阅读说明：本技术 适用于易燃易爆环境的浆体射流切割系统及方法 (Slurry jet cutting system and method suitable for inflammable and explosive environment ) 是由 胡旭光 卿玉 胡光辉 罗园 罗卫华 刘俊男 王留洋 李玉飞 赖向东 罗林 杨宁 于 2020-04-29 设计创作，主要内容包括：本发明提供了一种适用于易燃易爆环境的浆体射流切割系统及方法,所述浆体射流切割系统包括液箱、高压泵、安全阀、控制柜、单向阀、磨料混合装置、以及喷嘴,所述高压泵通过第一管线从液箱中吸取液体,并通过第二管线向磨料混合装置提供高压液流；单向阀设置在第二管线上并仅朝向磨料混合装置单向开启；安全阀设置在第二管线上以起到限压保护作用；磨料混合装置将存储的磨料与高压液流混合后提供至喷嘴。本发明能够适用于各种易燃易爆环境下的便携、移动式切割作业,尤其适用于对油气田中的井口装置、油气管道、输气管道的防燃防爆切割作业,且能够减少切割时的能量损失,提升了切割效率,同时因空气隔绝能从根本上杜绝爆燃的发生。(The invention provides a slurry jet cutting system and a method suitable for inflammable and explosive environments, wherein the slurry jet cutting system comprises a liquid tank, a high-pressure pump, a safety valve, a control cabinet, a one-way valve, an abrasive mixing device and a nozzle, wherein the high-pressure pump sucks liquid from the liquid tank through a first pipeline and provides high-pressure liquid flow to the abrasive mixing device through a second pipeline; the one-way valve is arranged on the second pipeline and is opened towards the abrasive mixing device in one way only; the safety valve is arranged on the second pipeline to play a role in pressure limiting protection; the abrasive mixing device mixes the stored abrasive with the high-pressure liquid flow and provides the mixture to the nozzle. The invention can be suitable for portable and movable cutting operation under various flammable and explosive environments, is particularly suitable for flame-proof and explosion-proof cutting operation of wellhead devices, oil and gas pipelines and gas transmission pipelines in oil and gas fields, can reduce energy loss during cutting, improves cutting efficiency, and can fundamentally prevent deflagration due to air isolation.)

1. A slurry jet cutting system suitable for inflammable and explosive environments is characterized by comprising a liquid tank, a high-pressure pump, a safety valve, a control cabinet, a one-way valve, an abrasive mixing device and a nozzle, wherein,

the high-pressure pump is provided with a low-pressure liquid inlet and a high-pressure liquid outlet, the low-pressure liquid inlet sucks liquid from the liquid tank through a first pipeline, and the high-pressure liquid outlet is communicated with an inlet of the abrasive mixing device through a second pipeline;

the one-way valve is arranged on the second pipeline and can only be opened towards the abrasive mixing device in one way;

the safety valve is arranged on the second pipeline, is positioned between the high-pressure liquid outlet and the one-way valve, and can play a role in limiting pressure and protecting the high-pressure pump and the second pipeline;

the abrasive mixing device is capable of mixing the stored abrasive with the high-pressure liquid stream entering through the second line and providing the mixture to the nozzle through an outlet;

the control cabinet can monitor and adjust the working voltage and the working current of the high-pressure pump in real time so as to ensure that the high-pressure pump works stably and can perform emergency stop operation on the high-pressure pump.

2. The slurry jet cutting system according to claim 1, further comprising a filter disposed on the first line, the filter being capable of filtering liquid entering the low pressure liquid inlet through the first line.

3. The slurry jet cutting system of claim 1, further comprising a pressure gauge disposed on the second line between the high pressure exit port and the one-way valve.

4. The slurry jet cutting system according to claim 1, wherein the control cabinet is further capable of monitoring and adjusting the working voltage and working current of the check valve and/or the abrasive storage tank in real time to ensure that the check valve and/or the abrasive storage tank work smoothly and to perform emergency stop operation on the check valve and/or the abrasive storage tank.

5. The slurry jet cutting system of claim 1, wherein the nozzle and the abrasive mixing device comprise: a gun nozzle, a female fastener, a male fastener and a conversion joint, wherein,

the female buckle fastener is provided with a through hollow structure, the hollow structure is formed by communicating a first inner cavity with a first inner diameter and a second inner cavity with a second inner diameter, and the first inner diameter is larger than the second inner diameter;

the gun nozzle is formed by connecting a liquid inlet section with a first outer diameter and a liquid outlet section with a second outer diameter, the gun nozzle can be installed in the hollow structure of the female buckle fastener, the first outer diameter is equal to the first inner diameter, the second outer diameter is equal to the first inner diameter, a first slurry flow channel is arranged in the liquid inlet section, and a second slurry flow channel is arranged in the liquid outlet section;

the conversion joint is provided with a high-pressure liquid flow input section, an abrasive material input section and a high-pressure slurry output section which are communicated with each other, the high-pressure liquid flow input section can receive high-pressure liquid flow, the abrasive material input section can receive abrasive materials, and the high-pressure slurry output section can output high-pressure slurry formed by the high-pressure liquid flow and the abrasive materials;

the pin thread fastener has third thick liquid stream passageway, and can adapter high pressure thick liquid output section and box fastener first inner chamber fixed connection, the high pressure thick liquid that the third thick liquid stream passageway can export the high pressure thick liquid of section provides the feed liquor section to the rifle mouth first thick liquid stream passageway.

6. The slurry jet cutting system of claim 5 wherein the nozzle further comprises a seal disposed in the first internal cavity of the box fastener between the pin fastener and the inlet section of the muzzle.

7. A slurry jet cutting method suitable for flammable and explosive environments is characterized by being achieved by the slurry jet cutting system according to any one of claims 1-6.

8. The slurry jet cutting method according to claim 7, wherein the slurry jet discharged from the nozzle of the slurry jet cutting method is composed of 95-98% by weight of liquid and the balance of abrasive.

9. The slurry jet cutting method according to claim 8, wherein the pressure of the slurry jet is in a range of 65 to 75MPa, and the flow rate is 18 to 25L/min.

10. The slurry jet cutting method according to claim 7, wherein the slurry jet cutting method is capable of performing flame-proof and explosion-proof cutting operations on wellhead devices, oil and gas pipelines and gas transmission pipelines in oil and gas fields.

Technical Field

The invention relates to the technical field of hydraulic cutting, in particular to hydraulic cutting operation under flammable and explosive environments such as oil and gas well mouths and the like.

Background

The well head oil (gas) production tree is the key device for the safety production of oil and gas wells. In China, such as Chongqing, Changqing and other oil and gas fields are developed earlier, many of the oil and gas fields enter the middle-aged and old stages, the conditions that a wellhead gate valve is corroded and cannot be opened and closed generally exist, the pressure in a well is unknown, the life and property safety of people around the well is seriously threatened, and part of wellhead devices can be replaced after being cut. The working principle of the current commonly-used ejection jet flow cutting process is as follows: the water and the abrasive are mixed in advance, and then the mixture is pressurized to the pressure of 200-400 MPa, so that the water and the abrasive generate huge kinetic energy and are sent to a small nozzle to form hydraulic cutting. In the process, jet flow components comprise 95% of air, 4% of water and 1% of grinding materials, and compared with a mode of simply pressurizing water to the same pressure by mixing the water and the grinding materials firstly and then pressurizing, the mode has higher requirement on a hydraulic cutting pressurization system and larger energy loss, and meanwhile, when water and the grinding materials are mixed in advance and intervene with the air, and inflammable and explosive objects such as pressurized oil and gas pipelines are cut, the severe accidents such as explosion and the like can be caused by the impact of high pressure on metal and the existence of the air.

The chinese patent application entitled "water jet cutting machine" and publication No. CN103846809A, which was published 6, 11/2014, discloses a water jet cutting machine. The device adopts super thick Y axle crossbeam, greatly reduced the deflection of crossbeam, adopts the crossbeam that the aviation aluminum product was processed, and is not flexible, has increased the stability of crossbeam promptly, has practiced thrift again because of the crooked cost of maintaining of crossbeam. The linear guide rail is selected for transmission, so that the straightness of the equipment is improved, and the precision of the equipment is ensured.

The Chinese patent application entitled "a split abrasive water jet cutting device" and publication number CN105751079A, published in 2016, 7, 13, discloses a split abrasive water jet cutting device which has high efficiency, continuously supplies sand, can continuously work underwater and on land, can be assembled and installed in a split manner, and can play a role in quick emergency. Aiming at the problem that most of the existing abrasive water jet cutting equipment is that a storage tank, a power system and a water suction pump are assembled together to form a frame structure, so that the equipment is large in size, heavy in weight and inconvenient to move, and cannot play a role in emergency rescue.

The chinese patent application entitled "a high pressure fine jet cutting system" and publication number CN105945735A, published in 2016, 9, 21, discloses a high pressure fine jet cutting system. The system is additionally provided with a second water tank on the original basis, a filtering device is arranged in the second water tank, liquid for the operation of the jet device is fully filtered, suspended matters and scale in the liquid are completely filtered, the blockage of the jet device is avoided, the first water tank is provided with a vacuum pump, the liquid in the first water tank can be subjected to vacuum treatment, air in the liquid is discharged by the vacuum pump, and the liquid for completing the vacuum treatment operation is delivered to the cutting device through a high-pressure pipeline.

Chinese patent application entitled "a portable jet cutting device" and publication No. CN109483406A, which was published 3, 19, 2019, discloses a small, lightweight, portable jet cutting device, which is reasonable in layout design, small in size, and light in weight.

The Chinese patent application, entitled 'water jet cutting nozzle, water jet cutting equipment and method' and published with the number of CN109746841A, which is published in 2019, 5, month and 14 discloses a water jet cutting nozzle, water jet cutting equipment and method, so as to solve the technical problem of extremely low efficiency in the bolt cutting operation process in the prior art.

The inventor has found through analysis that the above-mentioned published and applied patents are designed for strength, precision, portability and the like of the cutting device, so as to improve portability and versatility of the hydraulic cutting device, but none of them is designed for flammable and explosive environments such as wellhead devices and cutting environments of oil and gas pipelines, so that great potential safety hazards are caused when the cutting device is used in flammable and explosive environments, and in the field of oil and gas field development, a great amount of wellhead devices and oil and gas pipelines need to be cut urgently to solve production problems.

Disclosure of Invention

The present invention aims to address at least one of the above-mentioned deficiencies of the prior art. For example, one of the objectives of the present invention is to design a slurry jet cutting system and method suitable for flammable and explosive environments, such as oil and gas field production, for cutting requirements in flammable and explosive environments.

In order to achieve the above object, an aspect of the present invention provides a slurry jet cutting system suitable for flammable and explosive environments, the slurry jet cutting system comprising a liquid tank, a high-pressure pump, a safety valve, a control cabinet, a one-way valve, an abrasive mixing device, and a nozzle, wherein the high-pressure pump has a low-pressure liquid inlet and a high-pressure liquid outlet, the low-pressure liquid inlet sucks liquid from the liquid tank through a first pipeline, and the high-pressure liquid outlet is communicated with an inlet of the abrasive mixing device through a second pipeline; the one-way valve is arranged on the second pipeline and can only be opened towards the abrasive mixing device in one way; the safety valve is arranged on the second pipeline, is positioned between the high-pressure liquid outlet and the one-way valve, and can play a role in limiting pressure and protecting the high-pressure pump and the second pipeline; the abrasive mixing device is capable of mixing the stored abrasive with the high-pressure liquid stream entering through the second line and providing the mixture to the nozzle through an outlet; the control cabinet can monitor and adjust the working voltage and the working current of the high-pressure pump in real time so as to ensure that the high-pressure pump works stably and can perform emergency stop operation on the high-pressure pump.

In an exemplary embodiment of the invention, the slurry jet cutting system may further comprise a filter arranged on the first line, the filter being capable of filtering liquid entering the low pressure liquid inlet through the first line.

In an exemplary embodiment of the invention, the slurry jet cutting system may further include a pressure gauge disposed on the second line between the high pressure liquid outlet and the one-way valve.

In an exemplary embodiment of the invention, the control cabinet may further perform real-time monitoring and adjustment on the working voltage and the working current of the check valve and/or the abrasive storage tank, so as to ensure that the check valve and/or the abrasive storage tank work smoothly and perform emergency stop operation on the check valve and/or the abrasive storage tank.

In another exemplary embodiment of the present invention, the nozzle and the abrasive mixing device in a slurry jet cutting system adapted for use in a flammable and explosive environment comprise: the gun comprises a gun nozzle, a female buckle fastener, a male buckle fastener and a conversion joint, wherein the female buckle fastener is provided with a through hollow structure, the hollow structure is formed by communicating a first inner cavity with a first inner diameter and a second inner cavity with a second inner diameter, and the first inner diameter is larger than the second inner diameter; the gun nozzle is formed by connecting a liquid inlet section with a first outer diameter and a liquid outlet section with a second outer diameter, the gun nozzle can be installed in the hollow structure of the female buckle fastener, the first outer diameter is equal to the first inner diameter, the second outer diameter is equal to the first inner diameter, a first slurry flow channel is arranged in the liquid inlet section, and a second slurry flow channel is arranged in the liquid outlet section; the conversion joint is provided with a high-pressure liquid flow input section, an abrasive material input section and a high-pressure slurry output section which are communicated with each other, the high-pressure liquid flow input section can receive high-pressure liquid flow, the abrasive material input section can receive abrasive materials, and the high-pressure slurry output section can output high-pressure slurry formed by the high-pressure liquid flow and the abrasive materials; the pin thread fastener has third thick liquid stream passageway, and can adapter high pressure thick liquid output section and box fastener first inner chamber fixed connection, the high pressure thick liquid that the third thick liquid stream passageway can export the high pressure thick liquid of section provides the feed liquor section to the rifle mouth first thick liquid stream passageway.

Additionally, the nozzle may further include a seal disposed in the first interior cavity of the box fastener between the pin fastener and the inlet section of the muzzle.

According to another aspect of the invention, a slurry jet cutting method suitable for flammable and explosive environments is provided, and is realized by adopting the slurry jet cutting system.

In an exemplary embodiment of the present invention, the slurry jet cutting method may control a slurry jet discharged from a nozzle to be composed of 95 to 98% by weight of a liquid and the balance of an abrasive, and further, the slurry jet may have a pressure ranging from 65 to 75MPa and a flow rate ranging from 18 to 25L/min.

In an exemplary embodiment of the invention, the slurry jet cutting method can perform flame-proof and explosion-proof cutting operation on wellhead devices, oil and gas pipelines and gas transmission pipelines in oil and gas fields.

Compared with the prior art, the beneficial effects of the invention comprise at least one of the following aspects:

(1) in the prior art, water and abrasive are mixed at the front end and then pressurized, and finally jet cutting is formed through a nozzle;

(2) the abrasive does not need to be pressurized in the whole cutting process, so that the energy loss in cutting is reduced, and the cutting efficiency is improved;

(3) the cutting machine can isolate air, fundamentally avoids the occurrence of deflagration, has the advantages of high cutting speed, low energy consumption and small and uniform cutting seam, and is suitable for cutting operation in dangerous environments such as inflammable and explosive environments;

(4) need not plus the rifle mouth card fixed, avoided the nozzle fastening not in place, shake under the high pressure and take off, the risk of departure, the operation that can not appear leading to because of the nozzle departure is interrupted and personnel's injury, more is fit for the hydraulic cutting operation under the high pressure, has further promoted cutting ability and security.

Drawings

FIG. 1 illustrates a schematic block diagram of an exemplary embodiment of a slurry jet cutting system suitable for use in flammable and explosive environments of the present invention;

fig. 2 shows a schematic configuration of an abrasive mixing device and a nozzle in an exemplary embodiment of a slurry jet cutting system suitable for use in flammable and explosive environments according to the present invention.

The reference numerals are explained below:

1. a filter; 2. a water tank 3, a high-pressure water pump; 4. a safety valve; 5. a pressure gauge; 6. a variable frequency control cabinet; 7. a one-way valve; 8. an abrasive mixing device; 9. a nozzle;

11. a gun nozzle; 12. sealing washer, 13, female fastener fastening cap; 14. a male buckle fastening end; 15. and (4) converting the joint.

Detailed Description

Hereinafter, the slurry jet cutting system and method suitable for flammable and explosive environments of the present invention will be described in detail with reference to exemplary embodiments.

In an exemplary embodiment of the present invention, the slurry jet cutting system suitable for flammable and explosive environments may be composed of a liquid tank, a high pressure pump, a safety valve, a control cabinet, a check valve, an abrasive mixing device, a nozzle, and first and second lines.

Specifically, the high-pressure pump can be provided with a low-pressure liquid inlet and a high-pressure liquid outlet, wherein the low-pressure liquid inlet is connected with the liquid tank through a first pipeline to suck non-combustible liquid (such as water) from the liquid tank, the high-pressure liquid outlet is communicated with an inlet of the abrasive mixing device through a second pipeline to provide the liquid pressurized by the high-pressure pump into the abrasive mixing device, for example, the high-pressure liquid outlet can output liquid with the pressure ranging from 65 MPa to 75MPa and the flow rate ranging from 18 MPa to 25L/min, in addition, the liquid entering from the low-pressure liquid inlet can have the pressure ranging from 0.10 MPa to 1MPa, for example, the high-pressure liquid outlet can be provided with a plunger structure form of a gap sealing structure, the sealing purpose can be achieved through precise matching between the plunger and a sleeve, no sealing seasoning needs to be added, the performance is stable, the service life is long, the high-pressure pump is suitable for mobile cutting operation, and the hard alloy can be selected by the plunger material, the service.

The check valve is disposed on the second pipeline and can be opened only in one direction toward the abrasive mixing device, thereby forming a one-way passage for delivering the liquid pressurized by the high-pressure pump to the abrasive mixing device.

The safety valve is arranged on the second pipeline, is positioned between the high-pressure liquid outlet of the high-pressure pump and the one-way valve, and can play a role in limiting pressure and protecting the high-pressure pump and the second pipeline. For example, the relief valve may automatically relieve pressure when the pressure of the high pressure pump and/or the second line, etc. reaches 1.2 times the upper limit of the operating pressure of the high pressure pump. And for another example, the safety valve can be a spring micro-opening safety valve, has the advantages of light and compact structure, high sensitivity, unlimited installation position and small sensitivity to vibration, and is suitable for movable cutting operation.

The abrasive mixing device is capable of mixing stored abrasive with a high pressure liquid stream entering it via a second pipeline and providing it through its outlet to a nozzle forming a slurry jet for cutting a facility such as a wellhead, oil and gas pipeline, etc. in a flammable and explosive environment. Here, the formed slurry jet may be composed of 95-98% by weight of a liquid and the balance of an abrasive. The grain size of the abrasive can be 70-100 meshes. The nozzle may be stepped in profile so that it is reliable in installation and more suitable for high pressure slurry jet cutting.

The control cabinet can monitor and adjust the working voltage and the working current of the high-pressure pump in real time to ensure that the high-pressure pump works stably and can carry out emergency stop operation on the high-pressure pump. In addition, the control cabinet can further monitor and regulate the working voltage and the working current of the check valve and/or the abrasive storage tank in real time under the condition of monitoring and regulating the working current and the working voltage of the high-pressure pump, so that the check valve and/or the abrasive storage tank can work stably, and the emergency stop operation can be performed on the check valve and/or the abrasive storage tank. For example, the switch board can adopt the flame-proof type block terminal, and the box surface is furnished with motor adjustment button, voltage electric current watch, converter digital display screen and scram protection button, can set for motor operating frequency, monitors voltage electric current, can carry out equipment scram operation.

In another exemplary embodiment of the present invention, the slurry jet cutting system suitable for flammable and explosive environments may further include, on the basis of the structures of the above exemplary embodiments, a filter disposed on the first pipeline, and the filter may be configured to filter the liquid entering the low-pressure liquid inlet through the first pipeline, so as to avoid adverse effects of impurities in the liquid on subsequent high-pressure pumps and other mechanisms. For example, the filter can filter and store a volume of working medium (e.g., water) to prevent large particles from entering the subsequent structure and causing clogging of the nozzle, so the mesh size of the filter can be determined according to the nozzle diameter. For example, the filter can be a Y-shaped pipeline filter, has the advantages of small and exquisite structure, small resistance, convenient installation and maintenance and low cost, and meets the design requirements and economic applicability. In addition, the slurry jet cutting system can further comprise a pressure gauge which is arranged on the second pipeline and is positioned between the high-pressure liquid outlet and the one-way valve, so that the liquid pressure in the second pipeline can be timely and accurately measured.

In addition, for the slurry jet cutting system of the present invention, it may further include a manifold tank which may have a flame-proof and explosion-proof structure and centrally assembles (a) the high-pressure pump, the safety valve, the control cabinet and the check valve therein, on the basis of the above three kinds of exemplary embodiments; or the liquid tank, the high-pressure pump, the safety valve, the control cabinet and the one-way valve in the step (b) are assembled in a centralized way; or the filter, the high-pressure pump, the safety valve, the control cabinet and the one-way valve are assembled in a centralized way; or the liquid tank, the filter, the high-pressure pump, the safety valve, the control cabinet and the one-way valve in the step (d) are assembled in a centralized way; or the filter, the high-pressure pump, the safety valve, the control cabinet, the pressure gauge and the one-way valve in the step (e) are assembled in a centralized way; or (f) the liquid tank, the filter, the high-pressure pump, the safety valve, the control cabinet, the pressure gauge and the one-way valve are assembled in a centralized manner. This facilitates the formation of an integrated modular structure and also facilitates the mobile cutting operation.

In an exemplary embodiment of the present invention, a nozzle and abrasive mixing device in a slurry jet cutting system adapted for use in flammable and explosive environments may comprise: gun nozzle, box fastener, pin fastener and crossover sub. For example, the muzzle and box fastener may be considered a nozzle, and the pin fastener and adapter and abrasive storage device may be considered an abrasive mixing device; the muzzle may also be considered as a nozzle, while the box fastener, pin fastener and adapter, and abrasive storage device may be considered as an abrasive mixing device; the adapter and abrasive storage device may also be considered an abrasive mixing device, while the muzzle, box fastener, and pin fastener may be considered together as a nozzle.

The female buckle fastener is provided with a penetrating hollow structure, the hollow structure is formed by communicating a first inner cavity with a first inner diameter and a second inner cavity with a second inner diameter, and the first inner diameter is larger than the second inner diameter. In addition, the first inner cavity can be provided with internal threads.

Gun nozzle is formed and can install by the feed liquor section that has first external diameter and the play liquid section that has the second external diameter connect in the hollow structure of box fastener, and first external diameter equals or substantially equals first internal diameter, the second external diameter equals or substantially equals first internal diameter, simultaneously run through in the feed liquor section and be provided with first thick liquid and flow the passageway, run through in the play liquid section and be provided with second thick liquid and flow the passageway, first thick liquid flows passageway and second thick liquid and flows the passageway intercommunication. That is, the liquid inlet section and the liquid outlet section of the gun nozzle can form a stepped structure, the liquid inlet section of the gun nozzle can be assembled in the first inner cavity of the female buckle fastener, the liquid outlet section of the gun nozzle can be assembled in the second inner cavity of the female buckle fastener, and even the end, which is not connected with the liquid inlet section, of the gun nozzle can penetrate out of the second inner cavity of the female buckle fastener and is used as the final output end of the high-pressure slurry jet of the whole safety nozzle. Preferably, the caliber of the first slurry flow channel can be larger than the caliber of the second slurry flow channel. For example, the first and second slurry flow channels may together form a funnel shape that tapers in the direction of slurry flow.

The adapter has a high pressure liquid stream input section, an abrasive input section and a high pressure slurry output section in communication with each other. Wherein the high pressure liquid stream input section is capable of receiving a high pressure liquid stream. For example, the high-pressure liquid flow input section can be communicated with a high-pressure liquid outlet of the high-pressure pump through a pipeline with a check valve. The one-way valve can only be opened unidirectionally towards the high-pressure liquid flow input section, thereby forming a one-way channel for conveying liquid pressurized by the high-pressure pump to the high-pressure liquid flow input section. The abrasive input section is capable of receiving abrasive. For example, the abrasive input section can be in communication with an abrasive storage device (e.g., an abrasive storage tank) to receive abrasive therein. The high-pressure slurry output section can output the high-pressure slurry formed by mixing the high-pressure liquid flow received by the high-pressure liquid flow input section and the abrasive received by the abrasive input section. Preferably, the high-pressure liquid flow input section and the abrasive input section of the conversion joint are perpendicular to each other, and the high-pressure liquid flow input section and the high-pressure slurry output section are both horizontally arranged, so that the high-pressure liquid flow and the abrasive are fully mixed and are convenient to output from the high-pressure slurry output section.

The male buckle fastener is provided with a third slurry flow channel and can fixedly connect the high-pressure slurry output section of the adapter with the first inner cavity of the female buckle fastener. The third slurry flow channel can provide high-pressure slurry of the high-pressure slurry output section to the first slurry flow channel of the liquid inlet section of the gun nozzle, and finally the high-pressure slurry is sprayed out from the second slurry flow channel to form high-pressure slurry jet flow, so that cutting operation is carried out. One end of the male fastener close to the female fastener can be provided with external threads so as to form threaded fastening connection with the internal threads of the female fastener. However, the invention is not limited thereto, and other similar detachable fastening means are also possible. In addition, the male fastener and the adapter may also be directly integrally formed, for example, directly cast or finish formed.

In another exemplary embodiment of the present invention, a seal disposed in the first interior cavity of the box fastener between the pin fastener and the inlet section of the muzzle may be further included. Here, the sealing member can improve the connection and sealing effect of the male snap fastener, the female snap fastener, and the muzzle. In addition, the threaded fastening connection mode between the female buckle fastener and the male buckle fastener can further compress the sealing element and enhance the sealing effect.

FIG. 1 shows a schematic block diagram of an exemplary embodiment of a slurry jet cutting system of the present invention suitable for use in flammable and explosive environments.

As shown in fig. 1, in an exemplary embodiment of the present invention, a slurry jet cutting system suitable for flammable and explosive environments is composed of a filter 1, a water tank 2, a high pressure water pump 3, a safety valve 4, a pressure gauge 5, a variable frequency control cabinet 6, a check valve 7, an abrasive mixing device 8, and a nozzle 9.

Wherein, the water in the water tank 1 enters the main system after passing through the filter 2 under the suction of the high pressure water pump 3. The main system can comprise a high-pressure water pump and a second pipeline, and further can comprise a safety valve, a variable-frequency control cabinet, a pressure gauge and a one-way valve. The filter 2 is arranged between the water tank and the low-pressure water inlet of the high-pressure pump and belongs to a low-pressure pipeline. The pressure of the water inlet of the pump can be 0.2-0.3 MPa. The size of the mesh of the filter is determined according to the diameter of the nozzle, the filter is a Y-shaped pipeline filter, the structure is small and exquisite, the resistance is small, the installation and the overhaul are convenient, the cost is low, and the design requirement and the economic applicability are met.

The high-pressure water pump 3 adopts a plunger structure form to select a clearance sealing structure, the sealing purpose is achieved through precise matching between the plunger and the sleeve, no sealing seasoning is needed to be added, the performance is stable, the service life is long, the plunger is made of hard alloy, the service life of a sealing element is ensured, meanwhile, the sealing can be automatically compensated when the high-pressure water pump is worn, and the system stability is improved.

The safety valve 4 plays a pressure limiting protection role on the whole main system, and automatically releases pressure when the pressure of the system reaches 1.2 times of the working pressure. The safety valve can be a spring micro-opening safety valve, has light and compact structure, high sensitivity, unlimited installation position and small sensitivity to vibration, and is suitable for movable cutting operation. For example, the safety valve 4 may be a spring-type safety valve, and it can ensure automatic pressure relief when the pressure reaches 1.2 times (e.g., 84MPa) the working pressure, thereby performing overpressure protection.

The variable frequency control cabinet 5 monitors and adjusts the working voltage and the working current of the high-pressure water pump or the working voltage and the working current of the high-pressure water pump, the one-way valve and the abrasive storage tank in real time, keeps the system work stable, can adopt an explosion-proof distribution box, is provided with a motor adjusting button, a voltage and current monitoring meter, a frequency converter digital display screen and an emergency stop protection button on the surface of the box body, can set the working frequency of the motor, monitors the voltage and the current, and can perform emergency stop operation of equipment.

The pressure gauge 6 can observe the system pressure in real time. The check valve 7 is effective to prevent the abrasives in the abrasive mixing device 8 from being rewound into the main system.

The abrasive mixing device 8 provides abrasive to be mixed with the high-pressure water flow ejected from the one-way valve 7, and the abrasive is ejected from the nozzle 9 to form cutting water flow, so that the cutting operation is completed. The abrasive mixing device 8 can be used to store the abrasive and achieve sufficient mixing of the abrasive with the working medium (e.g., water) while controlling the flow of the abrasive to ensure optimal cutting efficiency and economy. The grinding material mixing device belongs to a pressure container, and a cylindrical tank body can be selected in the tank body shape, so that the tank body has the advantages of small occupied space, few welding interfaces, uniform wall thickness and the like. The tank body structure can be formed by adopting a fiber winding process, so that the weight of the tank body can be effectively reduced, compared with a metal tank body with the same volume, the weight is reduced by about 80%, the bearing capacity is enhanced, and the service life is prolonged. The nozzle 9 may be stepped in profile so that it is reliably mounted and more suitable for high pressure slurry jet cutting.

As shown by a dotted line block in fig. 1, the slurry jet cutting system of the present exemplary embodiment may further include a manifold having a flame and explosion proof structure. The centralized distribution box can be used for assembling a liquid tank, a filter, a high-pressure pump, a safety valve, a control cabinet, a pressure gauge and a one-way valve in a centralized manner. This facilitates the formation of an integrated device and also facilitates the portable cutting operation.

Fig. 2 shows a schematic configuration of an abrasive mixing device and a nozzle in an exemplary embodiment of a slurry jet cutting system suitable for use in flammable and explosive environments according to the present invention.

In yet another exemplary embodiment of the present invention, as shown in fig. 2, the abrasive mixing device and nozzle may be comprised of a muzzle 11, a sealing washer 12, a box fastening cap 13, a pin fastening end 14, and an adapter 15.

Specifically, the shape of the gun nozzle 11 can be a step shape, when the gun nozzle 11 is installed, the gun nozzle 11 penetrates into the female buckle fastening cap 13, and the step on the gun nozzle 11 is attached to the step of the female buckle fastening cap 13 to realize limiting. After the gun nozzle 11 penetrates into the female buckle fastening cap 13, the sealing washer 12 is flatly placed into the female buckle fastening cap 13 and is tightly attached to the upper end face of the gun nozzle 11, and a sealing effect is achieved. The male end of the male fastening end 14 is connected with the female end of the female fastening cap 13, and the threads are tightened to compress the end faces, so that the gun nozzle is fixed and the connection part is sealed. The male buckle fastening end 14 is connected with the adapter 15, and the adapter 15 can be respectively connected with the abrasive mixing chamber and the high-pressure water flow, so that the mixing and the spraying of the abrasive are realized. That is to say, through setting up rifle mouth 11 into the ladder form, can compress tightly the terminal surface through the screw thread fastening connection between pin thread fastening end and box fastening cap and the sealing member simultaneously, need not plus rifle mouth card and fix, avoided the risk that the nozzle fastening is not in place, shakes under the high pressure and takes off, flies out.

When the high-pressure slurry jet cutting operation of an oil and gas wellhead is carried out, abrasive enters from a vertical square interface of the conversion joint 15, and high-pressure water enters from a horizontal square interface of the conversion joint 15, so that the abrasive and the high-pressure water are mixed, and the cutting is realized through the gun nozzle 11.

In addition, in the slurry jet cutting method, the slurry jet sprayed out of the nozzle can be composed of 95-98% of liquid and the balance of abrasive materials according to the weight percentage, the pressure range of the slurry jet can be 65-75 MPa, and the flow rate can be 18-25L/min.

In conclusion, the invention can provide the slurry jet cutting system and the slurry jet cutting method suitable for the inflammable and explosive environment, the water is directly pressurized to the working pressure and then mixed with the grinding materials, the grinding materials are not required to be pressurized in the whole process, the energy loss during cutting is reduced, the cutting efficiency is improved, air is isolated, the detonation is fundamentally avoided, and the problems of high safety risk and low cutting efficiency in the cutting of the existing oil-gas well head device are solved.

Although the present invention has been described above in connection with the exemplary embodiments and the accompanying drawings, it will be apparent to those of ordinary skill in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.