CN209800833U - Throttling structure for nozzle baffle type positioner - Google Patents

Abstract

The utility model provides a throttle structure for nozzle baffle formula locator, its throttle structure that can solve current nozzle baffle formula locator, atmospheric pressure shakiness before its orifice, the easy stifled problem of orifice. The device comprises a throttling seat, a throttling port and a positioner shell, wherein the throttling seat is provided with a side port which is communicated along the radial direction, and the throttling port is provided with a throttling hole; the positioner shell is provided with a mounting hole, the interior of the positioner shell is provided with an air supply groove, the axial middle part of the mounting hole is provided with a section of internal thread, one end of the air supply groove is communicated with an external air source, the other end of the air supply groove is communicated with the mounting hole in the front part of the internal thread, and the axial front end of the mounting hole is communicated with a pilot valve back pressure chamber of the positioner; the outer side walls of the two axial ends of the throttling seat are respectively sealed with the inner side wall of the mounting hole; the side port is positioned in the front part of the external thread and is covered with a filter screen; an axial through hole is formed in the throttling seat, a throttling opening is fixedly mounted at the front end of the interior of the axial through hole, and the rear end of the interior of the axial through hole is sealed.

Description

Throttling structure for nozzle baffle type positioner

Technical Field

the utility model relates to a valve locator field specifically is a throttle structure for nozzle baffle formula locator.

background

The valve positioner is a main accessory of the regulating valve, can obviously improve the flow characteristic of the regulating valve, overcomes unbalanced force of the regulating valve caused by differential pressure between the front valve and the rear valve, improves the control precision, response speed and action flexibility of the regulating valve, and is widely applied to various important occasions such as chemical engineering, petrochemical engineering, coalification and the like.

The nozzle flapper type positioner is a common valve positioner, fig. 1 is a schematic diagram of a traditional nozzle flapper type positioner, the nozzle flapper type positioner mainly comprises a torque motor unit 1, a restrictor 2, a nozzle 3, a nozzle flapper 4, an amplifier unit (pilot valve) 5, a valve position feedback unit 6 and other components, wherein the torque motor unit 1, the nozzle 3, the nozzle flapper 4, the pilot valve 5 and the valve position feedback unit 6 are assembled in a positioner shell, the restrictor 2 is usually installed on the pilot valve 5. the working principle of the device is (see fig. 1 and fig. 2). the torque motor unit 1 converts an electric signal of 4 ~ 20mA into electromagnetic force to adjust the distance between the nozzle flapper 4 and the nozzle 3, the restrictor 2 converts the airflow into stable weak airflow and supplies the stable weak airflow to the nozzle 3 after passing through a backpressure chamber 7, the nozzle 3 continuously releases compressed air, when the distance between the nozzle 3 and the nozzle flapper 4 is different, the backpressure chamber 7 is caused to rise and fall, the backpressure of the backpressure chamber 7 generates unbalanced force after the pressure rises and falls by comparing with the constant pressure of the constant pressure chamber 8 of the pilot valve, the unbalanced force drives the pilot valve 5 to discharge or discharge the gas in an execution mechanism 9, and the opening degree of the valve is controlled again by the motor unit 1, and the balanced valve opening.

The throttler is used for converting intake airflow into stable weak airflow and sending the stable weak airflow into the pilot valve back pressure chamber, so that stable small-flow airflow is provided for the nozzle. Because the throttle is arranged on the pilot valve in the traditional structure and is limited by a narrow installation space, the throttle structure is simpler, the traditional throttle structure is shown in figures 2 and 3 and mainly comprises a throttle seat 10, a throttle opening 11 and a filter screen 12, a throttle hole 13 with the diameter of 0.3mm is formed in the throttle opening, a side opening 14 which is radially communicated is formed in the throttle seat, the throttle hole and the pilot valve share an air inlet 15, and the air flow direction in the throttle and the pilot valve is shown in the arrow direction in figure 2.

The conventional throttling structure has the following disadvantages:

1. Because the orifice and the pilot valve share the air inlet, when a channel between the pilot valve air outlet 16 and the air inlet 15 is opened, the air pressure in front of the orifice is unstable and easy to fluctuate, so that the backpressure of the back pressure chamber is unstable, the air flow supplied to the nozzle is unstable, and the positioner works unstably.

2. The filter screen is directly arranged at the front end of the throttling hole, and the effective filtering area is only about 5mm²The throttling hole is easy to be blocked, and after the throttling hole is blocked, the positioner directly and suddenly drives the valve to a full-open or full-closed position, so that accidents are easy to happen; meanwhile, oil stains are easily attached to the inner wall of the throttling hole to cause performance change, so that the back pressure of the back pressure chamber is reduced, valve position drift can be caused, even the back pressure is reduced too much in serious conditions, and the positioner cannot control the valve to reach the maximum opening degree.

Disclosure of Invention

The throttle structure to current nozzle baffle formula locator, atmospheric pressure is unstable before its orifice, the easy technical problem who blocks up of orifice, the utility model provides a throttle structure for nozzle baffle formula locator, the air current slowly closes before its orifice, and pressure is stable, and the orifice is difficult for stifled.

the technical scheme is as follows: a throttle structure for a nozzle flapper type locator comprises a throttle seat and a throttle orifice, wherein a side port which is communicated along the radial direction is arranged on the throttle seat, and a throttle orifice is arranged on the throttle orifice, and the throttle structure is characterized in that: it also includes a locator housing; the positioner is characterized in that a mounting hole is formed in the positioner shell, an air supply groove is formed in the positioner shell, a section of internal thread is processed in the axial middle of the mounting hole, one end of the air supply groove is communicated with an external air source, the other end of the air supply groove is communicated with the mounting hole in the front of the internal thread, and the axial front end of the mounting hole is communicated with a pilot valve back pressure chamber of the positioner; the outer side walls of the two axial ends of the throttling seat are respectively sealed with the inner side wall of the mounting hole; the side port is positioned in the front part of the external thread and is covered with a filter screen; an axial through hole is formed in the throttling seat, the throttling opening is fixedly mounted at the front end in the axial through hole, and the rear end of the throttling seat is sealed.

It is further characterized in that:

A first O-shaped ring groove is formed in the axial front end of the throttling seat along the circumferential direction of the throttling seat, a first O-shaped ring is installed in the first O-shaped ring groove, the rear groove surface of the first O-shaped ring groove is an installation depth positioning surface, a limiting step matched and abutted with the installation depth positioning surface is arranged in the installation hole, a step sealing surface is further arranged in the installation hole in front of the limiting step, the first O-shaped ring is pressed between the installation depth positioning surface and the step sealing surface, and the outer side wall of the axial front end of the throttling seat is sealed with the inner side wall of the installation hole through the first O-shaped ring; the axial rear end of the throttle seat is provided with a second O-shaped ring groove along the circumferential direction of the throttle seat, a second O-shaped ring is installed in the second O-shaped ring groove, and the outer side wall of the axial rear end of the throttle seat is sealed with the inner side wall of the mounting hole through the second O-shaped ring.

The utility model discloses a throttle seat, including throttle seat, side mouth, filter screen, jump ring, draw-in spring, it has two to open along its axial interval on the throttle seat the side mouth, and two the axial mutually perpendicular of side mouth, correspond on the lateral wall of throttle seat the side mouth is opened respectively has the annular groove, the filter screen is 100 mesh rectangle filter screens, and the coiling parcel is in on the lateral wall of throttle seat and fixed through the jump ring.

the dredging device also comprises a dredging component, wherein the dredging component comprises an ejector rod which is assembled in the axial through hole in a sliding fit manner, a spring is arranged between the ejector rod and the axial through hole in a pressing manner, a through hole needle is fixedly installed at the front end of the ejector rod, and the rear part of the ejector rod is limited by a check ring fixedly assembled in the axial through hole and sealed with the axial through hole; when the spring is in a natural state, the air supply groove is communicated with the throttle hole; when the ejector rod is pushed forwards to compress the spring, the through hole needle can be inserted into and dredge the throttling hole.

The inside of the throttling opening is also provided with a guide hole, the guide hole and the throttling opening are coaxially arranged, the diameter of the guide hole is larger than that of the throttling opening, the guide hole and the throttling opening are in transitional connection through a conical hole, and when the spring is in a natural state, the front end of the through-hole needle is located in the guide hole.

The through hole needle is a spring stainless steel wire with the diameter being matched with that of the throttling hole.

The dredging assembly further comprises a third O-shaped ring, the ejector rod comprises a cylindrical ejector rod main body, annular steps are arranged at the rear part of the ejector rod main body along the circumferential direction of the ejector rod main body, a through hole needle fixing rod with the diameter smaller than that of the ejector rod main body is machined at the front end of the ejector rod main body, and the rear end of the through hole needle is coaxially and fixedly connected to the through hole needle fixing rod; the front end face of the annular step is a spring supporting face, the middle part of the annular step is provided with a conical sealing face with a diameter gradually reduced backwards, and the rear end face of the annular step is a retainer ring limiting face; the axial through hole comprises a first ejector rod guide hole, a spring mounting hole, a second ejector rod guide hole, a third O-shaped ring groove and a check ring mounting hole which are coaxial and have diameters which are sequentially increased from front to back; the throttling port is assembled at the front end of the ejector rod guide hole I in an interference mode, the side port is communicated with the ejector rod guide hole I, the ejector rod guide hole I and the ejector rod guide hole II are in clearance fit with the ejector rod main body and the annular step respectively, two ends of the spring are abutted to the spring supporting surface and the front end face of the spring mounting hole respectively, the check ring is assembled in the check ring mounting hole in an interference mode and abutted to the check ring limiting surface, the rear end of the ejector rod penetrates through the check ring, and the third O-shaped ring is installed in the third O-shaped ring groove and is press-mounted between the check ring and the conical sealing surface.

The inner wall of the mounting hole is further provided with a sewage discharge groove communicated with the front side and the rear side of the internal thread, the throttling seat is located at the rear part of the external thread and is provided with a thread escape groove, a sewage discharge port which is radially communicated is formed in the thread escape groove, the sewage discharge port is communicated with the second ejector rod guide hole, the check ring is provided with a sewage discharge hole which is coaxial with the check ring, the rear end of the ejector rod penetrates out of the sewage discharge hole, and the diameter of the sewage discharge hole is larger than that of the rear end of the ejector rod.

The rear end face of the retainer ring is provided with a straight groove.

And a nitriding layer is arranged on the inner wall of the throttling hole.

the utility model has the advantages that:

the throttling structure of the utility model is different from the traditional method that the throttling structure is arranged on the pilot valve, but the mounting hole is arranged on the positioner shell independently, the throttling seat and the throttling opening are arranged on the positioner shell, and an independent air supply groove is arranged for supplying air to the throttling opening, thus solving the problem of unstable air pressure before throttling opening caused by the air inlet shared by the pilot valve; simultaneously, the air current direction has still been changed, it admits air to change traditional side mouth that admits air by the orifice terminal surface into by radially link up on the orifice seat into, and cover the filter screen on the side mouth of orifice seat, the side mouth admits air again through axial through-hole, lead to the back pressure chamber by the front end of mounting hole behind the orifice, because the filter screen covers on the side mouth, filter screen effective filtration area greatly increased, the filter effect is better, even partial mesh blocks up, also be difficult for causing the orifice to block up, and, the air current is slow and stable after passing through the filter screen, thereby make the air current after the orifice also more stable, and then make locator work more stable.

Drawings

FIG. 1 is a schematic diagram of a conventional nozzle flapper positioner;

FIG. 2 is an enlarged view of the pilot valve of FIG. 1;

FIG. 3 is an exploded view of a conventional choke construction;

FIG. 4 is a front cross-sectional view of the positioner housing of the present invention;

FIG. 5 is a main sectional view of the present invention in an automatic throttle state;

FIG. 6 is a main sectional view of the present invention in a manual through state;

FIG. 7 is a main sectional view of the present invention in a state of dredging the orifice;

Fig. 8 is a front sectional view of the throttle seat of the present invention;

fig. 9 is a front sectional view of the carrier rod of the present invention;

FIG. 10 is a front cross-sectional view of a choke in accordance with the present invention;

Fig. 11 is a schematic view of the external structure of the present invention.

the reference numerals in fig. 4 to 11 are as follows:

20-a locator housing; 21-mounting holes; 211-a limit step; 212-stepped sealing face; 22-an air supply slot; 221-an external gas source interface; 222-an air inlet; 23-internal thread; 24-a throttled gas outlet; 25-a sewage draining tank;

30-a throttle seat; 31-external threads; 32-side port; 33-a first O-ring groove; 331-mounting a depth positioning surface; 34-a second O-ring groove; 35-an annular groove; 361-mandril guide hole I; 362-spring mounting holes; 363-ejector pin guide hole two; 364-third O-ring groove; 365-a retainer ring mounting hole; 37-thread run-out; 38-a sewage draining outlet;

40-a choke; 41-orifice; 42-a pilot hole; 43-tapered holes;

50-a filter screen;

60-a first O-ring;

70-a second O-ring;

80-a clamp spring;

90-ejector pin; 91-a mandril main body; 92-an annular step; 921-spring support surface; 922-tapered sealing surface; 923-a retainer ring limiting surface; 93-through hole needle fixing rod; 94-through hole needle mounting hole;

100-a retainer ring; 1001-sewage draining hole; 1002-a straight slot;

110-a third O-ring;

120-through hole needle;

130-spring.

Detailed Description

Referring to fig. 4 to 11, the throttling structure for the nozzle flapper type locator of the present invention includes a locator housing 20, a throttling seat 30 and a throttling orifice 40; the positioner shell 20 is provided with a mounting hole 21, the inside of the positioner shell is provided with a gas supply groove 22, the axial middle part of the mounting hole 21 is provided with a section of internal thread 23, one end of the gas supply groove 22 is provided with an external gas source interface 221, the other end of the gas supply groove is communicated with the mounting hole 21 in front of the internal thread 23 through a gas inlet 222, and the axial front end of the mounting hole 21 is communicated with a pilot valve backpressure chamber of the positioner through a throttling back gas outlet 24; the axial middle part of the throttle seat 30 is provided with an external thread 31 and is matched and fastened with the internal thread 23, and the outer side walls of the two axial ends of the throttle seat 30 are respectively sealed with the inner side wall of the mounting hole 21; a side opening 32 which penetrates through in the radial direction is formed in the throttling seat 30 positioned in the front part of the external thread 31, and a filter screen 50 is covered on the side opening 32; an axial through hole is formed in the throttling seat 30, a throttling port 40 is fixedly mounted at the front end of the inner portion of the axial through hole, a throttling hole 41 is formed in the throttling port 40, and the rear end of the axial through hole is sealed. The direction of arrows in fig. 4 to 7 represents the direction of air flow. For ease of manufacture, the mounting holes 21 and the air supply grooves 22 may be formed in the manifold of the positioner housing 20, as shown in fig. 11.

referring to fig. 4, 6 and 8, a first O-ring groove 33 is formed in the axial front end of the throttle seat 30 along the circumferential direction of the throttle seat, a first O-ring 60 is installed in the first O-ring groove 33, a back groove surface of the first O-ring groove 33 is an installation depth positioning surface 331, a limiting step 211 matched and abutted with the installation depth positioning surface 331 is arranged in the installation hole 21, a step sealing surface 212 is further arranged in the installation hole 21 in front of the limiting step 211, the first O-ring 60 is pressed between the installation depth positioning surface 331 and the step sealing surface 212, and the outer side wall of the axial front end of the throttle seat 30 is sealed with the inner side wall of the installation hole 21 through the first O-ring 60; the second O-ring groove 34 is formed at the rear end of the throttle seat 30 in the axial direction along the circumferential direction thereof, the second O-ring 70 is installed in the second O-ring groove 34, and the outer side wall of the rear end of the throttle seat 30 in the axial direction is sealed with the inner side wall of the installation hole 21 by the second O-ring 70.

During installation, the two O-shaped rings 60 and 70 are respectively sleeved in the corresponding O-shaped ring grooves 33 and 34, the throttling seat 30 is screwed into the installation hole 21 until the installation depth positioning surface 331 abuts against the limiting step 211, the throttling seat 30 is assembled in place at the moment, and the front end and the rear end of the throttling seat are respectively sealed with the installation hole 21 through the O-shaped rings 60 and 70, so that the installation is simple and convenient, and the sealing is reliable. Meanwhile, the sealing structure has the following advantages: under some special fault bars, the locator can not normally work and does not have the maintenance condition, often need the locator to become direct function this moment, no longer play the regulation effect, through adopting above seal structure, only need with throttle seat 30 reverse rotation round, first O type circle 60 can break away from step seal face 212 this moment, no longer play the sealing effect, the air current is direct through air inlet 222 to throttle back gas outlet 24 (as shown in fig. 6), spout by the nozzle after getting into the pilot valve backpressure chamber, the nozzle backpressure risees, the pilot valve is in the open mode always, actuating mechanism internal pressure equals outside air supply pressure, the action of valve is only controlled by outside air supply pressure, thereby make the locator no longer participate in the regulation. Namely, the positioner can be directly changed from the adjusting function to the direct-through function through manual operation, so that special fault conditions can be conveniently dealt with.

Referring to fig. 5 and 8, two side openings 32 are formed in the throttle seat 30 at intervals along the axial direction of the throttle seat, the axial directions of the two side openings 32 are perpendicular to each other, annular grooves 35 are formed in the outer side wall of the throttle seat 30 corresponding to the two side openings 32 respectively, the filter screen 50 is a rectangular filter screen with 100 meshes, the filter screen 50 preferably adopts a 316 stainless steel wire net, the wire diameter of the steel wire is 0.1mm, the filter screen 50 is wound in a cylindrical shape and is wrapped on the outer side wall of the throttle seat 30 and fixed through a clamp spring 80, the clamp spring 80 is a single-coil spring designed according to the size of the installation position of the throttle seat, and the clamp spring 80 preferably adopts 304 spring steel wires. Through setting up two axial mutually perpendicular's side mouth 32 to set up side mouth 32 in annular groove 35, can further increase filter screen 50's effective filtration area, compare with conventional structure, filter screen 50 effective filtration area multiplicable more than 10 times, orifice 41 is carried through side mouth 32 after the air current is stable through the filter screen buffering of large tracts of land, can make the air current of orifice 41 front end more stable.

for the conventional throttling structure shown in fig. 1 to 3, when the throttling hole is blocked for some reasons and oil stains in the throttling hole are attached to cause the change of the aperture, so that the throttling hole cannot normally work, the throttling hole can only be disassembled for maintenance, the throttling hole is dredged, the filter screen is replaced, and the valve cannot be used temporarily, so that the production is influenced; moreover, a user generally cannot find a steel wire with the diameter less than 0.3mm to dredge the throttling hole, so that the steel wire cannot be repaired by self and can only wait for the after-sale of a manufacturer; even if the self-repairing throttle valve can be repaired by self, the throttle valve is easy to deform and damage, the maintenance under the factory environment often does not have the sanitary condition of maintenance, and the throttle valve seat is often stained with external impurities due to irregular operation to cause the next blockage. In order to enable a user to independently and conveniently complete the maintenance of the throttling hole, and not affect the normal production, the throttling structure for the nozzle baffle type locator further comprises a dredging component, as shown in fig. 4 to 10, the dredging component comprises an ejector rod 90, a check ring 100 and a third O-shaped ring 110, the ejector rod 90 comprises a cylindrical ejector rod main body 91, the rear part of the ejector rod main body 91 is provided with an annular step 92 along the circumferential direction, the front end is provided with a through hole needle fixing rod 93 with the diameter smaller than that of the ejector rod main body 91, a through hole needle mounting hole 94 is processed on the front end surface of the through hole needle fixing rod 93, the rear end of a through hole needle 120 is inserted into the through hole needle mounting hole 94 and then is fixed by soldering tin, and the through hole needle 120; the front end face of the annular step 92 is a spring supporting face 921, the middle part of the annular step is provided with a conical sealing face 922 with the diameter gradually reduced backwards, and the rear end face of the annular step is a retainer ring limiting face 923; the axial through hole comprises a first mandril guide hole 361, a spring mounting hole 362, a second mandril guide hole 363, a third O-shaped ring groove 364 and a retainer ring mounting hole 365 which are coaxial and have diameters which are sequentially increased from front to back; the throttling hole 40 is assembled at the front end of the first ejector rod guide hole 361 in an interference mode, the side port 32 is communicated with the first ejector rod guide hole 361, the ejector rod 90 is coaxially inserted into the axial through hole, the ejector rod main body 91 and the annular step 92 are in clearance fit with the first ejector rod guide hole 361 and the second ejector rod guide hole 363 respectively, the ejector rod 90 is further sleeved with the spring 130, two ends of the spring 130 abut against the spring supporting surface 921 and the front end face of the spring mounting hole 362 respectively, the check ring 100 is assembled in the check ring mounting hole 365 in an interference mode and abuts against the check ring limiting surface 923, the rear end of the ejector rod 90 penetrates through the check ring 100, the third O-shaped ring 110 is installed in the third O-shaped ring groove 364 and is pressed between the check ring 110 and the conical sealing surface 922; when the spring 130 is in a natural state, the air supply groove 22 is communicated with the throttle hole 41; when the plunger 90 is pushed forward to compress the spring 130, the through-hole needle 120 can be inserted into and unblock the orifice 41.

by the design, the integration between the special maintenance tool and the throttle seat is realized, under the normal condition, the spring 130 is in a natural state, and the gas in the gas supply groove 22 is converted into stable weak gas flow and sent into a pilot valve back pressure chamber (as shown by the arrow direction in fig. 5) after sequentially passing through the gas inlet 222, the filter screen 50, the side port 32 and the throttle hole 41; when the throttling hole 41 is blocked, the through hole needle 120 can be inserted into the throttling hole 41 to dredge the throttling hole 41 (as shown in fig. 7) only by pressing the ejector rod 90 forwards, and after the ejector rod 90 is loosened, the ejector rod 90 resets under the action of the spring 130, so that the throttling hole 41 is dredged simply and quickly to recover the function of the positioner, the positioner does not need to be disassembled, and the hidden danger that a user cannot dredge the throttling hole and secondarily pollute the throttling seat by himself is avoided. The first mandril guide hole 361 and the second mandril guide hole 363 in the axial through hole can play a role in centering and guiding the movement of the mandril 90, and meanwhile, the second mandril guide hole 363 limits the maximum pressing depth of the mandril 90.

Referring to fig. 5, 7 and 10, a guide hole 42 is further formed in the throttle opening 40, the guide hole 42 is coaxially arranged with the throttle hole 41, the diameter of the guide hole 42 is larger than that of the throttle hole 41, the guide hole 42 and the throttle hole 41 are transitionally connected through a tapered hole 43, and when the spring 130 is in a natural state, the front end of the through-hole needle 120 is located in the guide hole 42; the diameter of the through-hole needle 120 is matched with that of the throttle hole 41, the through-hole needle 120 is formed by straightening and shearing 304 spring stainless steel wires, one end of the through-hole needle pointing to the throttle hole 41 is sharpened, and due to the good elasticity of the spring stainless steel wires, even if the through-hole needle 120 is not concentric with the throttle opening 40, the through-hole needle can be guided through the guide hole 42 in front of the throttle hole 41 and smoothly passes through the throttle hole 41, and the shape can be kept unchanged for a long time. For a 0.3mm orifice, the diameter of the pilot hole may be selected to be 1.5 mm.

Referring to fig. 4 to 10, the inner wall of the mounting hole 21 is further provided with a sewage draining groove 25 communicating the front side and the rear side of the internal thread 23, the throttle seat 30 is provided with a thread withdrawal groove 37 at the rear part of the external thread 31, a radially through sewage draining port 38 is formed in the thread withdrawal groove 37, the sewage draining port 38 is communicated with the second ejector rod guide hole 363, the check ring 100 is provided with a sewage draining hole 1001 coaxial with the check ring 100, the rear end of the ejector rod 90 penetrates through the sewage draining hole 1001, and the diameter of the sewage draining hole 1001 is larger than that of the rear end of the ejector rod 90. So design, when pressing down ejector pin 90 mediation orifice 41, the sealed face 922 of toper on the ejector pin 90 separates with third O type circle 110, blow-off groove 25 this moment, the sewage pipes who forms the intercommunication between drain 38 and the blowoff hole 1001 (as shown in the arrow direction in fig. 7), the air current is by air inlet 222 entering mounting hole 21 back front impact filter screen 50, there is certain cleaning action, can take away the greasy dirt between filter screen 50 and the mounting hole 21 inner wall, the ponding, powder impurity, the greasy dirt, ponding and powder impurity pass through the sewage pipes discharge locator along with the air current, thereby play the effect of exempting from to disassemble automatically cleaning, mediation orifice and blowdown are accomplished in step, and is simple and convenient, time and labor saving, little to the production influence.

referring to fig. 7 and 11, a straight groove 1002 is formed on the rear end surface of the retainer ring 100 for a straight screwdriver to screw the throttle seat 30, so that the throttle seat 30 is more convenient and labor-saving to mount and dismount.

the inner wall of the orifice 41 is provided with a nitriding layer. Because the compressed air contains dust particles, the abrasion of the throttling hole is expanded due to long-term scouring of the throttling hole, so that the air consumption of the positioner is increased, the performance is reduced, the throttling hole can be scoured by air after nitriding hardening treatment, and the throttling performance is kept unchanged for a long time.

In order to prolong the service life of the throttling structure, the throttling seat 30, the throttling opening 40, the ejector rod 90, the spring 130 and the retainer ring 100 are made of stainless steel, preferably 304 stainless steel, and the positioner shell 20 is made of aluminum alloy ADC12 casting.

adopt the utility model discloses the assembly process of throttle structure under following the concrete description: the through-hole needle 120 is inserted into the through-hole needle mounting hole 94 on the ejector rod 90 and fixed by soldering; the throttling port 40 is pressed into the throttling seat 30 in an interference fit mode, the ejector rod 90 is sleeved with the spring 130 and is installed into the throttling seat 30, the third O-shaped ring 110 is placed, then the check ring 100 is pressed into the throttling seat 30 in an interference fit mode, the end face of the inlet of the check ring installation hole 365 is punched and deformed to enable the check ring 100 to be tightly snapped, the filter screen 50 is wrapped on the throttling seat 30 and is fixed through the clamp spring 80, the first O-shaped ring 60 and the second O-shaped ring 70 are respectively sleeved in the corresponding O-shaped ring grooves 33 and 34, and the whole throttling seat 30 is screwed into the installation hole 21 of the positioner shell 20 to complete assembly.

Claims (10)

1. a throttle structure for a nozzle flapper type locator comprises a throttle seat and a throttle orifice, wherein a side port which is communicated along the radial direction is arranged on the throttle seat, and a throttle orifice is arranged on the throttle orifice, and the throttle structure is characterized in that: it also includes a locator housing; the positioner is characterized in that a mounting hole is formed in the positioner shell, an air supply groove is formed in the positioner shell, a section of internal thread is processed in the axial middle of the mounting hole, one end of the air supply groove is communicated with an external air source, the other end of the air supply groove is communicated with the mounting hole in the front of the internal thread, and the axial front end of the mounting hole is communicated with a pilot valve back pressure chamber of the positioner; the outer side walls of the two axial ends of the throttling seat are respectively sealed with the inner side wall of the mounting hole; the side port is positioned in the front part of the external thread and is covered with a filter screen; an axial through hole is formed in the throttling seat, the throttling opening is fixedly mounted at the front end in the axial through hole, and the rear end of the throttling seat is sealed.

2. A flow restriction arrangement for a nozzle flapper positioner according to claim 1, wherein: a first O-shaped ring groove is formed in the axial front end of the throttling seat along the circumferential direction of the throttling seat, a first O-shaped ring is installed in the first O-shaped ring groove, the rear groove surface of the first O-shaped ring groove is an installation depth positioning surface, a limiting step matched and abutted with the installation depth positioning surface is arranged in the installation hole, a step sealing surface is further arranged in the installation hole in front of the limiting step, the first O-shaped ring is pressed between the installation depth positioning surface and the step sealing surface, and the outer side wall of the axial front end of the throttling seat is sealed with the inner side wall of the installation hole through the first O-shaped ring; the axial rear end of the throttle seat is provided with a second O-shaped ring groove along the circumferential direction of the throttle seat, a second O-shaped ring is installed in the second O-shaped ring groove, and the outer side wall of the axial rear end of the throttle seat is sealed with the inner side wall of the mounting hole through the second O-shaped ring.

3. a flow restriction arrangement for a nozzle flapper positioner according to claim 1, wherein: the utility model discloses a throttle seat, including throttle seat, side mouth, filter screen, jump ring, draw-in spring, it has two to open along its axial interval on the throttle seat the side mouth, and two the axial mutually perpendicular of side mouth, correspond on the lateral wall of throttle seat the side mouth is opened respectively has the annular groove, the filter screen is 100 mesh rectangle filter screens, and the coiling parcel is in on the lateral wall of throttle seat and fixed through the jump ring.

4. A flow restriction arrangement for a nozzle flapper positioner according to claim 1, wherein: the dredging device also comprises a dredging component, wherein the dredging component comprises an ejector rod which is assembled in the axial through hole in a sliding fit manner, a spring is arranged between the ejector rod and the axial through hole in a pressing manner, a through hole needle is fixedly installed at the front end of the ejector rod, and the rear part of the ejector rod is limited by a check ring fixedly assembled in the axial through hole and sealed with the axial through hole; when the spring is in a natural state, the air supply groove is communicated with the throttle hole; when the ejector rod is pushed forwards to compress the spring, the through hole needle can be inserted into and dredge the throttling hole.

5. A flow restriction arrangement for a nozzle flapper positioner according to claim 4, wherein: the inside of the throttling opening is also provided with a guide hole, the guide hole and the throttling opening are coaxially arranged, the diameter of the guide hole is larger than that of the throttling opening, the guide hole and the throttling opening are in transitional connection through a conical hole, and when the spring is in a natural state, the front end of the through-hole needle is located in the guide hole.

6. A flow restriction arrangement for a nozzle flapper positioner according to claim 4, wherein: the through hole needle is a spring stainless steel wire with the diameter being matched with that of the throttling hole.

7. A flow restriction arrangement for a nozzle flapper positioner according to claim 4, wherein: the dredging assembly further comprises a third O-shaped ring, the ejector rod comprises a cylindrical ejector rod main body, annular steps are arranged at the rear part of the ejector rod main body along the circumferential direction of the ejector rod main body, a through hole needle fixing rod with the diameter smaller than that of the ejector rod main body is machined at the front end of the ejector rod main body, and the rear end of the through hole needle is coaxially and fixedly connected to the through hole needle fixing rod; the front end face of the annular step is a spring supporting face, the middle part of the annular step is provided with a conical sealing face with a diameter gradually reduced backwards, and the rear end face of the annular step is a retainer ring limiting face; the axial through hole comprises a first ejector rod guide hole, a spring mounting hole, a second ejector rod guide hole, a third O-shaped ring groove and a check ring mounting hole which are coaxial and have diameters which are sequentially increased from front to back; the throttling port is assembled at the front end of the ejector rod guide hole I in an interference mode, the side port is communicated with the ejector rod guide hole I, the ejector rod guide hole I and the ejector rod guide hole II are in clearance fit with the ejector rod main body and the annular step respectively, two ends of the spring are abutted to the spring supporting surface and the front end face of the spring mounting hole respectively, the check ring is assembled in the check ring mounting hole in an interference mode and abutted to the check ring limiting surface, the rear end of the ejector rod penetrates through the check ring, and the third O-shaped ring is installed in the third O-shaped ring groove and is press-mounted between the check ring and the conical sealing surface.

8. A flow restriction arrangement for a nozzle flapper positioner according to claim 7, wherein: the inner wall of the mounting hole is further provided with a sewage discharge groove communicated with the front side and the rear side of the internal thread, the throttling seat is located at the rear part of the external thread and is provided with a thread escape groove, a sewage discharge port which is radially communicated is formed in the thread escape groove, the sewage discharge port is communicated with the second ejector rod guide hole, the check ring is provided with a sewage discharge hole which is coaxial with the check ring, the rear end of the ejector rod penetrates out of the sewage discharge hole, and the diameter of the sewage discharge hole is larger than that of the rear end of the ejector rod.

9. A flow restriction arrangement for a nozzle flapper positioner according to claim 8, wherein: the rear end face of the retainer ring is provided with a straight groove.

10. A flow restriction arrangement for a nozzle flapper positioner according to claim 1, wherein: and a nitriding layer is arranged on the inner wall of the throttling hole.