Disclosure of Invention
In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a flow rate pressure control valve.
In order to achieve the purpose, the invention adopts the following technical scheme:
a flow pressure controlled valve comprising:
the peripheral wall of the preceding stage draft tube is provided with a preceding stage fluid outlet, and a preceding stage flow channel is formed between the preceding stage fluid outlet and a head-end tube orifice of the preceding stage draft tube;
the rear-stage flow guide pipe is provided with a rear-stage fluid outlet on the peripheral wall, a pipe orifice at the head end of the rear-stage flow guide pipe is communicated with the front-stage fluid outlet, and a rear-stage flow passage is formed between the rear-stage fluid outlet and the front-stage fluid outlet;
the front-stage elastic valve plug is arranged in the front-stage flow guide pipe from a tail pipe orifice of the front-stage flow guide pipe, and elastically contracts along the axial direction of the front-stage flow guide pipe under the action of fluid pressure to conduct a front-stage flow channel;
and
a back level elasticity valve plug, back level elasticity valve plug is installed in the back level water conservancy diversion pipe by the tail end mouth of pipe of back level honeycomb duct, just back level elasticity valve plug makes the elastic shrinkage motion in order to cut off back level runner along the axial direction of back level honeycomb duct under the effect of fluid pressure.
Preferably, the preceding stage elastic valve plug includes a preceding stage limiting hollow plate which is arranged in the preceding stage flow guide pipe and located at the upstream side of the preceding stage fluid outlet, a preceding stage pipe orifice sealing plug which is inserted in the preceding stage flow guide pipe by a tail end pipe orifice of the preceding stage flow guide pipe and located at the downstream side of the preceding stage fluid outlet, a preceding stage stroke shaft hole which is arranged in the preceding stage pipe orifice sealing plug by the head end side of the preceding stage pipe orifice sealing plug along the axial direction of the preceding stage flow guide pipe, a preceding stage valve plug plate which is overlapped and covers on the downstream side surface of the preceding stage limiting hollow plate, a preceding stage guide valve rod which is inserted in the preceding stage stroke shaft hole in a sliding manner by the tail end part and is connected with the preceding stage valve plug plate into a whole, and a preceding stage pressure limiting spring which is arranged on the guide valve rod by the preceding stage and has.
Preferably, the front valve plug plate comprises a sealing plate which is stacked and covers the surface of the downstream side of the front spacing hollow plate, a guide plate which is coaxially distributed with the sealing plate and the peripheral wall of which is attached to the inner wall of the front guide pipe, a connecting column which is arranged between the sealing plate and the guide plate and connects the sealing plate and the guide plate into a whole, and a rubber sleeve which is coated on the sealing plate, wherein the head end of the front guide valve rod is connected with the guide plate into a whole and coaxially distributed with the connecting column.
Preferably, the preceding stage elastic valve plug comprises a preceding stage pressure limiting spring, a preceding stage pipe orifice sealing plug which is inserted into the preceding stage flow guide pipe from the tail end pipe orifice of the preceding stage flow guide pipe and is positioned at the downstream side of the preceding stage fluid outlet, a preceding stage stroke shaft hole which is opened in the preceding stage pipe orifice sealing plug from the head end side of the preceding stage pipe orifice sealing plug along the axial direction of the preceding stage flow guide pipe, a preceding stage valve plug plate of which the outer peripheral wall is attached to the inner pipe wall of the preceding stage flow guide pipe, and a preceding stage guide valve rod of which the tail end is inserted into the preceding stage stroke shaft hole in a sliding manner, a first limit ring is formed on the inner peripheral wall of the preceding stage stroke shaft hole, a second limit ring used for abutting against the first limit ring is formed on the outer peripheral wall of the tail end of the preceding stage guide valve rod, the fore-stage pressure limiting spring is arranged in the fore-stage stroke shaft hole and clamped between the tail end face of the fore-stage guide valve rod and the tail end face of the fore-stage stroke shaft hole.
Preferably, the backing stage pipe orifice sealing plug comprises a sealing plug column inserted in the tail end of the backing stage draft tube and provided with a backing stage stroke shaft hole, a spring pre-tightening seat arranged in the tail end of the backing stage stroke shaft hole and in axial linear sliding connection with the sealing plug column, and a backing stage adjusting knob with an axial cross-section in a shape similar to a T shape, wherein the transverse part of the backing stage adjusting knob is overlapped on the tail end face of the sealing plug column, the longitudinal part of the backing stage adjusting knob penetrates through the tail end of the sealing plug column and then is in threaded insertion connection with the spring pre-tightening seat, and the tail end of the backing stage pressure limiting spring abuts against the head end face of the spring pre-tightening seat.
Preferably, the rear-stage elastic valve plug comprises a rear-stage orifice sealing plug which is inserted and sleeved in the rear-stage flow guide pipe from a tail-end orifice of the rear-stage flow guide pipe and a main body of which is positioned at the downstream side of the rear-stage fluid outlet, a rear-stage limiting hollow plate which is arranged in the rear-stage flow guide pipe and positioned at the upstream side of the rear-stage fluid outlet, a rear-stage guide valve rod which penetrates through the rear-stage limiting hollow plate and is distributed, and the tail end of the rear-stage guide valve rod is coaxially connected with the rear-stage orifice sealing plug, a rear-stage valve plate which is slidably sleeved on the rear-stage guide valve rod and is positioned at the upstream side of the rear-stage limiting hollow plate, and a rear-stage pressure limiting spring which is sleeved on the rear-stage guide valve rod, the head end of which is abutted against the rear-stage orifice sealing plug, and the tail end of.
Preferably, the rear-stage valve plug plate is of a spherical structure, the rear-stage limiting hollow-out plate is of an annular plate-shaped or columnar structure, and the upstream side surface of the rear-stage limiting hollow-out plate is provided with a clamping ball groove for the rear-stage valve plug plate to be in counterpoint embedding.
Preferably, a plurality of guide grooves distributed along the axial direction of the rear-stage guide pipe are formed in the upstream area of the rear-stage limiting hollow plate on the inner pipe wall of the rear-stage guide pipe.
Preferably, the rear-stage pipe orifice sealing plug comprises a stroke guide sleeve with an outer diameter smaller than the inner diameter of the rear-stage flow guide pipe and a head end positioned at the downstream side of the rear-stage limiting hollow plate, a sealing sleeve cover which is covered on a tail end pipe orifice of the rear-stage flow guide pipe and is integrally formed with the stroke guide sleeve, and a rear-stage adjusting knob which has an axial section in a similar T shape, a longitudinal part which penetrates through the sealing sleeve cover and is coaxially inserted into the stroke guide sleeve and a transverse part which is overlapped on the outer end surface of the sealing sleeve cover;
the rear-stage guide valve rod comprises a main rod portion, a limiting end cap, a guide post and a threaded sleeve, wherein the main rod portion penetrates through the distribution of the rear-stage limiting hollow plate, the limiting end cap is arranged at the head end of the main rod portion and used for supporting the rear-stage valve plug plate, the threaded sleeve is formed at the tail end of the main rod portion and is in coaxial linear sliding connection with the stroke guide sleeve, the threaded sleeve is axially extended from the contour edge of the tail end face of the guide post and is in threaded connection with the longitudinal portion of the rear-stage adjusting knob, the rear-stage pressure limiting spring is sleeved on the main rod portion, and the head end of the rear-stage pressure limiting spring is abutted to the rear-stage valve plug plate and the head end of the.
By adopting the scheme, the two-stage flow channel opening and closing control unit is formed in the valve body by utilizing the front-stage elastic valve plug and the rear-stage elastic valve plug, so that the valve body can be automatically opened and closed and the opening degree of the valve body can be adjusted within a preset pressure range according to the change of fluid pressure, the problems that the application range of the valve is limited, the operation is complicated, the fluid flow cannot be effectively controlled and the like due to manual opening and closing adjustment of the traditional pipeline valve are effectively avoided, or the problems that the manufacturing and using cost of the valve is overhigh, the arrangement of a pipeline system is complicated, the management and maintenance difficulty is high and the like due to hydraulic and electromagnetic driving opening and closing adjustment of the traditional pipeline valve are solved, and conditions are created for the application.
Detailed Description
The embodiments of the invention will be described in detail below with reference to the drawings, but the invention can be implemented in many different ways as defined and covered by the claims.
As shown in fig. 1 to 9, the present embodiment provides a flow rate pressure control valve including:
a foreline draft tube 10, mainly used for connecting with the pipeline for conveying gaseous or liquid fluid medium such as water, gas, etc. for the input of the fluid medium, and its peripheral wall is provided with a foreline fluid outlet 11 (its specific structure can be in the form of tube hole or tube body, etc.), a foreline flow channel a is formed between the foreline fluid outlet 11 and the head end nozzle of the foreline draft tube 10;
a rear-stage draft tube 20, mainly used for connecting with a fluid output device such as a spray head for outputting fluid medium, the peripheral wall of which is provided with a rear-stage fluid outlet 21 (the specific structure and construction of which can exist in the form of pipe hole or pipe body, etc.), the head-end nozzle of the rear-stage draft tube 20 is communicated with the front-stage fluid outlet 11 (the two can be in butt joint communication by adopting the modes such as threaded sleeve, snap-fit, hoop fastening, etc. according to the actual situation; of course, in order to ensure the sealing performance of the connection area between the two to prevent fluid leakage or negative influence on the pressure control effect of the whole valve body, accessories such as a sealing gasket, etc. can be arranged between the two, and a rear-stage flow passage b is formed between the rear-stage fluid outlet 21 and the front-stage;
a preceding stage elastic valve plug 30, mainly playing the role of conducting the preceding stage flow channel a by elastic contraction movement along the axial direction of the preceding stage draft tube 10 under the action of fluid pressure, and installed in the preceding stage draft tube 10 from the tail end nozzle of the preceding stage draft tube 10;
and
a rear stage elastic valve plug 40, which mainly plays the role of elastic contraction movement along the axial direction of the rear stage draft tube 20 under the action of fluid pressure to separate the rear stage flow channel b, and is installed in the rear stage draft tube 20 by the tail end pipe orifice of the rear stage draft tube 20.
Therefore, by utilizing the elastic expansion effect of the front-stage elastic valve plug 30 in the front-stage draft tube 10 and the elastic expansion effect of the rear-stage elastic valve plug 40 in the rear-stage draft tube 20, the whole valve body forms at least two stages of units capable of controlling the opening and closing of the fluid flow channel under the action of fluid pressure in the flowing direction of the fluid medium, and through the selection or presetting of the specific elasticity or elasticity modulus of the front-stage elastic valve plug 30 and the rear-stage elastic valve plug 40, the valve body can be automatically opened and closed only in a preset pressure range to form a complete fluid flow channel, so that conditions are created for automatic opening and closing of the valve body and water saving application and the like, and the problems that the application range of the valve is limited, the operation is complicated, the fluid flow cannot be effectively controlled and the like easily caused by manual opening and closing or opening adjustment of the traditional pipeline valve are, or the driving type opening and closing or opening degree adjustment of hydraulic pressure, electromagnetism and the like is adopted, so that the problems that the valve manufacturing and using cost is too high, the pipeline system is complex in arrangement, the management and maintenance difficulty is large and the like are easily caused.
Taking the application of the pressure control valve of the present embodiment to the agricultural drip irrigation technology as an example, the pressure-bearing capacity of the front stage elastic valve plug 30 and the rear stage elastic valve plug 40 when they are elastically deformed (which can also be understood as an elastic modulus, for example, the elastic modulus of the front stage elastic valve plug 30 is preset to 3Mpa (i.e., an upper limit pressure threshold) and the elastic modulus of the rear stage elastic valve plug 40 is preset to 2Mpa (i.e., a lower limit pressure threshold)) can be pre-selected or set according to the actual situation or the drip irrigation water quantity requirement of the drip irrigation system, when the pressure of the fluid conveyed through the pipeline of the drip irrigation system is greater than the upper limit pressure threshold, the front stage elastic valve plug 30 conducts the front stage flow channel a due to the compression and contraction, so that the water flows into the rear stage flow channel b through the front stage flow channel a (conversely, when the pressure is less than the upper limit pressure, when the fluid pressure in the rear-stage fluid flow channel b is smaller than the lower limit pressure threshold, the rear-stage elastic valve plug 40 is elastically contracted due to insufficient fluid pressure, so that the rear-stage fluid flow channel b is always in a conducting state, and the fluid is output from the rear-stage fluid outlet 21 (such as being finally sprayed out from a drip irrigation spray head); on the contrary, when the fluid pressure in the rear-stage fluid flow passage b is greater than the lower threshold, the rear-stage elastic valve plug 40 is compressed to block the rear-stage fluid flow passage b, thereby preventing the fluid from being output. In summary, the entire pressure-controlled valve is fully opened only when the fluid pressure is in the range of "the front stage is greater than the upper limit pressure threshold value and the rear stage is smaller than the lower limit pressure threshold value". Based on this, when being applied to a plurality of pressure-controlled valves such as the agricultural field of driping irrigation, because the water pressure of the main pipeline of driping irrigation is certain, through the selection or the presetting of the bearing capacity to the two-stage sealing valve plug in front and back of every valve body, can be convenient for rationally distribute corresponding discharge according to characteristics such as the water demand of different crops to reach functions such as water conservation, flow evenly distributed, automatic start-stop, aperture automatically regulated.
In order to more reasonably utilize the tube space of the preceding stage draft tube 10 and ensure the switching effect of the preceding stage elastic valve plug 30 on the opening and closing of the preceding stage flow channel a, the preceding stage elastic valve plug 30 of the embodiment can preferably adopt the following two structural configurations according to practical situations, specifically:
1. as shown in fig. 2 to 6, the preceding stage elastic valve plug 30 includes a preceding stage limiting hollow plate 31 (which may be made of a plate structure such as a grid, a mesh, or a hollow structure according to practical circumstances) disposed in the preceding stage draft tube 10 and located on the upstream side of the preceding stage fluid outlet 11, a preceding stage nozzle sealing plug 32 (which mainly serves to seal the trailing end nozzle of the preceding stage draft tube 10 and form the preceding stage draft tube 10 into a single-port tube structure in the axial direction) inserted into the preceding stage draft tube 10 from the trailing end nozzle of the preceding stage draft tube 10 and located on the downstream side of the preceding stage fluid outlet 11, a preceding stage stroke shaft hole c formed in the preceding stage nozzle sealing plug 32 from the leading end side of the preceding stage nozzle sealing plug 32 in the axial direction of the preceding stage draft tube 10, a preceding stage valve plug plate 33 (which mainly serves to seal the upstream side limiting hollow plate 31) stacked and covering the downstream side surface of the preceding stage, A preceding stage guide valve rod 34 with its tail end inserted into the preceding stage travel shaft hole c in a sliding manner and its head end connected with the preceding stage valve plug plate 33 into a whole, and a preceding stage pressure limiting spring 35 set on the guide valve rod 34 with its head end abutting against the preceding stage valve plug plate 33 and its tail end abutting against the tail end face of the preceding stage travel shaft hole c.
Therefore, the front-stage nozzle sealing plug 32 can be used for not only plugging the tail-end nozzle of the front-stage draft tube 10, but also providing structural assembly space for other components; when the fluid pressure is greater than the upper limit pressure threshold, the front stage pressure limiting spring 35 is axially compressed and stored energy due to the pressure of the fluid acting on the front stage valve plug plate 33, and is separated from the front stage limiting hollow-out plate 31, so that the front stage flow channel a is conducted; on the contrary, the front stage pressure limiting spring 35 is in a normal state or returns to the original state, so as to tightly abut the front stage sealing valve plug 33 against the downstream side surface of the front stage limiting hollow plate 31, thereby realizing the cutoff of the front stage runner a; in this process, the fluid pressure is in a range larger than the upper limit pressure threshold due to the influence of the displacement stroke of the preceding stage valve plug plate 33 in the axial direction, and the different fluid pressures affect the opening degree of the preceding stage flow path a until the preceding stage valve plug plate 33 abuts against the head end face of the preceding stage nozzle sealing plug 32.
On this basis, in order to ensure the sealing effect of the preceding stage valve plug plate 33 on the preceding stage limiting hollow plate 31, the preceding stage valve plug plate 33 of the present embodiment includes a sealing plate 33-1 stacked and covering the downstream side surface of the preceding stage limiting hollow plate 31, a guide plate 33-2 coaxially disposed with the sealing plate 33-1 and having a peripheral wall attached to the inner wall of the preceding stage draft tube 10, a joining column 33-3 disposed between the sealing plate 33-1 and the guide plate 33-2 and connecting the sealing plate 33-1 and the guide plate 33-2 to one body, and a rubber sleeve 33-4 covering the sealing plate 33-1, and the leading end of the preceding stage guide valve stem 34 is integrally connected with the guide plate 33-2 and coaxially disposed with the joining column 33-3. Therefore, the preceding stage guide valve rod 34 and the preceding stage valve plate 33 together form a structural body with a dry-like axial cross section, the structural relationship between the guide plate 33-2 and the preceding stage draft tube 10 ensures that the preceding stage guide valve rod 34 and the preceding stage valve plate 33 can smoothly perform linear reciprocating operation along the axial direction of the preceding stage draft tube 10, and the rubber sleeve 33-4 is used as a consumable part for plugging the preceding stage limiting hollow plate 31.
2. As shown in fig. 7 to 9, the preceding stage elastic valve plug 30 includes a preceding stage pressure limiting spring 35, a preceding stage pipe orifice sealing plug 32 inserted into the preceding stage draft tube 10 from the tail end pipe orifice of the preceding stage draft tube 10 and located at the downstream side of the preceding stage fluid outlet 11, a preceding stage stroke shaft hole c opened in the preceding stage pipe orifice sealing plug 32 from the head end side of the preceding stage pipe orifice sealing plug 32 along the axial direction of the preceding stage draft tube 10, a preceding stage valve plug plate 33 having an outer peripheral wall attached to the inner wall of the preceding stage draft tube 10, and a preceding stage guide valve stem 34 having a tail end portion slidably inserted into the preceding stage stroke shaft hole c and a head end integrally connected to the preceding stage valve plug plate 33; a first stopper ring 36 is formed on the inner peripheral wall of the previous stage stroke shaft hole c, and correspondingly, a second stopper ring 37 is formed on the outer peripheral wall of the tail end of the previous stage guide valve rod 34 to abut against the first stopper ring 36, and the previous stage pressure limiting spring 35 is disposed in the previous stage stroke shaft hole c and is held between the tail end face of the previous stage guide valve rod 34 and the tail end face of the previous stage stroke shaft hole c. Therefore, by utilizing the characteristic that the preceding valve plug plate 33 is attached to the inner wall of the preceding stage draft tube 10 (of course, to ensure the sealing performance, the preceding valve plug plate 33 may be made of a flexible material such as rubber or silica gel or directly sleeved with a consumable part such as the aforementioned rubber sleeve 33-4), the isolation and the blocking of the tube body space of the preceding stage draft tube 10 can be directly realized to conduct or cut off the preceding stage flow channel a; by utilizing the matching relationship between the first limit ring 36 and the second limit ring 37, a structural space for the fore-stage pressure-limiting spring 35 to perform telescopic motion can be formed in the fore-stage travel shaft hole c, so that the spring can be effectively prevented from being corroded by fluid to influence the elastic effect of the spring. In addition, the front stage valve plate 33 can also be selectively disposed by referring to the aforementioned structural form and configured with the corresponding front stage limiting hollow plate 31.
Based on the two preferable configurations of the preceding stage elastic valve plug 30, in order to adjust the pressure-bearing capacity thereof at the right time, so that the whole valve body can be suitable for different pipeline pressures, the preceding stage pipe orifice sealing plug 32 of the present embodiment includes a sealing plug 32-1 inserted into the rear end portion of the preceding stage draft tube 10 and provided with a preceding stage stroke shaft hole c, a spring pre-tightening seat 32-2 disposed in the rear end portion of the preceding stage stroke shaft hole c and axially and linearly slidably connected to the sealing plug 32-1 (e.g., by means of a rail groove or other structure disposed on the inner peripheral wall of the preceding stage stroke shaft hole c in the axial direction, it is ensured that the spring pre-tightening seat 32-2 can only linearly slide but cannot relatively rotate), and a preceding stage adjusting knob 32-3 having a similar T-shaped axial cross-section; wherein, the horizontal part of the fore stage adjusting knob 32-3 is overlapped on the tail end face of the sealing plug column 32-1, the longitudinal part penetrates through the tail end of the sealing plug column 32-1 and then is in threaded insertion sleeve connection with the spring pre-tightening seat 32-2, and the tail end of the fore stage pressure limiting spring 35 is abutted against the head end face of the spring pre-tightening seat 32-2. Thus, by utilizing the threaded connection between the backing stage adjustment knob 32-3 and the spring pre-tightening seat 32-2 and the linear sliding connection of the spring pre-tightening seat 32-2 in the backing stage travel shaft hole c, the operator or user can adjust the position of the spring pre-tightening seat 32-2 in the backing stage travel shaft hole c by selectively tightening the backing stage adjustment knob 32-3, thereby adjusting the magnitude of the pressure-bearing capacity of the entire valve plug (i.e., adjusting the aforementioned upper limit pressure threshold) by changing the axial extent of the backing stage pressure-limiting spring 35. In addition, in order to ensure the structural stability between the backing tube opening sealing plug 32 and the backing tube 10 and create favorable structural conditions for the disassembly and assembly and maintenance of the relevant components, a lug structure (not shown) capable of abutting against the backing tube opening of the backing tube 10 may be provided or formed on the rear end face of the sealing plug 32-1 so as to be firmly and removably assembled into a whole by using components such as screws, clips, and the like. Of course, a seal fitting such as a gasket may be provided between both.
In order to optimize the structure of the whole valve body to the maximum extent and improve the practical performance, as shown in figures 2 to 9, the rear-stage elastic valve plug 40 of the present embodiment includes a rear-stage orifice sealing plug 41 inserted into the rear-stage draft tube 20 from the rear-stage orifice of the rear-stage draft tube 20 and having a main body located at the downstream side of the rear-stage fluid outlet 21, a rear-stage limiting hollow plate 42 disposed in the rear-stage draft tube 20 and located at the upstream side of the rear-stage fluid outlet 21, a rear-stage guide valve rod 43 extending through the rear-stage limiting hollow plate 42 and having a rear end coaxially connected to the rear-stage orifice sealing plug 41, a rear-stage valve plug plate 44 slidably disposed on the rear-stage guide valve rod 43 and located at the upstream side of the rear-stage limiting hollow plate 42, and a rear-stage pressure limiting spring 45 disposed on the rear-stage guide valve rod 43 and having a front end abutting against the rear-stage valve plug plate 44 and a rear end abutting against the front end face of the rear-stage orifice 41 sealing plug or connected to the rear end of the rear-stage guide valve rod 43. Thus, by utilizing the sliding connection relationship between the rear stage valve plate 42 and the rear stage guide valve rod 43 and the arrangement relationship thereof on the upstream side of the rear stage limiting hollow plate 42, when the fluid pressure entering the rear-stage flow passage b is smaller than the lower limit pressure threshold, the rear-stage pressure limiting spring 45 is in a normal state, once the fluid pressure is larger than the lower limit pressure threshold and gradually increases, the rear-stage valve plug plate 44 forms a compression force to the rear-stage pressure limiting spring 45 due to the compression, and gradually axially moves towards the direction of the rear-stage orifice sealing plug 41 and finally plugs the rear-stage limiting hollowed-out plate 42, so as to cut off the rear-stage flow passage a (certainly, in the process of forming the function action, the outer diameter of the rear-stage valve plug plate 44 needs to be ensured to be smaller than the pipe diameter of the rear-stage draft tube 20 on the upstream side of the rear-stage limiting hollowed-out plate 42 and larger than the aperture of the rear-stage limiting hollowed-out plate 42).
On this basis, the rear stage valve plug plate 44 of the present embodiment may adopt a plate-shaped structure similar to that adopted by the front stage valve plug plate 33, and the rear stage limiting hollow-out plate 42 may also adopt a structural form similar to that of the front stage limiting hollow-out plate 31; however, as a preferable scheme, in order to fully utilize the structural space of the entire valve body and enhance the structural compactness of the valve body, the rear-stage valve plug plate 44 of the present embodiment is preferably a spherical structure having a diameter smaller than the inner diameter of the pipe at the head end of the rear-stage draft tube 20, accordingly, the rear-stage limiting hollow plate 42 is an annular plate-shaped or columnar structure, and a position-clamping ball groove (not labeled in the figure) for the rear-stage valve plug plate 44 to be aligned and embedded is formed on the upstream side surface of the rear-stage limiting hollow plate 42. Therefore, by utilizing the structural form of the rear-stage valve plate 44 and the alignment relation between the rear-stage valve plate and the clamping ball groove, the blocking effect on the rear-stage limiting hollow-out plate 42 can be effectively ensured.
In order to ensure that the fluid can smoothly flow in the rear stage flow passage b when the rear stage elastic valve plug 40 is in an open state, a plurality of guide grooves 22 distributed along the axial direction of the rear stage flow guide pipe 20 are formed in an area on the inner pipe wall of the rear stage flow guide pipe 20 and located on the upstream side of the rear stage limiting hollow-out plate 42.
Based on the principle that the pressure-bearing capacity of the preceding elastic valve plug 30 is adjustable, the following-stage orifice sealing plug 41 of the present embodiment includes a stroke guide sleeve 41-1 having an outer diameter smaller than the inner diameter of the following-stage draft tube 20 and a head end portion located at the downstream side of the following-stage limiting hollow plate 42, a sealing sleeve cap 41-2 (which can be assembled with the following-stage draft tube 20 by using a member such as a screw or a clip, and a sealing fitting such as a sealing gasket can be provided therebetween) covering the tail end orifice of the following-stage draft tube 20 and integrally formed with the stroke guide sleeve 41-1, and an axial cross-sectional shape which is similar to a "T" shape and has a longitudinal portion passing through the sealing sleeve cap 41-2 and coaxially inserted into the stroke guide sleeve 41-1, a rear-stage adjusting knob 41-3 with a transverse part overlapped on the outer end face of the sealing sleeve cover 41-2; the rear stage guide valve rod 43 comprises a main rod part 43-1 distributed through the rear stage limiting hollow plate 42, a limiting end cap 43-2 arranged at the head end of the main rod part 43-1 for the rear stage valve plug plate 44 to abut against, a guide post 43-3 formed at the tail end of the main rod part 43-2 and coaxially and linearly slidably connected with the stroke guide sleeve 41-1 (for example, a rail groove and other structures arranged on the inner peripheral wall of the stroke guide sleeve 41-1 along the axial direction can ensure that the rear stage guide valve rod 43 can only linearly slide but can not relatively rotate), and a threaded sleeve 43-4 formed by axially extending the contour edge of the tail end surface of the guide post 43-3 and having thread refining grade with the longitudinal part of the rear stage adjusting knob 41-3, wherein the rear stage pressure limiting spring 45 is sleeved on the main rod part 43-1, and the head end of the rear pressure limiting spring 45 is abutted against the rear valve plug plate 44, and the head end is abutted against the head end surface of the guide column 43-3. Therefore, by utilizing the axial linear sliding relation between the guide post 43-3 and the stroke guide sleeve 41-1, the adjustment of the axial length of the rear-stage pressure limiting spring 45 can be realized by selectively screwing the rear-stage adjusting knob 41-3, namely the adjustment of the pressure bearing capacity of the rear-stage pressure limiting spring 45 is equivalent.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.