CN103267120A - High temperature and high pressure sealing window used for constant volume combustion bomb - Google Patents

Abstract

The invention discloses a high-temperature and high-pressure sealing window for constant-volume incendiary bombs. Glass is installed inside the cover, and the outer side of the glass is axially limited by the first sealing step surface inside the flange end cover, and the first sealing step surface is provided with a groove for installing an O-ring; the inner side of the glass is axially limited by the retaining ring , the retaining ring is fixed on the second sealing step inside the flange end cover by countersunk bolts and pressed against the glass, and a graphite gasket is arranged between the retaining ring and the glass. In the present invention, the glass and the flange end cover are integrated, and then the flange end cover and the elastic body are sealed, and the glass is installed at one time without frequent disassembly, which avoids the problems of sealing failure and easy crushing of the glass, and The expansion pressure of the gas in the cavity enhances the pre-tightening force of the compressed glass to achieve the effect of self-tightening and sealing, and realizes the sealing of the high-temperature and high-pressure gas of the constant-volume incendiary bomb.

Description

A high temperature and high pressure sealing window for constant volume incendiary bombs

technical field

The invention relates to the technical field of internal combustion engine combustion, in particular to a sealing window for constant-volume incendiary bombs.

Background technique

The constant-volume incendiary bomb has a simple structure and low construction cost, and can easily study the influence of a single parameter change on the combustion process; an optical quartz glass window is provided, and the internal flame propagation can be observed in combination with high-speed photography technology; while the gasoline engine burns at top dead center When the combustion speed is fast, it is considered to be a constant volume combustion. Therefore, constant volume incendiary bombs are widely used in the technical field of gasoline engine combustion. In China, Xi'an Jiaotong University, Tianjin University, Beijing University of Technology and Beijing Institute of Technology have used incendiary bombs to carry out research in related fields such as flame propagation, spray and alternative fuels.

The current constant-volume incendiary bombs generally have two to three windows. A gasket or sealant is provided between the glass and the metal, and then the end cover is directly pressed by the bolts to fix the glass on the bomb body. This sealing method exists. The following problems: First of all, when constant volume incendiary bombs are tested for many times and the fuel is replaced for experiments, the cavity and the inside of the glass need to be cleaned, so the window needs to be disassembled frequently, which will affect the sealing of the bomb body, and the glass material is relatively brittle. Frequent disassembly is easy to break. Secondly, the glass is directly pressed on the projectile by the end cover through bolts. If the pre-tightening force of each bolt is uneven, the glass is easily crushed. In addition, when the gasoline engine burns at the top dead center, the temperature can reach more than 1000K, and the pressure can reach more than 10Mpa. The constant volume incendiary bomb simulates the working conditions of the gasoline engine under high temperature and high pressure, and the aging of the gasket is the main problem. Therefore, the poor sealing of the window of constant volume incendiary bombs has always been the main obstacle in the simulation research of constant volume incendiary bombs.

Contents of the invention

The invention aims to solve the technical problems of poor sealing and easy breakage of the existing constant volume incendiary bomb window, and provides a high temperature and high pressure sealing window for constant volume incendiary bombs. As a whole, the flange end cover and the projectile body are sealed, and the glass is installed at one time without frequent disassembly, which avoids the problems of seal failure and easy crushing of the glass, and the gas expansion pressure in the cavity increases the preload of the compressed glass Force, to achieve the effect of self-tightening seal, to realize the sealing of high temperature and high pressure gas of constant volume incendiary bombs.

In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

A high-temperature and high-pressure sealing window for constant-volume incendiary bombs, including glass, including a flange end cover with an external boss on the outside, the outer boss is uniformly distributed with installation holes in the radial direction, and the flange end cover The mounting bolts in the mounting holes are fixed to the body of the constant-volume incendiary bomb, and there is a gap of 1-2mm between the external boss and the outer wall of the bomb, so that the pre-tightening force of the mounting bolts can fully act on the The sealing surface where the inner side of the flange end cover is in contact with the inside of the elastic body;

Glass is installed inside the flange end cover, and the outer side of the glass is axially limited by the first sealing step surface inside the flange end cover, and a groove on which an O-ring is installed is arranged on the first sealing step surface. Groove; the inner side of the glass is axially limited by a retaining ring that does not protrude from the sealing surface inside the flange end cover, and the retaining ring is fixed to the second seal inside the flange end cover by countersunk bolts The glass is pressed against the stepped surface, and a graphite gasket is arranged between the retaining ring and the glass.

Preferably, the groove has a rectangular cross-sectional shape.

The surface roughness of the first sealing step surface on the flange end cover is 1.6-3.2 μm.

The radial contact surface between the flange end cover and the glass is coated with sealant.

The surface roughness of the contact surface between the retaining ring and the glass is 1.6-3.2 μm.

The radial contact surface of the flange end cover and the retaining ring is coated with sealant.

The surface roughness of the sealing surface inside the flange end cover is 1.6-3.2 μm.

The sealing surface inside the flange end cover is coated with sealant.

The beneficial effects of the present invention are:

The invention makes the glass and the flange end cover into an integral sealing window, which can improve the sealing performance of the constant-volume incendiary bomb under high temperature and high pressure. Specifically, the inner side of the sealing window is in direct contact with the body of the constant volume incendiary bomb, and the glass is pressed and installed on the flange end cover from the inner side through the retaining ring, and the space between the retaining ring and the glass is close to the cavity of the constant volume incendiary bomb. High temperature resistant graphite gasket, O-ring axial seal between the glass and the flange end cover. On the one hand, because the O-ring has good compressibility, it can buffer the vibration of the glass; on the other hand, the gas expansion pressure in the cavity of the constant volume incendiary bomb is in the same direction as the pre-tightening force of the retaining ring pressing the glass, so that the glass can The tighter the pressure on the flange end cap, and the greater the pressure in the cavity, the better the sealing effect.

Compared with the prior art, the present invention has the following advantages:

(1) There is no need to disassemble the glass during the installation and disassembly of the sealing window from the projectile body, the disassembly operation is more convenient, which greatly improves the disassembly efficiency, and also solves the problems of frequent disassembly of the glass affecting the sealing and easy breakage;

(2) The bolt pre-tightening force connecting the flange end cover and the projectile acts on the projectile instead of directly pressing the glass, so as to avoid crushing the glass due to uneven force;

(3) The glass is installed inside the projectile body. The expansion pressure in the cavity of the constant volume incendiary bomb is in the same direction as the installation pre-tightening force, forming a self-tightening sealing effect. The greater the internal pressure of the cavity, the better the sealing performance.

Description of drawings

Fig. 1 is the structural exploded schematic view of the sealing window provided by the present invention;

Fig. 2 is a sectional view of the sealing window provided by the present invention;

Fig. 3 is the cross-sectional view of the flange end cap in the sealing window provided by the present invention;

Fig. 4 is a partially enlarged view of part A in Fig. 3;

Fig. 5 is a schematic diagram of the assembly of the sealing window provided by the present invention on the body of the constant volume incendiary bomb.

In the figure: 1: flange end cover; 1-1: external boss; 1-2: first sealing step surface; 1-3: second sealing step surface; 2: mounting hole; 3: O-ring; 4 : Quartz glass; 5: Countersunk head bolt; 6: Retaining ring; 7: High-strength graphite composite gasket; 8: Rectangular groove; 9: Sealing surface; 10: Elastic body.

Detailed ways

The present invention will be described in further detail below through specific examples. The following examples can enable those skilled in the art to understand the present invention more comprehensively, but do not limit the present invention in any way.

As shown in Figures 1 and 2, this embodiment discloses a high-temperature and high-pressure sealing window for constant-volume incendiary bombs, which mainly consists of a flange end cover 1, quartz glass 4, O-ring 3, retaining ring 6, high-strength The graphite composite gasket 7 and the mounting bolt 5 are composed.

As shown in FIG. 3 , the material of the flange end cover 1 is No. 45 steel, and its surface roughness is 3.2 μm to meet certain processing accuracy requirements; the diameter of the visible window is 100 mm. An external boss 1-1 is arranged radially on the outer side of the flange end cover 1, and the outer boss 1-1 is provided with a mounting hole 2, and the flange end cover 1 can be fixed by six evenly distributed M10 hexagon head mounting bolts On the projectile body 10 of the constant volume incendiary bomb, the high-strength bolts with a precision of 12.9 are all selected for use as the mounting bolts. During assembly, there should be a gap of 1-2mm between the inner side of the external boss 1-1 and the outer wall of the projectile 10, so that the pre-tightening force of the mounting bolts on the flange end cover 1 can fully act on the inner side of the flange end cover 1 and the projectile body. 10 on the sealing surface 9 that is in contact with the inside. The sealing surface 9 inside the flange end cover 1 can be coated with high-temperature sealing red glue for further sealing.

The flange end cover 1 is provided with a first outer sealing step surface 1-2 and an inner second sealing step surface 1-3.

The quartz glass 4 is installed from the inside of the flange end cover 1, and its outside is axially limited by the first sealing step surface 1-2. A rectangular groove 8 is opened on the first sealing step surface 1-2, and an O-ring 3 of matching type is installed in the rectangular groove 8, so that the quartz glass 4 and the flange end cover 1 are axially sealed, and the vibration is buffered role. Rectangular groove 8 is a commonly used groove form suitable for both motion sealing and fixed sealing, as shown in Figure 4, its width is 4.3mm, and its depth is 2.4mm. According to the working conditions, the diameter of the O-ring 3 is 110mm, the cross-section is a circle with a diameter of 3.1mm, the compression rate is 10%-15%, and the Shore hardness is 80±5. Sealed, its working pressure can reach 20Mpa. In addition, the O-ring 3 should have sufficient sealing contact area; the friction force should be as small as possible; permanent deformation should be avoided as much as possible. The radial contact surface between the flange end cover 1 and the quartz glass 4 is also coated with high-temperature sealing red glue.

A retaining ring 6 is installed at the position of the second sealing step surface 1-3 of the flange end cover 1, and the retaining ring 6 is axially limited by the second sealing step surface 1-3; at the same time, the inner diameter of the retaining ring 6 is smaller than the diameter of the quartz glass 4 , so that it is limited by the inner side of the quartz glass 4. The retaining ring 6 is made of No. 45 steel, with a surface roughness of 3.2 μm, and six bolt holes are evenly distributed, and is fixed on the flange end cover 1 with M6 inner hexagon socket head countersunk head bolts 5 . Countersunk head bolts 5 sink into retaining ring 6, and retaining ring 6 does not protrude from sealing surface 9 inside flange end cover 1, preventing installation pretightening force between flange end cover 1 and elastic body 10 from passing through retaining ring 6 Act on the quartz glass 4, thereby avoiding the crushing of the quartz glass 4 due to excessive force.

A high-strength graphite composite gasket 7 is installed between the retaining ring 6 and the quartz glass 4, so as to compress the quartz glass 4 and play a sealing role. High-strength graphite composite gasket 7 withstands a pressure of 0-25Mpa and a temperature of -200-1000°C (except for strong oxidants). The high-strength graphite composite gasket 7 axially seals the inner side of the quartz glass 4 and plays a role in buffering vibration. The gas expansion pressure in the cavity increases the pre-tightening force for pressing the quartz glass 4, which can achieve the effect of self-tightening sealing, and with the increase of the internal pressure of the cavity, its sealing performance is also strengthened at the same time.

The manufacturing and assembling steps of the above-mentioned high-temperature and high-pressure sealing window are as follows:

Step 1: Select No. 45 steel, process the flange end cover 1 and retaining ring 6 and ensure the machining accuracy of each component, and ensure that the roughness of each sealing surface is 3.2 μm. A rectangular groove 8 with a diameter of 110 mm, a width of 4.3 mm and a depth of 2.4 mm is processed on the first sealing step surface 1-2 where the flange end cover 1 contacts the quartz glass 4 .

Step 2: According to the size of the rectangular groove 8, select an O-ring 3 with a diameter of 110mm and put it into the rectangular groove 8. Wherein the cross-sectional diameter of the O-ring 3 is 3.1mm, and the Shore hardness is 80±5.

Step 3: Wipe the quartz glass 4 clean, coat the side with high-temperature sealing red glue, and install it from the inside of the flange end cover 1.

Step 4: Put in a suitable high-strength graphite composite gasket 7, install the retaining ring 6, and fix the retaining ring 6 with the hexagon socket head countersunk head bolt 5, so that the pre-tightening force is slightly greater than the ultimate pressure of the constant volume incendiary bomb cavity , to complete the assembly of the sealed window.

Step 5: Coat the sealing surface 9 on the inner side of the flange end cover 1 with high-temperature sealing red glue, and install the above-assembled sealing window on the projectile body 10 by M10 high-strength mounting bolts. When tightening the mounting bolts, adopt a symmetrical sequence so that The sealing window is evenly stressed. There is a gap of 1-2 mm between the inner side of the outer boss 1-1 of the flange end cover 1 and the elastic body 10, so that the pre-tightening force of the bolts pressing the flange end cover 1 all acts on the inner side of the flange end cover 1 On the sealing surface 9, the sealing effect of the sealing surface 9 is better due to concentrated force.

Among them, the O-ring 3 and the high-strength graphite composite gasket 7 must be replaced regularly to prevent aging and air leakage.

Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are only illustrative and not restrictive. Those of ordinary skill in the art Under the enlightenment of the present invention, without departing from the purpose of the present invention and the scope of protection of the claims, personnel can also make specific changes in many forms, and these all belong to the protection scope of the present invention.

Claims (8)

1. High Temperature High Pressure hermetyic window that is used for the constant volume combustion bullet, it is characterized in that, comprise that its arranged outside has the flange end cap of exterior boss, described exterior boss radial equipartition has mounting hole, described flange end cap is fixed by the construction bolt in the described mounting hole and constant volume combustion bullet body, described exterior boss and described body outer wall have 1～2mm gap, make the pretightening force of described construction bolt act on the inboard sealing surface that contacts with described body inside of described flange end cap fully;

Described flange end cap inside is equipped with glass, and the first sealed step over glaze of described glass outer side by described flange end cap inside arranges the groove that O type circle is installed to spacing on the described first sealed step face; Described glass inner side is not by protruding from the back-up ring axial limiting of the inboard described sealing surface of described flange end cap, described back-up ring is fixed on the second sealed step face of described flange end cap inside and compresses described glass by countersunk screw, be provided with the graphite grazing pad between described back-up ring and the described glass.

2. a kind of High Temperature High Pressure hermetyic window for the constant volume combustion bullet according to claim 1 is characterized in that the sectional shape of described groove is rectangle.

3. a kind of High Temperature High Pressure hermetyic window for the constant volume combustion bullet according to claim 1 is characterized in that, the surface roughness that described flange end covers the first sealed step face is 1.6～3.2 μ m.

4. a kind of High Temperature High Pressure hermetyic window for the constant volume combustion bullet according to claim 1 is characterized in that the radially surface of contact of described flange end cap and described glass is coated with sealer.

5. a kind of High Temperature High Pressure hermetyic window for the constant volume combustion bullet according to claim 1 is characterized in that, the surface roughness of described back-up ring and described glass institute surface of contact is 1.6～3.2 μ m.

6. a kind of High Temperature High Pressure hermetyic window for the constant volume combustion bullet according to claim 1 is characterized in that the radially surface of contact of described flange end cap and described back-up ring is coated with sealer.

7. a kind of High Temperature High Pressure hermetyic window for the constant volume combustion bullet according to claim 1 is characterized in that, the surface roughness of the inboard described sealing surface of described flange end cap is 1.6～3.2 μ m.

8. a kind of High Temperature High Pressure hermetyic window for the constant volume combustion bullet according to claim 1 is characterized in that, the inboard described sealing surface of described flange end cap is coated with sealer.

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