The unidirectional mixing arrangement of gas-liquid that is used for urea pump
Technical field
The utility model relates to a kind of urea pump, relates in particular to the unidirectional mixing arrangement of a kind of gas-liquid for urea pump.
Background technique
At present, serious pollution of atmosphere has been supervened in the fast development of Motor Vehicle, presents region composite type characteristics.Many metropolitan pollution of atmosphere turn to coal smoke and automotive composite type to pollute by coal-smoke pollution, and the minority megalopolis has obviously shown photochemical smog type (being the motor-vehicle tail-gas type) pollution of atmosphere.Therefore, the research of exhaust gas from diesel vehicle exhaust emission control technique and important and extremely urgent.
From the development of commercial car, diesel engine is its major impetus.Exhaust after treatment system in IV stage emission control mainly adopts SCR after-treatment system route.SCR(Selective Catalyst Reduction) refers to be installed in the diesel car vent systems, the NOx in the diesel emission is catalysed and reduced into N
2And O
2Catalytic reduction device, select aqueous solution of urea as reducing agent, aqueous solution of urea is ejected in the outlet pipe of catalyzer upstream, hydrolysis is produced as CO under the effect of exhaust gas temperature and air-flow
2And ammonia.The SCR after-treatment system is urea owing to what use.Urea crystalline polamer appears easily.More can produce crystallization when particularly urea mixes with gas.Cause the mixing chamber of mixing urea solution and gas, gateway or the nozzle of mixing chamber to be prone to obstruction, cause system normally to move.
The model utility content
The purpose of this utility model is to provide a kind of gas-liquid for urea pump unidirectional mixing arrangement, it can avoid the generation of mixing chamber, mixing chamber gateway and the crystallization of nozzle periphery urea liquid effectively, guarantee that the SCR after-treatment system normally moves, to solve the problem that exists when the urea pump gas-liquid is unidirectional in the prior art mixes.
For reaching this purpose, the utility model by the following technical solutions:
The unidirectional mixing arrangement of a kind of gas-liquid for urea pump, it comprises housing, offer mixing chamber in the described housing, one end of described mixing chamber is the gas access, the other end is mixture export, and offer the urea liquid entrance on the position corresponding to mixing chamber on the described housing, wherein, an end of offering the gas access on the described mixing chamber is provided with the one-way valve that seals with inner walls, described one-way valve comprises valve seat and piston, described piston seal is arranged on the valve seat, and described piston in mixing chamber and between the gas access place action of pressure lower edge valve seat move back and forth.
Especially, be provided with pressure adjusting spring between the valve seat of described one-way valve and the piston, regulate as required and order about the pressure size that piston moves.
Especially, described gas access, mixing chamber, mixture export and urea liquid entrance mix exposed to contact surface and all are processed into slick and sly flat configuration with urea, can prevent urea crystals.
Especially, the angle of described urea liquid entrance adopts any structure vertical or that tiltedly enter down.
Especially, be provided with the two seals circle between described valve seat and the housing at least and seal, described piston stretches between an end of mixing chamber and the valve seat and is provided with seal ring.
Especially, described seal ring is " O " RunddichtringO.
The beneficial effects of the utility model are, compared with prior art be provided with one-way valve in the mixing chamber of the described unidirectional mixing arrangement of gas-liquid for urea pump, when mixing chamber internal pressure during greater than the pressure of gas access end, the seal ring of one-way valve will seal piston, stop urea mixed solution to enter in the gas circuit, when the pressure of gas access end during greater than the pressure in the mixing chamber, the piston of one-way valve is opened, gas enters into mixing chamber, reaches the requirement that mixes with urea.Pass through the motion of the piston of one-way valve simultaneously, reach minimizing, remove the urea crystals effect that is deposited in the mixing chamber, to guarantee the normal operation of SCR after-treatment system.
Description of drawings
Fig. 1 is the structural representation of the unidirectional mixing arrangement of gas-liquid that is used for urea pump that provides of the utility model embodiment 1;
Fig. 2 is the structural representation of the unidirectional mixing arrangement of gas-liquid that is used for urea pump that provides of the utility model embodiment 2.
Embodiment
Further specify the technical solution of the utility model below in conjunction with accompanying drawing and by embodiment.
Embodiment one:
See also shown in Figure 1ly, Fig. 1 is the structural representation of the unidirectional mixing arrangement of gas-liquid that is used for urea pump that provides of the utility model embodiment 1.
In the present embodiment, the unidirectional mixing arrangement of a kind of gas-liquid for urea pump comprises housing 1, offer mixing chamber 2 in the described housing 1, one end of described mixing chamber 2 is gas access 3, the other end is mixture export 4, and offer urea liquid entrance 5 on the position corresponding to mixing chamber 2 on the described housing 1, described urea liquid entrance 5 adopts the structure that vertically enters mixing chamber 2, this structure makes the degree of gas-liquid mixed better, an end of offering gas access 3 on the described mixing chamber 2 is provided with the one-way valve 6 with housing 1 inner wall sealing, described one-way valve 6 comprises valve seat 7 and piston 8, described piston 8 is by " O " RunddichtringO 9 and valve seat 7 are tightly connected together, being provided with twice " O " RunddichtringO 9 between described valve seat 7 and the housing 1 seals, and be provided with pressure adjusting spring 10 between described valve seat 7 and the piston 8, regulate as required and order about the pressure size that piston 8 moves, described gas access 3, mixing chamber 2, slick and sly flat configuration all is processed on the surface that mixture export 4 and urea liquid entrance 5 contact with urea mixed solution.
Embodiment two:
See also shown in Figure 2ly, Fig. 2 is the structural representation of the unidirectional mixing arrangement of gas-liquid that is used for urea pump that provides of the utility model embodiment 2.
In the present embodiment, be that with embodiment one difference urea liquid entrance 5 enters the angle of mixing chamber 2, adopt the structure that tiltedly enters mixing chamber 2 down in this example, discharge is more smooth and easy this structure is mixed gas-liquid mixing chamber 2 in after.
During work, when mixing chamber 2 internal pressures during greater than the pressure of gas access 3 ends, the seal ring of one-way valve 6 will seal piston 8, stop urea mixed solution to enter in the gas circuit, when the pressure of gas access 3 ends during greater than the pressure in the mixing chamber 2, the piston 8 of one-way valve 6 is opened, and gas enters into mixing chamber 2, reach the requirement that mixes with urea, after mixing, discharged by mixture export 4.
In the mixing chamber of the above-mentioned unidirectional mixing arrangement of gas-liquid for urea pump one-way valve 6 is set, the motion of the piston 8 by one-way valve 6 reaches minimizing, removes the urea crystals effect that is deposited in the mixing chamber 2, to guarantee the normal operation of SCR after-treatment system.
Above embodiment has just set forth basic principle of the present utility model and characteristic; the utility model is not limited by above-mentioned example; under the prerequisite that does not break away from the utility model spirit and scope; the utility model also has various variations and change, and these variations and change all fall in claimed the utility model scope.The claimed scope of the utility model is defined by appending claims and equivalent thereof.