阅读说明：本技术 用于lgip主机燃气管道吹扫及气密试验的装置及方法 (Device and method for purging and air-tight test of gas pipeline of LGIP (light emitting diode) host ) 是由 杨耀 丁一 王子腾 于 2021-06-16 设计创作，主要内容包括：一种用于LGIP主机燃气管道吹扫及气密试验的装置及方法,所述装置包括依次连接的液氮储罐、气化器、氮气压缩机、缓冲罐、减压阀元件和阀组单元；其中,液氮储罐用于储存液氮,气化器用于将液氮转换为气态,氮气压缩机用于对低压氮气进行加压,达到管道吹扫和气密试验的压力条件,缓冲罐用于储存加压后的氮气,达到稳压稳流和管路吹扫时实现大流量下的持续吹扫,减压阀元件用于将高压氮气减压至气密试验规定的压力,阀组单元用于控制液化石油气供液回路、氮气吹扫回路以及管路压力的泄放,该阀组单元通过供液管和回液管分别连接LGIP主机的供液进口和回液出口,回液管上设有用于检查洁净度的取样口。本发明达到了实现多种压力条件、使用简单便捷和系统可靠性好的效果。(A device and method used for LGIP host computer fuel gas pipeline purging and airtight test, the said apparatus includes liquid nitrogen storage tank, vaporizer, nitrogen compressor, buffer tank, relief pressure valve component and valve group unit connected sequentially; wherein, the liquid nitrogen storage tank is used for storing the liquid nitrogen, the vaporizer is used for converting the liquid nitrogen into the gaseous state, nitrogen compressor is used for pressurizeing low pressure nitrogen gas, reach the pipeline and sweep and airtight experimental pressure condition, the buffer tank is used for storing the nitrogen gas after the pressurization, reach steady voltage stationary flow and realize that large-traffic down constantly sweeps when the pipeline sweeps, relief pressure valve element is used for reducing pressure high-pressure nitrogen gas to airtight experimental specified pressure, the valves unit is used for controlling liquefied petroleum gas and supplies liquid return circuit, nitrogen gas sweeps release of return circuit and pipeline pressure, this valves unit connects the confession liquid import and the liquid outlet that returns of LGIP host computer respectively through feed line and liquid return pipe, be equipped with the sample connection that is used for checking the cleanliness factor on the liquid return pipe. The invention achieves the effects of realizing various pressure conditions, simple and convenient use and good system reliability.)

1. The utility model provides a device that is used for LGIP host computer gas pipeline to sweep and airtight experiment, LGIP host computer uses liquefied petroleum gas as fuel, is equipped with and supplies liquid inlet and return liquid outlet, its characterized in that: the device is connected with the LGIP host and comprises:

the liquid nitrogen storage tank is used for storing liquid nitrogen;

the gasifier is connected with the liquid nitrogen storage tank and is used for converting the liquid nitrogen in the liquid nitrogen storage tank into a gaseous state;

the nitrogen compressor is connected with the gasifier and used for pressurizing low-pressure nitrogen from the gasifier to achieve the pressure conditions of pipeline purging and airtight test;

the buffer tank is connected with the nitrogen compressor and used for storing the pressurized nitrogen, so that the purpose of stabilizing the pressure and the flow is achieved, and continuous purging under large flow is realized when a pipeline is purged;

the pressure reducing valve element is connected with the buffer tank and is used for reducing the pressure of the high-pressure nitrogen in the buffer tank to a pressure range specified in an airtight test;

the valve group unit is used for controlling the relief of the liquefied petroleum gas supply loop, the nitrogen purging loop and the pipeline pressure, the valve group unit is connected with the pressure reducing valve element, and meanwhile, the pressure reducing valve element is connected with the liquid supply inlet and the liquid return outlet of the LGIP host through the liquid supply pipe and the liquid return pipe respectively, and a sampling port used for checking the cleanliness of the pipeline when the pipeline is purged is arranged on the liquid return pipe.

2. The device for LGIP host gas line purging and air-tight test of claim 1, wherein: the nitrogen compressor is a piston type 4-stage compressor, and the output pressure is adjusted between 150-400 bar.

3. The device for LGIP host gas line purging and air-tight test of claim 1, wherein: the nitrogen compressor is controlled by a PLC, the compressor is automatically started to pressurize when the pressure of the nitrogen falls to the lower limit value of the set pressure, and the compressor is automatically stopped when the pressure of the nitrogen reaches the upper limit value of the set pressure.

4. The device for LGIP host gas line purging and air-tight test of claim 1, wherein: and a three-way quick connector is arranged at the upstream of the pressure reducing valve element and is used for connecting a nitrogen cylinder group when the nitrogen compressor fails or is maintained.

5. The device for LGIP host gas line purging and air-tight test of claim 1, wherein: the pressure reducing valve element is connected with a silencer in parallel and used for reducing noise during pressure relief.

6. A method for performing a LGIP host hermeticity test using the apparatus of claim 5, wherein: the airtight test method comprises the following specific steps:

1) setting the outlet pressure of the nitrogen compressor to 250bar, and waiting for the pressure of the nitrogen compressor to build;

2) after the pressure build-up of the nitrogen compressor is finished, adjusting the output pressure value of the pressure reducing valve element to 55bar, adjusting the valve state of the valve group unit to a liquid inlet mode, opening a gas inlet valve of each cylinder on the LGIP main machine, and waiting for the pressure build-up in a gas part of the LGIP main machine;

3) when the pressure in a gas part of the LGIP host rises to 55bar, adjusting the valve state of the valve group unit to be a gas inlet cut-off state, adjusting the pressure reducing valve element to be a closed state, and discharging the pressure in a gas pipeline;

4) the LGIP host keeps the pressure for 1 hour, and then the pressure drop value is not more than 1.4bar, and the airtight test of the LGIP host is qualified; if the pressure drop value is larger than 1.4bar, fault removal and leak detection are carried out, and then the steps 1) to 4) are carried out again to carry out the airtight test;

5) and after the airtight test is passed, adjusting the state of a valve piece of the valve group unit to be a discharge state, and discharging the pressure in the gas part.

7. A method for an LGIP host hermeticity test according to claim 6, wherein: the step 3) also comprises the following steps: opening a switch of the muffler.

8. A method for purging a gas line of an LGIP host, implemented using the apparatus of claim 1, wherein: the purging method comprises the following specific steps:

1) removing blind flanges of a liquid supply inlet and a liquid return outlet of the LGIP host, installing a hose, bypassing the liquid supply inlet and the liquid return outlet, disconnecting a part of pipe sections connected with a liquid return pipe of the valve group unit, and only keeping the sampling port;

2) setting the outlet pressure of the nitrogen compressor to 250bar and waiting for the nitrogen compressor to build pressure;

3) after the pressure build-up of the nitrogen compressor is finished, adjusting the output pressure value of the pressure reducing valve element to the maximum value of 400bar, adjusting the valve state of the valve group unit to a liquid inlet mode, and starting to purge a gas pipeline;

4) after purging is carried out for 30 minutes, a 10-micron filter bag is installed at the sampling opening, and after purging is kept for 5 minutes, the filter bag is taken down and checked;

5) a magnet pen is used for sweeping and sucking the interior of the filter bag, and if no scrap iron or macroscopic dirt exists, the cleanliness of the gas pipeline is qualified; if scrap iron or dirt exists, repeating the step 4) to continuously purge until no dirt is detected in the filter bag and the cleanliness of the gas pipeline is qualified;

6) and (2) after the purging of the gas pipeline is completed, removing the hose installed in the step 1), reinstalling the blind flange, disconnecting the bypass of the liquid supply inlet and the liquid return outlet, and reinstalling part of the removed pipe section connected with the liquid return pipe of the valve group unit.

Technical Field

The invention relates to a MAN-LGIP series dual-fuel host, in particular to a device and a method for purging a gas pipeline and performing an airtight test on an LGIP host, and belongs to the technical field of marine diesel engines.

Background

Due to the increasingly strict emission regulations and high fuel costs on a global scale, marine low-speed diesel engines are currently being developed with a trend toward multifueling, where the host of the LGIP family is a dual fuel host. The ignition temperature of LPG is lower than that of other fuels, generally 430-460 ℃, the explosion limit is narrower and is 1.5-9.5%, and the lower explosion limit is lower than that of other fuels, so the LPG is dangerous, combustion and explosion can be caused by a little ignition spark, and if leakage occurs, great potential safety hazard can be generated. In addition, since the structure of the gas part of the main unit is relatively precise and complicated, if there are many impurities in the gas pipe, the gas part is easily damaged. Therefore, the test on the air tightness of the main machine and the purging and cleaning of the gas pipeline of the main machine are indispensable work in LGIP test run work. In order to complete the work, a set of device and method is needed to assist in completing the work of purging the gas pipeline and performing the airtight test.

Disclosure of Invention

The invention aims to provide a device and a method for purging and air-tight test of a gas pipeline of an LGIP (light emitting diode) host, which are used for detecting the cleanliness and air-tight of the pipeline so as to complete purging and air-tight test work of a gas component and the gas pipeline of the host, and achieve the effects of realizing various pressure conditions, being simple and convenient to use and having good system reliability.

The technical scheme adopted for solving the technical problems is as follows:

the utility model provides a device that is used for LGIP host computer gas pipeline to sweep and airtight experiment, LGIP host computer uses liquefied petroleum gas as fuel, is equipped with and supplies liquid inlet and return liquid outlet, its characterized in that: the device is connected with the LGIP host and comprises:

the liquid nitrogen storage tank is used for storing liquid nitrogen;

the gasifier is connected with the liquid nitrogen storage tank and is used for converting the liquid nitrogen in the liquid nitrogen storage tank into a gaseous state;

the nitrogen compressor is connected with the gasifier and used for pressurizing low-pressure nitrogen from the gasifier to achieve the pressure conditions of pipeline purging and airtight test;

the buffer tank is connected with the nitrogen compressor and used for storing the pressurized nitrogen, so that the purpose of stabilizing the pressure and the flow is achieved, and continuous purging under large flow is realized when a pipeline is purged;

the pressure reducing valve element is connected with the buffer tank and is used for reducing the pressure of the high-pressure nitrogen in the buffer tank to a pressure range specified in an airtight test;

the valve group unit is used for controlling the relief of the liquefied petroleum gas supply loop, the nitrogen purging loop and the pipeline pressure, the valve group unit is connected with the pressure reducing valve element, and meanwhile, the pressure reducing valve element is connected with the liquid supply inlet and the liquid return outlet of the LGIP host through the liquid supply pipe and the liquid return pipe respectively, and a sampling port used for checking the cleanliness of the pipeline when the pipeline is purged is arranged on the liquid return pipe.

Further, the nitrogen compressor is a piston type 4-stage compressor, and the output pressure is adjusted between 150 bar and 400 bar.

Furthermore, the nitrogen compressor is controlled by a PLC, the compressor is automatically started to pressurize when the pressure of the nitrogen falls to the lower limit value of the set pressure, and the compressor is automatically stopped when the pressure of the nitrogen reaches the upper limit value of the set pressure.

Furthermore, a three-way quick connector is arranged at the upstream of the pressure reducing valve element and is used for connecting a nitrogen cylinder group when the nitrogen compressor fails or is maintained.

Furthermore, the pressure reducing valve element is connected with a silencer in parallel and used for reducing noise during pressure relief.

The other technical scheme of the invention is as follows:

a method for LGIP host airtightness test realized by using the device comprises the following specific steps:

1) setting the outlet pressure of the nitrogen compressor to 250bar, and waiting for the pressure of the nitrogen compressor to build;

2) after the pressure build-up of the nitrogen compressor is finished, adjusting the output pressure value of the pressure reducing valve element to 55bar, adjusting the valve state of the valve group unit to a liquid inlet mode, opening a gas inlet valve of each cylinder on the LGIP main machine, and waiting for the pressure build-up in a gas part of the LGIP main machine;

3) when the pressure in a gas part of the LGIP host rises to 55bar, adjusting the valve state of the valve group unit to be a gas inlet cut-off state, adjusting the pressure reducing valve element to be a closed state, and discharging the pressure in a gas pipeline;

4) the LGIP host keeps the pressure for 1 hour, and then the pressure drop value is not more than 1.4bar, and the airtight test of the LGIP host is qualified; if the pressure drop value is larger than 1.4bar, fault removal and leak detection are carried out, and then the steps 1) to 4) are carried out again to carry out the airtight test;

5) and after the airtight test is passed, adjusting the state of a valve piece of the valve group unit to be a discharge state, and discharging the pressure in the gas part.

Further, the step 3) further comprises: opening a switch of the muffler.

The invention also provides another technical scheme as follows:

a method for purging a gas pipeline of an LGIP host machine by using the device comprises the following specific steps:

1) removing blind flanges of a liquid supply inlet and a liquid return outlet of the LGIP host, installing a hose, bypassing the liquid supply inlet and the liquid return outlet, disconnecting a part of pipe sections connected with a liquid return pipe of the valve group unit, and only keeping the sampling port;

2) setting the outlet pressure of the nitrogen compressor to 250bar and waiting for the nitrogen compressor to build pressure;

3) after the pressure build-up of the nitrogen compressor is finished, adjusting the output pressure value of the pressure reducing valve element to the maximum value of 400bar, adjusting the valve state of the valve group unit to a liquid inlet mode, and starting to purge a gas pipeline;

4) after purging is carried out for 30 minutes, a 10-micron filter bag is installed at the sampling opening, and after purging is kept for 5 minutes, the filter bag is taken down and checked;

5) a magnet pen is used for sweeping and sucking the interior of the filter bag, and if no scrap iron or macroscopic dirt exists, the cleanliness of the gas pipeline is qualified; if scrap iron or dirt exists, repeating the step 4) to continuously purge until no dirt is detected in the filter bag and the cleanliness of the gas pipeline is qualified;

6) and (2) after the purging of the gas pipeline is completed, removing the hose installed in the step 1), reinstalling the blind flange, disconnecting the bypass of the liquid supply inlet and the liquid return outlet, and reinstalling part of the removed pipe section connected with the liquid return pipe of the valve group unit.

The invention has the following technical effects:

firstly, the gasified low-pressure nitrogen is pressurized to more than 300bar by the nitrogen compressor and stored in the buffer tank, so that the pressure conditions required by gas pipeline airtight test and pipeline purging are solved, and continuous purging under large flow is realized;

the invention adopts a pressure reducing valve element to reduce the pressure of the high-pressure nitrogen to the pressure range specified in the airtight test specification, and the process is safe and quick;

the invention realizes the purging and airtight test of the gas pipeline by the external nitrogen cylinder group, and can be used as an alternative scheme when the liquid nitrogen storage of the buffer tank is insufficient, thereby ensuring the production progress.

Drawings

FIG. 1 is a schematic diagram of the system of the present invention.

In the figure, the position of the upper end of the main shaft,

the system comprises a liquid nitrogen storage tank 1, a liquid nitrogen storage tank 2, a gasifier 3, a nitrogen compressor 4, a buffer tank 5, a pressure reducing valve element 6, a valve bank unit 7, an LGIP host, an E1 liquid supply inlet, an E2 liquid return outlet, an X3 three-way quick connector and an S sampling port.

Detailed Description

The invention is described in further detail below with reference to the figures and the specific embodiments.

The invention is used for purging and air-tight test of LGIP main machine gas pipeline, please refer to fig. 1, the LGIP main machine 7 can use Liquefied Petroleum Gas (LPG) as fuel, and is provided with a liquid supply inlet E1 and a liquid return outlet E2, and each cylinder is provided with a valve for controlling gas inlet and outlet independently.

The device for purging the gas pipeline of the LGIP host and performing the airtight test is connected with the LGIP host 7, the schematic diagram of the device is shown in figure 1, and the whole device comprises a liquid nitrogen storage tank 1, a gasifier 2, a nitrogen compressor 3, a buffer tank 4, a pressure reducing valve element 5 and a valve group unit 6 which are connected in sequence.

The liquid nitrogen storage tank 1 is used for storing liquid nitrogen and has a volume of 20m³。

The vaporizer 2 is used for converting the liquid nitrogen in the liquid nitrogen storage tank 1 into a gaseous state.

The nitrogen compressor 3 is a piston compressor, 4-stage compression is realized, the output pressure can be adjusted between 150 and 400bar, and PLC control is adopted; when the pressure reaches the set pressure, the machine can be automatically stopped, and when the pressure drops to the lower limit value, the machine can be automatically started for pressurization. The nitrogen compressor 3 can realize automatic pollution discharge, and ensure the air outlet quality and the safety of the unit; the main function of the nitrogen compressor 3 is to pressurize the low-pressure nitrogen supplied from the liquid nitrogen storage tank 1, so that the pressure conditions of pipeline purging and pump pressure test are provided.

The volume of the buffer tank 4 is 1m³The main function is to store the pressurized nitrogen to achieve the functions of stabilizing voltage and flow; when the pipeline purging is carried out, the purging can be continuously carried out for a period of time under the condition of larger flow, so that better pipeline cleanliness is realized.

The relief valve element 5 has a maximum input pressure of 250bar and an output pressure in the range of 0-160bar for relieving the high-pressure nitrogen in the buffer tank 4 to the pressure range specified in the pumping specification. The front of the pressure reducing valve element 5 is connected with a three-way quick connector X3, and when the nitrogen compressor 3 breaks down or is being maintained, three groups of nitrogen bottle groups can be used for access at the same time to ensure the continuous operation of pipeline purging and air-tight test.

A muffler is connected in parallel to the pressure reducing valve element 5; because the pressure in the pipeline is very high, if directly release, the noise is too big, has the harm to operating personnel, uses the noise when silencer reducible pressure releases.

The valve bank unit 6 is a valve bank unit attached to the main machine, called FVT for short, and called FUEL VALVE TRAIN for controlling the LPG liquid supply loop, the nitrogen purging loop and the pressure relief in the pipeline. The valve group unit 6 is connected with the liquid supply inlet E1 and the liquid return outlet E2 of the LGIP host 7 through a liquid supply pipe and a liquid return pipe respectively, and a sampling port S is arranged on the liquid return pipe of the FVT and used for checking the cleanliness of a pipeline when the pipeline is swept.

The invention discloses a method for purging a gas pipeline of an LGIP (liquefied gas injection) host, which comprises the following specific steps of:

firstly, blind flanges of a liquid supply inlet E1 and a liquid return outlet E2 at a sport piece of a gas pipe of an LGIP host 7 are removed, a hose is installed, and the liquid supply inlet E1 and the liquid return outlet E2 are bypassed, so that dirt is prevented from entering a gas component of a cylinder cover during purging to cause damage to the gas component as shown in figure 1.

And secondly, disconnecting the part of the pipe section of the liquid return pipe connected with the valve group unit 6, and only keeping the sampling port S.

③ the outlet pressure of the nitrogen compressor 3 is set at 250bar and it is waited for the nitrogen compressor 3 to build up pressure.

And fourthly, after the pressure build-up of the nitrogen compressor 3 is finished, adjusting the output pressure value of the pressure reducing valve element 5 to be the maximum, adjusting the valve state of the valve unit 6 to be a liquid inlet mode, and starting purging of the gas outer pipeline.

And fifthly, after purging for 30 minutes, installing a 10-micron filter bag at the sampling port S, keeping purging, and checking and taking down the filter bag after 5 minutes.

Sixthly, adsorbing the interior of the filter bag by using a magnet pen, and if no scrap iron or macroscopic dirt exists, determining that the cleanliness of the gas pipeline is qualified; if dirt exists, the purging is continued until no dirt can be detected.

And seventhly, removing the hose installed in the first step, re-installing the blind flange, cutting off the bypass of the liquid supply inlet E1 and the liquid return outlet E2, and re-installing the part of the pipe section of the liquid return pipe which is removed in the second step and is connected with the valve group unit 6.

The airtightness test of the LGIP host machine is generally carried out after the pipeline purging, and the test method comprises the following specific steps:

set the outlet pressure of the nitrogen compressor 3 at 250bar and wait for the nitrogen compressor 3 to build pressure.

Secondly, after the pressure build-up of the nitrogen compressor 3 is completed, the output pressure value of the pressure reducing valve element 5 is adjusted to 55bar, the valve state of the valve group unit 6 is adjusted to a liquid inlet mode, and the gas inlet valve of each cylinder on the LGIP host 7 is opened to wait for the pressure build-up.

And thirdly, when the pressure of a fuel gas part of the LGIP host 7 is increased to 55bar, the valve state of the valve group unit 6 is adjusted to be a gas inlet cut-off state, the pressure reducing valve element 5 is adjusted to be a closed state, a silencer switch is opened, and the pressure in the pipeline is released.

The LGIP host 7 keeps the pressure for 1 hour, and the pressure drop value after 1 hour is not more than 2.5 percent of the pumping pressure, namely 1.4bar, the LGIP host is regarded as qualified; if the pressure drop value exceeds the rated value, fault removal and leakage detection are required, and then the air tightness test is carried out.

After the air tightness test is passed, the valve member state of the valve group unit 6 is adjusted to a discharge state, and the pressure in the pipeline is discharged.

The scope of the invention is not limited to the above embodiments, and all equivalent variations and modifications made according to the disclosure of the present invention are within the scope of the present invention.