CN202431344U

CN202431344U - Selective catalytic reduction (SCR) mixing device for preventing urea from becoming crystallized

Info

Publication number: CN202431344U
Application number: CN2012200589934U
Authority: CN
Inventors: 郝庆军
Original assignee: Suzhou Powergreen Emission Solution System Co Ltd
Current assignee: Suzhou Powergreen Emission Solution System Co Ltd
Priority date: 2012-02-23
Filing date: 2012-02-23
Publication date: 2012-09-12
Anticipated expiration: 2022-02-23

Abstract

The utility model discloses a selective catalytic reduction (SCR) mixing device for preventing urea from becoming crystallized, which comprises a mixing cavity and a throttling orifice. The mixing cavity is formed inside a pump body of a metering jet pump in an SCR system; the throttling orifice is arranged on the lateral wall of the mixing cavity; the mixing device also comprises a cylinder chamber formed on the pump body and a movable component arranged inside the cylinder chamber; a nozzle cleaner is formed at the tail end of the movable component and can be inserted into the throttling hole, and the movable component can seal the throttling hole. The SCR mixing device for preventing urea from becoming crystallized disclosed by the utility model has anti-blocking and sealing functions, and an atomized reducing agent is prevented from diffusing into the cylinder chamber to lead to crystallizing jam.

Description

The SCR mixing arrangement of anti-urea crystals

Technical field

The utility model relates to the throttle orifice sealing technique on the mixing chamber sidewall in a kind of SCR ejecting system, relates in particular to a kind of SCR mixing arrangement of anti-urea crystals.

Background technique

Along with Motor Vehicle " state IV ", " state V " emission standard in each big city and even national promotion and implementation; The SCR technology path is ripe gradually; Be about to reducing agent (32.5% aqueous solution of urea) through atomizing quantitative injection intake and exhaust pipeline, and pass through the SCR catalyzer the main harmful gas NO in the waste gas _XChange into the nitrogen G&W and discharge, reach the purpose of tail gas clean-up.

The SCR ejecting system is divided into no gas system and two kinds of gas systems is arranged, and wherein has the gas jet control system often before injection, in mixing chamber, to carry out premixing, and promptly high velocity air carries out gas-liquid mixed through throttle orifice on the mixing chamber sidewall and the reducing agent that is ejected in the mixing chamber; Good mixing effect provides jet pressure on the other hand on the one hand, yet; Because the throttle orifice diameter on the mixing chamber sidewall is less, stop up in order to prevent throttle orifice, the applicant has researched and developed the anti-blocking structure of a kind of cleansing pin, and (number of patent application is: 201120242990.1; Name of patent application is: the anti-block device of SCR ejecting system air throttle orifice), this structure can prevent effectively that through the cleansing pin motion throttle orifice from stopping up, but in the reality; Because the reducing agent after the atomizing is prone to diffusivity, the reducing agent in the mixing chamber still can spread, and at the throttle orifice intercrystalline; Even stretch to the cylinder chamber that anti-block device is installed; Long-term use can cause anti-block device to work, and throttle orifice blocks, and influences the ejecting system proper functioning.

The model utility content

The purpose of the utility model is to overcome the defective of existing technology, provide a kind of design ingenious, simple in structure, prevent the backflow a kind of SCR mixing arrangement of anti-urea crystals of crystallization of reducing agent, throttle orifice is played sealing function.

For realizing above-mentioned purpose; The utility model proposes following technological scheme: a kind of SCR mixing arrangement of anti-urea crystals; Comprise mixing chamber and throttle orifice, said mixing chamber is formed in the pump housing of metering jet pump in the SCR system, and said throttle orifice is arranged on the sidewall of mixing chamber; Said mixing arrangement also comprises cylinder chamber that is formed on the said pump housing and the movable component that is arranged at said cylinder chamber; Said movable component end is formed with cleansing pin, and said cleansing pin can insert in the said throttle orifice, and said movable component can seal said throttle orifice.

Said movable component forms a tapering near said cleansing pin position, and said tapering can form sealing with said throttle orifice.

Said movable component is divided into first chamber and second chamber with said cylinder chamber, is provided with the spring that joins with movable component in said first chamber, is provided with the compressed air inlet in said second chamber.

Said throttle orifice is communicated with the external high pressure source of the gas.

The flow passage structure that the said pump housing is formed in one.

The said pump housing is the flow passage structure by two aluminium sheet moulding.

Compared with prior art, the utility model not only has anti-blocking structure, also has the function of sealing, prevents that the reducing agent that atomizes from diffusing to cylinder chamber and causing crystallization to stop up.

Description of drawings

Fig. 1 is to use system's control graph of the utility model.

Fig. 2 is the schematic representation under the utility model movable component and the throttle orifice closed state.

Fig. 3 is the schematic representation of cleansing pin open mode behind the utility model feeding air-flow.

Fig. 4 is the partial structurtes schematic representation of throttle orifice and movable component tapering sealing in the utility model.

Embodiment

The accompanying drawing that will combine the utility model below carries out clear, complete description to the utility model embodiment's technological scheme.

As shown in Figure 1; Use the utility model to prevent that the SCR system of the SCR mixing arrangement of urea crystals generally comprises liquid tank 21, pumping installations 22, metering valve 23, mixing chamber 2 and the nozzle 24 of pipeline series connection successively; Pumping installations 22 is conveyed into metering valve 23 and mixing chamber 2 with reducing agent from liquid tank 21 successively; By nozzle 24 injection of reducing agent is injected again and carried out catalytic reduction reaction in the outlet pipe 25, reach the effect of tail gas clean-up.

Like Fig. 2, Fig. 3 and shown in Figure 4, said mixing chamber 2 is integrated in the pump housing 1 of metered injection pump, and the sidewall of mixing chamber 2 is provided with throttle orifice 3; Said throttle orifice 3 is communicated with the external high pressure source of the gas, and plays the effect of throttling, formation pressure, and said mixing chamber is used for reducing agent and mixes with air stirring; For preventing that said throttle orifice 3 is reduced agent and stops up; The pump housing 1 of metered injection pump is provided with cylinder chamber 4, is equiped with movable component 5 in the cylinder chamber 4, and movable component 5 can be in the cylinder chamber to-and-fro motion; The cleansing pin 51 that movable component 5 ends formation one can be inserted in the throttle orifice 3; In movable component to-and-fro motion process, movable component both can prevent the obstruction of throttle orifice, can play seal action to throttle orifice again.

Furtherly, said movable component 5 forms a tapering 52 near said cleansing pin 51 positions, and the position that said throttle orifice extends into said cylinder chamber 4 forms annular seal 31, and said tapering 52 can be resisted against said sealed department 31 and form sealing.

In the utility model specific embodiment; Said tapering and said sealed department can be soft materials such as rubber; Also can be hard materials such as metal, in this preferred embodiment, the said pump housing 1 be a metal material moulding; Said movable component 5 also is a metal material moulding, and said throttle orifice and said tapering form hard sealing.

Preferably; Said movable component 5 is divided into first chamber 41 and second chamber 42 with said cylinder chamber 4; Be provided with the spring 6 that joins with movable component in said first chamber 41, be provided with compressed air inlet 7 in said second chamber 42, said spring 6 one ends are against said movable component; The other end is resisted against on the pump housing, said air inlet 7 external compressed gas sources.

As shown in Figure 3; Along with pressurized air continues to be blown in second chamber 52 from said air inlet 7; The pressure that pressurized air produces can overcome the elastic force of said spring 6, promotes said movable component 5 and moves to the direction of said first chamber 41, from said throttle orifice 3, extracts in the process that said cleansing pin 51 moves along with said movable component 5; At this moment; Pressurized air then gets into the said mixing chamber 2 from said throttle orifice 3, and the reducing agent that ejects with the metering valve at mixing chamber 2 upper reaches fully mixes, and the reducing agent that ejects is atomized.

After closing source of the gas, as shown in Figure 2, there is not pressurized air to be blown in second chamber 42; Under the elastic force effect, spring can promote movable component and move to reset to second chamber 42, can insert in the throttle orifice 3 after said cleansing pin 51 resets; Can be resisted against said sealed department 31 after said tapering 52 resets, seal said throttle orifice 3 fully, at this moment; Both can prevent that residual reducing agent crystallization from stopping up throttle orifice 3, and can prevent again that the reducing agent diffusion from spreading to cylinder chamber to cause crystallization.

In the utility model specific embodiment, the said pump housing 1 can be one-body molded, also can be the flow passage structure of two aluminium sheet moulding.

Technology contents of the utility model and technical characteristics have disclosed as above; Yet those of ordinary skill in the art still maybe be based on the teaching of the utility model and announcements and are done all replacement and modifications that does not deviate from the utility model spirit, can be for the sealing means of other structures that cooperatively interact or to the cone structure improved procedure to the sealing of cylinder chamber like movable component.Therefore, the utility model protection domain should be not limited to the content that embodiment discloses, and should comprise various replacement and the modifications that do not deviate from the utility model, and is contained by the present patent application claim.

Claims

1. the SCR mixing arrangement of an anti-urea crystals; Comprise mixing chamber and throttle orifice; Said mixing chamber is formed in the pump housing of metering jet pump in the SCR system; Said throttle orifice is arranged on the sidewall of mixing chamber, and said mixing arrangement also comprises cylinder chamber that is formed on the said pump housing and the movable component that is arranged at said cylinder chamber, and said movable component end is formed with cleansing pin; It is characterized in that: said cleansing pin can insert in the said throttle orifice, and said movable component can seal said throttle orifice.

2. the SCR mixing arrangement of a kind of anti-urea crystals according to claim 1; It is characterized in that: said movable component forms a tapering near said cleansing pin position; The position that said throttle orifice extends into said cylinder chamber forms sealed department, and said tapering and said sealed department form and be sealed and matched.

3. the SCR mixing arrangement of a kind of anti-urea crystals according to claim 1 and 2; It is characterized in that: said movable component is divided into first chamber and second chamber with said cylinder chamber; Be provided with the spring that joins with movable component in said first chamber, be provided with the compressed air inlet in said second chamber.

4. the SCR mixing arrangement of a kind of anti-urea crystals according to claim 1 and 2, it is characterized in that: said throttle orifice is communicated with the external high pressure source of the gas.

5. the SCR mixing arrangement of a kind of anti-urea crystals according to claim 1 is characterized in that: the flow passage structure that the said pump housing is formed in one.

6. the SCR mixing arrangement of a kind of anti-urea crystals according to claim 1 is characterized in that: the said pump housing is the flow passage structure by two aluminium sheet moulding.