Mechanical test sealing structure in liquid helium environment

Abstract

A mechanical test sealing structure in a liquid helium environment is used for a material testing machine, and the material testing machine comprises a liquid tank, an upper chuck and a lower chuck; a liquid helium cavity is formed in the liquid tank, the top of the liquid tank is covered and sealed by a liquid tank cover, a through hole is formed in the liquid tank cover, and an upper pull rod penetrates through the through hole; the sealing structure is arranged above a through hole, penetrating out of the liquid tank cover, of the upper pull rod and comprises a stainless steel corrugated pipe, flanges are fixed to the upper end and the lower end of the stainless steel corrugated pipe respectively, flanges arranged at the lower end are welded and fixed to the liquid tank cover, and the inner wall of a flange arranged at the upper end is concaved inwards to form an annular groove. A plurality of threaded holes are formed in the outer side of the annular groove; a sealing ring is arranged in the annular groove, and the upper portion of the sealing ring is pressed and fixed through a fixing ring. The telescopic performance of the stainless steel corrugated pipe is used for replacing relative axial movement between the sealing ring and the upper pull rod, so that the sealing ring is prevented from being damaged by a solidified ice layer, the service life of the sealing ring is guaranteed, and waste is avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field of mechanical test sealing in a liquid helium environment, in particular to a mechanical test sealing structure in a liquid helium environment. Background Art

[0002] In the mechanical test under liquid helium environment, the liquid helium chamber is filled with liquid helium to the set height, and the sample is immersed in liquid helium. Since liquid helium is very volatile in the room temperature atmosphere, the liquid helium chamber that stores liquid helium must be in a sealed state.

[0003] The existing mechanical test under liquid helium environment mainly includes a tank body with a liquid helium cavity inside, a tank cover is fixed on the top of the tank body, and a hole is opened on the tank cover for the upper tie rod to pass through. The upper end of the upper tie rod is clamped and fixed with the upper chuck of the testing machine, and the lower end is used to fix with the sample in the liquid helium cavity; a welded tie rod seat is passed through the bottom of the tank body, the upper end of the tie rod seat is used to fix with the sample in the liquid helium cavity, and the lower end is connected to the lower tie rod, which is clamped and fixed by the lower chuck of the testing machine. In this way, in the mechanical test under liquid helium environment, the testing machine applies the test load to the sample through the upper tie rod and the lower tie rod. Since the upper tie rod needs to pass through the hole of the liquid tank cover and be clamped on the upper chuck of the testing machine, a sealing ring needs to be used to seal between the upper tie rod and the hole of the liquid tank cover. However, due to the extremely low temperature of liquid helium (-269℃), water vapor in the air will freeze and solidify on the surface of the sealing ring during the test. In static tests, especially in dynamic fatigue tests, the axial linear motion of the upper pull rod will pull the ice layer solidified on the surface of the seal ring, which is easy to damage the seal ring, resulting in a shortened service life of the seal ring and causing waste. Therefore, it is necessary to improve it. Utility Model Content

[0004] The purpose of the utility model is to provide a mechanical test sealing structure in a liquid helium environment to solve the problem of damage to the sealing ring caused by the axial linear motion of the upper pull rod pulling the ice layer solidified on the surface of the sealing ring.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A mechanical test sealing structure in a liquid helium environment is used for a material testing machine, the material testing machine comprising a liquid tank, an upper chuck and a lower chuck; a liquid helium cavity is provided inside the liquid tank, and the top is sealed with a liquid tank cover, the liquid tank cover is provided with a through hole and an upper pull rod is passed through the through hole;

[0007] Among them, the mechanical test sealing structure under liquid helium environment is arranged above the through hole of the upper pull rod passing through the liquid tank cover, including a stainless steel bellows, the upper and lower ends of the stainless steel bellows are fixed with flanges, the flange formed at the lower end is welded and fixed to the liquid tank cover, the inner wall of the flange formed at the upper end is concave to form a circle of annular groove, and a plurality of threaded holes are opened on the outer side of the annular groove along the outer edge of the upper flange; a sealing ring is arranged in the annular groove, and is pressed and fixed at the top with a fixing ring; a fixing hole is opened on the fixing ring at a position corresponding to the threaded hole, and the fixing ring is fixed to the upper flange of the stainless steel bellows by a fixing piece.

[0008] According to the utility model, a tie rod seat is fixed to the bottom of the liquid helium chamber, and the bottom end of the tie rod seat passes through the bottom of the liquid tank and is connected to a tie rod.

[0009] According to the utility model, the upper clamp is located above the liquid tank and is used to clamp the upper end of the upper pull rod; the lower clamp is located below the liquid tank and is used to clamp the bottom end of the lower pull rod.

[0010] According to the utility model, the bottom end of the upper pull rod is located in the liquid helium chamber, and a threaded hole is provided on the bottom surface for being fixed to the upper end of the test piece through threads.

[0011] According to the utility model, the upper end of the pull rod seat is located in the liquid helium chamber, and an inverted T-shaped groove is provided on the upper surface. An inverted T-shaped block is arranged in the inverted T-shaped groove, and a threaded hole is provided on the upper surface of the inverted T-shaped block for fixing with the lower end of the test piece through threads.

[0012] According to the utility model, the lower end of the tie rod seat extends out of the bottom of the liquid tank and is provided with threads at the lower end, and the upper end of the lower tie rod is provided with a corresponding threaded hole so as to be threadedly connected with the lower end of the tie rod seat.

[0013] The utility model discloses a mechanical test sealing structure in a liquid helium environment, which utilizes the telescopic performance of a stainless steel bellows to replace the relative axial movement between the sealing ring and the upper pull rod, thereby avoiding damage to the sealing ring by a solidified ice layer, ensuring the service life of the sealing ring and avoiding waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a structural cross-sectional view of a material testing machine.

[0015] Figure 2 Schematic diagram of the cross section of the stainless steel bellows used in the mechanical test sealing structure under liquid helium environment.

[0016] Description of the figure number:

[0017] 10-liquid tank; 11-liquid helium chamber; 12-liquid tank cover; 13-through hole; 14-upper tie rod; 15-tie rod seat; 16-lower tie rod; 20-upper chuck; 30-lower chuck; 40-stainless steel bellows; 41-flange; 42-annular groove; 43-threaded hole; 44-sealing ring; 45-fixing ring; 47-fastening screw; 100-test piece; 151-inverted T-slot; 152-inverted T-block. DETAILED DESCRIPTION

[0018] The present invention is further described in detail with reference to specific embodiments in conjunction with the accompanying drawings. It should be understood that the following embodiments are only used to illustrate the present invention, but not to limit the scope of the present invention.

[0019] like Figure 1 As shown, the mechanical test sealing structure in a liquid helium environment of the utility model is used for a material testing machine, and the material testing machine includes a liquid tank 10, an upper chuck 20 and a lower chuck 30, wherein:

[0020] The liquid tank 10 has a liquid helium chamber 11 inside, and the top is sealed by a liquid tank cover 12. The liquid tank cover 12 has a through hole 13 through which an upper pull rod 14 is passed. A pull rod seat 15 is fixed to the bottom of the liquid helium chamber 11, and the bottom end of the pull rod seat 15 passes through the bottom of the liquid tank 10 and is connected to a lower pull rod 16.

[0021] The upper clamp 20 is located above the liquid tank 10 and is used to clamp the upper end of the upper pull rod 14;

[0022] The lower clamp 30 is located below the liquid tank 10 and is used to clamp the bottom end of the lower pull rod 16 .

[0023] Combination Figure 2 As shown, the mechanical test sealing structure under liquid helium environment of this embodiment is arranged above the through hole 14 through which the upper pull rod 14 passes through the liquid tank cover 12, and includes a stainless steel bellows 40, and flanges 41 are fixed to the upper and lower ends of the stainless steel bellows 40. The flange 41 formed at the lower end is welded and fixed to the liquid tank cover 12, and the inner wall of the flange 41 formed at the upper end is concave to form a circle of annular groove 42, and a plurality of threaded holes 43 are opened on the outer side of the annular groove 42 along the outer edge of the upper end flange 41; a sealing ring 44 is arranged in the annular groove 42, and is pressed and fixed at the top with a fixing ring 45; a fixing hole is opened on the fixing ring 45 at a position corresponding to the threaded hole 43, and the fixing ring 45 is fixed to the upper end flange 41 of the stainless steel bellows 40 by a fastening screw 47.

[0024] In this way, by providing the stainless steel bellows 40, its elasticity is utilized to replace the relative movement between the sealing ring 44 and the sealed component, thereby avoiding the damage to the sealing ring caused by pulling the ice layer solidified on the surface of the sealing ring 44 due to ultra-low temperature.

[0025] Furthermore, the bottom end of the upper tie rod 14 is located in the liquid helium chamber 11, and a threaded hole is provided on the bottom surface for threaded fixation with the upper end of the test piece 100; the upper end of the tie rod seat 15 is located in the liquid helium chamber 11, and an inverted T-shaped groove 151 is provided on the upper surface, and an inverted T-shaped block 152 is provided in the inverted T-shaped groove 151, and a threaded hole is also provided on the upper surface of the inverted T-shaped block for threaded fixation with the lower end of the test piece 100. The lower end of the tie rod seat 15 extends out of the bottom of the liquid tank 10, and a thread is provided on the lower end, and the upper end of the lower tie rod 16 is provided with a corresponding threaded hole, so as to be threadedly connected with the lower end of the tie rod seat 15. In this way, by connecting and fixing the upper and lower ends of the test piece 100 with the upper tie rod 14 and the tie rod seat 15 respectively, and by clamping the lower tie rod 16 connected to the tie rod seat 15 and the upper chuck 20 and the lower chuck 30, the tensile fatigue test can be performed on the test piece 100.

[0026] Furthermore, the liquid tank cover 12 is also provided with a liquid inlet pipe, an exhaust pipe, a pressure gauge, and the liquid helium chamber 11 is provided with a liquid level meter, etc. These are inherent configurations of existing material testing machines and will not be described in detail here.

[0027] Although the present invention has been described in detail above through specific embodiments, it should be understood that the above is only a preferred embodiment of the present invention, and those skilled in the art can make appropriate modifications, equivalent substitutions and improvements within the spirit and principles of the present invention, all of which should be included in the protection scope of the present invention.

Claims

1. A mechanical test sealing structure in a liquid helium environment, used in a material testing machine, the material testing machine comprising a liquid tank, an upper chuck and a lower chuck; a liquid helium chamber is provided inside the liquid tank, and the top is sealed with a liquid tank cover, the liquid tank cover is provided with a through hole and an upper pull rod is passed through the through hole; It is characterized in that The mechanical test sealing structure under liquid helium environment is arranged above the through hole through which the upper pull rod passes through the liquid tank cover, and comprises a stainless steel bellows, the upper and lower ends of which are fixed with flanges, the flange formed at the lower end is welded and fixed to the liquid tank cover, the inner wall of the flange formed at the upper end is concave to form a circle of annular groove, and a plurality of threaded holes are provided on the outer side of the annular groove along the outer edge of the upper flange; a sealing ring is provided in the annular groove, and is fixed and compressed by a fixing ring at the top; a fixing hole is provided on the fixing ring at a position corresponding to the threaded hole, and the fixing ring is fixed to the upper flange of the stainless steel bellows by a fixing member.

2. The mechanical test sealing structure in liquid helium environment according to claim 1, characterized in that: A tie rod seat is fixed at the bottom of the liquid helium chamber, and the bottom end of the tie rod seat passes through the bottom of the liquid tank and is connected to a tie rod.

3. The mechanical test sealing structure in liquid helium environment according to claim 2, characterized in that: The upper clamp is located above the liquid tank and is used to clamp the upper end of the upper pull rod; the lower clamp is located below the liquid tank and is used to clamp the bottom end of the lower pull rod.

4. The mechanical test sealing structure in liquid helium environment according to claim 1, characterized in that: The bottom end of the upper pull rod is located in the liquid helium chamber, and a threaded hole is provided on the bottom surface for being fixed to the upper end of the test piece through threads.

5. The mechanical test sealing structure in liquid helium environment according to claim 2, characterized in that: The upper end of the pull rod seat is located in the liquid helium cavity, and an inverted T-shaped groove is provided on the upper surface. An inverted T-shaped block is arranged in the inverted T-shaped groove, and a threaded hole is provided on the upper surface of the inverted T-shaped block for fixing with the lower end of the test piece through threads.

6. The mechanical test sealing structure in liquid helium environment according to claim 2, characterized in that: The lower end of the tie rod seat extends out of the bottom of the liquid tank and is provided with a thread at the lower end. The upper end of the lower tie rod is provided with a corresponding threaded hole so as to be threadedly connected with the lower end of the tie rod seat.

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