in the first glass layer, thereby improving response of the resistor element. The second glass layer has a softening point lower than the first glass layer, thereby small bubbles remain dispersed in each glass layer without aggregation. An outermost glass layer is composed of a glass resisting chemicals or a glass resisting abrasion. An innermost glass layer is composed of a glass containing up to 3 percent by mole of a sum of Na.sub.2 O and K.sub.2 O.

Abstract: A thermal flowmeter for determining a parameter of a fluid flowing through a passage, includes: (a) resistor element including: an electrically insulating substrate; a metallic resistor supported by the substrate and having an electrical resistance which varies with an ambient temperature; and a pair of electrical conductors provided at opposite ends of the substrate and (b) electrically connected to the metallic resistor; and a pair of electrically conductive supports, fixed to a wall defining the passage, for securing the pair of electrical conductors, respectively, at securing portions in the pair of supports so that the resistor element is arranged in the passage; wherein a first distance between the pair of supports at the wall is smaller than a second distance between the pair of supports at the securing portions. The thermal flowmeter is durable under thermal stresses, especially when an ambient temperature around the thermal flowmeter frequently varies.

Abstract: A thermal type of flow rate sensor includes heat-generating and temperature-compensating resistors R.sub.H and R.sub.C which are located within a fluid passage to measure the flow rate of the fluid. The linear term coefficient, .alpha., of the temperature coefficient of resistance of R.sub.C is made smaller than that of R.sub.H, whereby any temperature-compensating electric circuit and circuit control can all be dispensed with and the flow rate of a fluid can be precisely detected over a wide temperature range.

Abstract: A resistor for a thermal type of flowmeter includes a ceramic substrate, a thin platinum film formed on the surface of the ceramic substrate, and lead wires for connecting the thin platinum film with an external circuit, and is located in a fluid to detect its flow rate. When the resistance value, R (.OMEGA.) , of the resistor for a thermal type of flowmeter is expressed in terms of a function of temperature, T (.degree.C.):R=R.sub.0 (1+.alpha.T+.beta.T.sup.2)where R.sub.0 is the resistance value in .OMEGA. of the resistor for a thermal type of flowmeter at 0.degree. C., .alpha. is the first-order term coefficient of the temperature coefficient of resistance, and .beta. is the second-order term coefficient of the temperature coefficient of resistance, the value of the first-order term coefficient, .alpha., of the temperature coefficient of resistance is at least 3,650 ppm/.degree.C.

Abstract: A thermal flowmeter for determining a parameter of a fluid flowing through a passage, including a detecting element, and a pair of electrically conductive supports fixed to a wall defining the passage for supporting the detecting element. The detecting element includes a substrate, an electrically resistive body disposed on the substrate and having an electrical resistance which varies with an ambient temperature, and a pair of electrical conductors provided at opposite ends of the support and electrically connected to the electrically resistive body. The detecting element is positioned in the passage such that the electrical conductors are secured to the electrically conductive supports. The electrically conductive supports have respective engaging portions which engage the electrical conductors, respectively, for positioning the detecting element with respect to the wall of the passage.

Abstract: A resistor element for determining a parameter, including a ceramic support, an electrically resistive body formed on the ceramic support, at least one lead wire electrically connected to the electrically resistive body, and an adhesive containing platinum for securing the lead wire(s) to the ceramic support. Each lead wire includes a wire rod having a lower thermal conductivity than platinum, and a covering layer which covers the wire rod and is formed of an alloy including platinum as a major component.

Abstract: A resistor element including a cylindrical ceramic support having two openings open on longitudinally opposite end faces thereof, an electrically resistive layer formed on an outer circumferential surface, a pair of electrical conductors for connecting the electrically resistive layer to an external circuit, each of which has an end portion inserted into a corresponding one of the openings of the ceramic support, and an electrically conductive adhesive filling each opening of the ceramic support, for securing the end portion of the corresponding conductor to the ceramic support. The electrically resistive layer has two integrally formed extensions for covering the opposite end faces of the ceramic support, respectively, and respective inner wall surfaces of the openings of the ceramic support. The conductors are electrically connected to the extensions of the resistive layer by the electrically conductive adhesive filling each opening of the ceramic support.

Abstract: A thermal flowmeter for determining a parameter of a fluid flowing through a passage, including a detecting element, and a pair of electrically conductive supports fixed to a wall defining the passage for supporting the detecting element. The detecting element includes a substrate, an electrically resistive body disposed on the substrate and having an electrical resistance which varies with an ambient temperature, and a pair of electrical conductors provided at opposite ends of the support and electrically connected to the electrically resistive body. The detecting element is positioned in the passage such that the electrical conductors are secured to the electrically conductive supports. The electrically conductive supports have respective engaging portions which engage the electrical conductors, respectively, for positioning the detecting element with respect to the wall of the passage.

Abstract: A resistor element for determining a parameter, which includes a ceramic support having a bearing surface, an electrically resistive metallic layer formed on the bearing surface of the ceramic support, and a glass coating covering the metallic layer. The metallic layer has a plurality of pores which extend from an outer surface of the metallic layer to the bearing surface of the ceramic support, each pore having an area which is not smaller than that of a circle having a diameter of 1 .mu.m. An average spacing between adjacent ones of the pores is not larger than 5 .mu.m.

Abstract: A detection element including a cylindrical base body, an electric resistor formed on an outer peripheral surface of the base body, and lead wires attached to ends of the base body. The lead wires are electrically connected to the electric resistor. An electrically thick film is provided over end faces of the base body, an inner peripheral surface and an outer peripheral surface of the base body near each of the opposite ends of the base body, and the lead wires are electrically connected to the resistor at least through the electrically conductive thick film.

Abstract: A stress sensor for detecting a stress, including a ceramic hollow member, a pair of support members for supporting the ceramic hollow member, and at least one resistor provided on the ceramic hollow member. The ceramic hollow member is deformable according to a stress applied thereto in a direction in which a hollow of the hollow member extends. The support members are disposed at opposite ends of the hollow member, so as to support the hollow member such that the stress is imparted to the hollow member through the pair of support members. The resistor or resistors is/are disposed on one of the inner and outer surfaces of the hollow member. The stress is detected based on a change in the electrical resistance value of the resistor or resistors which is caused by the deformation of the hollow member.

Abstract: A pressure sensor including a ceramic diaphragm which is deformable in response to a pressure applied thereto, a ceramic base associated with a periphery of the ceramic diaphragm, for supporting the ceramic diaphragm, and at least one resistor formed on the ceramic diaphragm. Resistance values of the resistor are adapted to vary depending upon a magnitude of deformation of the ceramic diaphragm, and thereby represent the pressure applied to the ceramic diaphragm. The ceramic diaphragm and the ceramic base consist of a co-fired body obtained by co-firing an unfired diaphragm member and an unfired base member.

Abstract: A thermo-sensitive resistor including an electrically insulating substrate, a thin-film heating resistor formed on the substrate and lead wires electrically connected to the thin-film heating resistor, wherein the resistance of the thin-film heating resistor is adjusted by increasing or decreasing a film thickness of a previously formed base thin-film heating resistor by means of an electroplating method or an electroless plating method, and thus the area for heating of the thermo-sensitive resistor can remain constant even if the resistance adjustment is performed.

Abstract: The invention relates to a pressure sensor having a ceramic diaphragm which is exposed at one of opposite surfaces thereof to a measurement fluid in an external space and deformable in response to a pressure of the measurement fluid, and a strain detector for producing an electrical output representative of an amount of deformation of the ceramic diaphragm. The ceramic diaphragm is fixedly supported at an outer portion thereof, so that a central working portion of the diaphragm is deformable in response to the pressure of the measurement fluid applied thereto. The sensor includes a baffling structure disposed adjacent the above-indicated one surface of the ceramic diaphragm. The baffling structure has portions which partially define a chamber to which the above-indicated one surface of the ceramic diaphragm is exposed.

Abstract: A pressure sensor having a ceramic pressure sensing element including a bottom wall serving as a diaphragm, and a tubular wall which extends from a periphery of the bottom wall and cooperates with the bottom wall to define a cavity. The diaphragm has resistors formed thereon. The resistors are electrically connected to an external electric device by electrically conductive members. The sensing element is held in a housing by a retainer member such that one end of the retainer member is aligned with an end face of the tubular wall remote from the bottom wall. A biasing member is provided for biasing the retainer member toward the ceramic pressure sensing element, to exert a retaining force to the sensing element.

Abstract: The invention relates to a pressure sensor including a metallic housing having an open end with an opening, a ceramic diaphragm accommodated within the housing such that the diaphragm is exposed at its one major surface to a pressure of a fluid in an external space through the opening of the housing, and resistors formed integrally on the diaphragm. The electrical resistance of the resistors varies with the pressure acting on the ceramic diaphragm, whereby the pressure is determined by the electrical resistance. An electromagnetic shielding member is disposed within the metallic housing such that the shielding member is positioned between the resistor or resistors and the open end of the metallic housing. The shielding member is adapted to protect the resistors from an electromagnetic wave in the external space.

Abstract: A pressure sensor including a cylindrical metallic housing having an open end having an opening, a ceramic pressure sensing element having a ceramic diaphragm and fixedly accommodated within an open end portion of the metallic housing, and a strain detector associated with the ceramic diaphragm. The ceramic diaphragm is exposed at one of opposite major surfaces thereof to an external space through the opening of the metallic housing and is deformable in response to a pressure of a measurement fluid in the external space. An electrical output of the strain detector varies with an amount of deformation of the ceramic diaphragm, thereby representing the pressure of the fluid.

Abstract: A pressure sensor including a ceramic diaphragm which is deformable in response to a pressure applied thereto, a ceramic base associated with a periphery of the ceramic diaphragm, for supporting the ceramic diaphragm, and at least one resistor formed on the ceramic diaphragm. Resistance value of the resistor are adapted to vary depending upon a magnitude of deformation of the ceramic diaphragm, and thereby represent the pressure applied to the ceramic diaphragm. The ceramic diaphragm and the ceramic base consist of a co-fired body obtained by co-firing an unfired diaphragm member and an unfired base member.