Abstract: A pressure sensor includes a joint portion, and a shock mitigating member including therein a flow path communicating with a branch path. The shock mitigating member includes a first flow path configured to cause a fluid to linearly flow, a blocking wall configured to block the fluid from linearly flowing, and a second flow path communicating with the first flow path and configured to cause the fluid to flow in a direction different from an axial center of the first flow path. Further, the shock mitigating member includes outlets with which the second flow path communicates, and a gap for adjusting a pressure of the fluid is formed between the shock mitigating member and the joint portion.

Abstract: A pressure sensor includes a joint portion, and a shock mitigating member including therein a flow path communicating with a branch path. The shock mitigating member includes a first flow path configured to cause a fluid to linearly flow, a blocking wall configured to block the fluid from linearly flowing, and a second flow path communicating with the first flow path and configured to cause the fluid to flow in a direction different from an axial center of the first flow path. Further, the shock mitigating member includes outlets with which the second flow path communicates, and a gap for adjusting a pressure of the fluid is formed between the shock mitigating member and the joint portion.

Abstract: A rectifying module is arranged on an upstream side of a flow passage containing a flow velocity sensor. The rectifying module includes mesh members each having a plurality of circular small holes and ring-shaped spacers, wherein the mesh members and the spacers are alternately stacked in an axial direction and integrally joined to one another by means of thermal diffusion bonding. The mesh members have identical structures, in which the plurality of small holes are arranged concentrically at angles of separation of 60 degrees in the circumferential direction about the center of a reference small hole. The small holes are formed over the entire surface of the mesh member continuous with adjoining other small holes. The small holes of one mesh member and another mesh member adjacent thereto in the axial direction are arranged so as to have a phase angle difference of 90 degrees in the circumferential direction.

Abstract: A rectifying module is arranged on an upstream side of a flow passage containing a flow velocity sensor. The rectifying module includes mesh members each having a plurality of circular small holes and ring-shaped spacers, wherein the mesh members and the spacers are alternately stacked in an axial direction and integrally joined to one another by means of thermal diffusion bonding. The mesh members have identical structures, in which the plurality of small holes are arranged concentrically at angles of separation of 60 degrees in the circumferential direction about the center of a reference small hole. The small holes are formed over the entire surface of the mesh member continuous with adjoining other small holes. The small holes of one mesh member and another mesh member adjacent thereto in the axial direction are arranged so as to have a phase angle difference of 90 degrees in the circumferential direction.

Abstract: A threshold value is stored in a CPU using setting switches. When a fluid is introduced into a flow passage, a rod disposed in the flow passage sheds Karman vortexes downstream thereof in the fluid as it flows through the flow passage. A piezoelectric device generates an electric signal depending on pressure fluctuations of the Karman vortexes, and the electric signal is applied through a comparator to the CPU. The CPU refers to a data table stored in a memory to determine a flow rate of the fluid based on the period of the electric signal. When the determined flow rate is greater than the threshold value, the CPU turns on transistors to energize loads as external devices. When the determined flow rate is smaller than the threshold value, the CPU turns off transistors to de-energize loads.

Abstract: A threshold value is stored in a CPU using setting switches. When a fluid is introduced into a flow passage, it lowers the temperature of a first thermistor heated by a regulated constant-current source, increasing the output voltage of the first thermistor. A second thermistor outputs a voltage corresponding to the temperature of the fluid. A differential amplifier outputs a differential voltage between the output voltages of the first and second thermistors, and the differential voltage is converted by an A/D converter into a digital voltage that is applied to a CPU. The CPU refers to a data table stored in a memory to determine a flow rate of the fluid based on the digital differential voltage. When the determined flow rate is greater than the threshold value, the CPU turns on transistors to energize loads as external devices. When the determined flow rate is smaller than the threshold value, the CPU turns off transistors to de-energize loads.

Abstract: A pressure detector includes a pressure introducer formed in a pipe with a through-hole defined therein and connected to a pressure sensor at one end. A tube fitting is mounted in advance to a fluid passage to which the pressure detector is connected. The other end of the pressure introducer of the pressure detector is inserted axially into an opening of the tube fitting. Thus, the pressure detector is easily connected to the fluid passage without requiring rotating of the pressure detector about the axis of the pressure introducer.