Pressure gauge

Abstract

The present invention provides a pressure gauge (1) that is easy to handle, compact, and suitable for remote pressure monitoring. This pressure gauge (1) comprises: a shaft rotation mechanism (3) that rotates a rotary shaft (2) by an angle corresponding to a pressure to be measured; a pressure display unit (6) that displays a measured value of the pressure by means of a pointer (4) fixed to one end of the rotary shaft (2); and a magnet (7) which is fixed to the other end of the rotary shaft (2) and which rotates in conjunction with the rotary shaft (2). A signal transmission unit (1) is attachable to and detachable from the pressure gauge (1). The signal transmission unit (10) comprises a transmission means (13) that, in a state with the signal transmission unit (10) attached to the pressure gauge (1), transmits an output signal of a sensor (12) that detects the magnetic field of the magnet (7) to a position at which to monitor said pressure.

Description

Pressure gauge

[0001] The present invention relates to a pressure gauge having a magnet fixed to the shaft of a pointer and rotating in conjunction with the shaft.

[0002] Conventionally, there is known a display device for the pressure that can be displayed, which displays the pressure in a compressed gas container by a pointer that swings along a scale plate and also in a display instrument arranged at a predetermined distance from the instrument (see, for example, Patent Document 1).

[0003] In the device of Patent Document 1, in order to display the pressure even in a display instrument separated from the instrument, a magnetic field change at a fixed point is sent as a function of the movement amount of the pointer by using a permanent magnet attached to the pointer of the pressure gauge. Therefore, a magnetic Hall effect sensor that sends an electrical signal proportional to the change in the magnetic field is arranged. The output signal of this sensor is amplified by an amplifier and sent to a display unit. The display instrument displays the pressure based on this amplified signal.

[0004] Japanese Patent Application Laid-Open No. 57-212600

[0005] However, according to the pressure display device of Patent Document 1 described above, the magnetic Hall effect sensor is arranged at a fixed point at a certain distance from the permanent magnet. This fixed point is a point where the magnetic force lines from the permanent magnet are as linear as possible. Therefore, since the distance from the permanent magnet to the magnetic Hall effect sensor is somewhat large, the size of the display device including the magnetic Hall effect sensor becomes large accordingly.

[0006] Further, since the magnetic Hall effect sensor, the pointer, the permanent magnet, and the power source are arranged in the same instrument, for example, when performing battery replacement or the like, maintenance work becomes complicated because it involves disassembling the instrument. Even when it is sufficient to display the measured value of the pressure only with the pointer, since the magnetic Hall effect sensor and its power source are always integrally configured inside the instrument, it may become an excessive function.

[0007] Furthermore, although there is also a commercially available remote monitoring device that can be selectively attached to a single-function pressure gauge and converts and transmits the pressure electrically, there is a problem that disassembling the pressure gauge is involved in its attachment.

[0008] In view of the problems of the prior art, the object of the present invention is to provide a pressure gauge that is easy to handle, compact, and convenient, and is also suitable for remote pressure monitoring.

[0009] The pressure gauge of the present invention comprises a rotating shaft that is rotatably supported, a shaft rotation mechanism that applies a rotational force to the intermediate part of the rotating shaft to rotate it by an angle corresponding to the pressure to be measured, a pressure display unit that displays the measured value of the pressure using a pointer and a scale plate fixed to one end of the rotating shaft and rotating in conjunction with the rotating shaft, and a magnet fixed to the other end of the rotating shaft and rotating in conjunction with the rotating shaft.

[0010] A signal transmission unit is detachably attached to the pressure gauge. The signal transmission unit includes a transmission means that, when the signal transmission unit is attached to the pressure gauge, transmits the output signal of a sensor that detects a magnetic field that changes due to the rotation of the magnet linked to the rotating shaft to a monitoring position that monitors the pressure.

[0011] According to the present invention, when a signal transmission unit is attached to a pressure gauge, a signal indicating the measured value from the pressure gauge can be detected by a sensor in the signal transmission unit, transmitted to a remote location by a transmission means, and fluctuations in the measured value can be monitored.

[0012] Furthermore, if remote monitoring is not required, the pressure gauge can be used as a standalone unit without the signal transmission unit. In this case, maintenance work such as replacing batteries or secondary batteries that supply power to the sensors and transmission means of the signal transmission unit can be performed with the signal electrical unit detached from the pressure gauge, greatly improving convenience. Therefore, according to the present invention, it is possible to provide a pressure gauge that is easy to handle, compact, convenient, and suitable for remote pressure monitoring.

[0013] Furthermore, in sealed pressure gauges designed to absorb vibrations and pulsations by filling the pressure gauge with glycerin, disassembly is difficult. However, the pressure gauge of the present invention, in which the signal transmission unit is detachable, is particularly effective against such glycerin-type pressure gauges.

[0014] This is a simplified side view showing the configuration of a pressure gauge and signal transmission unit according to one embodiment of the present invention. This is a diagram showing the axial rotation mechanism that rotates the rotation axis of the pressure gauge in Figure 1. This is a cross-sectional view showing the configuration of the pressure gauge and signal transmission unit in Figure 1. This is an exploded perspective view showing the configuration of the pressure gauge and signal transmission unit in Figure 1. This is a perspective view showing the structure of the magnet held by the magnetic spacer in the pressure gauge in Figure 3.

[0015] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 shows a simplified pressure gauge and signal transmission unit according to one embodiment of the present invention. As shown in Figure 1, the pressure gauge 1 includes a rotating shaft 2 that is rotatably supported, a shaft rotation mechanism 3 that applies a rotational force to the intermediate part of the rotating shaft 2 to rotate the rotating shaft 2 by an angle corresponding to the pressure to be measured, and a pressure display unit 6 that displays the measured pressure value using a pointer 4 fixed to one end of the rotating shaft 2 and rotating in conjunction with the rotating shaft 2, and a scale plate 5.

[0016] Furthermore, the pressure gauge 1 is equipped with a magnet 7 fixed to the other end of the rotating shaft 2, which rotates in conjunction with the rotating shaft 2. The pressure gauge 1 having the above configuration is housed in a housing 8. The front of the housing 8 is made of a glass plate 9 so that the pointer 4 and the scale plate 5 can be seen.

[0017] A signal transmission unit 10, which transmits a signal corresponding to the measurement value from the pressure gauge 1 to a monitoring location, is detachably attached to the housing 8 of the pressure gauge 1. The signal transmission unit 10 is configured to be detachably attached to the back surface of the housing 8 of the pressure gauge 1 while housed in a transmission unit storage case 11.

[0018] The signal transmission unit 10 includes a sensor 12 that detects the magnetic field that changes due to the rotation of a magnet 7 linked to a rotating shaft 2 while mounted on the housing 8 of the pressure gauge 1, and outputs a signal corresponding to the measured pressure, and a transmission means 13 that transmits the output signal of the sensor 12 to a monitoring position that monitors the pressure. In this case, a magnetoresistive element (MR sensor) is used as the sensor 12.

[0019] Figure 2 shows the specific configuration of the pressure transmission mechanism 14 as viewed from the back of the scale plate 5. As shown in Figure 2, the pressure transmission mechanism 14 includes an introduction section 15 for introducing the pressure to be measured, a Bourdon tube 16 connected to the introduction section 15 that deforms in accordance with the change in pressure, and the aforementioned axial rotation mechanism 3 that rotates the rotation axis 2 of the pointer 4 in accordance with the deformation of the Bourdon tube 16. Note that the magnet 7 is not shown in Figure 2.

[0020] Figures 3 and 4 are cross-sectional and exploded perspective views, respectively, specifically illustrating the configuration of the pressure gauge 1 and the detachable signal transmission unit 10 shown in Figure 1. As shown in Figures 3 and 4, the magnet 7 inside the pressure gauge 1 is fixed to the rotating shaft 2 via a magnetic spacer 17. Inside the back plate that closes the back side of the housing 8 of the pressure gauge 1, a magnetic plate 19 is provided for detachably attaching the transmission unit housing case 11, which houses the signal transmission unit 10, to the housing 8 of the pressure gauge 1.

[0021] The transmission unit housing case 11 consists of a circuit board fixing case 20 in which the signal transmission unit 10 is fixed, and a case cover 21 that covers the circuit board fixing case 20. The transmission unit housing case 11 is attached to the pressure gauge 1 via the outer surface of the circuit board fixing case 20.

[0022] On the outer surface of the circuit board fixing case 20, a mounting magnet 22 is provided at a position corresponding to the magnetic plate 19 of the pressure gauge 1, and is capable of being attracted to the magnetic plate 19. In other words, the transmission unit housing case 11 is detachably attached to the housing 8 of the pressure gauge 1 by the magnetic plate 19 and the mounting magnet 22. Therefore, the signal transmission unit 10 is attached to the pressure gauge 1 by attaching the transmission unit housing case 11 to the housing 8.

[0023] In this embodiment, a method of attachment and detachment using a magnetic plate 19 and a mounting magnet 22 is illustrated, but the method is not limited to this. Screws can be used, the housing 8 and the transmission unit housing case 11 can be screwed together, or a removable silicone-based adhesive can be used.

[0024] The signal transmission unit 10 includes the aforementioned sensor 12, which detects a magnetic field that changes due to the rotation of a magnet 7 linked to a rotating shaft 2 and outputs a signal corresponding to the pressure to be measured, when the signal transmission unit 10 is attached to the pressure gauge 1, and the aforementioned transmission means 13, which transmits the output signal of the sensor 12 to a monitoring position that monitors the pressure. Wi-Fi, Bluetooth®, other wireless communication means, or wired communication means can be used as the transmission means 13.

[0025] The power transmission means 13 includes a circuit board 23 fixed to a substrate fixing case 20, a wireless communication board 24 provided on the circuit board 23, a battery holder 25 fixed to the circuit board 23, a battery 26 attached to the circuit board 23 via the battery holder 25, and an antenna sheet 27 provided on the battery 26. Power is supplied from the battery 26 to the sensor 12 and the wireless communication board 24 via a power connector 28.

[0026] The sensor 12 is positioned to face the magnet 7 and appropriately detect changes in the magnetic field caused by the magnet 7 when the signal transmission unit 10 is attached to the pressure gauge 1. Specifically, the sensor 12 is located in the center of the circuit board 23, which is fixed inside the substrate fixing case 20. The power on and off operation of the sensor 12 and the transmission means 13 is performed by the power switch 29. The power on / off status is monitored by the power LED 30.

[0027] Figure 5 shows a magnet 7 held by a magnetic spacer 17. As shown in Figure 5, the center line of the magnet 7, extending between its south pole S and north pole N, is located on the central axis of the rotation axis 2 or its extension L. Preferably, as shown in Figure 5, the magnet 7 is a cylindrical ferromagnetic metal material magnetized radially (in the direction of the arrow in the figure) such that one semi-cylindrical portion becomes the north pole N and the other semi-cylindrical portion becomes the south pole S. The magnet 7 is then positioned so that the center line of its cylindrical shape coincides with the central axis of the rotation axis 2 or its extension L.

[0028] In this configuration, when pressure from water, gas, compressed air, etc., is introduced into the inlet 15 of the pressure gauge 1, the Bourdon tube 16 deforms. The axial rotation mechanism 3 rotates the rotation shaft 2 according to the amount of this deformation. The pointer 4 rotates in conjunction with this rotation and indicates a mark on the scale plate 5, so the measured pressure value can be determined by reading the indicated mark on the scale.

[0029] In this case, if the signal transmission unit 10 is attached to the pressure gauge 1 by attraction between the mounting magnet 22 of the transmission unit housing case 11 and the magnetic plate 19 of the housing 8 of the pressure gauge 1, the magnetic field of the magnet 7, which rotates in conjunction with the rotation of the rotating shaft 2, fluctuates according to the amount of rotation. This fluctuation in the magnetic field is detected by the sensor 12, and the detection signal is transmitted by the transmission means 13 to the monitoring position (display instrument) that monitors the pressure.

[0030] This detection signal has a signal value corresponding to the measurement value by the pressure gauge 1. Therefore, at the monitoring location, the transmitted detection signal can be received, and a value equivalent to the measurement value by the pressure gauge 1 can be displayed based on that signal value.

[0031] As described above, according to this embodiment, since the magnet 7 that rotates in conjunction with the pointer 4 is provided at the end of the rotating shaft 2 opposite to the pointer 4, the change in the magnetic field accompanying the rotation of the magnet 7 can be easily detected by the sensor 12 from the back side of the pressure gauge 1.

[0032] Therefore, by attaching a transmission unit housing case 11 having a sensor 12 and a transmission means 13 to the housing 8 of the pressure gauge 1, detection signal values ​​equivalent to the measured values ​​from the pressure gauge 1 can be transmitted to a remote location, and the measured values ​​can be monitored at the remote location to monitor pressure fluctuations.

[0033] Furthermore, when remote monitoring is not required, the pressure gauge 1 can be used as a standard, easy-to-handle, and compact pressure gauge by removing the transmission unit housing case 11 from the pressure gauge 1. In this case, maintenance such as replacing the battery 26 that supplies power to the sensor 12 and transmission means 13 can be performed with the transmission unit housing case 11 removed from the housing 8 of the pressure gauge 1, improving convenience.

[0034] Furthermore, since the center line extending between the south pole S and north pole N of the magnet 7 is located on the central axis of the rotation axis 2 or its extension L, strong magnetic field lines from the south pole S to the north pole N exist near the end of the magnet 7 on the sensor 12 side. For this reason, the sensor 12 can detect changes in the magnetic field lines caused by the magnet 7 with high accuracy. Consequently, the pressure gauge 1 and the signal transmission unit 10 can be configured compactly.

[0035] Although embodiments of the present invention have been described above, the present invention is not limited thereto. For example, a sensor 12 using a Hall element may be used.

[0036] 1... Pressure gauge, 2... Rotating shaft, 3... Shaft rotation mechanism, 4... Pointer, 5... Scale plate, 6... Pressure display unit, 7... Magnet, 8... Housing, 9... Glass plate, 10... Signal transmission unit, 11... Transmission unit housing case, 12... Sensor, 13... Transmission means, 14... Pressure transmission mechanism, 15... Inlet unit, 16... Bourdon tube, 17... Magnet spacer, 19... Magnetic plate, 20... Substrate fixing case, 21... Case cover, 22... Mounting magnet, 23... Circuit board, 24... Wireless communication board, 25... Battery holder, 26... Battery, 27... Antenna sheet, 28... Power connector, 29... Power switch, 30... Power LED, L... Central axis or its extension, N... North pole, S... South pole.

Claims

1. A pressure gauge comprising: a rotating shaft that is rotatably supported; a shaft rotation mechanism that applies a rotational force to the intermediate part of the rotating shaft to rotate the rotating shaft by an angle corresponding to the pressure to be measured; a pressure display unit that displays the measured value of the pressure using a pointer and a scale plate fixed to one end of the rotating shaft and rotating in conjunction with the rotating shaft; and a magnet fixed to the other end of the rotating shaft and rotating in conjunction with the rotating shaft, wherein a signal transmission unit is detachably attached to the pressure gauge, and the signal transmission unit comprises a transmission means that, when the signal transmission unit is attached to the pressure gauge, transmits the output signal of a sensor that detects a magnetic field that changes due to the rotation of the magnet linked to the rotating shaft to a monitoring position that monitors the pressure.

2. The pressure gauge according to claim 1, characterized in that the center line extending between the south pole portion and the north pole portion of the magnet is located on the central axis of the rotation shaft or an extension thereof.

3. The pressure gauge according to claim 2, characterized in that the magnet is a cylindrical ferromagnetic metal material magnetized radially such that one semi-cylindrical portion becomes the south pole portion and the other semi-cylindrical portion becomes the north pole portion.

Images