Manual reset pressure type temperature controller

Abstract

The utility model discloses a manual reset pressure type temperature controller, and belongs to the technical field of pressure type temperature controllers. The balance plate is formed by integrating two left vertical plates, an upper flat section, two right vertical sections and a lower flat section, the right end part of the upper flat section is connected with the balance tension spring in a hooking manner, the lower flat section is positioned below the lower limit, and the lower flat section is provided with a balance screw and a lock spring; a reset rod is further arranged and is formed by integrating an upper narrow section, an upper wide section, a transverse wide section, a lower wide section and a lower narrow section, the upper narrow section is matched with the first rectangular hole of the support and connected with the first rectangular hole in an up-down sliding mode, and the lower narrow section is matched with the second rectangular hole of the balance plate and connected with the second rectangular hole in an up-down sliding mode. The manual reset pressure type temperature controller is small in reset temperature difference, adjustable in action temperature, high in temperature control precision and suitable for overtemperature protection in a refrigeration temperature control system with the action temperature close to the environment temperature.

Description

Technical Field

[0001] The utility model relates to the technical field of pressure type temperature controllers, in particular to a manual reset pressure type temperature controller. Background Art

[0002] Pressure thermostats are widely used in refrigeration control of refrigerators, freezers, etc. They sense temperature rise and fall and convert them into pressure changes inside the temperature sensing component to turn the micro switch on and off, thereby controlling the start and stop of the refrigeration compressor to achieve temperature control. Sometimes, it is necessary to use a pressure thermostat for over-temperature protection of the refrigeration system. At this time, the pressure thermostat is required not to reset automatically. It is necessary to eliminate the fault and wait for the refrigeration system to cool down to a temperature close to the ambient temperature before manually pressing the reset button to restore the system operation. The usual pressure thermostats are automatic reset thermostats that control the start and stop cycle, so they cannot meet this requirement.

[0003] The Chinese patent discloses a manual reset pressure thermostat technology scheme with the utility model name "pressure thermostat" with the authorization announcement number CN201910368U. Its temperature sensing mechanism consists of a temperature sensing element (capillary), a diaphragm seat, and a diaphragm, wherein the diaphragm is made into a disc shape and has a sudden jump and bounce characteristic. When the temperature rises, the diaphragm suddenly flips over, and it is necessary to manually press the reset pin after the temperature drops to flip and reset the diaphragm.

[0004] The above manual reset pressure type thermostat has the following disadvantages:

[0005] ① After the diaphragm is processed and formed, its movement is fixed and cannot be adjusted, so it is difficult to accurately reach the certain temperature required for the over-temperature protection action of the air-conditioning system.

[0006] ② The temperature at which the diaphragm can be manually reset after it is actuated is generally about 15°C lower than the actuating temperature, that is, the reset temperature difference is relatively large. If the actuating temperature requirement is 40°C, and the ambient temperature in summer can reach 32°C, even if the temperature-sensing part has been cooled to the ambient temperature, the reset temperature condition cannot be met, so it cannot be reset.

[0007] In addition, the liquid expansion type manual reset temperature limiter generally requires a reset temperature difference of more than 30°C, and the bimetallic disc jump type manual reset thermostat generally requires a reset temperature difference of more than 20°C. Under the condition of a small temperature difference where the operating temperature is only slightly higher than the ambient temperature, these two thermostats are not suitable. The technical solution of the above patent also explains that the bimetallic disc jump type manual reset thermostat has a structural feature in which the temperature sensing part and the working part are close together, which is easy to fail under high temperature and harsh working conditions.

[0008] Therefore, it is necessary to develop a manual reset pressure thermostat with adjustable action temperature, high precision and small reset temperature difference. Utility Model Content

[0009] The technical problem to be solved by the utility model is to provide a manual reset pressure type thermostat, which has a small reset temperature difference, an adjustable operating temperature and high temperature control accuracy, and is suitable for over-temperature protection in a refrigeration temperature control system whose operating temperature is close to the ambient temperature.

[0010] The technical solution proposed by the utility model is as follows:

[0011] A manual reset pressure type temperature controller comprises a switch box assembly, a temperature sensing assembly, a main body, a pressure plate, a balance plate, a main tension spring assembly, a balance tension spring assembly and a bracket. In the inner cavity formed by the main body and the bracket, a switch box assembly is arranged on the left, a horizontally placed main tension spring assembly and a vertically placed balance tension spring assembly are arranged on the upper right part, a pressure plate and a balance plate are arranged on the middle right part, and a bellows is arranged on the lower right part, the bottom of the bellows is connected with an external temperature sensing tube through a capillary; one end of the main tension spring of the main tension spring assembly is hooked and connected with the groove in the middle and upper part of the vertical section of the pressure plate, and V-groove fulcrums are respectively arranged on the front and rear sides of the left part of the horizontal section of the pressure plate and are movably supported on the corresponding knife edges of the front and rear walls of the main body, a downward cone is arranged in the middle of the horizontal section and is in contact with the upper top surface of the bellows, and a push rod is horizontally movably arranged between the reed of the micro-jump switch of the switch box assembly and the left side plate surface of the vertical section of the pressure plate The lever is respectively provided with an upper limit and a lower limit on the inner side of the right side wall of the main body, and the right end portion of the horizontal section of the pressure plate is located between the upper limit and the lower limit. The balance plate is integrated from left to right by two left vertical plates, an upper flat section, two right vertical sections and a lower flat section. A second circular hole is provided at the lower portion of the two left vertical plates, which is rotatably connected to an axle pin supported at the corresponding position of the front and rear side walls of the main body. The right end portion of the upper flat section is hooked and connected with the balance spring of the balance spring assembly. The lower flat section is located below the lower limit, and a vertical balance screw and a locking spring with the tip facing upward are provided on the lower flat section; a reset lever and a button are also provided. The reset lever is integrated from top to bottom by an upper narrow section, an upper wide section, a horizontal wide section, a lower wide section and a lower narrow section, and the upper narrow section matches the first rectangular hole of the bracket for upward and downward sliding connection, and the lower narrow section matches the second rectangular hole provided on the flat section of the balance plate for upward and downward sliding connection.

[0012] The cross section of the reset rod is rectangular, the width of the upper wide section is 1-2 mm wider than the width of the upper narrow section, and the width of the lower wide section is 1-2 mm wider than the width of the lower narrow section.

[0013] Compared with the prior art, the utility model has the following beneficial effects:

[0014] (1) The utility model can be a manual reset pressure type thermostat with a settable operating temperature, which can be accurately adjusted to the required operating temperature, and the operating temperature accuracy can reach ±1.5°C.

[0015] (2) The manual reset pressure type thermostat of the utility model can be manually reset even when the ambient temperature is 3 to 5°C lower than the operating temperature. The reset temperature difference is small and the operating temperature is adjustable. It is particularly suitable for over-temperature protection of refrigeration systems when the operating temperature is close to the ambient temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The utility model is a schematic diagram of the main cross-sectional structure of a manual reset pressure type temperature controller.

[0017] Figure 2 yes Figure 1 Schematic diagram of right side cross-section.

[0018] Figure 3 yes Figure 1 The schematic diagram of the front cross-section of the manual reset pressure type thermostat is shown in the state where the reset button is pressed.

[0019] Figure 4 yes Figure 1 The diagram shows the position structure of the pressure plate, balance plate, balance screw, push rod and reset rod at the moment of switch action.

[0020] Figure 5 yes Figure 1 The diagram shows the position structure of the pressure plate, balance plate, balance screw, push rod and reset rod at the moment of switch reset.

[0021] Figure 6 yes Figure 1 The schematic diagram of the position structure of the pressure plate, the balance plate, the balance screw, the push rod and the reset rod in the critical balance state is shown.

[0022] Explanation of the numbers shown in the figure: 1. switch box assembly; 2. temperature sensing assembly; 2-1. temperature sensing tube; 2-2. capillary tube; 2-3 bellows; 3. main body; 3-1. upper limit; 3-2. lower limit; 3-3. first circular hole; 4. pressure plate; 4-1. V-groove fulcrum; 4-2. cone; 4-3. horizontal section; 4-4. vertical section; 5. balance plate; 5-1. left vertical plate; 5-2. upper flat section; 5-2-1. right end; 5-3. right vertical section; 5-4. lower flat section; 5 -5. Second round hole; 5-6. Second rectangular hole; 7. Lock spring; 8. Main tension spring assembly; 8-1. Main tension spring; 8-2. First adjusting screw; 9. Balance tension spring assembly; 9-1. Balance tension spring; 9-2. Second adjusting screw; 10. Bracket; 10-1. First rectangular hole; 10-2. Third round hole; 11. Reset rod; 11-1. Upper narrow section; 11-2. Upper wide section; 11-3. Horizontal wide section; 11-4. Lower wide section; 11-5. Lower narrow section; 12. Button. DETAILED DESCRIPTION

[0023] The utility model is further described in detail through the following examples.

[0024] See also Figures 1 to 6 As shown, a manual reset pressure type thermostat includes a switch box assembly 1, a temperature sensing assembly 2, a main body 3, a pressure plate 4, a balance plate 5, a main tension spring assembly 8, a balance tension spring assembly 9, and a bracket 10. In the inner cavity formed by the main body 3 and the bracket 10, the switch box assembly 1 is provided on the left, the main tension spring assembly 8 placed horizontally and the balance tension spring assembly 9 placed vertically are provided on the upper right, the pressure plate 4 and the balance plate 5 are provided on the middle right, and the bellows 2-3 is provided on the lower right. The bottom of the bellows 2-3 is connected to the external temperature sensing tube 2-1 through the capillary 2-2. One end of the main tension spring 8-1 of the main tension spring assembly 8 is hooked and connected with the groove in the middle and upper part of the vertical section 4-4 of the pressure plate 4. The front and rear sides of the left part of the horizontal section 4-3 of the pressure plate 4 are respectively provided with V-shaped groove fulcrums 4-1 and are movably supported on the corresponding knife edges on the front and rear walls of the main body 3. A downward frustum 4-2 is provided in the middle of the horizontal section 4-3 and is in contact with the upper top surface of the bellows 2-3. A push rod 1-1 is horizontally movably arranged between the reed of the micro-jump switch of the switch box assembly 1 and the left side plate surface of the vertical section 4-4 of the pressure plate 4. An upper limit is respectively provided on the inner side of the right side wall of the main body 3. The upper limit position 3-1 and the lower limit position 3-2, the right end of the pressure plate cross section 4-3 is located between the upper limit position 3-1 and the lower limit position 3-2, the balance plate 5 is integrated from left to right by two left vertical plates 5-1, an upper flat section 5-2, two right vertical sections 5-3 and a lower flat section 5-4, the lower part of the two left vertical plates 5-1 is provided with a second circular hole 5-5, which is rotatably connected with an axle pin supported at the corresponding position of the front and rear side walls of the main body 3, the right end of the upper flat section 5-2 is hooked and connected with the balance spring 9-1 of the balance spring assembly 9, and the lower flat section 5-4 is connected with the balance spring assembly 9. Located below the lower limit 3-2, a vertical balancing screw 6 and a locking spring 7 with the tip facing upward are provided on the lower flat section 5-4; a reset rod 11 and a button 12 are also provided. The reset rod 11 is integrated from top to bottom by an upper narrow section 11-1, an upper wide section 11-2, a horizontal wide section 11-3, a lower wide section 15-4 and a lower narrow section 11-5. The upper narrow section 11-1 is matched with the first rectangular hole 10-1 of the bracket for upward and downward sliding connection, and the lower narrow section 11-5 is matched with the second rectangular hole 5-6 provided on the flat section 5-2 of the balance plate for upward and downward sliding connection.

[0025] The cross section of the reset rod 11 is rectangular, the upper wide section 11 - 2 is 1 to 2 mm wider than the upper narrow section 11 - 1 , and the lower wide section 11 - 4 is 1 to 2 mm wider than the lower narrow section 11 - 5 .

[0026] The switch box assembly 1 is a single-pole double-throw micro switch, C is a common terminal, H is a normally-on terminal (disconnected when the temperature rises), and L is a normally-off terminal (connected when the temperature rises). The switch can be turned on and off by pushing the push rod 1-1.

[0027] The temperature sensing component 2 is mainly composed of a temperature sensing tube 2-1, a capillary tube 2-2, a bellows 2-3 and a bottom plate, and is filled with a temperature sensing medium gas. When in use, the temperature sensing tube 2-1 and the bellows 2-3 are at a relatively long distance from each other.

[0028] The main body 3 , the bracket 10 , the switch box assembly 1 , and the bottom plate of the temperature sensing assembly 2 are fixedly connected.

[0029] The main tension spring assembly 8 is mainly composed of a main tension spring 8-1, a spring nut and a first adjusting screw 8-2. The head of the first adjusting screw 8-2 is movably connected to the first circular hole 3-3 on the right side wall of the main body 3 by snapping.

[0030] The balance tension spring assembly 9 is mainly composed of a balance tension spring 9 - 1 , a spring nut and a second adjusting screw 9 - 2 . The head of the second adjusting screw 9 - 2 is movably connected with the third circular hole 10 - 1 of the bracket 10 by snap-fitting.

[0031] The upper narrow section 11-1 of the reset rod 11 passes through the first rectangular hole 10-1 of the bracket 10 and extends out from the upper part and is installed with a button 12. The width of the upper wide section 11-2 is slightly larger than the long side length of the first rectangular hole 10-1, so that it cannot penetrate upward into the first rectangular hole 10-1. The horizontal wide section 11-3 is bent to the right side and is provided with a vertical lower wide section 11-4 and a lower narrow section 11-5. The lower narrow section 11-5 penetrates into the second rectangular hole 5-6 of the flat section 5-2 on the balance plate. The width of the lower wide section 11-4 is slightly larger than the long side length of the second rectangular hole 5-6, so that it cannot penetrate downward into the second rectangular hole 5-6.

[0032] In this embodiment, the reset rod 11 is formed by stamping a metal plate with a thickness of 1.2 mm.

[0033] In this embodiment, the temperature sensing component 2 adopts an activated carbon adsorption type inflation component with a temperature sensing tube that can correctly sense temperature even if the temperature of the main body of the thermostat is lower than the temperature of the temperature sensing part, and the operating temperature requirement is 40°C.

[0034] The working principle of the manual reset pressure type thermostat of the utility model is as follows:

[0035] The push rod 1-1 of the switch box assembly 1 is pushed to the left to actuate the switch, and is pushed back to the right to reset the switch. Due to the energy storage effect of the micro-jump switch adopted by this switch, the push rod 1-1 has a certain position difference when the switch is actuated and reset (the switch flips when the rotation center of the moving contact piece of the switch structure and the two fulcrums of the bow spring are in a three-point collinearity. Since the outer frame of the moving contact of the switch is in different positions during actuation and resetting, the positions of the three-point collinearity are different). The position of the balancing screw 6 should be set so that when the switch is actuated, the lower flat section 5-4 of the balancing plate is blocked by the lower limit 3-2 of the main body. At this time, the top end of the balancing screw 6 is separated from the right part of the pressure plate cross section 4-3, and when the switch is reset, the top end of the balancing screw 6 is in contact and connected with the right end of the pressure plate cross section 4-3. At the same time, the lower flat section 5-4 of the balancing plate is separated from the lower limit 3-2 of the main body. The optimal critical separation position is the middle position between the switch actuation and the switch resetting. When the temperature of the temperature sensor rises, the bellows 2-3 of the temperature sensor assembly 2 expands and pushes the pressure plate cone 4-2 upward, causing the pressure plate 4 to swing counterclockwise around the V-groove fulcrum 4-1 and push the switch action through the push rod 1-1. The first adjustment screw 8-2 of the main tension spring assembly 8 is adjusted to the spring force Fs to be overcome to achieve the required action temperature. When the switch is actuated, only the spring force Fs of the main tension spring 8-1 acts on the pressure plate 4, and at this time the balance tension spring 9-1 is separated from the pressure plate 4. Ignoring the switch thrust, the pressure plate moment balance equation is:

[0036] F B *a = F Son *c

[0037] Where F B ---The top thrust of bellows 2-3 (corresponding to the temperature of temperature sensing component 2); F Son ---The tension of the main tension spring 8-1 when the switch is in action; a---The horizontal distance between the pressure plate cone 4-2 and the V-groove fulcrum 4-1; c---The vertical distance between the groove hook point of the pressure plate vertical section 4-4 and the V-groove fulcrum 4-1.

[0038] The second adjusting screw 9-2 of the balance spring assembly 9 is adjusted to a point where the tension of the balance spring 9-1 is greater than the tension of the main spring 8-1. Even if the temperature is as low as -30°C and the bellows 2-3 is fully contracted (F B = 0), the cone 4-2 of the pressure plate is separated from the top of the bellows 2-3, which can also ensure that the lower flat section 5-4 of the balance plate is in contact with the lower limit 3-2 of the main body. At this time, the pressure plate 4 no longer swings clockwise, and the switch remains in the actuated state. The pressure plate moment balance formula ignoring the switch thrust is:

[0039] F S *c = F D *d

[0040] The moment balance formula of the balance plate is:

[0041] F P *f = F D *e + F X *g

[0042] Where F S ---Tension of the main tension spring 8-1 in equilibrium state; F D ---The force of the balancing screw 6 acting on the pressure plate 4 in the balanced state; F P ---Tension force of the balance tension spring 9-1 in the balance state; F X ---The force exerted by the lower limit 3-2 of the main body on the balance plate 5; d---The horizontal distance from the head of the balance screw 6 to the fulcrum 4-1 of the V-shaped groove of the pressure plate; e---The horizontal distance from the top of the balance screw 6 to the center of the second circular hole 5-5 of the balance plate 5; f---The horizontal distance from the groove 5-2-1 at the right end of the flat section 5-2 on the balance plate to the center of the second circular hole 5-5 of the balance plate; g---The horizontal distance from the contact part of the lower limit 3-2 of the main body to the center of the second circular hole 5-5 of the balance plate.

[0043] From the above two equations, we can get: F P = F S *c / d*e / f + F X *g / f. If F X > 0, then F P > F S *c / d*e / f, so that even if F B = 0 will not cause the switch to reset automatically.

[0044] When the reset button 12 is pressed, the pressing force F R The reset rod 11 is driven to move downward, and the lower wide section 11-4 pushes the balance plate 5 to overcome the tension F of the balance tension spring 9-1. P The balance plate 5 swings clockwise around the center of the second circular hole 5-5, so that the lower flat section 5-4 of the balance plate is separated from the lower limit 3-2 of the main body, and then the lower end of the lower narrow section 11-5 of the reset rod pushes the right side of the pressure plate cross section 4-3 to overcome the upper top thrust F of the bellows 2-3. B The pressure plate 4 swings clockwise around the V-groove fulcrum 4-1 to reset the switch. After releasing the hand, the tension F of the balance spring 9-1 P The lower flat section 5-4 of the balance plate and the lower limit position 3-2 of the main body return to the contact state. At this time, the switch remains in the reset state. The next switch action will not occur until the next temperature sensing temperature rises to a high enough level.

[0045] The method for setting the temperature of the manual reset pressure thermostat in this embodiment is as follows: first, completely withdraw the balancing screw 6 so that the balancing screw 6 has no contact with the pressure plate cross section 4-3 regardless of the switch action or reset of the switch box assembly 1. Then, place the thermostat temperature sensing tube 2-1 in a water tank with a constant temperature of 40°C, and set the first adjusting screw 8-2 of the main tension spring assembly 8 to make the thermostat switch action. Then place the temperature sensing tube 2-1 of the thermostat in a water tank with a constant temperature of 15℃. At this time, the thermostat is an ordinary pressure-type thermostat with automatic reset action, with a certain start-stop temperature difference (generally 5℃~10℃). Now the temperature difference between the temperature sensing temperature and the action temperature reaches 25℃, which is greater than the above start-stop temperature difference. The thermostat switch is in the reset state. At this time, tighten the second adjusting screw 9-2 of the balance spring assembly 9 so that the lower flat section 5-4 of the balance plate is close to the lower limit 3-2 of the main body, screw the balance screw 6 into the screw hole of the lower flat section 5-4 and push the horizontal section 4-3 upward through its top until the thermostat switch is activated, and then screw it out at an angle of 170°~190°. In this critical balance state, the position A of the push rod 1-1 3 Approximately equal to switch action position A 1 With switch reset position A 2 Finally, place the temperature sensing tube 2-1 of the thermostat in an alcohol tank at a constant temperature of -30℃, loosen the second adjusting screw 9-2 of the balancing spring assembly 9 until the lower flat section 5-4 of the balancing plate begins to separate from the lower limit 3-2 of the main body, and then tighten the second adjusting screw 9-2 of the balancing spring assembly 9 within the angle range of 350° to 370°. During the setting process, the locking spring 7 locks the balancing screw 6 to prevent loosening and displacement.

[0046] The actual test results show that the manual reset pressure thermostat can fully meet the accuracy of 40℃±1.5℃, and the temperature of the temperature sensing tube 2-1 can be manually reset when the temperature is as low as 37℃, without the risk of being unable to manually reset due to the ambient temperature being too high. If the reset button 12 is not pressed, the temperature sensing tube 2-1 will not automatically reset even if the temperature is below -30℃.

[0047] The switch box assembly 1 of the manual reset pressure type thermostat is provided with a normally-off terminal L, a normally-on terminal H and a common terminal C. By connecting the C terminal and the H terminal of the switch box assembly 1 to the corresponding relay or AC contactor of the control circuit, over-temperature protection of the refrigeration system can be achieved.

Claims

1. A manual reset pressure type thermostat, comprising a switch box assembly (1), a temperature sensing assembly (2), a main body (3), a pressure plate (4), a balance plate (5), a main tension spring assembly (8), a balance tension spring assembly (9), and a bracket (10). In an inner cavity formed by the main body (3) and the bracket (10), a switch box assembly (1) is provided on the left, a main tension spring assembly (8) placed horizontally and a balance tension spring assembly (9) placed vertically are provided on the upper right, a pressure plate (4) and a balance plate (5) are provided on the middle right, and a bellows (2-3) is provided on the lower right. The bottom of the bellows (2-3) is connected to an external temperature sensing tube (2-1) through a capillary tube (2-2); one end of the main tension spring (8-1) of the main tension spring assembly (8) is connected to the pressure plate ( 4) The groove in the middle and upper part of the vertical section (4-4) is hooked and connected, the front and rear sides of the left part of the horizontal section (4-3) of the pressure plate (4) are respectively provided with V-shaped groove fulcrums (4-1) and are movably supported on the corresponding knife edges of the front and rear walls of the main body (3), the middle part of the horizontal section (4-3) is provided with a downward cone (4-2) and is in contact with the upper top surface of the bellows (2-3), a push rod (1-1) is horizontally movably arranged between the reed of the micro-jump switch of the switch box assembly (1) and the left side plate surface of the vertical section (4-4) of the pressure plate (4), an upper limit (3-1) and a lower limit (3-2) are respectively provided on the inner side of the right side wall of the main body (3), and the right end of the horizontal section (4-3) of the pressure plate is located between the upper limit (3-1) and the lower limit (3-2), characterized in that: The balance plate (5) is formed from left to right by two left vertical plates (5-1), an upper flat section (5-2), two right vertical sections (5-3) and a lower flat section (5-4) in an integrated manner. The lower parts of the two left vertical plates (5-1) are provided with second circular holes (5-5) which are rotatably connected to an axle pin supported at corresponding positions of the front and rear side walls of the main body (3). The right end of the upper flat section (5-2) is hooked and connected to the balance tension spring (9-1) of the balance tension spring assembly (9). The lower flat section (5-4) is located below the lower limit position (3-2). A vertical The invention also provides a balancing screw (6) and a locking spring (7) with the tip facing upward; and a reset rod (11) and a button (12). The reset rod (11) is integrated from top to bottom by an upper narrow section (11-1), an upper wide section (11-2), a horizontal wide section (11-3), a lower wide section (11-4) and a lower narrow section (11-5). The upper narrow section (11-1) is matched with a first rectangular hole (10-1) of the bracket for vertical sliding connection, and the lower narrow section (11-5) is matched with a second rectangular hole (5-6) provided on the flat section (5-2) of the balancing plate for vertical sliding connection.

2. A manual reset pressure type thermostat according to claim 1, characterized in that: The cross section of the reset rod (11) is rectangular, the width of the upper wide section (11-2) is 1 to 2 mm wider than the width of the upper narrow section (11-1), and the width of the lower wide section (11-4) is 1 to 2 mm wider than the width of the lower narrow section (11-5).

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