A micro-pressure switch suitable for positive and negative pressure environments

Abstract

The present invention discloses a micro-pressure switch applicable to positive and negative pressure environments, comprising a housing, a micro switch, a force transmission mechanism and a pressure sensing mechanism, wherein the micro switch and the force transmission mechanism are both installed inside the housing, the pressure sensing mechanism is connected to the lower end of the housing, the upper end of the force transmission mechanism contacts the micro switch, and the lower end of the force transmission mechanism is connected to the pressure sensing mechanism; the pressure sensing mechanism comprises an upper cover, a lower cover and a diaphragm fixed between the upper cover and the lower cover, the upper cover is connected to the lower end of the housing, a pressure sensing cavity is formed between the upper cover and the diaphragm, a threaded connection portion of the upper cover for connecting the housing is provided with an exhaust hole, the exhaust hole connects the inner cavity of the housing and the pressure sensing cavity, and a pressure sensing channel is provided at the center of the lower cover. The designed exhaust hole makes the transmission smoother, so that the pressure switch has no hysteresis when reaching the set point, and has higher precision.

Description

Technical Field

[0001] The invention relates to the technical field of pressure switches, and in particular to a micro-pressure switch applicable to positive and negative pressure environments. Background Art

[0002] The pressure switch uses a high-precision, high-stability pressure sensor and transmission circuit, and then outputs a control signal. The pressure switch can be widely used in petroleum, chemical, metallurgy, electric power, water supply, etc. CPU modular signal processing technology can realize the detection, display, alarm and other fields of medium pressure signal, and the measurement and control of the gauge pressure and absolute pressure of various gases and liquids. It is an ideal intelligent measurement and control instrument for industrial sites.

[0003] Traditional differential pressure control switches, in order to control smaller pressures, usually use micro-pressure digital display sensors, or use micro switches with extended levers to open the micro switches to achieve control functions. Their structures are unreliable, the pressure difference cannot be adjusted, the accuracy is difficult to control, the debugging is inconvenient, the sensitivity is low, and they usually cannot achieve set pressures below 20pa, and there is no adjustable display when in use.

[0004] In addition, the current pressure switch application market has both positive pressure and negative pressure application needs; however, there are currently few pressure switches that can be used for positive and negative pressure sensing. Even if there are, they are complex in structure, unreliable in product quality, or have a very low application pressure range. Traditional pressure switches used for positive and negative pressure have two sealed cavities: a positive pressure sealing cavity and a negative pressure sealing cavity. In order to achieve negative pressure sealing, the negative pressure cavity requires a set of diaphragms or clamping devices, making the product structure complex; in addition, the negative pressure sealing cavity must be sealed reliably, and existing structures are difficult to make well, often leaking or having low pressure resistance. Summary of the invention

[0005] In view of the deficiencies in the prior art, an object of the present invention is to provide a micro-pressure switch applicable to positive and negative pressure environments, which is both applicable to positive and negative pressure application requirements and has sufficient accuracy.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A micro-pressure switch applicable to positive and negative pressure environments, the key of which is: comprising a housing, a micro switch, a force transmission mechanism and a pressure sensing mechanism, the micro switch and the force transmission mechanism are both installed inside the housing, the pressure sensing mechanism is connected to the lower end of the housing, the upper end of the force transmission mechanism contacts the micro switch, and the lower end of the force transmission mechanism is connected to the pressure sensing mechanism;

[0008] The pressure sensing mechanism includes an upper cover, a lower cover and a diaphragm fixed between the upper cover and the lower cover, the upper cover is connected to the lower end of the shell, a pressure sensing cavity is formed between the upper cover and the diaphragm, a threaded connection part of the upper cover used to connect to the shell is provided with an exhaust hole, the exhaust hole connects the inner cavity of the shell and the pressure sensing cavity, and a pressure sensing channel is provided in the center of the lower cover.

[0009] Furthermore, a first chamber and a second chamber are formed in the shell, and the first chamber is located below the second chamber. The force transmission mechanism is arranged in the first chamber and extends upward into the second chamber to contact the micro switch.

[0010] Furthermore, the force transmission mechanism includes a transmission top rod, a first spring seat, and a first compression spring. The lower end of the transmission top rod forms a limiting step, the center of the limiting step is fixedly connected to the pressure sensing mechanism, the first spring seat is limited in the first chamber and the sliding sleeve is in the middle of the transmission top rod, the first compression spring abuts between the first spring seat and the limiting step, and the upper end of the transmission top rod is in contact with the micro switch.

[0011] Furthermore, an adjusting screw is sleeved on the transmission push rod above the first spring upper seat, and the adjusting screw is threadedly connected to the housing between the first chamber and the second chamber.

[0012] Furthermore, a mounting groove is provided on the upper part of the adjusting screw, a second spring upper seat is sleeved on the upper part of the transmission top rod, the second spring upper seat is limited on the transmission top rod by a retaining spring, and a second compression spring is abutted between the second spring upper seat and the bottom of the mounting groove.

[0013] Furthermore, an adjusting nut is connected to the top end of the transmission push rod.

[0014] Furthermore, the pressure sensing mechanism also includes a top seat and a clamping seat, the top seat is located above the diaphragm, and the upper end of the top seat penetrates the upper cover upward and contacts the lower end of the force transmission mechanism, the clamping seat is located below the diaphragm, and a connecting screw is passed through the center of the clamping seat, and the connecting screw passes upward through the diaphragm and the top seat and is fixedly connected to the force transmission mechanism.

[0015] Furthermore, a limiting convex ring is extended downwardly from the inner wall of the upper cover, and the limiting convex ring is located above the top seat.

[0016] Furthermore, a pressing plate is respectively attached to the upper and lower surfaces of the diaphragm.

[0017] Furthermore, a plurality of limiting protrusions are distributed on the inner wall of the upper cover above the diaphragm and the inner wall of the lower cover below the diaphragm.

[0018] The remarkable effects of the present invention are:

[0019] 1. The exhaust hole designed on the threaded connection part of the upper cover allows the air in the upper cavity of the diaphragm to be discharged smoothly when the diaphragm is displaced by force, making the transmission smoother and unobstructed, so that the pressure switch has no hysteresis when reaching the set point and has higher accuracy;

[0020] 2. There is only one sealed cavity with a relatively simple structure and reliable sealing. It can be used in both positive pressure and negative pressure situations. It simplifies the product structure while ensuring negative pressure application, improves product reliability, and can achieve a larger negative pressure setting and a larger pressure resistance.

[0021] 3. The sensitivity of the ejector rod can be adjusted in two levels, coarse and fine, by adjusting the nut and the adjusting screw, so as to adjust the set point of the pressure switch, so as to adapt to the application requirements of different pressures and ensure the accuracy of the pressure switch through the coarse and fine two-level method;

[0022] 4. Pressure plates are attached to the upper and lower surfaces of the diaphragm, and limit protrusions are arranged on the inner walls of the upper and lower covers above and below the diaphragm, which can ensure that the diaphragm will not be damaged by excessive pressure, so that the service life of the diaphragm of the wearing part of this switch can be extended under the premise of having sufficient resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the present invention;

[0024] Figure 2 yes Figure 1 A is a partial enlarged schematic diagram of the middle part. DETAILED DESCRIPTION

[0025] The specific implementation manner and working principle of the present invention are further described in detail below with reference to the accompanying drawings.

[0026] like Figure 1 As shown, a micro-pressure switch applicable to positive and negative pressure environments includes a housing 1, a micro switch 2, a force transmission mechanism and a pressure sensing mechanism. The micro switch 2 and the force transmission mechanism are both installed inside the housing 1, and the micro switch 2 is fixedly connected to the housing 1 by mounting screws 3. The pressure sensing mechanism is connected to the lower end of the housing 1, the upper end of the force transmission mechanism contacts the micro switch 2, and the lower end of the force transmission mechanism is connected to the pressure sensing mechanism. Specifically:

[0027] In this example, a first chamber 20 and a second chamber 21 are formed in the housing 1, and the first chamber 20 is located below the second chamber 21. The force transmission mechanism is arranged in the first chamber 20 and extends upward into the second chamber 21 to contact the micro switch 2. The micro switch 2 is arranged in the second chamber 21.

[0028] In this example, the force transmission mechanism includes a transmission push rod 8, a first spring seat 10, and a first compression spring 11. The lower end of the transmission push rod 8 forms a limiting step 22, and the center of the limiting step 22 is fixedly connected to the pressure sensing mechanism. The first spring seat 10 is limited in the first chamber 20 and slides in the middle of the transmission push rod 8. The first compression spring 11 abuts between the first spring seat 10 and the limiting step 22, and the upper end of the transmission push rod 8 is in contact with the micro switch 2.

[0029] When the pressure enters the sensor through the pressure sensing channel 25, the diaphragm 14 is displaced by the force, driving the transmission push rod 8 to directly touch the micro switch 2, thereby playing the role of controlling the device.

[0030] In this example, in order to adjust the set point of the pressure switch, an adjusting screw 9 is sleeved on the transmission push rod 8 above the first spring upper seat 10, and the adjusting screw 9 is threadedly connected to the housing 1 between the first chamber 20 and the second chamber 21.

[0031] Furthermore, a mounting groove 23 is opened on the upper part of the adjusting screw 9, and a second spring upper seat 6 is sleeved on the upper part of the transmission top rod 8. The second spring upper seat 6 is limited on the transmission top rod 8 by a retaining spring 5, and a second compression spring 7 is abutted between the second spring upper seat 6 and the bottom of the mounting groove, and an adjusting nut 4 is connected to the top end of the transmission top rod 8.

[0032] The size of the pressure switch set point is determined by the adjusting screw 9 and the adjusting nut 4; when the set point increases, the adjusting screw 9 or the adjusting nut 4 rotates to the right (clockwise), and when the set point decreases, the adjusting screw 9 or the adjusting nut 4 rotates to the left (counterclockwise); when the adjusting screw 9 or the adjusting nut 4 rotates to the right, the first compression spring 11 is directly acted on the diaphragm 14 by force, and the second compression spring 7 indirectly acts on the diaphragm 14 through the transmission push rod 8, so that the resistance of the diaphragm 14 increases when it moves, thereby increasing the set point; otherwise, the set point decreases.

[0033] By adjusting the nut 4 and the adjusting screw 9, the sensitivity of the transmission push rod 8 can be adjusted in two levels, namely, coarse and fine. This allows the set point of the pressure switch to be adjusted, thereby being able to adapt to application requirements of different pressures and ensuring the accuracy of the pressure switch through a coarse and fine two-level method.

[0034] See attached Figure 2The pressure sensing mechanism includes an upper cover 12, a lower cover 13, and a diaphragm 14 made of 316 stainless steel fixed between the upper cover 12 and the lower cover 13. The upper cover 12 is connected to the lower end of the shell 1. A pressure sensing cavity 24 is formed between the upper cover 12 and the diaphragm 14. A threaded connection portion of the upper cover 12 for connecting to the shell 1 is provided with an exhaust hole 19, and the exhaust hole 19 communicates with the inner cavity of the shell 1 and the pressure sensing cavity 24. A pressure sensing channel 25 is provided at the center of the lower cover 13.

[0035] Through the exhaust hole 19 designed on the threaded connection part of the upper cover 12, when the diaphragm 14 is displaced by force, the air in the upper cavity of the diaphragm 14 can be discharged smoothly from the cavity, making the transmission smoother and unobstructed, so that the pressure switch has no hysteresis when reaching the set point and has higher accuracy. Of course, the number of the exhaust holes 19 can be one or more, and the shape can be circular, triangular, square or other shapes.

[0036] Preferably, the pressure sensing mechanism also includes a top seat 16 and a clamping seat 17, the top seat 16 is located above the diaphragm 14, and the upper end of the top seat 16 penetrates the upper cover 12 upward and contacts the lower end of the force transmission mechanism, the clamping seat 17 is located below the diaphragm 14, and a connecting screw 15 is passed through the center of the clamping seat 17, and the connecting screw 15 passes upward through the diaphragm 14 and the top seat 16 and is fixedly connected to the force transmission mechanism.

[0037] In this example, a limit convex ring 26 is formed on the inner wall of the upper cover 12 and is extended downward, and the limit convex ring 26 is located above the top seat 16. By setting the limit convex ring 26, there is always a gap between the lower surface of the upper cover 12 and the top seat 16, thereby ensuring that the gas in the pressure sensing cavity can be discharged smoothly through the exhaust hole 19, so that the switch can always quickly discharge the air in the upper cavity of the diaphragm 14 out of the cavity, making the transmission smoother and unobstructed, so that the pressure switch has no hysteresis when reaching the set point, and has higher precision.

[0038] In this example, a pressure plate 18 is respectively attached to the upper and lower surfaces of the diaphragm 14, and a plurality of limit protrusions 27 are distributed on the inner wall of the upper cover 12 above the diaphragm 14 and the inner wall of the lower cover 13 below the diaphragm 14. The pressure plate 18 is attached to the upper and lower surfaces of the diaphragm 14, and the limit protrusions 27 are arranged on the inner walls of the upper cover 12 and the lower cover 13 above and below the diaphragm 14, which can ensure that the diaphragm 14 will not be damaged by excessive pressure, so that the service life of the vulnerable part diaphragm 14 can be extended under the premise of having sufficient resistance.

[0039] The micro-pressure switch described in this embodiment has an exhaust hole 19 designed on the threaded connection part of the upper cover 12 of the pressure sensing mechanism. When the diaphragm 14 is displaced by force, the air in the upper cavity of the diaphragm 14 can be discharged smoothly from the cavity, which makes the transmission smoother and unobstructed, so that there is no hysteresis when the pressure switch reaches the set point, and the accuracy is higher; the entire pressure switch has only one inlet and one sealed cavity, the structure is relatively simple, the sealing is reliable, and it can be used in both positive pressure occasions and negative pressure occasions, so that the product can simplify the product structure while ensuring the negative pressure application, improve the product reliability, and realize a larger negative pressure setting and greater pressure resistance; by adjusting the nut 4 and the adjusting screw 9, the sensitivity of the transmission push rod 8 can be adjusted in two levels, namely, coarse and fine, to achieve the adjustment of the set point size of the pressure switch, so as to adapt to the application requirements of different pressure sizes and ensure the accuracy of the pressure switch in a coarse and fine two-level manner; a pressure plate 18 is attached to the upper and lower surfaces of the diaphragm 14, and the limit protrusions arranged on the inner walls of the upper cover 12 and the lower cover 13 above and below the diaphragm 14 can ensure that the diaphragm 14 will not be damaged by excessive pressure, so that the service life of the wearing part diaphragm 14 can be extended under the premise of having sufficient Suzuki degree.

[0040] The technical solution provided by the present invention is described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A micro-pressure switch applicable to positive and negative pressure environments, characterized in that: The invention comprises a housing, a micro switch, a force transmission mechanism and a pressure sensing mechanism, wherein the micro switch and the force transmission mechanism are both installed inside the housing, the pressure sensing mechanism is connected to the lower end of the housing, a first chamber and a second chamber are formed inside the housing, and the first chamber is located below the second chamber, the force transmission mechanism is arranged in the first chamber and extends upward into the second chamber to contact with the micro switch, the upper end of the force transmission mechanism contacts with the micro switch, and the lower end of the force transmission mechanism is connected to the pressure sensing mechanism; The pressure sensing mechanism comprises an upper cover, a lower cover and a diaphragm fixed between the upper cover and the lower cover, the upper cover is connected to the lower end of the shell, a pressure sensing chamber is formed between the upper cover and the diaphragm, the force transmission mechanism comprises a transmission push rod, a first spring upper seat, and a first compression spring, a limit step is formed at the lower end of the transmission push rod, the center of the limit step is fixedly connected to the pressure sensing mechanism, the first spring upper seat is limited in the first chamber and the sliding sleeve is in the middle of the transmission push rod, the first compression spring abuts between the first spring upper seat and the limit step, and the upper end of the transmission push rod contacts the micro switch; an adjusting screw is sleeved on the transmission push rod above the first spring upper seat, and the adjusting screw is threadedly connected to the shell between the first chamber and the second chamber; A mounting groove is provided on the upper part of the adjusting screw, and a second spring upper seat is sleeved on the upper part of the transmission push rod, and the second spring upper seat is limited on the transmission push rod by a retaining spring, and a second compression spring is abutted between the second spring upper seat and the bottom of the mounting groove; the pressure sensing mechanism also includes a top seat and a clamping seat, the top seat is located above the diaphragm, and the upper end of the top seat penetrates the upper cover upward and contacts the lower end of the force transmission mechanism, the clamping seat is located below the diaphragm, and a connecting screw is passed through the center of the clamping seat, and the connecting screw passes upward through the diaphragm and the top seat and is fixedly connected to the force transmission mechanism, and a pressing plate is respectively attached to the upper and lower side surfaces of the diaphragm; an adjusting nut is connected to the top end of the transmission push rod; an exhaust hole is provided on the threaded connection part of the upper cover for connecting the outer shell, and the exhaust hole connects the inner cavity of the outer shell with the pressure sensing cavity, and a pressure sensing channel is provided at the center of the lower cover.

2. The micro-pressure switch applicable to positive and negative pressure environments according to claim 1 is characterized in that: A limiting convex ring is extended downwardly from the inner wall of the upper cover, and the limiting convex ring is located above the top seat.

3. The micro-pressure switch applicable to positive and negative pressure environments according to claim 1 or 2, characterized in that: A plurality of limiting protrusions are distributed on the inner wall of the upper cover above the diaphragm and the inner wall of the lower cover below the diaphragm.

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