阅读说明：本技术 一种用于液体管路的脉动缓冲装置、尿素喷射总成及系统 (Pulsation buffering device for liquid pipeline, urea injection assembly and system ) 是由 张利刚 宋鹏 牛景弘 毕明松 李博 刘肖剑 姚凯 马伟斌 韩锋涛 吴亚絮 齐苗苗 于 2019-10-24 设计创作，主要内容包括：本发明提供的用于液体管路的脉动缓冲装置,通过脉动缓冲装置内分别设置2个独立的腔室,并在这2个独立腔室之间设一膜片缓冲件或帽状缓冲件,其中一个是液体腔室,连接在液体管路中,另一个是空气腔室,与大气相通,有效地减弱膜片尿素计量泵运行过程中的震动,并降低与其连接液体管路内的压力波动,减少压力波动对液体管路、弯头、接头的冲击,同时减小压力波动造成的惯性损失,大大地降低膜片尿素计量泵电机的功耗,从而使膜片尿素计量泵的工况大大改善,延长了膜片尿素计量泵的运行寿命。(The pulsation buffering device for the liquid pipeline, provided by the invention, has the advantages that 2 independent chambers are respectively arranged in the pulsation buffering device, and a diaphragm buffering piece or a cap-shaped buffering piece is arranged between the 2 independent chambers, wherein one chamber is a liquid chamber and is connected in the liquid pipeline, and the other chamber is an air chamber and is communicated with the atmosphere, so that the vibration of the diaphragm urea metering pump in the operation process is effectively weakened, the pressure fluctuation in the liquid pipeline connected with the diaphragm urea metering pump is reduced, the impact of the pressure fluctuation on the liquid pipeline, an elbow and a joint is reduced, the inertia loss caused by the pressure fluctuation is reduced, the power consumption of a motor of the diaphragm urea metering pump is greatly reduced, the working condition of the diaphragm urea metering pump is greatly improved, and the service life of the diaphragm urea metering pump.)

1. A pulsation buffering device for a liquid pipeline is characterized by mainly comprising a shell of an integral surrounding structure, an inner cavity of the shell and a buffering piece, wherein the buffering piece is fixed on the shell of the integral surrounding structure and separates the inner cavity into two independent chambers; one of the chambers is a liquid chamber, a shell of the chamber is provided with a liquid inlet and a liquid outlet respectively, the other chamber is an air chamber, and the shell of the chamber is provided with at least one vent or hole communicated with the atmosphere.

2. A pulsation damper according to claim 1, characterized in that the housing of the integral enclosure is made of plastic or metal material.

3. A pulsation damper according to claim 2, wherein said housing is composed of a can-shaped housing (2) having an open end and a hollow inside, and a fixing block (5), said damper is a cap-shaped damper (3) having a structure corresponding to that of the can-shaped housing (2), wherein said cap-shaped damper (3) is put in from the open end of the can-shaped housing (2), and an outer rim is provided around the right end thereof, and said fixing block (5) is screwed into the can-shaped housing (2).

4. A pulsation damper according to claim 3, wherein said liquid inlet and outlet ports (1,4) are provided on the upper and lower side walls of the tank-like casing (2), respectively; the air vent or hole (6) is arranged on the fixing block (5).

5. A pulsation damper device according to claim 1, 2, 3 or 4, characterized in that said damper member is made of rubber.

6. A pulsation damper according to claim 2, wherein said housing of the integral enclosure structure is composed of upper and lower housings (7, 9) of a hollow structure, and said damper is a diaphragm damper (8), wherein said diaphragm damper (8) is fixed between said upper and lower housings (7, 9).

7. A pulsation damper device according to claim 6, characterized in that said vent or hole (6) is provided in the upper housing (7), and said inlet and outlet ports (1,4) are provided in the lower housing (9), respectively.

8. A pulsation damper device according to claim 6 or 7, characterized in that said damper member is made of rubber.

9. A pulsation damper according to claim 1, 2, 3, 4, 6 or 7, characterized in that said liquid is an aqueous urea solution or water.

10. A urea injection assembly based on the pulsation damping device according to claim 9, further comprising a diaphragm urea metering pump, an atomizing nozzle, a liquid pipeline sequentially connecting the diaphragm urea metering pump, the pulsation damping device, the atomizing nozzle, and an injection control unit.

11. A diesel selective catalytic reduction system based on the urea injection assembly of claim 10, further comprising a urea supply assembly, a catalytic muffler and a liquid pipeline connecting the urea supply assembly and the urea injection assembly in sequence.

Technical Field

The invention belongs to the technical field of liquid conveying pipelines, and relates to a pulsation buffering device, in particular to a pulsation buffering device, a urea injection assembly and a system for a liquid pipeline.

Background

A Selective Catalytic Reduction (SCR) system of a diesel engine is used for removing nitrogen oxides in the emission of the diesel engine and comprises three parts: catalytic muffler, urea supply assembly, urea injection assembly. Under the high-temperature environment, the urea injection assembly injects urea aqueous solution into the catalytic muffler, the urea generates water and ammonia gas at high temperature, and the ammonia gas and the nitrogen oxide in the tail gas generate oxidation-reduction reaction in the SCR catalyst to generate nitrogen and water, so that the aim of reducing the emission of the nitrogen oxide of the diesel engine is fulfilled.

The urea injection assembly consists of a DCU (named as an injection control unit), a urea metering pump and an atomizing nozzle. In the prior art, part of urea injection assemblies in the market absorb urea aqueous solution from a urea box into a liquid inlet of the urea metering pump through a filter screen by the urea metering pump, then the urea aqueous solution enters a liquid absorbing port of a pump core of the urea metering pump, then flows to a filter core from a liquid outlet of the pump core of the urea metering pump, then flows to a liquid outlet of the urea metering pump, and finally conveys the urea aqueous solution to a nozzle device through a pipeline for atomization injection, so that the urea box and the injection stage are completed.

In the prior art, the urea metering pump part adopts a diaphragm urea metering pump which is driven by a motor through an eccentric wheel transmission device, so that once the motor is started, the motor drives the diaphragm urea metering pump to continuously and periodically suck urea aqueous solution and discharge the urea aqueous solution through the eccentric wheel transmission device, and therefore, flow periodical fluctuation can be formed in a liquid conveying pipeline, and larger noise is generated in the liquid conveying pipeline, so that the rotating speed of the motor of the diaphragm urea metering pump is unstable, the power consumption of the diaphragm urea metering pump during liquid conveying is increased, the operation reliability of the diaphragm urea metering pump is seriously influenced, and the service life of the diaphragm urea metering pump is shortened.

Disclosure of Invention

In order to solve the above problems, an object of the present invention is to provide a pulsation damper for a diaphragm urea metering pump, which is used in a liquid pipeline, and has the advantages of energy saving, noise reduction, and long service life, and mainly comprises a casing of an integral enclosing structure, an inner cavity of the casing, and a damper, wherein the damper is fixed on the casing of the integral enclosing structure and separates the inner cavity into two independent chambers; one of the chambers is a liquid chamber, a shell of the chamber is provided with a liquid inlet and a liquid outlet respectively, the other chamber is an air chamber, and the shell of the chamber is provided with at least one vent or hole communicated with the atmosphere.

The housing is made of plastic or metal material.

Firstly, the above-mentioned casing of the integral enclosing structure is composed of a pot-shaped casing with an opening at one end and a hollow interior and a fixed block, the buffer is a cap-shaped buffer corresponding to the pot-shaped casing structure, wherein the cap-shaped buffer is put in from the opening port of the pot-shaped casing, an outer edge is arranged around the right end of the cap-shaped buffer, and the cap-shaped buffer is fixed in the pot-shaped casing by the fixed block through a thread.

The liquid inlet and the liquid outlet are respectively arranged on the upper side wall and the lower side wall of the tank-shaped shell; the air vent or hole is arranged on the fixing block.

The buffer member is made of rubber.

Secondly, the above-mentioned casing of whole surrounding structure comprises upper and lower casing of hollow structure, the bolster be the diaphragm bolster, wherein, the diaphragm bolster fix upper and lower casing between.

The vent or hole is arranged on the upper shell, and the liquid inlet and the liquid outlet are respectively arranged on the lower shell.

The buffer member is made of rubber.

The liquid is urea aqueous solution or water.

The invention also provides a urea injection assembly of the pulsation buffering device, which further comprises a diaphragm urea metering pump, an atomizing nozzle, a liquid pipeline and an injection control unit, wherein the liquid pipeline is sequentially connected with the diaphragm urea metering pump, the pulsation buffering device and the atomizing nozzle.

The invention also provides a diesel engine selective catalytic reduction system based on the urea injection assembly, which further comprises a urea supply assembly, a catalytic muffler and a liquid pipeline sequentially connecting the urea supply assembly and the urea injection assembly.

The pulsation buffering device for the liquid pipeline, provided by the invention, is additionally arranged in the liquid conveying pipeline driven by the diaphragm metering pump, so that the vibration of the diaphragm metering pump in the operation process is effectively weakened, the pressure fluctuation in the liquid pipeline connected with the diaphragm metering pump is reduced, the impact of the pressure fluctuation on the liquid pipeline, an elbow and a joint is reduced, the inertia loss caused by the pressure fluctuation is reduced, the power consumption of a motor of the diaphragm metering pump is greatly reduced, the working condition of the diaphragm metering pump is greatly improved, and the operation life of the diaphragm metering pump is prolonged.

Drawings

Fig. 1 is a schematic longitudinal sectional view of a pulsation damper for a liquid line according to an embodiment.

Fig. 2 is a right side view of the device of fig. 1.

FIG. 3 is a schematic cross-sectional view of the device shown in FIG. 1, taken along line C-C.

FIG. 4 is a graph showing the pressure fluctuation curve of the apparatus of FIG. 1 installed in a liquid line.

FIG. 5 is a schematic view of the device of FIG. 1 during operation with fluid flowing therethrough.

Fig. 6 is a schematic view of the buffer member in a compressed state and under stress during the operation of the device shown in fig. 1.

Fig. 7 is a schematic view of the buffer member in a release state under stress during operation of the device shown in fig. 1.

Fig. 8 is a schematic structural view of a pulsation damper for a liquid line according to a second embodiment.

Fig. 9 is a schematic view of the device of fig. 8 during operation with fluid flowing therethrough.

Fig. 10 is a schematic view of the device shown in fig. 8 illustrating the force applied to the buffer member in a compressed state during operation.

Detailed Description

The pulsation damping device for a liquid pipeline provided by the invention is described in detail below by taking a diaphragm urea metering pump as an example and combining the accompanying drawings and specific embodiments.

Example one

As shown in fig. 1, 2 and 3, the pulsation buffering device for the diaphragm urea metering pump driving liquid conveying pipeline is mainly composed of a tank-shaped shell 2 with an opening at one end and a hollow interior, wherein the upper side wall and the lower side wall of the tank-shaped shell are respectively provided with a liquid outlet 4 and a liquid inlet 1, and a hollow cap-shaped buffering element 3 with a hollow structure corresponding to the structure of the tank-shaped shell 2, the cap-shaped buffering element 3 is put into the tank-shaped shell 2 from an opening port, an outer edge is arranged around the right end of the cap-shaped buffering element 3, and a fixing block (5) with a through hole is fixed in the opening port of the tank-shaped shell 2 through threads (a buckle or a cover plate), so that the cap-shaped buffering element.

The cross section of the tank-shaped shell 2 can be designed to be round, square, trapezoid, oval, U-shaped and the like, the shell material can be made of plastic or metal according to the highest using pressure, meanwhile, in order to meet the using requirements of the pulsation damper, the structure of the cap-shaped damper 3 corresponds to the structure of the tank-shaped shell 2 and can be made into corresponding shapes, such as round, square, trapezoid, oval, U-shaped and the like, and the material and the hardness can be made of different materials according to the properties of the conveyed medium, such as corrosion-resistant materials, such as rubber and the like.

The working principle is as follows:

as shown in figures 4, 6 and 7_，The line pulsation is smoothed by varying the volume of gas or liquid. For a liquid conveying system with flow velocity having sinusoidal characteristics, when wave peaks occur, the gas volume in the inner cavity of the cap-shaped buffer component 3 is reduced, and the cap-shaped buffer component 3 plays a role in shock absorption and absorbs redundant liquid; during the wave valley, the inner cavity of the cap-shaped buffer part 3 is restored to the original state, and the stored liquid is released, so that the effect of smooth pulsation is achieved.

The specific process is as follows:

as shown in fig. 5, when the diaphragm urea metering pump starts to operate, the total flow of liquid is: enters from the liquid inlet 1, flows through along A-B-C-D-E-F in the liquid inlet and flows out from the liquid outlet 4.

As shown in figure 6, when the eccentric cam of the eccentric wheel transmission device on the motor shaft of the diaphragm urea metering pump moves to the lower dead point, the liquid suction port of the pump core of the diaphragm urea metering pump is closed, the liquid discharge port is opened, the liquid in the pipeline has backflow phenomenon due to the influence of inertia and gravity, at the moment, the liquid in the pulsation buffering device flows backwards from the F-E-D-C-B-A direction, the cap-shaped buffering element 3 is impacted by the backflow liquid and is compressed, the air in the inner cavity air chamber of the cap-shaped buffering element flows out from the a-B-C direction, the volume of the inner cavity of the cap-shaped buffering element is reduced, and therefore the cap-shaped buffering element 3 absorbs the.

As shown in fig. 7, when the eccentric cam of the eccentric wheel transmission device on the motor shaft of the diaphragm urea metering pump moves to the top dead center, the liquid suction port of the pump core of the diaphragm urea metering pump is opened, the liquid discharge port of the diaphragm urea metering pump is closed, the liquid in the pulsation buffering device is reduced at the moment, the cap-shaped buffering element 3 is restored to the original state, the stored liquid is released, the liquid flow in the liquid inlet pipeline is supplemented, the valley value of the flow in the pipeline is increased, and therefore the smooth pulsation effect is achieved.

The pulsation buffering device can be used in liquid conveying pipelines of diaphragm metering pumps of integrated non-air-assisted metering pumps, split non-air-assisted metering pumps and the like. In order to ensure the effectiveness of the use of the pulsation damper, when the pulsation damper is installed, a vibration material is added and subtracted at the fixing position of the pulsation damper and a liquid conveying pipeline so as to absorb the vibration energy of the pulsation damper and prevent the generation of resonance vibration, and meanwhile, the inner cavity of the cap-shaped damper 3 of the pulsation damper is ensured to be communicated with the atmosphere.

Example two

As shown in fig. 8, the structural schematic diagram of the pulsation buffering device used in the liquid conveying pipeline driven by the diaphragm urea metering pump is mainly composed of an upper shell 7 with an air vent, a lower shell 9 with a liquid inlet and outlet 1 and 4, and a diaphragm buffering member 8 fixed between the upper and lower shells, wherein the upper and lower shells are both hollow structures, and the space (inner cavity) formed by combining the upper and lower shells is divided into two independent chambers by the diaphragm buffering member 8: i.e. the upper chamber is an air chamber and the lower chamber is a liquid chamber.

The upper shell and the lower shell can be reasonably designed according to the use environment, and the materials are mainly selected from plastic, metal and other materials according to the working pressure, so that the use performance and the service life requirements of the shell are met.

At least one vent 6 communicated with the atmosphere is arranged on the upper shell 7, and the position, the number and the size of the vent can be reasonably set according to the requirement of service performance; the lower shell 9 is provided with a liquid inlet and a liquid outlet 1 and 4, and the position and the aperture can be reasonably set according to the use environment; if the positions of the liquid inlet and the liquid outlet are set on the left and the right side walls of the lower shell 9 due to the limitation of the use environment, the positions of the liquid inlet and the liquid outlet should be avoided as much as possible that the pulsation damping device is at the same horizontal height when being installed and used.

The diaphragm buffering piece 8 can be fixedly sealed between the upper shell 7 and the lower shell 9 through bolts, the sealing performance and the looseness prevention performance of the diaphragm buffering piece are guaranteed, and other fixing connection modes such as clamping buckles can be selected. The shape of the diaphragm buffer member 8 can be designed according to the shape of the upper and lower shells by adopting a corresponding shape, and different materials, such as rubber and other corrosion-resistant materials, can be selected according to the property of the conveyed liquid by the material and the hardness of the diaphragm buffer member.

The working principle is as follows:

as shown in fig. 4 and 10, the line pulsation is smoothed by varying the volume of gas or liquid. For a liquid conveying system with flow velocity having sinusoidal characteristics, when wave peaks occur, the diaphragm buffer member 8 is extruded and deformed, the volume of air in the air chamber is reduced, and the diaphragm buffer member 8 absorbs redundant liquid; during the wave valley, the diaphragm buffer member 8 is restored to the original state to release the stored liquid, thereby achieving the effect of smooth pulsation.

The specific process is as follows:

as shown in fig. 8 and 9, when the diaphragm metering pump starts to operate, the liquid always flows to: enters from the liquid inlet 1, flows through the pulsating buffer device along the A-B-C-D-E and flows out from the liquid outlet 4.

When an eccentric cam of an eccentric wheel transmission device arranged on a motor shaft of the diaphragm urea metering pump moves to a lower dead point, a liquid suction port of a pump core of the diaphragm urea metering pump is closed, a liquid discharge port is opened, liquid in a pipeline flows backwards due to the influence of inertia and gravity, the liquid in the pulsation buffering device flows backwards along with the flow direction of E-D-C-B-A, the diaphragm buffering device 8 is impacted by the backwards flowing liquid and is compressed, the volume in the air chamber is reduced, the diaphragm buffering device 8 absorbs the redundant liquid, and the flow peak value is reduced.

When the eccentric cam of the eccentric wheel transmission device arranged on the motor shaft of the diaphragm urea metering pump moves to a top dead center, the liquid suction port in the pump core of the diaphragm urea metering pump is opened, the liquid discharge port is closed, the liquid in the liquid cavity is reduced at the moment, the diaphragm buffer piece 8 recovers the original state, the stored liquid is released, the liquid flow in the liquid inlet pipeline is supplemented, the flow valley value in the pipeline is increased, and therefore the smooth pulsation effect is achieved.

The pulsation buffering device can be used in a liquid conveying pipeline of a diaphragm metering pump of an integrated non-air-assisted metering pump, a split non-air-assisted metering pump and the like. In order to ensure the effectiveness of the use of the pulsation damper, when the pulsation damper is installed, a vibration material is added and reduced at the fixing position of the pulsation damper and the liquid conveying pipeline so as to absorb the vibration energy of the pulsation damper and prevent the generation of resonance vibration, and meanwhile, the air chamber of the pulsation damper is ensured to be communicated with the atmosphere.

The invention is characterized in that 2 independent chambers are respectively arranged in the pulsation buffering device, and a membrane buffering piece or a cap-shaped buffering piece is arranged between the 2 independent chambers, wherein one of the chambers is a liquid chamber and is connected in a liquid conveying pipeline, and the other air chamber is communicated with the atmosphere. As for the liquid chamber, the air chamber and the buffer member (the diaphragm buffer member or the cap buffer member) between them, no matter what shape and structure they are designed, they are equivalent technical solutions of the present invention, and of course, the embodiment of the present invention is specifically described by taking the diaphragm urea metering pump as an example, and the technical solution of the present invention can be adopted as long as there is liquid pulsation in the other liquid conveying pipes, and here, the claims describe the protection scope of the present invention, but the gist of the present invention is included, and any variation is within the protection scope of the present invention without departing from the spirit of the present invention.