Abstract: A differential pressure transmitter for detecting a difference between a pressure of a first detection fluid in a first pressure-receiving chamber and a pressure of a second detection fluid in a second pressure-receiving chamber, including a first diaphragm for sealing the first detection fluid, a second diaphragm for sealing the second detection fluid which is installed almost in parallel to the first diaphragm, a first isolation chamber communicated to the first pressure-receiving chamber, a second isolation chamber communicated to the second pressure-receiving chamber, a third diaphragm installed between the first and the second chambers and in a direction different from those of the first and second diaphragms, and a differential pressure detection sensor installed on and connected to at least one of the first and the second isolation chambers.

Abstract: A compact pressure differential/pressure detector is a process detection apparatus for measuring a pressure, a level, a pressure differential of a process fluid. The detector is constructed of a pressure sensing block having sensors for sensing a pressure and a pressure differential, a signal processing block for processing signals from the pressure sensing block, and a terminal board block for receiving power supply from outside and transmitting signals to outside. These blocks are arranged along the same axis. Furthermore, an indicator indicating a process state is also arranged along the same axis and received in a covering case. The case is firmly attached to the pressure sensing block. The process detection apparatus permits a compact design and offers an excellent maintainability.

Abstract: A differential pressure transmitter detects a differential pressure condition of a fluid by means of a semiconductor sensor. First and second seal diaphragms are provided in a member which constitutes the differential pressure transmitter, to form first and second pressure receiving chambers. An overload protection diaphragm and first and second damper chambers are provided at positions close to the first and second pressure receiving chambers. Also, there are provided a passage for connecting the first pressure receiving chamber and the first damper chamber, a passage for connecting the second pressure receiving chamber and the second damper chamber, and passages for connecting the first and second damper chambers respectively with the semiconductor sensor. Even when a change is caused in the temperature of a processed fluid to be detected, the differential pressure transmitter quickly detects the temperature change, so that a differential pressure of the processed fluid can be measured with high accuracy.

Abstract: A differential pressure transmitter having a differential pressure sensor, a temperature sensor and a static pressure sensor all provided on the semiconductor substrate of a single semiconductor chip. A reference resistor is provided in a part of the chip. Resistances of the differential pressure sensor and the reference resistor are compared periodically in order to determine the condition including service life of the differential pressure sensor.

Abstract: A multi-function differential pressure sensor includes a semiconductor chip, a stationary base having a joining portion joined to a thick wall portion of the semiconductor chip, and a housing joined to the stationary base. The semiconductor chip is provided with a differential pressure detection unit, a static pressure detection unit, and a temperature detection unit. The joining portion of the stationary base is not thicker than the semiconductor chip. The stationary base has one or more thin wall portions located, in a plan view, within a circular pressure sensitive diaphragm of the semiconductor chip.

Abstract: A measuring and controlling system is provided which has a control function as well as a measurement function to perform the measurement and control of fluid amounts such as the flow rate, pressure, liquid level, weight and so on by itself in the same field. A pressure receiving unit is directly mounted on a pipe or a container, in which a fluid under measurement exists, in order to detect the temperature, differential pressure and static pressure of the fluid under measurement independently of each other. Means for storing the characteristic of fluids under measurement is provided such that the mass flow rate, weight and liquid level can be calculated.

Abstract: A differential pressure sensor is disclosed, and in particular, there is disclosed a multiple function type differential pressure sensor capable of reducing a zero-point-change and a span change of means for detecting a differential pressure when applying a static pressure and being readily manufactured at high accuracy. The multiple function type differential pressure sensor is constructed by a semiconductor chip 1 for detecting a differential pressure, a fixing base 2 which has a joining part 21 joined to a thick part of the semiconductor chip 1 and which has a thickness less than or equal to that of the semiconductor chip 1, and also which has at least one thin part 22 in an outer periphery other than the joining part 21, and a housing 4 joined to the fixing base.

Abstract: In an integrated multisensor used in a differential and static pressure transmitter, a pair of static pressure gages are formed on a static pressure detecting diaphragm and another pair of static pressure gages are formed at positions on a fixed portion which are near to the center of a differential pressure detecting diaphragm. The second term generated by a differential pressure appearing in a static pressure sensor is a function of a distance. Therefore, equal influence is exerted on each static pressure gage. Accordingly, by constructing a static pressure sensor so as to form a bridge circuit, a static pressure value free of the influence of a differential pressure can be detected, thereby making it possible to determine an accurate differential and static pressure.

Abstract: There is provided a pressure measuring sensor having a diaphragm including a peripheral fixing portion so formed as to be fixed to a pressure measuring sensor proper and be thick, a pressure receiving portion responsive to a pressure to be measured to move, and a strain causing portion responsive to the movement of the pressure receiving portion to cause strain, the pressure receiving portion having a shape so formed as to substantially perform the same function as a member having a high rigidity when moving in response to a change in the above described pressure to be measured, and the strain causing portion being substantially subject to bending stress in response to the movement of the pressure receiving portion moved according to the change in the above described pressure to be measured and thereby the strain causing portion providing a plurality of gauge resistors formed on the strain causing portion with tensile stress or compressive stress proportionate to the pressure to be measured.

Abstract: In a differential pressure transmitter having pressure receiving diaphragms forming recesses, a center diaphragm therebetween so as to define two chambers filled with pressure transmission medium, first communication passages respectively connecting the two chambers to the recesses and second communication passages respectively connecting the two chambers to pressure measuring chambers. The diameters of the first communication passages are less than predetermined values determined by the viscosity and volume modulus of the pressure passages, and the volume of the pressure-measuring chamber. The frequency of characteristic vibration and gain of the pressure-measuring chamber and the second communication passage in one side is respectively and substantially equal to that in the other side. A drastic transient pressure transmitted to sensors in the pressure-receiving recesses is absorbed by the communication passages and is not transmitted to the sensor in the form of a differential pressure.

Abstract: A semiconductor pressure converting device including a fixing table joined to a silicon diaphragm consists of 2 structures superposed on each other, in which the longitudinal elastic modulus of the first fixing table is significantly different from the longitudinal elastic modulus of the semiconductor diaphragm. The first fixing table is highly insulating and the linear expansion coefficient thereof is approximately equal to the linear expansion coefficient of the semiconductor diaphragm. The second fixing table is made of a material having a longitudinal elastic modulus and a linear expansion coefficient approximately equal to those of the semiconductor diaphragm.

Abstract: A semiconductor differential pressure transducer comprises a pair of pressure receiving chambers at both sides of a pressure receiving part, and a pair of compensating chambers and a pair of pressure measuring chambers which are placed in the pressure receiving part, and the pressure receiving chambers communicate with the pressure measuring chambers through the compensating chambers.