An interlayer liquid-filled ultra-high pressure equipment based on secondary pressurization

Abstract

The invention discloses an interlayer liquid-filled ultra-high pressure equipment based on secondary pressurization, comprising an inner cylinder, a middle cylinder and an outer cylinder which are coaxially arranged in sequence from the inside to the outside; the inner cylinder is made of tungsten carbide alloy; an annular cavity is arranged between the inner cylinder and the middle cylinder, and between the middle cylinder and the outer cylinder, and the inner cavity of the inner cylinder, the space between the inner cylinder and the middle cylinder, and the space between the middle cylinder and the outer cylinder are all filled with medium liquid; the mouths of the inner cylinder, the middle cylinder and the outer cylinder are sequentially provided with an inner cylinder piston, a middle cylinder piston and a pressure shaft, and the pressure shaft is used to apply pressure; the middle cylinder piston is pressurized by the medium liquid, and then the inner cylinder piston is pressurized for a second time by the medium liquid.

Description

Technical Field

[0001] The invention belongs to the technical field of ultra-high pressure vessels, and in particular to an interlayer liquid-filled ultra-high pressure device based on secondary pressurization. Background Art

[0002] At present, the commonly used ultra-high pressure cylinder structures at home and abroad include shrink sleeve type, self-reinforced type, wire winding type, split type and liquid support type. The traditional single-layer thick-walled cylinder is relatively low in terms of pressure bearing capacity and safety. The pressure bearing capacity cannot be significantly improved with the increase of wall thickness. In the field of aluminum-magnesium alloy extrusion molding, a reliable ultra-high static pressure device is needed. For this reason, it is very necessary to study ultra-high pressure devices with liquid as the pressure transmission medium. The existing related research content, such as the cylinder that combines the double-layer thick-walled type and the self-reinforced type at the same time, and the interlayer liquid-filled composite cylinder with a self-reinforced cylinder. Chinese patent CN107989997 discloses an interlayer liquid-filled ultra-high pressure device. The results of the above literature show that the interlayer liquid-filled composite cylinder utilizes the characteristics of elastic materials to a greater extent, but it is not applicable to brittle materials with ultra-high hardness, which limits the limit of the pressure cylinder's bearing capacity. Summary of the invention

[0003] The object of the present invention is to provide an interlayer liquid-filled ultra-high pressure equipment based on secondary pressurization to improve the bearing capacity of the equipment.

[0004] The technical solution to achieve the purpose of the present invention is:

[0005] An interlayer liquid-filled ultrahigh pressure device based on secondary pressurization comprises an inner cylinder, a middle cylinder and an outer cylinder which are coaxially arranged in sequence from the inside to the outside;

[0006] The inner cylinder is made of tungsten carbide alloy;

[0007] An annular cavity is provided between the inner cylinder and the middle cylinder, and between the middle cylinder and the outer cylinder. The inner cavity of the inner cylinder, the space between the inner cylinder and the middle cylinder, and the space between the middle cylinder and the outer cylinder are all filled with medium liquid.

[0008] The mouths of the inner cylinder, middle cylinder and outer cylinder are provided with an inner cylinder piston, middle cylinder piston and a pressure shaft in sequence, and the pressure shaft is used to apply pressure; the middle cylinder piston is pressurized by the medium liquid, and then the inner cylinder piston is pressurized for a second time by the medium liquid.

[0009] Compared with the prior art, the present invention has the following significant advantages:

[0010] Strong bearing capacity: the inner tube uses tungsten carbide alloy as the material, which greatly improves the bearing capacity of the inner wall of the inner tube; the inner wall and the outer wall of the inner tube bear the pressure of the interlayer medium liquid at the same time, so that the inner tube can work better in the compressive stress state of the material and better play the characteristics of tungsten carbide alloy. Tungsten carbide alloy is a brittle material and can withstand limited tensile stress. The present invention makes good use of the material properties of carbide alloys, so that the inner tube can achieve a very high bearing capacity.

[0011] Two-stage pressurization: Two-stage pressurization reduces the high requirements for the materials of the middle and outer cylinders; the pressure is transmitted from the outer cylinder to the inner cylinder one level after another. According to the principle of static pressure, the pressure of the interlayer medium liquid at each position increases successively from the outer cylinder to the inner cylinder.

[0012] Safe and reliable: Due to the presence of the interlayer medium liquid, the inner cylinder is subjected to the hydrostatic pressure of the inner and outer walls of the inner cylinder at the same time, which improves the pressure bearing capacity of the cylinder and ensures safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a quarter cross-sectional view of the interlayer liquid-filled ultra-high pressure equipment of the present invention.

[0014] Figure 2 It is a schematic diagram of the structure of the interlayer liquid-filled ultra-high pressure equipment of the present invention.

[0015] Figure 3 Schematic diagram of the cylinder diameter of the equipment.

[0016] Figure 4 It is a path diagram from the center of the inner cylinder to the outer wall of the outer cylinder.

[0017] Figure 5 This is the stress distribution diagram of the inner cylinder, middle cylinder and outer cylinder of the equipment. DETAILED DESCRIPTION

[0018] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0019] Combination Figure 1 and Figure 2The present embodiment is an interlayer liquid-filled ultra-high pressure device based on secondary pressurization, comprising an inner tube 1, a middle tube 2, an inner tube piston 3, an outer tube 4, a middle tube piston 5, a pressure shaft 6, a sealing member 7 and a medium liquid 8. The inner cylinder, middle cylinder and outer cylinder are coaxially arranged; the outer cylinder 4 is a cylindrical structure with one end open; the bottom of the middle cylinder 2 is fixed to the bottom of the outer cylinder 4; the bottom of the inner cylinder 1 is fixed to the bottom of the middle cylinder 2; the lower end cylinder of the inner cylinder piston 3 fits with the lower end of the step hole of the inner cylinder 1; the inner cylinder piston 3 can slide up and down in the inner cylinder 1; the middle cylinder piston 5 can slide up and down in the middle cylinder 2; the pressure shaft 6 slides in the outer cylinder 4 and is located at its upper end; annular cavities are provided between the inner cylinder 1 and the middle cylinder 2, and between the middle cylinder 2 and the outer cylinder 4; the inner wall space of the inner cylinder 1, the space between the outer wall of the inner cylinder 1 and the inner wall of the middle cylinder 2, and the space between the outer wall of the middle cylinder 2 and the inner wall of the outer cylinder 4 are all filled with medium liquid 8; by applying pressure on the upper part of the pressure shaft 6, the middle cylinder piston 5 is pressurized by the medium liquid 8, and then the inner cylinder 1 piston is pressurized for the second time by the medium liquid 8.

[0020] The inner tube 1 is made of tungsten carbide alloy; the middle tube 2 and the outer tube 4 are made of 00Ni18Co12Mo4Ti2Al ultra-high strength steel; tungsten carbide alloy has a compressive strength of up to 5GPa, but weak tensile strength; 00Ni18Co12Mo4Ti2Al ultra-high strength steel has a yield strength of 2460MPa.

[0021] like Figure 3 , the inner diameter of the inner tube is set to r1, the outer diameter of the inner tube is r2, the inner diameter of the middle tube is r3, the outer diameter of the middle tube is r4, the inner diameter of the outer tube is r5, and the outer diameter of the outer tube is r6. The tensile strength of the inner tube is weak, and the inner tube is ensured to work when the tangential stress of the inner wall of the inner tube is less than 0. Now take the tangential stress equal to 0 to obtain the relationship:

[0022]

[0023] Where: p1 is the inner wall pressure of the inner cylinder;

[0024] p m1 is the interlayer liquid pressure between the outer wall of the inner tube and the inner wall of the middle tube;

[0025] K1 is the inner cylinder diameter ratio r2 / r1.

[0026] The materials of the middle cylinder and the outer cylinder are the same, and it is considered that the middle cylinder and the outer cylinder work in the elastic stage of the material.

[0027]

[0028] Where: s2 is the yield strength of the middle tube;

[0029] p m1Max The maximum pressure that the inner wall of the middle tube can withstand;

[0030] K2 is the middle cylinder diameter ratio r4 / r3;

[0031] K3 is the outer tube diameter ratio r6 / r5.

[0032] Combining the above two equations, we can get the relationship between the influence of each diameter ratio. Assume that the total diameter ratio K = K1K2K3. The minimum value of the total diameter ratio is about 14, at which time the inner tube diameter ratio is about 2.7, and the middle tube and outer tube diameter ratio is about 2.3.

[0033] The inner radius of the inner cylinder is set to 15mm, the outer radius of the inner cylinder is set to 40.5mm; the inner radius of the middle cylinder is set to 42mm, the outer radius of the middle cylinder is set to 96.5mm; the inner radius of the outer cylinder is set to 98mm, the outer radius of the outer cylinder is set to 225mm; the working pressure of the inner cylinder is 3500MPa. Then the interlayer liquid pressure p between the outer wall of the inner cylinder and the inner wall of the middle cylinder can be obtained. m1 is 1990MPa, and the interlayer liquid pressure p between the outer wall of the middle tube and the inner wall of the outer tube m2 It is 995MPa.

[0034] like Figure 4 , along the inner diameter of the cylinder, we get Figure 5 The stress path diagrams are shown in Figure 2. The tangential stress of the inner cylinder is less than 0, indicating that the inner cylinder meets the working requirements. The maximum shear stress of the inner cylinder is 1404.1MPa; the maximum shear stress of the middle cylinder is 892MPa; and the maximum shear stress of the outer cylinder is 835MPa. Each maximum shear stress value is less than half of the yield limit of its material. The results show that the inner cylinder, the middle cylinder and the outer cylinder can all work in an elastic state; at this time, the bearing capacity of the inner cylinder reaches 3500MPa.

Claims

1. An interlayer liquid-filled ultrahigh pressure device based on secondary pressurization, characterized in that: It includes an inner cylinder, a middle cylinder and an outer cylinder which are coaxially arranged in sequence from the inside to the outside; The inner cylinder is made of tungsten carbide alloy; An annular cavity is provided between the inner cylinder and the middle cylinder, and between the middle cylinder and the outer cylinder. The inner cavity of the inner cylinder, the space between the inner cylinder and the middle cylinder, and the space between the middle cylinder and the outer cylinder are all filled with medium liquid. The middle tube and the outer tube are made of 00Ni18Co12Mo4Ti2Al; The mouths of the inner cylinder, middle cylinder and outer cylinder are provided with an inner cylinder piston, middle cylinder piston and a pressure shaft in sequence, and the pressure shaft is used to apply pressure; the middle cylinder piston is pressurized by the medium liquid, and then the inner cylinder piston is pressurized for a second time by the medium liquid.

2. The interlayer liquid-filled ultrahigh pressure equipment based on secondary pressurization according to claim 1 is characterized in that: satisfy: Where: p1 is the inner wall pressure of the inner cylinder; p m1 is the interlayer liquid pressure between the outer wall of the inner tube and the inner wall of the middle tube; K1 is the inner cylinder diameter ratio.

3. The interlayer liquid-filled ultrahigh pressure equipment based on secondary pressurization according to claim 1 is characterized in that: The middle tube and the outer tube are made of the same material.

4. The interlayer liquid-filled ultrahigh pressure equipment based on secondary pressurization according to claim 3 is characterized in that: satisfy: Where: s2 is the yield strength of the middle tube; p m1Max The maximum pressure that the inner wall of the middle tube can withstand; K2 is the middle cylinder diameter ratio; K3 is the outer cylinder diameter ratio.

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