Device and method for measuring micro pressure

Abstract

The invention belongs to the technical field of pressure measurement, and particularly relates to a device and method for measuring micro pressure. According to the invention, the problem of micro-pressure measurement greater than 0.1 N is solved by reducing liquid or gas pressure conduction friction force, enlarging the pressure area, adopting an ultra-micro spring, horizontally placing the measurement device and the like. The device comprises a piston push rod, a sealing shell, a spring, a fixing frame, a rubber sealing gasket and other parts which form a micro-pressure measuring device, the pressure compresses an ultra-micro spring through a micro-pressure transmission device, the deformation quantity of the spring is measured, and the micro-pressure is calculated. The method is reliable and low in cost, solves the problem of difficulty in micro-pressure measurement, and has high practical value.

Description

Technical Field

[0001] This application relates to the field of micro-pressure detection, specifically to a device for measuring micro-pressure, and also to a method for measuring micro-pressure. Background Technology

[0002] A micro-pressure sensor is a device that detects and converts minute pressure changes into electrical signals. It has wide applications in various fields, including medical, meteorological, and environmental monitoring. The working principle of micro-pressure sensors is typically based on principles such as piezoresistive, piezoelectric, or capacitive effects, and they are generally manufactured using semiconductor materials and MEMS processes. The piezoresistive effect is the most common, measuring pressure by detecting changes in resistance caused by pressure variations. Capacitive micro-pressure sensors utilize the principle of capacitance and offer good stability and accuracy. Piezoelectric micro-pressure sensors utilize the property of piezoelectric materials generating charge when subjected to force, making them suitable for high-frequency response and minute pressure detection. Application areas include: Medical fields, such as ventilators and blood pressure monitors, for accurate monitoring of patients' physiological parameters; Meteorological fields, for measuring and predicting air pressure; and Environmental monitoring, for monitoring air quality and gas leaks. Selection considerations include: Measurement range – selecting a suitable sensor range based on actual needs; Accuracy requirements – selecting a sensor based on the accuracy requirements of the application scenario; and Environmental adaptability – considering the sensor's performance under specific environmental conditions, such as temperature and humidity.

[0003] Some equipment requires compressed air to drive cylinders, some requires cooling circulating water systems, and some requires liquid abrasives to be supplied to the equipment via water pumps. During equipment operation, a drop in air or water pressure may occur due to pump malfunction, leaks in pipes or valves, or even pipe ruptures. Regardless of the cause, this can lead to equipment malfunction, damage, or even failure of the equipment or product. All of these devices require air or water pressure monitoring to ensure normal operation. Except for a few specific devices, air or water supply to equipment generally uses flexible hoses. The pressure resistance of these hoses and interfaces is not very high, so pressure monitoring is necessary to reduce the gas or liquid pressure. For devices that only need to determine the presence of gas or liquid, pneumatic or hydraulic pressure switching is often used.

[0004] Existing methods for measuring pressure, such as pressure sensors manufactured using semiconductor materials and MEMS processes, are often affected by environmental factors such as temperature, humidity, and wear and tear on the pressure sensor components caused by abrasive materials, and their manufacturing costs are relatively high. Another type of barometer for measuring micro-pressure is also affected by temperature, vibration during transportation, and installation conditions, resulting in high manufacturing costs. The micro-pressure measuring device of this application has a simple structure, low cost, low requirements for temperature, humidity, vibration, and installation conditions, is environmentally friendly, reliable, and durable, and represents a better solution for micro-pressure measurement. Summary of the Invention

[0005] This application provides a device for measuring micro-pressure, addressing the problem that existing measuring devices are subject to environmental influences such as temperature, humidity, and abrasive wear on pressure sensor components, as well as the effects of vibration during transportation and installation conditions, resulting in high manufacturing costs. This application also provides a method for measuring micro-pressure.

[0006] This application provides a device for measuring micro-pressure, comprising: a piston rod, a sealed housing, a spring, two electrode contacts, a small insulating gasket, a large insulating gasket, a through-thread screw, a round hole gasket, a screw, a fixing bracket, and a rubber sealing gasket; The rubber gasket, piston rod, and sealing housing together form a sealed micro-pressure transmission device. The spring, two electrode contacts, small insulating pad, large insulating pad, through thread screw, round hole washer, nut, and fixing frame constitute a device for measuring micro pressure; the spring deformation reaching a set amount can cause the two contacts to touch, which can form a circuit to determine whether it is conducting, and is used for pressure switching applications. The micro-pressure transmission device transmits the pressure of external gas or liquid to the micro-pressure measuring device.

[0007] Optionally, the piston rod may be made of at least one of the following materials: stainless steel, aluminum, copper, iron, glass, ceramic, plastic, polytetrafluoroethylene, or nylon.

[0008] Optionally, the material of the sealed housing includes at least one of the following: stainless steel, aluminum, copper, iron, glass, ceramic, plastic, polytetrafluoroethylene, and nylon.

[0009] Optionally, the spring comprises at least one of the following: carbon steel, alloy steel, and stainless steel.

[0010] Optionally, the spring can be a compression spring or a tension spring; by changing the installation method of the spring, a tension spring can be used.

[0011] Optionally, the electrode contacts may include at least one of the following: copper, silver, or gold.

[0012] Optionally, the large insulating pad and the small insulating pad may be selected from at least one of the following: polytetrafluoroethylene, epoxy resin board, nylon board, or plastic.

[0013] Optionally, the through-threaded screw may be made of at least one of the following: iron, carbon steel, or stainless steel.

[0014] Optionally, the round hole washer and nut can be made of at least one of the following: iron, carbon steel, stainless steel, aluminum alloy, copper, nylon, epoxy resin board, or plastic.

[0015] Optionally, the fixing frame may be made of at least one of the following: iron, carbon steel, stainless steel, aluminum alloy, or copper.

[0016] Optionally, the rubber gasket includes at least one of the following: nitrile rubber, fluororubber, silicone rubber, and polytetrafluoroethylene.

[0017] Optionally, the micro-pressure measuring device can be placed horizontally; if the weight of the piston rod itself does not affect the measurement sensitivity, the micro-pressure measuring device can be placed vertically.

[0018] Optionally, to reduce friction and improve the sensitivity of micro-pressure measurement, a rubber sealing gasket may be omitted, provided that the sealing is guaranteed.

[0019] This application also provides a method for measuring micro-pressure, including: Within the micro-pressure range of 1~50kPa, increasing the area S of the piston rod can increase the force F applied to the piston rod; under the same pressure F, decreasing the spring constant k can increase the spring deformation Δx and improve the sensitivity of micro-pressure measurement.

[0020] Optionally, it also includes: when the pressure is greater than 50 kPa, reducing the area S of the piston rod can reduce the force F applied to the piston rod; under the same pressure F, increasing the spring constant k can reduce the spring deformation Δx, thus improving the range of pressure measurement.

[0021] Compared with the prior art, this application has the following advantages: This application discloses a device and a method for measuring micro-pressure. The device includes: a rubber sealing gasket, a piston rod, a sealing shell, a spring, two electrode contacts, a small insulating gasket, a large insulating gasket, a through-thread screw, a round hole gasket, a nut, and a fixing frame. The rubber sealing gasket is fixed to one end of the piston rod and forms a sliding seal with the sealing shell, and is placed horizontally. The large insulating gasket and one of the electrode contacts are fixed to one end of the piston rod. The small insulating gasket and the other electrode contact are fixed to one end of the through-thread screw. The through-thread screw is fixed to the sealing shell by the fixing frame, and the through-thread screw and the sealing shell are coaxial and maintain a constant distance. The nut, spring, and round hole gasket pass through the through-thread screw. Adjusting the nut can adjust the distance between the round hole gasket and the large insulating gasket, change the deformation of the spring, adjust the preload of the spring, and set the lower limit of the measured pressure. One interface of the sealing shell is a gas or liquid inlet.

[0022] According to Pascal's Law, one interface of the sealed housing in this application's device transmits the pressure of the gas or liquid to the piston rod. The piston rod pushes the spring, causing the spring to deform. The deformation Δx of the spring is measured. Within the elastic limit of the spring, according to Hooke's Law, the spring pressure can be calculated using the formula F=kΔx, which is the pressure of the gas or liquid, where k is the spring constant, Δx=x0-x, x0 is the natural length of the spring, and x is the length of the spring after being compressed. The pressure P of the gas or liquid can be calculated by calculating the port area S where the rubber sealing gasket is fixed to the piston rod, i.e., P=F / S. With the gas or liquid pressure P constant, changing the area S of the piston rod changes the force F applied to it; a larger area S results in a larger force F. Changing the spring wire diameter d, shear modulus G, and effective number of coils n changes the spring constant k; when F is constant, a smaller k results in a larger Δx. When the compressed length x=nd, reaching the maximum value of the spring deformation, the upper limit of the pressure test is reached. When the pressure of the gas or liquid is low, the micro-pressure device is placed horizontally to reduce the additional force generated by the weight of the piston rod itself. Simultaneously, by selecting a relatively large S and a relatively small k, Δx is larger, making it easier to measure the pressure of the gas or liquid, thus solving the difficulty of micro-pressure measurement in existing technologies. The position of the adjusting nut can adjust the spring deformation Δx and the magnitude of the force F. When the pressure of the gas or liquid is greater than F, the piston rod is pushed to compress the spring, causing the two electrode contacts to make contact and conduct. Therefore, the device can be used as a switching device with a certain pressure threshold. The lower limit of the pressure measured by the device is related not only to the area S and the spring constant k, but also to the friction between the piston rod and the sealing shell. Increasing S and decreasing k, reducing the friction, can further lower the lower limit of the micro-pressure measurement. For liquids, the gap between the piston rod and the sealing shell can be relatively large, or a rubber sealing gasket can be omitted. For example, in a glass syringe, the problem of liquid sliding sealing in the syringe can be solved well without a rubber sealing gasket, and the friction between the plunger and the sleeve of the glass syringe is very small. Removing the rubber gasket while maintaining a sliding seal between the piston rod and the sealing housing can further lower the lower limit of the measured pressure. Adding a pointer and graduations to the spring allows for easy adjustment of the spring's deformation. Using a laser rangefinder or other distance measuring device that does not generate additional resistance, the spring's deformation Δx can be automatically measured, enabling automatic measurement of micro-pressures.

[0023] In a further embodiment of this application, the piston rod and sealing housing are made of at least one of stainless steel, aluminum, copper, iron, glass, ceramic, plastic, polytetrafluoroethylene (PTFE), and nylon; the spring is made of at least one of carbon steel, alloy steel, and stainless steel; the electrode contacts are made of at least one of copper, silver, and gold; the large and small insulating gaskets are made of at least one of PTFE, epoxy resin board, nylon board, and plastic; the through-thread screw is made of at least one of iron, carbon steel, and stainless steel; and the round hole washer and nut are made of iron, carbon steel, stainless steel, aluminum alloy, copper, nylon, etc. The device comprises at least one of the following: a piston rod, an epoxy resin board, and plastic; the mounting bracket is made of at least one of the following: iron, carbon steel, stainless steel, aluminum alloy, and copper; the rubber sealing gasket is made of at least one of the following: nitrile rubber, fluororubber, silicone rubber, and polytetrafluoroethylene; to reduce friction and improve the sensitivity of micro-pressure measurement, the rubber sealing gasket may be omitted while ensuring sealing; the spring may be a compression spring; by changing the installation method of the spring, a tension spring may be used; the micro-pressure measuring device may be placed horizontally; if the weight of the piston rod itself does not affect the measurement sensitivity, the micro-pressure measuring device may be placed vertically. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the device for measuring micro-pressure provided in Embodiment 1 of this application.

[0025] Figure 2 This is a cross-sectional schematic diagram of the device structure for measuring micro-pressure provided in Embodiment 1 of this application. Detailed Implementation

[0026] The following description sets forth many specific details to facilitate a thorough understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the scope of the present application. Therefore, the present application is not limited to the specific implementations disclosed below.

[0027] This application provides a device for measuring micro-pressure and a method for measuring micro-pressure. The structure and working principle of the device for measuring micro-pressure and the method for measuring micro-pressure are described below using specific embodiments.

[0028] Embodiment 1 of this application provides a device for measuring micro-pressure, such as... Figure 1 and Figure 2The diagram shows a schematic of the device for measuring micro-pressure provided in this embodiment. The device includes: a piston rod 101, a sealed housing 102, a spring 103, two electrode contacts 104, a large insulating gasket 105, a small insulating gasket 106, a through-thread screw 107, a round hole gasket 108, a nut 109, a fixing frame 110, and a rubber sealing gasket 111. The device in this embodiment mainly utilizes Pascal's law to transmit the pressure of a gas or liquid to the piston rod 101, compressing the spring 103 to generate a deformation Δx. Hooke's law can then be used to calculate and measure the micro-pressure generated by the gas or liquid.

[0029] like Figure 2 As shown, the rubber sealing gasket 111 is fixed to one end of the piston push rod 101 and forms a sliding seal with the sealing housing 102, and is placed horizontally; Figure 1 As shown, one of the large insulating gasket 105 and the electrode contact 104 is fixed to the other port of the piston rod; the other of the small insulating gasket 106 and the electrode contact 104 is fixed to one port of the through screw 107; the through screw 107 and the sealing housing 102 are mounted together by the fixing frame 110, and the through screw 107 and the sealing housing 102 are coaxial; the nut 109, the spring 103 and the round hole washer 108 pass through the through screw 107, and adjusting the nut 109 can adjust the distance between the round hole washer 108 and the large insulating gasket 105, change the deformation of the spring 103, and adjust the preload of the spring 103; the other interface of the sealing housing 102 is a gas or liquid inlet port.

[0030] The rubber sealing gasket 111 and one end of the piston push rod 101 can be glued together, or a large round protrusion can be designed on one side of the rubber sealing gasket 111, and a corresponding small round groove can be designed on one end of the piston push rod 101. The flexible and deformable protrusion of the rubber sealing gasket 111 can be inserted into the recess of the piston push rod 101, and they can be fixed together in this hinge manner. The piston push rod 101, or the piston push rod formed after fixing the rubber sealing gasket 111 to the piston push rod 101, and the sealing shell 102 can be fitted with appropriate tolerances to form a... A sliding seal fits; one of the contacts of the large insulating gasket 105 and the electrode contact 104 can be fixed to the other port of the piston rod by adhesive bonding or screw locking; the other contact of the small insulating gasket 106 and the electrode contact 104 can be fixed to one port of the through screw 107 by adhesive bonding or screw locking; the through screw 107, the sealing housing 102 and the fixing frame 110 are installed together; the nut 109, the spring 103 and the round hole washer 108 pass through the through screw 107.

[0031] In the above description, the rubber sealing gasket 111, piston push rod 101, and sealing housing 102 constitute a sealed micro-pressure transmission device; the spring 103, two electrode contacts 104, large insulating gasket 105, small insulating gasket 106, through thread screw 107, round hole gasket 108, nut 109, and fixing bracket 110 constitute a device for measuring micro-pressure; the micro-pressure transmission device transmits the pressure of external gas or liquid to the micro-pressure measuring device.

[0032] The structure and connection method of the device for measuring micro-pressure have been described above. The following description will continue to explain the material selection of each part of the device.

[0033] The piston rod 101 and the sealing housing 102 can be made of at least one of the following materials as the material of the micro-pressure measuring device in this embodiment, such as stainless steel, aluminum, copper, iron, glass and ceramics; when the measured gas or liquid pressure is not large, plastic, polytetrafluoroethylene and nylon can be selected.

[0034] The spring 103 can be made of at least one of the following materials as the material for the micro-pressure measuring device in this embodiment, such as carbon steel, alloy steel and stainless steel, which are elastic and not easily broken.

[0035] The electrode contact 104 may be made of at least one of the following materials as the material of the micro-pressure measuring device in this embodiment, such as conductive materials such as copper, silver and gold.

[0036] The large insulating pad 105 and the small insulating pad 106 can be made of at least one of the following materials as the materials for the micro-pressure measuring device of this embodiment, such as polytetrafluoroethylene, epoxy resin board, nylon board and plastic insulating materials.

[0037] The through-thread screw 107 can be made of at least one of the following materials as the material for the micro-pressure measuring device in this embodiment, such as iron, carbon steel and stainless steel.

[0038] The circular hole gasket 108 and nut 109 can be made of at least one of the following materials as the material for the micro-pressure measuring device in this embodiment: for example, relatively hard and wear-resistant materials such as iron, carbon steel, stainless steel, aluminum alloy, copper, nylon, epoxy resin board and plastic.

[0039] The fixing frame 110 can be made of at least one of the following materials as the material for the micro-pressure measuring device in this embodiment. For example, materials that are relatively easy to process, relatively hard and not easily deformed, such as iron, carbon steel, stainless steel, aluminum alloy and copper can be selected. When the gas or liquid pressure being measured is not large, lightweight materials such as epoxy resin board and plastic nylon can be selected.

[0040] The rubber sealing gasket 111 can be made of at least one of the following materials as the material for the micro-pressure measuring device in this embodiment, such as soft materials like nitrile rubber, fluororubber, silicone rubber, and polytetrafluoroethylene. To reduce friction and improve the sensitivity of micro-pressure measurement, the rubber sealing gasket can be omitted while ensuring a tight seal. For example, when measuring liquid pressure, a syringe made of glass can be used. Glass has a low density, and the piston rod made from it is lightweight and has good liquid sealing properties. Therefore, this sealed micro-pressure transmission device can function without a rubber sealing gasket.

[0041] The principle of measuring micro-pressure in this embodiment is described below.

[0042] According to Pascal's law, in this embodiment, one interface of the sealed outer shell 102 transmits the pressure of the gas or liquid to the piston rod 101. The piston rod 101 pushes the spring 103, causing the spring 103 to deform. The deformation Δx of the spring 103 is measured. Within the elastic limit of the spring 103, according to Hooke's law, the pressure of the spring 103 can be calculated by the formula F=kΔx, which is the pressure of the gas or liquid, where k is the spring constant, Δx=x0-x, x0 is the natural length of the spring, and x is the length of the spring after being stressed. By calculating the port area S where the rubber sealing gasket 111 is fixed to the piston rod 101, the pressure of the gas or liquid P=F / S can be calculated. With the pressure P of the gas or liquid remaining constant, changing the area S of the piston rod 101 can change the force F applied to the piston rod 101; the larger the area S, the larger the force F. By changing the wire diameter d, shear modulus G, and effective number of coils n of spring 103, the spring constant k can be changed. When F remains constant, a smaller k results in a larger Δx. When the compressed length x=nd of spring 103 reaches the maximum value of spring 103's deformation, the upper limit of the pressure test is reached. When the gas or liquid pressure is low, placing the micro-pressure device horizontally reduces the additional force generated by the weight of the piston rod 101 itself. Simultaneously, using a relatively large S and a relatively small k results in a larger Δx, making it easier to measure the gas or liquid pressure, thus solving the difficulty of micro-pressure measurement in the prior art. The position of the adjusting nut 109 can adjust the spring deformation Δx and the magnitude of the force F. When the gas or liquid pressure is greater than F, it pushes the piston rod 101 to compress the spring 103, causing the two electrode contacts 104 to make contact and conduct. Therefore, the device of this application can be used as a switching device with a certain pressure threshold. The lower limit of the pressure measurement of this device is related not only to the area S and the spring constant k, but also to the frictional force between the piston rod 101 and the sealing shell 102. Increasing S and decreasing k reduces the frictional force, which can further lower the lower limit of the device's micro-pressure measurement. For liquids, the gap between the piston rod 101 and the sealing shell 102 can be relatively large, such as in a glass syringe. The problem of liquid sliding seal in a syringe can be well solved without a rubber sealing gasket, and the frictional force between the plunger and the sleeve of a glass syringe is very small. While ensuring a sliding seal between the piston rod 101 and the sealing shell 102, removing the rubber sealing gasket 111 reduces frictional resistance, which can further lower the lower limit of the measured pressure. Adding a pointer and a scale to the spring 103 allows for convenient adjustment of the spring's deformation. Using a laser rangefinder or other rangefinder that does not generate additional resistance, the spring's deformation Δx can be automatically measured, enabling automatic measurement of micro-pressure.

[0043] The principle behind using this device to measure micro-pressure is described below. For example... Figure 1As shown, adjusting nut 109, one end of spring 103 contacts the round hole washer 108, and the other end of spring 103 contacts the large insulating washer 105, allowing spring 103 to be in a naturally relaxed state. At this time, the length of spring 103 is x0. The sealing shell 102 is sealed to the external liquid or gas supply system. When liquid or gas is introduced into the external liquid or gas supply system, a certain pressure is generated. This pressure pushes piston rod 101, which compresses spring 103, causing a deformation Δx in the spring. By measuring Δx and knowing the elastic constant k of spring 103, the pressure of the liquid or gas can be calculated, thereby allowing the measurement of the micro-pressure of the gas or liquid.

[0044] Embodiment 1 of this application provides a device for measuring micro-pressure; correspondingly, Embodiment 2 of this application provides a method for a switching application. Figure 1 As shown, it is a schematic diagram of the switching quantity application of Embodiment 2 of this application. Since this method is similar to the measurement method of the micro-pressure measuring device in the above embodiment, please refer to the relevant description in the first embodiment for the relevant parts. The following measurement method is only illustrative.

[0045] like Figure 1 As shown, adjusting the relative position of the spring 103 and the fixed bracket 110, that is, adjusting the distance between the two electrode contacts 104, controls the maximum deformation Δx of the spring 103. According to Hooke's Law, the pressure required for the spring 103 to deform by Δx can be calculated, which is the preset maximum force on the spring 103. When the pressure of the gas or liquid pushes the piston rod 101 a distance of Δx, the two electrode contacts 104 touch each other, and the contacts are in a closed, short-circuit conducting state. When the external gas or liquid pressure decreases, the two electrode contacts 104 separate under the action of the spring 103, and the contacts are in an open-circuit state. The external circuit detects the short circuit or open circuit state and can determine whether the gas or liquid pressure has reached the preset pressure, thereby taking corresponding actions to protect the equipment from the effects of gas or water shortages. This is another embodiment of this device as a switch quantity protection device.

[0046] Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of this application. Therefore, the scope of protection of this application should be determined by the scope defined in the claims of this application.

Claims

1. A device for measuring micro pressure, characterized in that: include: Piston push rod, sealing housing, spring, two electrode contacts, small insulating gasket, large insulating gasket, through screw, round hole gasket, nut, fixing frame and rubber sealing gasket; The rubber sealing pad, piston push rod and sealing shell form a sealed micro-pressure transmission device; the spring, two electrode contacts, small insulating gasket, large insulating gasket, through-screw, round hole gasket, nut and fixing frame form a micro-pressure measuring device; the spring deformation reaching a set amount can cause the two contacts to touch, and can form a circuit to determine whether it is conductive, which is used for the application of pressure switch quantity; the micro-pressure transmission device transmits the pressure of external gas or liquid to the micro-pressure measuring device.

2. The device for measuring micropressure according to claim 1, characterized in that: The sealed micro-pressure transmission device comprises a rubber sealing pad, a piston push rod and a sealing shell; the materials of the piston push rod and the sealing shell comprise at least one of the following: stainless steel, copper, iron, aluminum, glass, plastic, polytetrafluoroethylene, and nylon.

3. The device for measuring micropressure according to claim 1, characterized in that: The rubber sealing pad includes at least one of the following: nitrile rubber, fluororubber, silicone rubber, polytetrafluoroethylene; in order to reduce friction and improve the sensitivity of micro-pressure measurement, the rubber sealing pad may not be added under the condition of ensuring sealing.

4. The device for measuring micropressure according to claim 1, characterized in that: The spring can be a compression spring or a tension spring; by changing the installation method of the spring, a tension spring can be used.

5. The device for measuring micropressure according to claim 1, characterized in that: The micro-pressure measuring device can be placed horizontally; when the weight of the piston push rod itself does not affect the measurement sensitivity, the micro-pressure measuring device can be placed vertically.

6. A method for measuring micro pressure, characterized in that: include: In the micro-pressure range of 1~50kPa, increasing the area S of the piston push rod can increase the force F applied to the piston push rod; under the same pressure F, reducing the spring constant k can increase the deformation Δx of the spring and improve the sensitivity of measuring micro-pressure.

7. A method for measuring micro pressure, characterized in that: include: When the pressure is greater than 50kPa, reducing the area S of the piston push rod can reduce the force F applied to the piston push rod; under the same pressure F, increasing the spring constant k can reduce the spring deformation Δx and increase the range of measured pressure.

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