阅读说明：本技术 一种双壁管 (Double-wall pipe ) 是由 孙瑞 王杨志 杨威 王协英 张宝辉 杨志豪 许正杰 林丰财 杜恒 于 2021-01-19 设计创作，主要内容包括：本发明适用于LPG动力船舶燃料供料管技术领域,提供了一种双壁管,包括：双壁管外管；双壁管内管,设于所述双壁管外管的内部；支撑件,设置在所述双壁管外管上；弹性件；所述双壁管外管上具有缺口,所述弹性件穿过所述缺口设置在双壁管内管与支撑件之间。与现有技术相比,本发明采取在双壁管外管上设置支撑件,并在支撑件与双壁管内管之间设置弹性件,通过设置的弹性件来消减吸收来自主机气缸的固有频率振动和冲击力,从而形成良好的减震效果。(The invention is suitable for the technical field of LPG power ship fuel feed pipes, and provides a double-wall pipe, which comprises: a double-walled pipe outer pipe; the double-wall pipe inner pipe is arranged inside the double-wall pipe outer pipe; the supporting piece is arranged on the double-wall pipe outer pipe; an elastic member; the double-wall pipe outer pipe is provided with a notch, and the elastic piece penetrates through the notch and is arranged between the double-wall pipe inner pipe and the supporting piece. Compared with the prior art, the invention adopts the technical scheme that the support piece is arranged on the outer pipe of the double-wall pipe, the elastic piece is arranged between the support piece and the inner pipe of the double-wall pipe, and the natural frequency vibration and impact force from the main engine cylinder are absorbed and reduced by the arranged elastic piece, so that a good damping effect is formed.)

1. A double-walled pipe, comprising:

a double-walled pipe outer pipe;

the double-wall pipe inner pipe is arranged inside the double-wall pipe outer pipe;

the supporting piece is arranged on the double-wall pipe outer pipe;

an elastic member; the double-wall pipe outer pipe is provided with a notch, and the elastic piece penetrates through the notch and is arranged between the double-wall pipe inner pipe and the supporting piece.

2. A double-walled pipe according to claim 1, wherein the support comprises:

the connecting pipe is arranged on the outer pipe of the double-wall pipe;

the screw plug is in threaded connection with the connecting pipe; the elastic piece passes through the gap and is arranged between the double-wall pipe inner pipe and the screw plug.

3. A double-walled pipe according to claim 2, wherein the connecting pipe is welded to the outer pipe.

4. A double-walled pipe according to claim 2 wherein a sealing member is provided between the connecting pipe and the plug screw.

5. A double-walled pipe according to claim 2, wherein an isolation sheath is provided in the screw plug, an isolation pad is provided between the elastic member and the inner pipe of the double-walled pipe, and the elastic member is provided between the isolation sheath and the isolation pad through the gap.

6. A double-walled pipe as claimed in claim 5 wherein the insulating sheath and the insulating mat are of Teflon material.

7. A double-walled pipe according to claim 1 wherein the support member and the resilient member are each provided in a plurality of pieces; a plurality of supporting pieces are uniformly distributed on the circumference of the double-wall pipe outer pipe; the double-wall pipe outer pipe is provided with a plurality of gaps, and a plurality of elastic pieces respectively penetrate through the gaps and are arranged between the double-wall pipe inner pipe and the plurality of supporting pieces.

8. A double-walled pipe according to claim 1, wherein the bend radius of the double-walled pipe is 5 times the outer diameter of the double-walled pipe.

Technical Field

The invention belongs to the technical field of LPG power ship fuel feeding pipes, and particularly relates to a double-wall pipe.

Background

On an LPG powered vessel, a double-walled pipe is required to connect the cylinders of the main engine to facilitate the transportation and return of liquid fuel between the cylinders. The vibration of the pipeline is a common phenomenon, and is divided into two types, wherein the 1 st type is vibration caused by the reciprocating motion of an internal cylinder piston when a host machine operates, the 2 nd type is transverse impact force and vibration caused by unstable single-phase flow or two-phase flow at the corner position of the pipeline when high-pressure and high-speed medium in the pipeline is conveyed, namely the flow direction is vertical, and the impact frequency of the 2 nd type vibration is close to the natural frequency of the pipeline or equipment vibration, namely the 1 st type vibration, so that resonance appears and the vibration is obvious or aggravated. This is a dangerous condition and must be addressed. However, vibration is inevitable, and therefore, it is necessary to control the vibration within a certain range.

A general double-wall pipe, as shown in fig. 1 to 3, includes a double-wall pipe outer pipe 101, a double-wall pipe inner pipe 103, and a double-wall pipe clamp 102, and the bending radius of the double-wall pipe corner is generally 1.5D. When the liquid fuel circulates in the double-wall pipe, a downward vertical impact is generated at the first elbow on the left side in fig. 1, and a rightward vertical impact is generated at the second elbow on the right side in fig. 1.

The applicant of the present invention finds that, in implementing the above technical solution, the above technical solution has at least the following disadvantages:

the double-wall pipe clamp 102 is welded and rigidly fixed between the double-wall pipe outer pipe 101 and the double-wall pipe inner pipe 103, and mainly plays a supporting role, and the damping effect is poor.

Disclosure of Invention

An object of an embodiment of the present invention is to provide a double-walled pipe, which aims to solve the problems mentioned in the background art.

The embodiment of the present invention is achieved as follows, in a double-walled pipe, comprising:

a double-walled pipe outer pipe;

the double-wall pipe inner pipe is arranged inside the double-wall pipe outer pipe;

the supporting piece is arranged on the double-wall pipe outer pipe;

an elastic member; the double-wall pipe outer pipe is provided with a notch, and the elastic piece penetrates through the notch and is arranged between the double-wall pipe inner pipe and the supporting piece.

Preferably, the support member includes:

the connecting pipe is arranged on the outer pipe of the double-wall pipe;

the screw plug is in threaded connection with the connecting pipe; the elastic piece passes through the gap and is arranged between the double-wall pipe inner pipe and the screw plug.

Preferably, the connecting pipe is welded to the double-walled pipe outer pipe.

Preferably, a sealing element for sealing is arranged between the connecting pipe and the screw plug.

Preferably, an isolation sheath is arranged in the plug screw, an isolation pad is arranged between the elastic piece and the inner tube of the double-wall tube, and the elastic piece penetrates through the notch and is arranged between the isolation sheath and the isolation pad.

Preferably, the isolation sheath and the isolation pad are made of Teflon materials.

Preferably, the supporting piece and the elastic piece are both provided with a plurality of pieces; a plurality of supporting pieces are uniformly distributed on the circumference of the double-wall pipe outer pipe; the double-wall pipe outer pipe is provided with a plurality of gaps, and a plurality of elastic pieces respectively penetrate through the gaps and are arranged between the double-wall pipe inner pipe and the plurality of supporting pieces.

Preferably, the double-walled pipe has a bending radius of 5 times the outer diameter of the double-walled pipe.

The embodiment of the invention provides a double-wall pipe, which comprises: a double-walled pipe outer pipe; the double-wall pipe inner pipe is arranged inside the double-wall pipe outer pipe; the supporting piece is arranged on the double-wall pipe outer pipe; an elastic member; the double-wall pipe outer pipe is provided with a notch, and the elastic piece penetrates through the notch and is arranged between the double-wall pipe inner pipe and the supporting piece.

Compared with the prior art, the invention adopts the technical scheme that the support piece is arranged on the outer pipe of the double-wall pipe, the elastic piece is arranged between the support piece and the inner pipe of the double-wall pipe, and the natural frequency vibration and impact force from the main engine cylinder are absorbed and reduced by the arranged elastic piece, so that a good damping effect is formed.

Drawings

FIG. 1 is a front view of a double-walled tube as provided in the background art;

FIG. 2 is a cross-sectional axial view of a double-walled tube as provided in the background art;

FIG. 3 is a cross-sectional view of a double-walled tube provided in the background art;

fig. 4 is a schematic structural diagram of a double-walled tube according to an embodiment of the present invention;

FIG. 5 is a cross-sectional view taken along line A-A of FIG. 4;

fig. 6 is a schematic illustration of the elastic member being removed and replaced.

In the drawings: 101. a double-walled pipe outer pipe; 102. a double-walled pipe clamp; 103. a double-walled pipe inner pipe; 201. a double-walled pipe outer pipe; 202. a double-walled pipe inner pipe; 203. a connecting pipe; 204. a plug screw; 205. a seal member; 206. an elastic member; 207. an isolation sheath; 208. an insulating pad; 209. welding seams; 210. an elastic shock-absorbing member; 301. a main engine cylinder; 302. a control valve block; 303. and (4) a flange.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Specific implementations of the present invention are described in detail below with reference to specific embodiments.

Example 1

As shown in fig. 4 and 5, a double-walled pipe according to an embodiment of the present invention includes:

a double-walled pipe outer pipe 201;

a double-walled pipe inner pipe 202 provided inside the double-walled pipe outer pipe 201;

a support member disposed on the double-walled pipe outer pipe 201;

an elastic member 206; the double-walled pipe outer pipe 201 has a gap, through which the elastic member 206 is disposed between the double-walled pipe inner pipe 202 and the support member.

In the embodiment of the present invention, flanges 303 are disposed at two ends of the double-walled pipe, and the double-walled pipe is connected to a control valve block 302 outside the main engine cylinder 301 through the flanges 303. The double-wall pipe inner pipe 202 is used for conveying LPG fuel between the main engine cylinder 301, the double-wall pipe outer pipe 201 is used for providing protection when the double-wall pipe inner pipe 202 is broken and leaked, combustible LPG is prevented from volatilizing to mechanical places such as a main engine room to form fire, leakage control is carried out in the middle of the inner pipe and the outer pipe, ventilation is carried out by a fan in a circulating mode, the leaked LPG is volatilized, and gas is pumped out of the room and is discharged to a safety area.

In this embodiment, the elastic member 206 may be selected as a damping spring.

The working principle of the embodiment of the invention is as follows:

the elastic member 206 is in a partially compressed state between the inner tube 202 and the support member of the double-walled tube, and when the double-walled tube transports LPG fuel, the elastic member 206 provides a continuous elastic force (pretightening force) which vertically acts on the outer surface of the inner tube 202 of the double-walled tube, and the elastic force provided by the elastic member 206 can absorb and absorb the natural frequency vibration and impact force from the main engine cylinder 301, thereby forming a good damping effect.

Compared with the prior art, the invention adopts the technical scheme that the support member is arranged on the double-wall pipe outer pipe 201, the elastic member 206 is arranged between the support member and the double-wall pipe inner pipe 202, and the natural frequency vibration and impact force from the main engine cylinder 301 are absorbed and reduced through the arranged elastic member 206, so that a good damping effect is formed.

Moreover, another disadvantage of the prior art double-walled pipe clamp 102 is that it is only convenient to install in straight double-walled pipes, which is difficult to install in annular double-walled pipes. The invention can be conveniently installed in double-wall pipes with any shape, and the problem of difficult installation is avoided.

As shown in fig. 5, as a preferred embodiment of the present invention, the supporter includes:

a connection pipe 203 disposed on the double-walled pipe outer pipe 201;

a screw plug 204 screwed with the connection pipe 203; the elastic element 206 is arranged between the double-walled pipe inner pipe 202 and the plug screw 204 through the gap.

Specifically, an internal thread is arranged in the connecting pipe 203, an external thread matched with the internal thread is arranged on the screw plug 204, and the connecting pipe 203 and the screw plug 204 are connected together through the screw thread.

Another disadvantage of the conventional double-walled pipe is that the double-walled pipe clamp 102 is fixedly disposed between the inner pipe and the outer pipe, and once the double-walled pipe clamp 102 is installed, the double-walled pipe clamp cannot be disassembled and replaced. In the present embodiment, the replacement of the elastic member 206 can be easily performed. As shown in fig. 6, the elastic member 206 can be easily removed by unscrewing the screw plug 204 from the connecting tube 203, so as to replace the elastic member 206.

In this embodiment, the connection pipe 203 may be a half pipe joint or other pipe with internal threads, and the plug 204 may be an outer hexagonal plug or other plug 204.

In a preferred embodiment of the present invention, the connection pipe 203 is welded to the double-walled pipe outer pipe 201.

In particular, as shown in fig. 5, a weld 209 between the connecting tube 203 and the double-walled tube can be seen. Alternatively, the connection pipe 203 may be connected to the double-walled pipe by other fixing means such as adhesion.

As shown in fig. 5, as a preferred embodiment of the present invention, a sealing member 205 for sealing is disposed between the connection pipe 203 and the plug screw 204.

In particular, the seal 205 may take the form of a gasket, the function of which is to prevent leakage.

As shown in fig. 5, as a preferred embodiment of the present invention, an isolation sheath 207 is disposed inside the plug screw 204, an isolation pad 208 is disposed between the elastic member 206 and the double-walled pipe inner pipe 202, and the elastic member 206 is disposed between the isolation sheath 207 and the isolation pad 208 through the gap.

Specifically, the isolation sheath 207 and the isolation pad 208 are disposed to prevent the LPG, which is potentially leaked due to sparks generated by friction between the elastic member 206 and metal (the inner and outer tubes, the connection tube 203 and the screw plug 204 are generally made of metal) during vibration compression, from burning or exploding.

As a preferred embodiment of the present invention, the insulating sheath 207 and the insulating pad 208 are made of teflon.

In particular, the Teflon material has good corrosion resistance and low temperature resistance, and is suitable for LPG.

As shown in fig. 5, the double-walled pipe has a bending radius 5 times the outer diameter of the double-walled pipe as a preferred embodiment of the present invention.

In particular, the double-walled pipe has a bending radius of 5 times the outer diameter of the double-walled pipe, i.e. a 5D bend. The existing double-wall pipe is generally 1.5D bent, and due to insufficient bending degree, for two kinds of vibration mentioned in the background art, larger impact can be generated at the elbow of the double-wall pipe, and the damping effect is poor.

In this embodiment, the double-wall pipe is designed to be a 5D bend, so that firstly, the 1 st partial vibration and impact force from the natural frequency of the main engine cylinder 301 in the background art can be absorbed and reduced through the self-bending and the rigidity of the double-wall pipe, and secondly, the 2 nd most impact force from the pipe fluid at the corner position in the background art can be absorbed and reduced through the self-bending and the rigidity of the double-wall pipe, thereby further improving the damping effect of the double-wall pipe.

Example 2

An embodiment of the present invention provides a double-walled pipe, including:

a double-walled pipe outer pipe 201;

a double-walled pipe inner pipe 202 provided inside the double-walled pipe outer pipe 201;

a plurality of groups of elastic shock absorption assemblies 210 uniformly arranged along the circumferential direction of the double-wall pipe outer pipe 201; the elastic shock absorbing assembly 210 comprises a connecting pipe 203, a plug screw 204, a sealing member 205, an isolation pad 208, an isolation sheath 207 and an elastic member 206; the connecting pipe 203 is welded on the double-wall pipe outer pipe 201, the connecting pipe 203 is in threaded connection with the screw plug 204, the sealing element 205 is arranged between the connecting pipe 203 and the screw plug 204 and plays a role in sealing, the isolating sheath 207 is arranged in the screw plug 204, the isolating pad 208 is arranged on the outer surface of the double-wall pipe inner pipe 202, a gap is arranged on the double-wall pipe outer pipe 201, and the elastic element 206 penetrates through the gap and is arranged between the isolating pad 208 and the isolating sheath 207.

In the embodiment of the present invention, the plurality of elastic members 206 are distributed in an annular array along the circumference of the double-walled pipe outer pipe 201, and provide pre-tightening force from multiple directions to act perpendicularly on the outer surface of the double-walled pipe inner pipe 202, so as to absorb natural frequency vibration and impact force from the main engine cylinder 301 from multiple directions, thereby providing the best damping effect.

In addition, the double-walled pipe of the present embodiment may be provided with a 5D bend, and the double-walled pipe may absorb, by its own bending and rigidity, part of the vibration and impact force absorbing the natural frequency from the main engine cylinder 301 and most of the impact force from the fluid in the pipe at the corner position, thereby damping the double-walled pipe as much as possible.

Example 3

As shown in fig. 5, the embodiment of the present invention is based on embodiment 2, and the elastic shock-absorbing assemblies 210 are arranged into 3 groups, when the double-wall pipe is used for conveying LPG fuel, the elastic force provided by the 3 elastic members 206 is distributed along the circumferential direction of the outer pipe 201 of the double-wall pipe in a 120 ° annular array, and the natural frequency vibration and impact force from the main engine cylinder 301 can be substantially and completely absorbed. And the best damping effect can be provided by arranging the double-wall pipe into a 5D bend.

Example 4

The embodiment of the present invention is a specific implementation of embodiment 3, and specifically includes the following steps:

the DN of the double-wall pipe inner pipe 202 is 25mm, the DN of the double-wall pipe outer pipe 201 is 100mm, and the materials are all 316L stainless steel. The outer diameter of the double-walled pipe outer pipe 201 is 114mm, and the bending radius is 570mm, thereby realizing a 5D bending design. The 3 sets of elastomeric shock absorbing assemblies 210 are uniformly disposed on the double-walled tube outer tube 201 in a 120 annular array. Each elastic shock absorption assembly 210 is composed of a half pipe joint, an outer hexagonal plug screw, a sealing ring, a damping spring, an isolation sheath 207 and an isolation pad 208. The insulating sheath 207 and the insulating pad 208 are made of teflon material with a thickness of 5 mm. The two half pipe joints are distributed in bilateral symmetry, and the half pipe joint is arranged vertically upwards. The inside internal thread that has of half coupling, outer hexagonal plug screw surface have the external screw thread, and the two threaded connection is sealed through the sealing washer, avoids forming the leakage. The natural length of the damping spring is L1, and when the hexagonal screw plug is screwed tightly and sealed, the damping spring is compressed to length L2, and provides a continuous elastic force (pretightening force) to vertically act on the outer surface of the inner pipe. The elastic force provided by the three damping springs is distributed in a 120-degree annular array, and the natural frequency vibration from the main machine can be basically and completely absorbed.

The selection of the damping spring is related to the natural frequency of the main engine cylinder 301, and can be obtained through corresponding calculation. The calculation process formula of the natural frequency of the main engine cylinder 301 is as follows:

fn Hz is 1.414 RPM (main engine speed) N (number of cylinders)/60.

Taking the master rotation speed of 72 and the number of cylinders of 6 as an example, fn is 1.414, 72, 6/60 is 10.2 Hz. The data are input into vibration calculation software AutoPSA for simulation, and the maximum axial stiffness F1 of the double-wall pipe outer pipe 201 is 90KN/m and the maximum amplitude is 3mm, the maximum axial stiffness F2 of the double-wall pipe inner pipe 202 is 30KN/m and the maximum amplitude is 1.8 mm.

Assuming that 3 sets of elastic damping members 210 are uniformly distributed at intervals of one meter on the double-walled pipe, the amount of deformation of each damping spring should generate a stiffness force greater than that of the double-walled pipe. According to Hooke's law, delta F is-K.delta X and AutoPSA, a safety factor is 1.5, and the result is selected as that the rigidity of a single spring is 25KN/m, the natural length L1 is 120mm, the pre-compression length L2 is 110mm, the natural absorption frequency can cover 10.2Hz corresponding to a damping spring with the absorption frequency of 5 Hz-15 Hz, and the selection meets the requirement. Through the damping spring of above lectotype can subdue the vibration and the rigidity power of the host computer natural frequency of conduction on the double-walled pipe, can provide suitable flexible support, form good shock attenuation effect.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.