A kind of high pressure fuel pump of oil lubricating
Technical field
The utility model is related to internal combustion engine technologies field, more particularly to a kind of high pressure fuel pump of oil lubricating.
Background technology
More and more strict with the requirement of energy consumption and Abgasgesetz, compression ignition engine fuel injection system faces higher want
Ask.High pressure fuel pump faces higher challenge as pressure feed source in fuel injection system.It is mainly reflected in:Height supply
Pressure (design object pressure up to 2000bar and more than), (fuel feeding efficiency high, energy consumption is low, and compact conformation, space are accounted for for compact efficient
With small), high rotating speed (high pressure fuel pump can work under higher rotation speed, under stringent case rated speed up to 5000rpm and with
On), (product hermeticity is good, and wear out failure point danger is low, for the lubricity of fuel oil oil product, dust-laden, aqueous adaptation for high reliability
Property is good).
Using fuel oil lubrication, i.e. driving part (cam, roller, the roller of high-pressure oil pump more than current high pressure, express pump
Seat, tappet body, plunger tail etc.) the friction pair fuel oil that is supplied by its own lubricate.But due to the poor lubricity of fuel oil,
Under top load, high rotating speed, often there is drive mechanism friction pair wear out failure, and the requirement to fuel oil oil product is higher.
To break through the limitation of fuels lubricity, introduce engine lubrication machine oil and rubbed to lubricate the driving part of high-pressure oil pump
Wipe secondary, be also the fuel pump of oil lubricating.Because oil lubricating is good, the attached wear out failure of its drive mechanism lubricated friction is big
For reduction.But oil lubricating high pressure fuel pump can face new machine oil and blend problem with fuel oil simultaneously.Fuel oil, which enters machine oil, to be made
Into oil dilution, the lubricity of machine oil is drastically reduced;Machine oil, which enters fuel oil, can cause fuel injection system obstruction, coking, soot
Discharge increase.Especially for state five, the stage of state six, the emission request of particle is stricter, and the blending of machine oil and fuel oil needs sternly
Lattice are limited.Relatively reliable, effective measure for preventing machine oil and fuel oil from blending is needed to this oil lubricating pump.
As can be seen here, above-mentioned existing high pressure fuel pump is upper with using in structure, it is clear that still suffered from inconvenience and defect, and
Urgently it is further improved.A kind of high pressure fuel pump of new oil lubricating how is founded, need to be changed as current industry pole
The target entered.
Utility model content
The technical problems to be solved in the utility model is to provide a kind of high pressure fuel pump of oil lubricating, makes its lubricant effect
It is good, moreover it is possible to prevent machine oil fuel oil from blending, so as to overcome the shortcomings of existing high pressure fuel pump.
In order to solve the above technical problems, the utility model provides a kind of high pressure fuel pump of oil lubricating, including it is the pump housing, convex
Wheel shaft, actuator, one or more plunger pair, and the tappet body corresponding with the plunger pair, the plunger pair bag
Plunger mat and the plunger in the hole that sets within it are included, the camshaft is located in the middle part of the pump housing, and the actuator is arranged on institute
State and contacted with the tappet body bottom on the outside of camshaft, the plunger bushing is fixedly connected with the pump housing, the plunger base and
Plunger spring is provided between the tappet body boss face contact, plunger bushing and the tappet body, the bottom of the plunger spring is set
There is the plunger spring seat for plunger base to be held in the tappet body boss face, the tappet body and plunger are in the cam
Moved up and down in the presence of axle and plunger spring along the plunger bushing endoporus direction,
The high pressure fuel pump includes oil lubricating mechanism, and the oil lubricating mechanism includes being opened on the pump housing
Machine oil oil inlet pipe and machine oil flowline, and the pump housing groove being opened on the pump housing with the tappet body wall contacts, it is described
Machine oil oil inlet pipe is divided into two-way in the pump housing, and the first branch is connected with the pump housing machine oil chamber in the pump housing, the pump housing machine oil
Chamber is accommodates the cavity of the camshaft, and the second branch is connected with the pump housing groove, opened up on the lateral wall of the tappet body
There is the oil hole for connecting tappet body cavity, with moving up and down for the tappet body, between the oil hole and the pump housing groove
Have a rest connection, the tappet body cavity is connected with the pump housing machine oil chamber by drain path, the machine oil flowline and the pump housing
Machine oil chamber is connected.
As a kind of improvement of the present utility model, the oil-out vertical height of the machine oil flowline is higher than the camshaft
The vertical height at axle center, the drain path is opened on the tappet body or on the pump housing.
Further improve, the high pressure fuel pump also includes plunger seal mechanism, the plunger seal mechanism includes opening up
Counterbore in the plunger bushing bottom, and the seal ring assembly and jump ring being arranged in the counterbore, the jump ring is used for will
The seal ring assembly axial compression is in the counterbore.
Further improve, the seal ring assembly includes internal plastic seal ring and two exterior resilient seal circles, described
Annular protrusion is provided with the middle part of the outer wall of internal plastic seal ring, described two exterior resilient seal circles are respectively sleeved at the annular
Raised both sides, and the mating surface of the internal plastic seal ring and the plunger outer wall is provided with upper lip and lower lip.
Further improve, the internal plastic seal ring uses polytetrafluoroethylene (PTFE) or polytetrafluoroethylene (PTFE) filler material, institute
Exterior resilient seal circle is stated using fluorubber material.
Further improve, sealing ring pad is provided between the seal ring assembly and jump ring.
Further improve, be additionally provided with plunger bushing briquetting in the counterbore, the plunger bushing briquetting is arranged on the sealing ring
Between component and the counterbore top surface.
Further improve, on the inside of the end face that the plunger bushing briquetting is contacted with the counterbore top surface or in the counterbore top surface
Side offers the plunger bushing spill port for being further opened with being connected on ring-shaped step hole, the counterbore top surface with the ring-shaped step hole,
The plunger bushing spill port enters fuel oil oil duct with the pump housing on the plunger bushing and communicated.
Further improve, between the plunger bushing endoporus inwall and the plunger outer wall above the ring-shaped step hole are used
Gap is sealed, and the plunger bushing briquetting inwall below the ring-shaped step hole uses clearance seal, and institute with the plunger outer wall
The length for stating plunger bushing briquetting is more than the stroke up and down of the plunger, and the seal ring assembly is matched somebody with somebody with plunger outer wall sealing
Close.
Further improve, the gap between plunger bushing endoporus inwall and the plunger outer wall above the ring-shaped step hole
Width is 2 μm~5 μm, and the length of the clearance seal is more than 20mm.
Further improve, offer and offered on undercut groove, the plunger bushing and institute on the endoporus inwall of the plunger bushing
The connected plunger bushing spill port of undercut groove is stated, the plunger bushing spill port enters fuel oil oil duct phase with the pump housing on the plunger bushing
It is logical.
Further improve, the plunger bushing endoporus inwall above the undercut groove is close using gap with the plunger outer wall
In the plunger bushing endoporus inwall, the plunger bushing briquetting inwall and the seal ring assembly below envelope, the undercut groove
Wall is sealed with the plunger outer wall to be coordinated.
Further improve, when the high pressure fuel pump includes multiple plunger pairs and corresponding multiple tappet bodies, with
Connected between multiple pump housing grooves of the multiple tappet body wall contacts by groove intercommunicating pore.
Further improve, tappet body cavity connecting hole is provided between the tappet body cavity of the multiple tappet body.
Further improve, the high pressure fuel pump also includes pressure limiting valve module,
Offer the multiple machine oil oil ducts connected respectively with tappet body cavity on the pump housing, the multiple machine oil oil duct it is another
One end connects the entrance of the pressure limiting valve module respectively, and the outlet of the pressure limiting valve module is connected with the pump housing machine oil chamber.
Further improve, the actuator is roller, and it is recessed that the tappet body bottom is provided with the arc coordinated with the roller
Groove.
Further improve, the tappet body bottom outside is provided with step surface, and the step surface is interference fitted with bushing, described
Bushing is used to limit the roller axial float.
After such design, the utility model at least has advantages below:
1) the utility model is by setting oil lubricating mechanism, using the friction pair of the oil lubricating high pressure fuel pump, profit
Slip can be good, overcome that fuel oil lubricating pump is easy to wear, oil product requirement high, bad adaptability the shortcomings of, be adapted to high pressure, high rotating speed, tight
Gather efficient product demand.
2) intermittent communication when the utility model is moved up and down by pump housing groove and oil hole with tappet body, it is ensured that tappet
Machine oil is filled with body cavity, is that plunger base and tappet body boss face friction pair provide oil lubricating;Simultaneously by optimizing oil hole
Relative position along plunger axial direction of diameter, pump housing recess width and oil hole and pump housing groove, control suitable oil flow rate.
3) for the high pressure fuel pump of twin columns plug structure, the company between two tappet body cavitys is realized by tappet body intercommunicating pore
Logical, using pump, in the course of the work there is compression and the phase difference expanded in both sides tappet body cavity, and two tappets of balance are endoceliac
Engine oil pressure;Also it is connected by tappet body cavity with pressure limiting valve module, prevents that intracavitary engine oil pressure is too high, is reduced machine oil and enter combustion
The risk of oil;Elastoplasticity seal ring assembly is avoided to be failed because bearing too high engine oil pressure simultaneously.For single-column plug structure
High pressure fuel pump, opening up drain path is used to connect tappet body cavity and pump housing machine oil chamber, to balance the engine oil pressure in two chambers.
4) method of the utility model by taking segmented seal, and processing fuel flow returns hole and annular oil cavity, and will
Ring-like oil pocket enters fuel oil oil duct by fuel flow returns hole and pump and is connected, it can be ensured that plunger stage casing is in low-pressure state, drops significantly
Low disclosure risk of the fuel oil to machine oil side, also prevents lower seal structure from being failed because bearing too high fuel pressure, fabulous
The blending for limiting machine oil and fuel oil, applied to meet state five, the discharge of the stage particle of state six oil lubricating high pressure fuel
Pump.
5) plunger bushing spill port, plunger bushing stepped hole processing technology are simple in the utility model, and position adjustment is flexible.
6) the utility model also utilizes monoblock type tappet body structure, eliminates roller base member, roller directly with tappet body
Coordinate, assembly process process is improved, and use monoblock type tappet body structure, tappet body rigidity increase, structure arrangement is compacter.
Brief description of the drawings
Above-mentioned is only the general introduction of technical solutions of the utility model, in order to better understand technology hand of the present utility model
Section, below in conjunction with accompanying drawing, the utility model is described in further detail with embodiment.
Fig. 1 is the structural representation of the utility model high pressure fuel pump embodiment one.
Fig. 2 is the side sectional view of the utility model high pressure fuel pump embodiment one.
Fig. 3 is the structure sectional view of the utility model high pressure fuel pump embodiment one.
Fig. 4 is the middle pump body of the utility model high pressure fuel pump embodiment one connection arrangement sectional view.
Fig. 5 is the sectional view of seal ring assembly in the utility model high pressure fuel pump embodiment one.
Fig. 6 is the sectional view of plunger bushing embodiment one in the utility model high pressure fuel pump embodiment one.
Fig. 7 is the sectional view of plunger bushing embodiment two in the utility model high pressure fuel pump embodiment one.
Fig. 8 is the structure sectional view of tappet body in the utility model high pressure fuel pump embodiment one.
Fig. 9 is the structure sectional side view of tappet body in the utility model high pressure fuel pump embodiment one.
Figure 10 is pressure limiting valve module installation site and oil circuit in the pump housing in the utility model high pressure fuel pump embodiment one
Sectional view.
Figure 11 is the structural representation of the utility model high pressure fuel pump embodiment two.
Figure 12 is the side sectional view of the utility model high pressure fuel pump embodiment two.
Wherein, the pump housing 1, plunger bushing 2, plunger 3, tappet body 4, bushing 5, roller 6, camshaft 7, bearing shell 8, oil sucting valve 9, go out
Oil valve assembly 11, plunger spring 12, plunger bushing briquetting 13, elastoplasticity sealing ring coil assembly 14, sealing ring pad 15, jump ring 16,
Plunger spring seat 17, plug 19, plunger cavity 20, tappet body cavity 21, pump housing machine oil chamber 22, machine oil oil inlet pipe 23, machine oil flowline
24th, annular oil cavity 25, fuel oil oil inlet pipe 26, fuel oil return pipe 27, fuel metering valve module 28, pressure limiting valve module 29.
Embodiment
Embodiment one
Referring to the drawings shown in 1 to 10, the present embodiment high pressure fuel pump is the high pressure fuel pump of twin columns plug structure, including the pump housing
1st, camshaft 7, actuator, two plunger pairs, and the two tappet bodies 4 corresponding with two plunger pairs.The plunger pair bag
Plunger bushing 2 and the plunger 3 in the hole that sets within it are included, the camshaft 7 is located at the middle part of pump housing 1, and it is convex that the actuator is arranged on this
The outside of wheel shaft 7 is contacted with the bottom of tappet body 4, and the plunger bushing 2 is fixedly connected with the pump housing 1, the bottom of plunger 3 and the tappet body
4 boss face 4c are contacted, and plunger spring 12 are provided between the plunger bushing 2 and tappet body 4, the bottom of the plunger spring 12, which is provided with, to be used for
The bottom of plunger 3 is held in tappet body boss face 4c plunger spring seat 17, the tappet body 4 and plunger 3 are in the He of camshaft 7
Moved up and down in the presence of plunger spring 12 along the endoporus direction of plunger bushing 2.
The high pressure fuel pump includes oil lubricating mechanism, and the oil lubricating mechanism includes the machine oil being opened on the pump housing 1
Oil inlet pipe 23 and machine oil flowline 24, and the pump housing groove 1c being opened on the pump housing 1 with the wall contacts of tappet body 4.Should
Machine oil oil inlet pipe 23 is connected with engine oil pump, and the machine oil oil inlet pipe 23 is divided into two-way, first in the high pressure fuel pump pump housing 1
Branch 1d is connected with the pump housing machine oil chamber 22 in the pump housing 1, and the pump housing machine oil chamber 22 is accommodates the cavity of the camshaft 7, so
The machine oil being pressed into from first branch can be lubricated to the friction pair between high-pressure oil pump camshaft 7 and bearing shell 8, the combustion after lubrication
Oil is flowed back in pump housing machine oil chamber 22.Second branch is connected with pump housing groove 1c, and being offered on the lateral wall of the tappet body 4 is used for
Connect the oil hole 4b of tappet body cavity.In the high pressure fuel pump course of work, with moving up and down for the tappet body 4, the oil hole
4b and the pump housing groove 1c intermittent communications, can be filled with machine oil in tappet body cavity 21, it is ensured that plunger tail under the driving of machine oil hydraulic
Lubrication secondary with tappet body boss top surface 4c friction fits portion 3f.By adjusting oil hole 4b apertures and its with pump housing groove 1c's
Relative position, can control the oil flow rate flowed into.Certainly, two pump housing grooves in the high pressure fuel pump of the twin columns plug structure
Connected between 1c and 1c ' by groove intercommunicating pore 1e.
The machine oil flowline 24 is connected with the pump housing machine oil chamber 22.And the oil-out vertical height of the machine oil flowline 24 is high
Vertical height in the axle center of camshaft 7, to ensure the machine oil for having certain liquid level in pump housing machine oil chamber 22.In high pressure
In the fuel pump course of work, the reciprocating motion band oil for getting rid of oil, tappet body assembly is rotated with camshaft 7, makes the drive of high pressure fuel pump
The friction pair of dynamic component is placed in the environment of machine oil.
In order to reduce the engine oil pressure in tappet body cavity 21, drain path, this reality are opened up on tappet body 4 or on the pump housing 1
It is the draining through hole 4f being opened on tappet body 4 to apply example, as shown in Figure 9, can make pump housing machine oil chamber 22 and tappet body cavity 21 it
Between connect, the machine oil of the tappet body cavity 21 can be back in pump housing machine oil chamber 22.
Due also in high pressure fuel pump operation process, the reciprocating motion of the component high speed of tappet body 4, draining through hole 4f stream
Logical limited area, to prevent the machine oil in tappet body cavity 21 is compressed from producing too high instantaneous pressure, the height of the twin columns plug structure
Tappet body cavity intercommunicating pore 1f is opened up between two tappet body cavitys 21 of compression ignition oil pump, to connect tappet body cavity 21 and an other cylinder
Hold out the ' of body cavity 21, and using pump, tappet body cavity in both sides has compression and the phase difference expanded in the course of the work, balances both sides tappet
Endoceliac engine oil pressure.
Also for preventing the too high situation of the engine oil pressure in tappet body cavity 21 from occurring, reduce the wind that machine oil enters fuel oil
Danger, also opens up machine oil oil duct 1g, 1g of two tappet body cavitys of connection ', two machine oil oil ducts 1g, the 1g respectively on the pump housing 1 '
The two entrances of pressure limiting valve module 29 are connected respectively, and when the pressure of tappet body cavity 21 is higher than setting pressure limit, pressure limiting valve is opened
Open, machine oil is flowed back in pump housing machine oil chamber 22 through pressure limiting valve oil return oil duct 1i.
In order to prevent the blending of machine oil fuel oil in the high pressure fuel pump, the high pressure fuel pump also includes plunger seal mechanism.
Referring to the drawings shown in 2, the plunger seal mechanism includes being opened in the counterbore of the bottom of plunger bushing 2, and the counterbore includes counter bore side
2e and counterbore top surface 2f, processes plunger bushing spill port 2b and the ring-shaped step hole 2g communicated therewith, the ring on counterbore top surface 2f
Shape stepped hole 2g formation annular oil cavities 25, the plunger bushing spill port 2b enters fuel oil oil duct 2a with the pump housing on the plunger bushing 2 and communicated.
Certain ring-shaped step hole can be also opened on the inside of the end face of plunger bushing briquetting 13.Plunger bushing briquetting 13, post are pressed into counterbore
Plug sleeve briquetting outside wall surface 13b and counter bore side 2e crosses win assembling, and overall fine grinding plunger bushing endoporus 2d and plunger bushing after mounting
Briquetting endoporus 13a.Seal ring assembly 14, sealing ring pad 15 are pressed into pump assembling process in plunger bushing counterbore 2e, and passes through card
The axial compression of spring 16 realizes that seal assembly is fixed.
Wherein, referring to the drawings shown in 5, the seal ring assembly 14 includes inside plastic seal ring 14a and two outside elasticity
Annular protrusion is provided with the middle part of sealing ring 14b, the inside plastic seal ring 14a outer wall, 14b points of two exterior resilient seal circles
The annular protrusion both sides are not set in, and inside plastic seal ring 14a and the outer wall of plunger 3 mating surface are provided with upper lip
14c and lower lip 14d.Inside plastic seal ring 14a uses polytetrafluoroethylene (PTFE) or polytetrafluoroethylene (PTFE) filler material, outside this
Elastic seal ring 14b uses fluorubber material.
Referring to the drawings shown in 3, the high pressure fuel pump of the oil lubricating belongs to dynamic sealing, in the high pressure fuel pump course of work
In, plunger head 3a is contacted with high pressure fuel, and bottom 3f is contacted with machine oil;Pumped with plunger 3, fuel oil is easy with machine oil
Blend.The characteristics of for oil lubricating high pressure fuel pump, take the method for segmented seal to realize and avoid machine oil fuel oil from blending.
Concrete structure is as follows:
Plunger bushing endoporus inwall 2d and plunger outer wall epimere 3b above the ring-shaped step hole uses clearance seal, should
Gap width is 2 μm~5 μm, and to reduce the amount of leakage of high pressure fuel, the length of the clearance seal is more than 20mm.That is,
Amount of leakage of the high pressure fuel to low pressure can be reduced by controlling the fit clearance of male part and coupling seal length.This measure can
The pump oil efficiency of the fuel pump significantly improved, it is especially pronounced in the slow-speed of revolution, high rail pressure operating mode.On the upside of plunger stage casing at 3c, post
Ring-like oil pocket 25 is formed between plug sleeve 2 and plunger bushing briquetting 13, the ring-like oil pocket 25 passes through plunger bushing spill port 2b and pump oil-feed oil
Road 2a is connected, because the pressure in pump oil-feed oil duct 2a is relatively low (being less than 8bar), the fuel oil from the leakage of epimere gap is through ring-like oil
Chamber 25 is back to pump oil-feed oil duct 2a. again because plunger head fit clearance is longer, and the fuel oil amount of leakage through the mating surface is less,
The pressure of fuel pressure and pump oil-feed oil duct 2a in ring-like oil pocket 25 is close, and thereby guarantees that at the fuel oil in annular oil cavity 25
In low-pressure state.
The plunger bushing briquetting inwall below the ring-shaped step hole uses clearance seal with 3d on the downside of the plunger outer wall stage casing,
The fuel oil caused by the outside wall surface band oil of plunger 3 moves up and down can be preferably limited to blend with machine oil, and the plunger bushing briquetting
13 length is more than the stroke up and down of the plunger.The seal ring assembly 14 is sealed with plunger outer wall hypomere 3e to be coordinated, for preventing
Only machine oil is scurried into blends while limiting machine oil with fuel oil.
It is, of course, also possible to offer undercut groove 2i on the endoporus inwall of the plunger bushing 2, offered on the plunger bushing with being somebody's turn to do
On the plunger bushing spill port 2b ' that inclination connected undercut groove 2i is processed, the plunger bushing spill port 2b ' and the plunger bushing 2
The pump housing enters fuel oil oil duct 2a and communicated.During the structure, the plunger bushing endoporus inwall above undercut groove 2i is adopted with the plunger outer wall
With clearance seal, the endoporus inwall of plunger bushing 2, the inwall of plunger bushing briquetting 13 and the sealing ring group below undercut groove 2i
The inwall of part 14 is sealed with the outer wall of plunger 3 to be coordinated.
The course of work of high pressure fuel pump of said engine oil lubrication is:
The fuel oil in the connection oil transfer pump of fuel oil oil inlet pipe 26 downstream, fuel oil oil-out 2c connects oily rail, combustion by high-pressure oil pipe
The oily BOR Bunker of Redelivery oil return circuit of oil return pipe 27, fuel metering valve 28 connects control electric current signal, and machine oil oil inlet pipe 23 introduces engine machine
Lubricating oil after oil pump pressurization, machine oil flowline 24 connects engine sump tank, and the input engine driving of high-pressure oil pump camshaft 7 is turned round
Square drives camshaft 7 to rotate.
High-pressure oil pump oil suction stage, throttle orifice of the fuel oil through fuel metering valve 28 of oil transfer pump pressurization flows into plunger bushing oil-feed
Oil duct 2a, plunger spring 12 promotes plunger 3 descending, and the fuel pressure of plunger cavity 20 reduction, oil sucting valve 9 is opened, and fuel oil flows into post
Fill in chamber 20.
High-pressure oil pump presses oil the stage, and the rotation of camshaft 7 drives tappet body 4 and plunger 3 to be moved to top dead centre, and 3 pairs of plunger is right
Fuel oil compression in plunger cavity 20, fuel pressure is increased to after a threshold value, promotes oil outlet valve component 11 to open, high pressure fuel by
Oil-out 2c feeds oily rail.
Embodiment two
Referring to the drawings shown in 11 and 12, the present embodiment high pressure fuel pump is the high pressure fuel pump of single-column plug structure, its with it is upper
Stating the difference of embodiment one to be, only one of which plunger pair and a tappet body, two are connected during without setting above-mentioned twin columns plug structure
Passage between individual pump housing groove, two tappet body cavitys, need to only open up drain path 1h connection tappets body cavity 21 and pump housing machine oil
Chamber 22, to balance the engine oil pressure in two chambers.Remainder is identical with above-described embodiment one, no longer goes to live in the household of one's in-laws on getting married herein
State.
Certainly, the high pressure fuel pump of the oil lubricating can also be three and above plunger pair, its structure and embodiment one
Plant twin columns plug structure similar.
In addition, using monoblock type tappet body in the utility model, the monoblock type tappet body integrated driving part and tappet body are
One.Referring to the drawings shown in 8 and 9, concrete structure is:Actuator is roller 6, and the bottom of tappet body 4 is provided with and the roller appearance
The arc groove 4d that face 6a coordinates.The bottom outside of tappet body 4 is additionally provided with step surface 4e, step surface 4e and sleeve inner surface 5a
Interference fit, for limiting the axial float of roller 6.
The utility model lubricates the main friction pairs of the driving part of high pressure fuel pump, lubricant effect using engine motor oil
Good, the shortcomings of overcoming fuel oil lubricating pump easy to wear, oil product requirement height, bad adaptability is adapted to high pressure, high rotating speed, compact height
The product demand of effect.
The utility model is integrated with roller with the function of tappet body in one using monoblock type tappet body structure, improves dress
With manufacturability;Also for preventing the blending of machine oil and fuel oil, using the method for segmented seal, to the leakage between machine oil and fuel oil with
Gradual control is taken in blending.The high pressure fuel pump of the utility model oil lubricating is satisfied with high pressure, high rotating speed, compact efficient, height
The product demand of discharge index.
It is described above, only it is preferred embodiment of the present utility model, not makees any formal to the utility model
Limitation, those skilled in the art make a little simple modification, equivalent variations or modification using the technology contents of the disclosure above,
Fall in protection domain of the present utility model.