CN112284713A - Expansion joint fatigue test device - Google Patents

Abstract

The invention discloses an expansion joint fatigue test device which comprises a bracket, fixing frames symmetrically arranged on two sides of the bracket, a test cabin, an upper connecting pipe, a lower connecting pipe and a vibration instrument, wherein the fixing frames are arranged on the two sides of the bracket; two sides of the test chamber are fixedly connected with the fixing frame respectively, a plurality of groups of heating resistance wire groups are arranged on the inner wall of the test chamber, and the expansion joint is arranged in the middle of the test chamber; the lower end flange of the upper connecting pipe is fixedly connected with the upper flange of the expansion joint in a sealing way, and the upper end flange of the upper connecting pipe is fixedly connected with a piston rod of the hydraulic system; the upper end flange of the lower connecting pipe is fixedly connected with the lower flange of the expansion joint in a sealing way, and the lower end flange of the lower connecting pipe is fixedly connected with the bottom plate of the bracket; the vibration meter is fixed on one side of the lower end of the lower connecting pipe. The invention can simulate the high-temperature environment and the vibration working condition of the diesel engine, accurately test the fatigue strength and the service life of the expansion joint, monitor the temperature in the test chamber through the temperature sensor, and accurately judge the failure condition of the expansion joint through the reading change of the pressure gauge.

Description

Expansion joint fatigue test device

Technical Field

The invention relates to a fatigue test device, in particular to a device for testing the fatigue strength of an expansion joint on a diesel engine exhaust pipe, and belongs to the technical field of internal combustion engine detection equipment.

Background

The expansion joint of the exhaust pipe of the diesel engine is an important part of the diesel engine, because the working temperature of a diesel engine unit is high, the vibration is large, the working condition is very severe, the exhaust pipes of all cylinders are mutually connected through the expansion joint to prevent the thermal expansion stress of a pipeline, the fatigue strength of the expansion joint directly influences the reliability of the diesel engine, and meanwhile, if the expansion joint is subjected to fatigue damage, black particles in tail gas of the diesel engine are discharged into the atmosphere to form strong black smoke, so that the environment is not only harmed, and the economy of the diesel engine is also reduced. Therefore, the expansion joint must be tested for fatigue strength when selected, so as to ensure the strength and the service life of the expansion joint.

Disclosure of Invention

The invention aims to provide an expansion joint fatigue test device which can simulate the temperature environment and the vibration working condition of a diesel engine and test the fatigue strength of an expansion joint.

The invention is realized by the following technical scheme:

an expansion joint fatigue test device comprises a bracket, fixing frames symmetrically arranged at two sides of the bracket, a test chamber, an upper connecting pipe, a lower connecting pipe and a vibration meter; the test chamber is positioned in the middle of the support, two sides of the test chamber are fixedly connected with the fixing frame respectively, a plurality of groups of heating resistance wire groups are arranged on the inner wall of the test chamber, each group of heating resistance wire groups comprises a plurality of heating resistance wires which are axially arranged side by side, and the expansion joint is arranged in the middle of the test chamber; the upper connecting pipe is arranged on the upper side of the test chamber, the lower end of the upper connecting pipe vertically extends into the upper side of the test chamber and is movably connected with the top of the test chamber, a flange at the lower end of the upper connecting pipe is fixedly connected with an upper flange of the expansion joint in a sealing manner, and a flange at the upper end of the upper connecting pipe is fixedly connected with a piston rod of the hydraulic system; the lower connecting pipe is arranged on the lower side of the test chamber, the upper end of the lower connecting pipe vertically extends into the lower side of the test chamber, an upper end flange of the lower connecting pipe is fixedly connected with a lower flange of the expansion joint in a sealing manner, a lower end flange of the lower connecting pipe is fixedly connected with a bottom plate of the bracket, and inner cavities of the upper connecting pipe, the lower connecting pipe and the expansion joint form a closed space; the vibration meter is fixed on one side of the lower end of the lower connecting pipe.

The object of the invention is further achieved by the following technical measures.

According to the expansion joint fatigue test device, one side of the test chamber is provided with the temperature sensor, and the chamber door of the test chamber is provided with the observation window.

According to the expansion joint fatigue test device, two travel switches are arranged on the fixing rod on one side of the top plate of the support at intervals, and the travel rod is arranged on one side of the flange at the upper end of the upper connecting pipe.

In the expansion joint fatigue test device, the bypass pipe at the lower end of the lower connecting pipe is provided with the pressure gauge.

In the expansion joint fatigue test device, the electric cabinet is arranged on the fixing frame on one side.

The invention has simple structure, convenient operation and accurate test result. Be equipped with heating resistor silk group on the test chamber inner wall, can carry out high temperature heating to the test chamber, set up the vibrometer simultaneously on connecting pipe down, can exert the vibration to the expansion joint, just so can simulate the high temperature environment and the vibration operating mode of diesel engine, the fatigue strength and the life of accurate inspection expansion joint can monitor the temperature in the test chamber through temperature sensor moreover, ensure that the test chamber internal temperature reaches the setting value. In addition, the bypass pipe of the lower connecting pipe is provided with a pressure gauge, the failure condition of the expansion joint can be accurately judged through the reading change of the pressure gauge, and the compression stroke and the stretching stroke of the expansion joint can be controlled by the two stroke switches. The invention is suitable for fatigue strength tests of various expansion joints and has very wide application range.

Advantages and features of the present invention will be illustrated and explained by the following non-restrictive description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings.

Drawings

FIG. 1 is a schematic perspective view of the present invention;

FIG. 2 is a schematic cross-sectional structural view of the present invention;

fig. 3 is a schematic view of a partial perspective cross-sectional structure of a test chamber of the present invention.

Detailed Description

The invention is further illustrated by the following figures and examples.

As shown in fig. 1 and 2, the present invention includes a bracket 1, fixing frames 2 symmetrically arranged at both sides of the bracket 1, a test chamber 3, an upper connecting pipe 4, a lower connecting pipe 5 and a vibrating instrument 6, wherein an electric cabinet 7 is arranged on the fixing frame 2 at one side. The test chamber 3 is located the middle part of support 1, the both sides of test chamber 3 are welded with mount 2 respectively, be equipped with two sets of heating resistor silk group 31 on its inner wall, as shown in fig. 3, every heating resistor silk group 31 of group includes the heating resistor silk 311 that a plurality of axial set up side by side, one side of test chamber 3 is equipped with temperature sensor 32 simultaneously, can realize in the test chamber 3 between 0 ℃ and 600 ℃ stepless settlement of temperature value, through heating resistor silk 311 heating and temperature sensor 32 real-time feedback, thereby keep experimental ambient temperature at the setting value (error 5 ℃), so that the experimental temperature that realizes expansion joint 8 is close as far as possible with the ambient temperature of in-service use process, thereby ensure that the test result is accurate. An observation window 33 is arranged on the door of the test chamber 3 to observe the test condition in the test chamber 3, and the expansion joint 8 is arranged in the middle of the test chamber 3.

Go up connecting pipe 4 and set up in 3 upsides of test chamber, go up in the lower extreme of connecting pipe 4 stretches into test chamber 3's upside perpendicularly, can follow test chamber 3's top and reciprocate, go up the lower extreme flange of connecting pipe 4 and the last flange of expansion joint 8 is sealed to be linked firmly, goes up the upper end flange of connecting pipe 4 and links firmly with hydraulic system's piston rod. An upper travel switch 10 and a lower travel switch 10 are arranged on a fixed rod 9 on the left side of a top plate of the bracket 1 at intervals, and a travel rod 41 is arranged on the left side of an upper end flange of the upper connecting pipe 4.

Lower connecting pipe 5 sets up the downside at test chamber 3, the upper end of lower connecting pipe 5 stretches into in test chamber 3's the downside perpendicularly, its upper end flange links firmly with the lower flange of expansion joint 8 is sealed, the lower extreme flange of lower connecting pipe 5 links firmly with the bottom plate of support 1, be equipped with manometer 52 on the bypass pipe 51 of lower connecting pipe 5 lower extreme, go up connecting pipe 4, lower connecting pipe 5 and the inner chamber of expansion joint 8 three form airtight space, when expansion joint 8 compression or tensile, the air pressure in the airtight space changes, manometer 52's reading also changes thereupon. When the expansion joint 8 is not in fatigue failure, the pointer of the pressure gauge 52 periodically fluctuates in a certain range during the stretching or compressing process of the expansion joint 8, when the expansion joint 8 is in failure, the pipe wall of the expansion joint 8 is in fatigue crack, the sealing property of the closed space is lost, the pressure gauge 52 does not periodically fluctuate along with the stretching or compressing of the expansion joint 8, but indicates a specific numerical value or obviously reduces the fluctuation range, so that the fatigue test of the expansion joint 8 verifies whether the expansion joint 8 is in fatigue failure according to the fluctuation condition of the pressure gauge 52. The vibration meter 6 is fixed on the right side of the lower end of the lower connecting pipe 5 and can simulate the vibration index of the expansion joint 8 in the actual use process.

When connecting pipe 4 and lower connecting pipe 5 were installed, open the hatch door of test chamber 3 earlier, the top drill way and the bottom drill way of test chamber 3 open, can put into test chamber 3 respectively with the lower extreme of last connecting pipe 4 and the upper end of lower connecting pipe 5 to respectively with expansion joint 8's upper and lower flange joint, then close the hatch door can.

The test process of the invention is as follows:

1) opening the cabin door of the test cabin 3, fixedly connecting the upper flange and the lower flange of the expansion joint 8 with the lower end flange of the upper connecting pipe 4 and the upper end flange of the lower connecting pipe 5 respectively, and enabling the expansion joint to be in a free state;

2) and starting the hydraulic system, circularly stretching and compressing the expansion joint 8 under the driving of the hydraulic system, and checking whether the reading of the pressure gauge 52 fluctuates periodically at the moment so as to check the tightness of the closed space. Simultaneously detecting the maximum stretching amount and the maximum compressing amount of the expansion joint 8, and judging whether the maximum stretching amount and the maximum compressing amount of the expansion joint meet the maximum stretching amount of 16mm and the maximum compressing amount of 16mm, if not, adjusting;

3) closing the cabin door of the test cabin 3, setting the temperature value of the test environment as 600 ℃, starting the electric heating system to heat the test cabin 3, and simultaneously starting the vibration instrument 6 to apply vibration to the expansion joint 8;

4) starting a hydraulic system, wherein a piston rod of the hydraulic system extends downwards, the piston rod pushes an upper connecting pipe 4 to move downwards, an expansion joint 8 is compressed at the moment, when a stroke rod 41 on the left side of the upper connecting pipe 4 touches a stroke switch 10 on the lower side of a fixed rod 9, the piston rod stops extending, correspondingly, the upper connecting pipe 4 stops moving downwards, the expansion joint 8 stops compressing along with the piston rod, the system controls the piston rod to contract upwards, the piston rod drives the expansion joint 8 to stretch upwards through the upper connecting pipe 4, when the stroke rod 41 touches the stroke switch 10 on the upper side of the fixed rod 9, the piston rod stops contracting, the expansion joint 8 stops stretching along with the piston rod, and the cycle is repeated;

5) recording the cycle times of compression and stretching of the expansion joint 8 during the temperature rise from 0 ℃ to 600 ℃, wherein the cycle times of the expansion joint 8 are recorded as one from the end of compression to the end of stretching to the end of compression, wherein the cycle times are 1 period;

6) and recording the cycle times of compression and stretching of the expansion joint 8 at the temperature of 600 ℃ until the pointer of the pressure gauge 52 is not moved or the fluctuation range is obviously reduced, and at the moment, the expansion joint 8 has fatigue crack failure.

In addition to the above embodiments, the present invention may have other embodiments, and any technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of the claims of the present invention.

Claims (5)

1. The utility model provides an expansion joint fatigue test device which characterized in that: the device comprises a bracket, fixing frames symmetrically arranged at two sides of the bracket, a test chamber, an upper connecting pipe, a lower connecting pipe and a vibration instrument; the test chamber is positioned in the middle of the support, two sides of the test chamber are fixedly connected with the fixing frame respectively, a plurality of groups of heating resistance wire groups are arranged on the inner wall of the test chamber, each group of heating resistance wire groups comprises a plurality of heating resistance wires which are axially arranged side by side, and the expansion joint is arranged in the middle of the test chamber; the upper connecting pipe is arranged on the upper side of the test chamber, the lower end of the upper connecting pipe vertically extends into the upper side of the test chamber and is movably connected with the top of the test chamber, a flange at the lower end of the upper connecting pipe is fixedly connected with an upper flange of the expansion joint in a sealing manner, and a flange at the upper end of the upper connecting pipe is fixedly connected with a piston rod of the hydraulic system; the lower connecting pipe is arranged on the lower side of the test chamber, the upper end of the lower connecting pipe vertically extends into the lower side of the test chamber, an upper end flange of the lower connecting pipe is fixedly connected with a lower flange of the expansion joint in a sealing manner, a lower end flange of the lower connecting pipe is fixedly connected with a bottom plate of the bracket, and inner cavities of the upper connecting pipe, the lower connecting pipe and the expansion joint form a closed space; the vibration meter is fixed on one side of the lower end of the lower connecting pipe.

2. The expansion joint fatigue test device of claim 1, wherein: and a temperature sensor is arranged on one side of the test chamber, and an observation window is arranged on the chamber door of the test chamber.

3. The expansion joint fatigue test device of claim 1, wherein: two travel switches are arranged on the fixed rod on one side of the top plate of the support at intervals, and a travel rod is arranged on one side of the flange at the upper end of the upper connecting pipe.

4. The expansion joint fatigue test device of claim 1, wherein: the bypass pipe at the lower end of the lower connecting pipe is provided with a pressure gauge.

5. The expansion joint fatigue test device of claim 1, wherein: an electric cabinet is arranged on the fixing frame on one side.

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