Adjustable comparison frame device for vacuum attenuation leak detection equipment and vacuum attenuation leak detection equipment with same

Abstract

The invention discloses an adjustable comparison frame device for vacuum attenuation leak detection equipment and the vacuum attenuation leak detection equipment with the adjustable comparison frame device. The adjustable comparison frame device comprises a comparison frame group with a mounting cavity, a first sealing element, an adjustable piston assembly and an adjustable pressing assembly. The adjusting ends of the adjustable piston assembly and the adjustable pressing assembly are both located outside the comparison frame set, and the acting ends of the adjustable piston assembly and the adjustable pressing assembly penetrate through the comparison frame set and then stretch into the installation cavity so as to divide the installation cavity into a rod cavity and a rodless cavity. The first sealing piece is located in the installation cavity and arranged between the acting end of the adjustable pressing assembly and the acting end of the adjustable piston assembly so as to be used for deforming under the downward pressing effect of the adjustable pressing assembly to be tightly attached to the inner wall face of the installation cavity, and meanwhile the first sealing piece is pressed between the adjustable pressing assembly and the adjustable piston assembly so that the rodless cavity can not communicate with the rod cavity. In the equipment, the operation of adjusting the volume change of the rodless cavity is simple, time and labor are saved, and new comparison frames are not required to be prepared or new compensation blocks are not required to be increased, decreased and processed due to different specifications and volumes of packaging containers.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum decay leak detection equipment, and in particular, to an adjustable contrast frame device for vacuum decay leak detection equipment; in addition, the present invention also relates to a vacuum decay leak detection equipment having an adjustable contrast frame device for vacuum decay leak detection equipment. Background Art

[0002] The vacuum decay leak detection equipment determines whether there is a leak in the packaging container by the change of pressure difference. The equipment is provided with a detection frame and a comparison frame. The detection frame contains the packaging container to be tested, and the comparison frame is an empty frame. The volume of the space in the detection frame and the comparison frame is equal. During the detection, the detection frame and the comparison frame are evacuated at the same time. When the packaging container to be tested does not leak, the negative pressure values ​​of the detection frame and the comparison frame are equal, and there is no pressure difference. When the packaging container to be tested leaks, since the packaging container to be tested is at normal pressure, its pressure is greater than the negative pressure of the detection frame, and the gas or liquid in the packaging container to be tested will enter the detection frame through the leakage hole. At this time, the negative pressure values ​​of the detection frame and the comparison frame will not be equal, and there will be a pressure difference between the two. The detection system determines the leakage of the packaging container based on the change of the pressure difference.

[0003] During the inspection, the equal volume of the space in the inspection frame and the comparison frame is the prerequisite for detecting whether the packaging container is leaking. In order to increase the output, a machine is equipped with multiple inspection frames and comparison frames at the same time, generally reaching dozens. When the same machine needs to detect packaging containers of various specifications and different volumes, the volume of the remaining space in the inspection frame is not equal. During the inspection, the remaining space volume in the inspection frame is required to be equal to the space volume in the comparison frame, and the comparison frame must also have different space volumes. The current general practice is to add or subtract compensation blocks in the comparison frame. Although this can achieve the purpose, it is very troublesome, time-consuming and laborious to disassemble dozens of comparison frames and then add or subtract compensation blocks. When a new packaging container appears, a new compensation block must be processed accordingly. Summary of the invention

[0004] The invention provides an adjustable contrast frame device for vacuum decay leak detection equipment and vacuum decay leak detection equipment having the same, so as to solve the technical problems of troublesome operation, time-consuming and labor-intensive operation when the existing equipment needs to be disassembled to add or remove compensation blocks or to make new compensation blocks.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A vacuum attenuation leak detection device with an adjustable contrast frame device comprises: a contrast frame group having a hollow and closed mounting cavity, a first sealing member having a sealing function, an adjustable piston assembly and an adjustable clamping assembly which are coaxially arranged and cooperate with each other; the adjusting ends of the adjustable piston assembly and the adjustable clamping assembly are both located outside the contrast frame group, and the active ends of the two extend into the mounting cavity after sealingly passing through the contrast frame group, so as to separate the mounting cavity into a rod cavity and a rodless cavity, and the rodless cavity is connected to an external vacuum pumping device for vacuum pumping; the first sealing member is located in the mounting cavity and is installed between the active end of the adjustable clamping assembly and the active end of the adjustable piston assembly, so as to slide up and down in the mounting cavity with the adjustable piston assembly, and is used to deform under the downward pressure of the adjustable clamping assembly to fit closely to the inner wall surface of the mounting cavity, and at the same time be pressed between the active end of the adjustable clamping assembly and the active end of the adjustable piston assembly, so that the rodless cavity is not connected to the rod cavity.

[0007] Furthermore, the adjustable piston assembly includes a piston slidably arranged in the mounting cavity, and a piston driving member connected to the piston to drive the piston to slide up and down in the mounting cavity, the upper end of the piston driving member extends upward from the comparison frame group, a vertically penetrating mounting through hole is provided on the outer circle of the piston, and the outer peripheral surface of the piston below the mounting through hole convexly forms an annular limiting flange; the adjustable clamping assembly includes a hollow cylindrical upper pressure ring mounted on the outer circle of the piston, a pin shaft passed through the mounting through hole and connected to the upper pressure ring at both ends, and a pin shaft driving member passed through the piston driving member and connected to the pin shaft; the first sealing member is a first sealing ring, and the first sealing ring is located between the upper pressure ring and the limiting flange.

[0008] Furthermore, the outer cylindrical surface of the lower end of the upper pressure ring is chamfered to form an inverted cone, the upper end surface of the limiting flange is chamfered to form a positive cone, and a ring-shaped accommodating groove with an opening toward the wall of the installation cavity is formed between the positive cone and the inverted cone; the first sealing ring is installed in the ring groove.

[0009] Furthermore, the piston includes a small diameter section and a large diameter section which are arranged in sequence and connected along the axial direction, and the outer diameter of the large diameter section is larger than the outer diameter of the small diameter section; the mounting through hole vertically penetrates the large diameter section, and the inner diameter of the mounting through hole is larger than the outer diameter of the pin shaft, and the upper pressure ring is sleeved on the outer circle of the large diameter section; the outer circle of the small diameter section is processed with a rotation limiting groove which is concave and extends along its sliding direction, and the adjustable piston assembly also includes a rotation limiting bolt threaded through the outer wall surface of the contrast frame group, and the rotation limiting bolt extends into the rotation limiting groove to limit the circumferential rotation of the piston through the cooperation between the rotation limiting bolt and the rotation limiting groove.

[0010] Furthermore, the piston driving component includes a driving handle, an adjusting screw fixed to the driving handle, and a lifting nut cooperatively mounted on the outer circle of the adjusting screw; the driving handle is located outside the contrast frame group; the lower end of the adjusting screw seals and passes through the contrast frame group before extending into the mounting cavity; the lifting nut is located in the mounting cavity and is fixed to the piston.

[0011] Furthermore, a through hole for the adjusting screw rod to pass through is processed on the contrast frame assembly; the adjustable piston assembly also includes a composite sleeve installed on the outer circle of the adjusting screw rod and located in the through hole.

[0012] Furthermore, the adjustable contrast frame device for vacuum decay leak detection equipment also includes a position display installed on the outer circle of the adjusting screw, and the position display is located outside the contrast frame group to display the up and down displacement of the piston according to the rotation angle of the adjusting screw.

[0013] Furthermore, the adjusting screw is hollow in the axial direction; the pin shaft driving component includes a hand screw and a pressure rod which are arranged in the inner channel of the adjusting screw and connected in sequence, the upper end of the hand screw extends out of the driving handle, the lower end of the hand screw is threadedly connected to the pressure rod, and the lower end of the pressure rod extends out of the adjusting screw and is vertically connected to the pin shaft.

[0014] Furthermore, the comparison frame includes a comparison frame which is hollow and open at the lower end, a mounting seat connected to the lower open end of the comparison frame, a second sealing member arranged between the lower open end of the comparison frame and the mounting seat, and a quick-release clamp for detachably fixing the comparison frame and the mounting seat; the inner cavity of the comparison frame forms a mounting cavity; a channel connecting the mounting cavity and the vacuum device is processed on the mounting seat; and the quick-release clamp is installed on the outer circle of the connection between the comparison frame and the mounting seat.

[0015] According to another aspect of the present invention, there is also provided a vacuum decay leak detection device having an adjustable contrast frame device for a vacuum decay leak detection device as described in any one of the above.

[0016] The present invention has the following beneficial effects:

[0017] Compared with the prior art in which the volume of the space in the comparison frame is changed by adding or reducing or processing new compensation blocks, in the adjustable comparison frame device of the present invention, the volume of the rodless cavity can be arbitrarily adjusted by moving the adjustable piston assembly. At the same time, the rodless cavity can be sealed at any position through the interaction of the adjustable piston assembly, the adjustable clamping assembly and the first seal. Therefore, the adjustment operation of the change of the volume of the rodless cavity is simple, time-saving, labor-saving and flexible. There is no need to prepare a new comparison frame or add or reduce or process new compensation blocks due to the different specifications and volumes of the packaging containers to be inspected, which greatly reduces the detection cost and improves the detection efficiency.

[0018] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0020] Figure 1 This is a schematic diagram of the cross-sectional front view of the structure of an adjustable contrast frame device for vacuum decay leak detection equipment according to a preferred embodiment of the present invention.

[0021] 1. Comparison frame assembly; 101. Rod cavity; 102. Rodless cavity; 11. Comparison frame; 12. Mounting seat; 13. Second sealing member; 14. Quick-release clamp;

[0022] 2. The first sealing member;

[0023] 3. Adjustable piston assembly; 31. Piston; 310. Mounting through hole; 311. Position limiting flange; 312. Rotation limiting groove; 32. Driving handle; 33. Adjusting screw rod; 34. Lifting nut; 35. Rotation limiting bolt; 36. Composite sleeve;

[0024] 4. Adjustable clamping assembly; 41. Upper pressure ring; 42. Pin; 43. Thumb screw; 44. Pressure rod;

[0025] 5. Position display. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0027] Reference Figure 1 The preferred embodiment of the present invention provides an adjustable contrast frame device for vacuum decay leak detection equipment, comprising: a contrast frame group 1 having a hollow and closed installation cavity, a first sealing member 2 having a sealing function, an adjustable piston assembly 3 and an adjustable pressing assembly 4 which are coaxially arranged and cooperate with each other. The adjusting ends of the adjustable piston assembly 3 and the adjustable pressing assembly 4 are both located outside the contrast frame group 1, and the active ends of the two seal through the contrast frame group 1 and extend into the installation cavity, so as to separate the installation cavity into a rod cavity 101 and a rodless cavity 102, and the rodless cavity 102 is connected to an external vacuum pumping device for vacuum pumping. The first sealing member 2 is located in the mounting cavity and is installed between the active end of the adjustable clamping assembly 4 and the active end of the adjustable piston assembly 3, so as to slide up and down in the mounting cavity with the adjustable piston assembly 3, and is used to deform under the downward pressure of the adjustable clamping assembly 4 to fit closely to the inner wall surface of the mounting cavity, and at the same time be clamped between the active end of the adjustable clamping assembly 4 and the active end of the adjustable piston assembly 3, so that the rodless cavity 102 is not connected to the rod cavity 101.

[0028] In the adjustable contrast frame device of the present invention, since the active ends of the adjustable piston assembly 3 and the adjustable clamping assembly 4 both extend into the installation cavity, the installation cavity can be divided into a rod cavity 101 on which the active ends of the adjustable piston assembly 3 and the adjustable clamping assembly 4 are installed, and a rodless cavity 102 connected to an external vacuum pumping device. At this time, the rodless cavity 102 is connected to the rod cavity 101; and the first sealing member 2 is installed between the active end of the adjustable clamping assembly 4 and the active end of the adjustable piston assembly 3, so it can slide up and down in the installation cavity with the adjustable piston assembly 3 to adjust the area size of the rodless cavity 102; when the area of ​​the rodless cavity 102 is equal to the area of ​​the corresponding detection frame, force is applied to the adjusting end of the adjustable clamping assembly 4 to make the adjustable clamping assembly 4 presses down the first sealing member 2. Since the first sealing member 2 is installed between the working end of the adjustable pressing assembly 4 and the working end of the adjustable piston assembly 3, when the adjustable pressing assembly 4 presses down the first sealing member 2, the first sealing member 2 is deformed under the relative extrusion of the adjustable pressing assembly 4 and the adjustable piston assembly 3 to be tightly attached to the inner wall surface of the installation cavity, and is also clamped between the working end of the adjustable pressing assembly 4 and the working end of the adjustable piston assembly 3. Therefore, through the setting of the first sealing member 2 and the mutual extrusion and tightening action between the first sealing member 2 and the adjustable pressing assembly 4, the adjustable piston assembly 3 and the inner wall surface of the installation cavity, a partition layer is formed to seal and separate the rodless cavity 102 from the rod cavity 101, so that the rodless cavity 102 is a sealed cavity that is only connected to the external vacuum device.

[0029] Compared with the prior art in which the volume of the space in the comparison frame is changed by adding or reducing or processing new compensation blocks, in the adjustable comparison frame device of the present invention, the volume of the rodless chamber 102 can be arbitrarily adjusted by moving the adjustable piston assembly 3. At the same time, the rodless chamber 102 can be sealed at any position through the interaction of the adjustable piston assembly 3, the adjustable clamping assembly 4 and the first seal 2. Therefore, the volume change adjustment operation of the rodless chamber 102 is simple, time-saving, labor-saving and flexible. There is no need to prepare a new comparison frame or add or reduce or process new compensation blocks due to the different specifications and volumes of the packaging containers to be inspected, which greatly reduces the inspection cost and improves the inspection efficiency.

[0030] Alternatively, if Figure 1As shown, the adjustable piston assembly 3 includes a piston 31 slidably arranged in the installation cavity, and a piston driving member connected to the piston 31 to drive the piston 31 to slide up and down in the installation cavity. The upper end of the piston driving member extends upward from the comparison frame group 1, and a vertically penetrating installation through hole 310 is provided on the outer circle of the piston 31, and the outer peripheral surface of the piston 31 below the installation through hole 310 convexly forms an annular limiting flange 311; when working, the piston 31 can be driven to slide up and down in the installation cavity by applying force to the upper end of the piston driving member, and the operation is simple. The adjustable clamping assembly 4 includes an upper pressure ring 41 which is hollow and cylindrical and is mounted on the outer circle of the piston 31, a pin 42 which is passed through the mounting through hole 310 and is respectively connected to the upper pressure ring 41 at both ends, and a pin driving member which is passed through the piston driving member and is connected to the pin 42; in this optional scheme, the pin 42 is arranged in the piston 31, the upper pressure ring 41 is mounted on the outside of the piston 31, the pin driving member is passed through the piston driving member, etc., all of which are used to make the overall structure of the adjustable contrast frame device of the present invention compact and the layout reasonable, thereby reducing the overall volume of the device so that it is suitable for the installation of vacuum attenuation leak detection equipment, while also reducing the preparation cost. The first sealing member 2 is a first sealing ring, and the first sealing ring is located between the upper pressure ring 41 and the limiting flange 311. In this optional solution, the limiting flange 311 is provided so that the first sealing ring is located between the bottom end of the upper pressure ring 41 and the limiting flange 311, thereby realizing the positioning of the first sealing ring and the sliding of the adjustable piston assembly 3, and the deformation after being squeezed by the adjustable clamping assembly 4 and the adjustable piston assembly 3.

[0031] Preferably, if Figure 1 As shown, the outer circumferential surface of the lower end of the upper pressure ring 41 is chamfered to form an inverted cone, the upper end surface of the limiting flange 311 is chamfered to form a positive cone, and a ring groove with an opening facing the wall of the installation cavity and in an annular shape is formed between the positive cone and the inverted cone. The first sealing ring is installed in the ring groove. By setting the upper pressure ring 41 and the inverted cone of the limiting flange 311, a ring groove for installing and positioning the first sealing ring can be formed, so that the first sealing ring installed in the ring groove can not only be installed and positioned, but also can slide with the adjustable piston assembly 3, can be deformed after being squeezed by the adjustable clamping assembly 4 and the adjustable piston assembly 3, and can be pressed against the inner wall of the installation cavity after deformation.

[0032] Furthermore, if Figure 1As shown, the piston 31 includes a small diameter section and a large diameter section which are sequentially arranged and connected along the axial direction, and the outer diameter of the large diameter section is larger than the outer diameter of the small diameter section. The installation through hole 310 vertically penetrates the large diameter section, and the inner diameter of the installation through hole 310 is larger than the outer diameter of the pin 42, so that after the piston 31 slides into place, the position of the pin 42 can be adjusted up and down by the pin drive member, so that the pin 42 can better press the first sealing ring below; the upper pressure ring 41 is sleeved on the outer circle of the large diameter section, and the sliding of the upper pressure ring 41 can be limited and guided at the same time, thereby improving the sliding accuracy of the upper pressure ring 41, and finally improving the compression and sealing effect of the first sealing member. The outer circle of the small diameter section is processed with a rotation limiting groove 312 which is concave and extends along its sliding direction. The adjustable piston assembly 3 also includes a rotation limiting bolt 35 which is threaded through the outer wall of the comparison frame group 1. The rotation limiting bolt 35 extends into the rotation limiting groove 312 to limit the circumferential rotation of the piston 31 through the cooperation between the rotation limiting bolt 35 and the rotation limiting groove 312, so as to avoid affecting the sealing effect of the first seal.

[0033] Alternatively, if Figure 1 As shown, the piston driving member includes a driving handle 32, an adjusting screw 33 fixed to the driving handle 32, and a lifting nut 34 mounted on the outer circle of the adjusting screw 33. The driving handle 32 is located outside the contrast frame group 1. The lower end of the adjusting screw 33 is sealed and penetrates the contrast frame group 1 and then extends into the installation cavity. The lifting nut 34 is located in the installation cavity and is fixed to the piston 31. During operation, the driving handle 32 is rotated, and the driving handle 32 drives the adjusting screw 33 to rotate. When the adjusting screw 33 rotates, the lifting nut 34 is lifted up and down through the cooperation with the lifting nut 34, thereby driving the piston 31 to lift up and down, thereby realizing stepless adjustment of the volume of the rodless cavity 102. The adjustment operation is simple, time-saving and labor-saving. At the same time, the overall structure of the adjustable piston assembly 3 is simple and the preparation cost is low.

[0034] Preferably, if Figure 1 As shown, a through hole is processed on the contrast frame assembly 1 for the adjusting screw rod 33 to pass through. The adjustable piston assembly 3 also includes a composite sleeve 36 installed on the outer circle of the adjusting screw rod 33 and located in the through hole; through the provision of the composite sleeve 36, direct friction between the adjusting screw rod 33 and the contrast frame assembly 1 is avoided, thereby extending the service life of the contrast frame assembly 1, and also making the rotation of the adjusting screw rod 33 easy and flexible, and the composite sleeve 36 is also easy to replace after being worn.

[0035] Preferably, if Figure 1As shown, the adjustable contrast frame device for vacuum decay leak detection equipment also includes a position indicator 5 installed on the outer circle of the adjusting screw 33, and the position indicator 5 is located outside the contrast frame group 1, and is used to display the up and down displacement of the piston 31 according to the rotation angle of the adjusting screw 33. In this preferred embodiment, the position indicator 5 is an externally purchased part, and is used to display the up and down sliding amount of the piston 31 according to the rotation angle of the adjusting screw 33, so that the operator can know the change in the volume of the rodless chamber 102 according to the sliding amount of the piston 31.

[0036] Alternatively, if Figure 1 As shown, the adjusting screw 33 is hollow in the axial direction. The pin drive member includes a hand screw 43 and a pressure rod 44 which are arranged in the inner channel of the adjusting screw 33 and are connected in sequence. The upper end of the hand screw 43 extends out of the driving handle 32, and the lower end of the hand screw 43 is threadedly connected to the pressure rod 44. The lower end of the pressure rod 44 extends out of the adjusting screw 33 and is vertically connected to the pin 42. During operation, the hand screw 43 is rotated to drive the pressure rod 44 to slide up and down, and then the pin 42 is driven to slide up and down in the mounting through hole 310 through the pressure rod 44, and when the pressure rod 44 moves down, the pin 42 drives the upper pressure ring 41 to move down to press the first sealing ring.

[0037] Alternatively, if Figure 1 As shown, the contrast frame 11 includes a contrast frame 11 which is hollow and has an open lower end, a mounting seat 12 connected to the lower open end of the contrast frame 11, a second sealing member 13 disposed between the lower open end of the contrast frame 11 and the mounting seat 12, and a quick-release clamp 14 for detachably fixing the contrast frame 11 and the mounting seat 12. The inner cavity of the contrast frame 11 forms a mounting cavity. The mounting seat 12 is processed with a channel connecting the mounting cavity and the vacuum device. The quick-release clamp 14 is installed on the outer circle of the connection between the contrast frame 11 and the mounting seat 12. In this optional solution, the contrast frame group 1 has a simple structural setting, and a second sealing member 13, which is generally a sealing ring, is arranged between the contrast frame 11 and the mounting seat 12. At the same time, the contrast frame 11 and the mounting seat 12 are detachably fixed by an external quick-release clamp 14, which not only makes the installation and disassembly operations of the contrast frame 11 and the mounting seat 12 simple, but also facilitates the disassembly and maintenance of the entire adjustable contrast frame device. At the same time, through the action of the quick-release clamp 14, the contrast frame 11 and the mounting seat 12 are relatively tightened in the axial direction, thereby compressing the second sealing member 13, thereby improving the reliability of the seal between the contrast frame 11 and the mounting seat 12 and avoiding leakage of the rodless cavity 102.

[0038] The preferred embodiment of the present invention also relates to a vacuum decay leak detection device, which has an adjustable contrast frame device for vacuum decay leak detection devices as described above. Therefore, in the vacuum decay leak detection device of the present invention, the volume change adjustment of the rodless cavity 102 is simple, time-saving and labor-saving, and there is no need to prepare a new contrast frame or add, reduce or process a new compensation block due to different specifications and volumes of the packaging containers to be detected, which greatly reduces the detection cost and improves the detection efficiency.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An adjustable contrast frame device for vacuum decay leak detection equipment, characterized in that: include: A contrast frame assembly (1) having a hollow and closed mounting cavity, a first sealing member (2) having a sealing function, an adjustable piston assembly (3) and an adjustable pressing assembly (4) which are coaxially arranged and cooperate with each other; The adjusting ends of the adjustable piston assembly (3) and the adjustable pressing assembly (4) are both located outside the contrast frame assembly (1), and the active ends of the two sealably penetrate the contrast frame assembly (1) and extend into the installation cavity, so as to separate the installation cavity into a rod cavity (101) and a rodless cavity (102), and the rodless cavity (102) is connected to an external vacuum pumping device for vacuuming; The first sealing member (2) is located in the installation cavity and is installed between the active end of the adjustable clamping assembly (4) and the active end of the adjustable piston assembly (3) so as to slide up and down in the installation cavity along with the adjustable piston assembly (3) and to deform under the downward pressure of the adjustable clamping assembly (4) so ​​as to be close to the inner wall surface of the installation cavity and to be pressed between the active end of the adjustable clamping assembly (4) and the active end of the adjustable piston assembly (3) so as to prevent the rodless cavity (102) from communicating with the rod cavity (101).

2. The adjustable contrast frame device for vacuum decay leak detection equipment according to claim 1, characterized in that: The adjustable piston assembly (3) comprises a piston (31) slidably arranged in a mounting cavity, and a piston driving member connected to the piston (31) to drive the piston (31) to slide up and down in the mounting cavity, the upper end of the piston driving member protrudes upward from the frame assembly (1), a mounting through hole (310) vertically penetrating the outer circle of the piston (31) is provided, and the outer peripheral surface of the piston (31) below the mounting through hole (310) is convex outward to form an annular limiting flange (311); The adjustable pressing assembly (4) comprises an upper pressing ring (41) which is hollow and cylindrical and is mounted on the outer circle of the piston (31), a pin (42) which is inserted into the mounting through hole (310) and connected to the upper pressing ring (41) at both ends, and a pin driving member which is inserted into the piston driving member and connected to the pin (42); The first sealing member (2) is a first sealing ring, and the first sealing ring is located between the upper pressure ring (41) and the limiting flange (311).

3. The adjustable contrast frame device for vacuum decay leak detection equipment according to claim 2, characterized in that: The outer circumferential surface of the lower end of the upper pressure ring (41) is chamfered to form an inverted cone surface, the upper end surface of the limiting flange (311) is chamfered to form a positive cone surface, and a ring-shaped receiving groove with an opening facing the wall surface of the installation cavity is formed between the positive cone surface and the inverted cone surface; The first sealing ring is installed in the accommodating ring groove.

4. The adjustable contrast frame device for vacuum decay leak detection equipment according to claim 3, characterized in that: The piston (31) comprises a small diameter section and a large diameter section which are sequentially arranged and connected along the axial direction, and the outer diameter of the large diameter section is larger than the outer diameter of the small diameter section; The mounting through hole (310) vertically penetrates the large diameter section, and the inner diameter of the mounting through hole (310) is larger than the outer diameter of the pin shaft (42), and the upper pressure ring (41) is sleeved on the outer circle of the large diameter section; The outer circle of the small diameter section is processed with a rotation limiting groove (312) which is concave and extends along the sliding direction thereof. The adjustable piston assembly (3) also includes a rotation limiting bolt (35) threadedly penetrated on the outer wall surface of the contrast frame assembly (1). The rotation limiting bolt (35) extends into the rotation limiting groove (312) so as to limit the circumferential rotation of the piston (31) through the cooperation between the rotation limiting bolt (35) and the rotation limiting groove (312).

5. The adjustable contrast frame device for vacuum decay leak detection equipment according to claim 2, characterized in that: The piston driving member comprises a driving handle (32), an adjusting screw rod (33) fixed to the driving handle (32), and a lifting nut (34) cooperatively mounted on the outer circle of the adjusting screw rod (33); The driving handle (32) is located outside the contrast frame assembly (1); The lower end of the adjusting screw rod (33) is sealed and penetrates through the contrast frame assembly (1) and then extends into the installation cavity; The lifting nut (34) is located in the installation cavity and is fixed to the piston (31).

6. The adjustable contrast frame device for vacuum decay leak detection equipment according to claim 5, characterized in that: The contrast frame assembly (1) is provided with a through hole for the adjusting screw rod (33) to pass through; The adjustable piston assembly (3) also includes a composite sleeve (36) which is mounted on the outer circle of the adjusting screw rod (33) and is located in the through hole.

7. The adjustable contrast frame device for vacuum decay leak detection equipment according to claim 5, characterized in that: The adjustable contrast frame device for vacuum decay leak detection equipment also includes a position display (5) mounted on the outer circle of the adjusting screw (33). The position display (5) is located outside the contrast frame group (1) and is used to display the up and down displacement of the piston (31) according to the rotation angle of the adjusting screw (33).

8. The adjustable contrast frame device for vacuum decay leak detection equipment according to claim 5, characterized in that: The adjusting screw rod (33) is hollowly arranged along the axial direction; The pin shaft driving member comprises a hand screw (43) and a pressure rod (44) which are arranged in the inner channel of the adjusting screw rod (33) and are connected in sequence. The upper end of the hand screw (43) extends out of the driving handle (32), the lower end of the hand screw (43) is threadedly connected to the pressure rod (44), and the lower end of the pressure rod (44) extends out of the adjusting screw rod (33) and is vertically connected to the pin shaft (42).

9. The adjustable contrast frame device for vacuum decay leak detection equipment according to claim 2, characterized in that: The contrast frame (11) comprises a contrast frame (11) which is hollow and has an open lower end, a mounting seat (12) connected to the lower open end of the contrast frame (11), a second sealing member (13) arranged between the lower open end of the contrast frame (11) and the mounting seat (12), and a quick-release clamp (14) for detachably fixing the contrast frame (11) and the mounting seat (12); The inner cavity of the contrast frame (11) forms a mounting cavity; The mounting seat (12) is provided with a passage connecting the mounting cavity and the vacuum pumping device; The quick-install clamp (14) is installed on the outer circle of the connection between the comparison frame (11) and the mounting seat (12).

10. A vacuum decay leak detection device, characterized in that: An adjustable contrast frame device for a vacuum decay leak detection device according to any one of claims 1 to 9.

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