CN100572887C - The balance type arced pipe joint that large displacement compensation capability is arranged - Google Patents

Abstract

The balance type arced pipe joint that large displacement compensation capability is arranged relates to a kind of rubber fittings that is used under big bit shift compensation situation.Adpting flange and middle arc body by two ends constitute, body is made up of inner glue layer, framework layer and outer glue-line, the curved revolution convex configuration of body, framework layer are to be made of the even level fiber cord that intersection is twined, and the track that fiber cord calculates by the balance design principle twines formation.The present invention is as the pipe-line system flexible connector, alleviate the power and the moment of flexure that produce because of factors such as thermal expansions in the pipe-line system, compensation realizes the big bit shift compensation of pipeline on the three degree of freedom direction owing to vibration, percussion cause the big displacement of pipeline on the three degree of freedom direction.The present invention has reduced size, and body has good balance, and it is axially indeformable substantially under the working pressure effect of tube fluid, can not bring additional power and additional displacement to system.

Description

Balanced curved pipe joint with large displacement compensation capability

technical field

The invention relates to a rubber pipe joint for large displacement compensation.

Background technique

In some important piping systems in ships and industries, due to the influence of special environmental factors such as vibration, shock, thermal expansion and contraction of the system, certain relative displacement or Additional force will damage the pipeline system and equipment in severe cases. In order to prevent this type of damage, it is necessary to add flexible connectors to the piping system, which can achieve good displacement compensation capabilities in the directions of three degrees of freedom; at the same time, it must also have the ability to achieve large Excellent displacement compensation, excellent vibration damping performance, pull-off resistance and high fatigue strength. However, in the pipeline system, the working pressure of the pipeline system often changes or produces pulsating impacts. These changes and impacts may deform the flexible connectors, thereby causing additional additional force and displacement on the piping system and equipment. In severe cases, it will affect the normal operation of the system or bring serious consequences. It can be seen that the pipeline connector must have low vertical stiffness, transverse stiffness and bending stiffness to achieve displacement compensation in three directions, balance the bending and internal force caused by the deformation of the piping system, and must also satisfy the balance Require. The measurement index of balance is the length change rate, bending deformation and corresponding reaction force of the flexible connector of the pipeline under the working pressure of the fluid in the pipeline.

The Naval Engineering University of the Chinese People's Liberation Army has applied for the invention patent "Three Flange Structure Self-Balanced Flexible Connector" (Chinese Patent 200410012867.7), including the connecting flange and the hose body. The connecting flange consists of an outer flange, an intermediate flange, an inner The flange and the spacer cover are composed of four parts. The inner rubber layer of the rubber hose, the skeleton layer and the outer rubber layer are composed. The skeleton layer is formed by winding a cord made of aramid fiber at an angle calculated by balance.

cos α ₁ =0.578(1+δ)

In the formula, α ₁ - initial winding angle, δ - elongation of aramid fiber

After the aramid cord is wound around the middle flange, it is clamped and fixed by the inner flange and the outer flange.

Contents of the invention

The purpose of the present invention is to address the above-mentioned status quo, and aims to provide a pipe with a smaller size, which can keep the axial direction without deformation under the working pressure in the pipe, and can compensate the pipeline caused by vibration and impact in the direction of three degrees of freedom. Large displacement balanced arc pipe joint.

The way to achieve the purpose of the present invention is that a balanced arc pipe joint with large displacement compensation capability is composed of connecting flanges at both ends and an arc pipe body in the middle, and the pipe body is composed of an inner rubber layer, a skeleton layer and an outer rubber layer , the tube body has an arc-shaped rotary convex structure, and the skeleton layer is composed of cross-wound even-numbered fiber cords. The fiber cords are wound according to the trajectory calculated by the balance design principle. The winding trajectory formula is:

$\mathrm{<span\; class="notranslate">\; the\; tan</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; =</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; b</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; b</span>}}}$

In the formula, α is the cord winding angle, b is the distance from the center of curvature of the generatrix of the pipe body to the axis, and r is the radius of gyration of the pipe body.

The present invention comprehensively considers the influence of axial stiffness and flow noise, and through theoretical and experimental studies, adopts the trajectory winding formula calculated according to the principle of balance design to cross-wind the fiber cords into an arc-shaped rubber hose with balanced characteristics. The connecting flange is used as a flexible connector of the pipeline system to relieve the force and bending moment caused by thermal expansion and other factors in the pipeline system, and to compensate for the large deviation of the pipeline in the three degrees of freedom due to vibration and impact. Displacement, to realize the large displacement compensation of the pipeline in the direction of three degrees of freedom.

The invention has a small size, and the pipe body has good balance. Under the action of the working pressure of the fluid in the pipe, the axial deformation is small, and no excessive additional force and additional displacement will be brought to the system.

Description of drawings

Fig. 1 is a structural representation of the present invention

Figure 2 is a diagram of the cross-winding form of fiber cords

Figure 3 is a schematic diagram of parameters taken by the winding trajectory formula

Detailed ways

With reference to Fig. 1, the present invention is made of connecting flange 4 at both ends and the pipe body in the middle, and the pipe body is made up of inner rubber layer 1, skeleton layer 2 and outer rubber layer 3. The skeleton layer is composed of even-numbered layers of fiber cords wound crosswise.

The fiber cords are fiber cords such as aramid fiber, polyester, nylon or polyester.

A large number of studies have shown that the reasonable design of the skeleton winding angle of the flexible pipe body can achieve the basic axial deformation of the flexible pipe body under a certain internal pressure, which is reflected in the cross winding of the skeleton material on the straight pipe section at a fixed angle. However, the winding angle of the skeleton material reflected on the arc-shaped pipe body is a variable spatial angle.

Using the trajectory winding formula calculated according to the principle of balance design, the fiber cord is wound into a curved rubber hose with balanced characteristics in the cross-winding form shown in Figure 2, so that the curved pipe joint can achieve balance requirements. This kind of arc-shaped rubber hose with balanced characteristics, matched with appropriate connecting flanges, is used as a flexible connection piece of the pipeline system, which can realize the large displacement compensation of the pipeline in the direction of three degrees of freedom, and at the same time has a small The space size and good vibration damping performance meet the requirements of pipeline system vibration damping and shock resistance.

Figure 3 shows the winding trajectory formula $\mathrm{the\; tan}\mathrm{\&alpha;}=\sqrt{1+\frac{b}{r+b}}$ The parameters α, b, r in the formula.

α is the cord winding angle, that is, the angle between the cord and the busbar of the pipe where the winding point is located; b is the distance from the center of curvature of the busbar of the pipe body to the axis, that is, the center of curvature of the busbar of the pipe where the winding point is located to the axis of the pipe body The distance; r is the radius of gyration of the pipe body, that is, the distance from the winding point to the axis of the pipe body.

The compressive strength of the pipe body is calculated by taking its weakest point, that is, the largest diameter point, and the calculation formula is as follows:

In the formula: P _B is the compressive strength of the hose, Kgf/cm ² ; K _B is the strength of the cord, Kgf/cm; i is the number of winding layers; D _is the calculated diameter, cm; C ₃ is the elongation at break of the cord+ 1; C' is the comprehensive correction coefficient.

According to the above compressive strength calculation formula and test verification, when the axial deformation of the joint is ±20mm or the radial deformation is ±18mm, the compressive strength of the pipe body can reach more than 14MPa, that is, it can still reach three times the rated working pressure. Therefore, it is considered that this joint has the ability to compensate for large displacements.

Enumerate the example of the present invention below: interface diameter is that the arc pipe joint pipe body structure parameter of 100mm is as follows:

Tube length 150mm Bus bar curvature radius 150mm

The central angle corresponding to the busbar 60° The distance from the center of curvature of the busbar to the axis b 79.9mm

Skeleton Layers 4 Cord Diameter 1.3mm

Cover layer 3 thickness 3mm Frame layer 2 thickness 0.3mm

Inner rubber layer 1 thickness 3mm,

See the table below for the radius of gyration and cord winding angle at different cross-section circumference angles

According to the present invention produced according to the above radius of gyration and cord winding angle, the axial deformation is less than 2mm under the 3-4Mpa working pressure of the fluid in the tube. When the axial deformation is ±20mm or the radial deformation is ±18mm, the compressive strength of the pipe body can reach more than 14MPa.

Claims (2)

1. The balance type arced pipe joint that 1, displacement compensation capability is arranged, adpting flange and middle flexible pipe body by two ends constitute, body is made up of inner glue layer, framework layer and outer glue-line, it is characterized in that the curved revolution convex configuration of body, framework layer is to be made of the even level fiber cord that intersection is twined, the track that fiber cord calculates by the balance design principle twines and constitutes, and the winding path formula is:

   $\tan \mathrm{\&alpha;}=\sqrt{1+\frac{b}{r+b}}$

   In the formula, α is the cord winding angle, b be the circular arc centre of curvature to axial line distance, r is the body turning radius.
2. 2, the balance type arced pipe joint that displacement compensation capability is arranged according to claim 1 is characterized in that fiber cord is aramid fiber, polyester, nylon or polyster fibre cord.

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