JP7333959B2 - Screen automatic cleaning mechanism and pressure reducing valve equipped with this - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic cleaning mechanism for cleaning a screen provided in a fluid passage for removing foreign substances in the passage, and a pressure reducing valve having the same.

Devices such as pressure reducing valves that are used in connection with fluid passages such as steam pipes are equipped with a filter-like mechanical part called a screen in the inflow path to the valve device that opens and closes the passage. If this screen is not cleaned, it will become clogged with foreign matter such as scale, causing problems such as a decrease in the flow rate of the fluid. Therefore, periodic maintenance is required. Opportunity loss occurs because the flow of fluid is stopped during maintenance. Prior arts of valve devices and pressure reducing valves include the following.

JP 2020-029872 A

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic screen cleaning mechanism and a pressure reducing valve using the same, which prevent the deposition of such scales.

In order to achieve the above object, the automatic screen cleaning mechanism of the present invention comprises a valve body that opens and closes between an inflow path and an outflow path of a fluid, and a valve body that is disposed in the inflow path and removes foreign matter in the fluid. It is equipped with a cylindrical screen and an annular brush unit for brushing off foreign matter adhering to the screen. The brush unit has an axial center arranged in a vertical direction, and the brush unit rotates around its axial center and rotates in the axial direction by the flow of the fluid passing through the inflow passage when the valve is opened. grooves or vanes are provided to move the

According to this configuration, when the valve is opened, the flow of fluid passing through the inflow path acts on the grooves or blades provided in the brush unit. The fluid flow acting on the grooves or blades turns into a swirling flow, and moves the brush unit in the axial direction while rotating around the axis of the brush unit, that is, lifts it up. When the brush unit rotates and moves upward, the screen is cleaned by rubbing and forcibly scraping off foreign matter adhering to the screen. This prevents clogging due to the accumulation of foreign matter on the screen.

The automatic screen cleaning mechanism of the present invention may further include a guide member that supports the brush unit movably in its axial direction. In this case, the annular brush unit can be smoothly moved on the screen along the guide member.

A pressure reducing valve according to a first configuration of the present invention is a pressure reducing valve that is arranged in a main fluid passage and reduces a pressure on a primary side to a pressure on a secondary side, comprising: a main valve body that opens and closes the main passage; and a pilot valve unit that opens and closes the main valve body. The pilot valve unit includes an automatic screen cleaning mechanism of the present invention, a shaft member that presses the valve body in the valve opening direction, and a shaft member that presses the valve body in the valve opening direction to separate the valve body from the valve seat. and a first valve drive for allowing the valve to operate. The first valve drive unit includes a second spring body that advances and presses the shaft member in the valve opening direction, and a spring force that receives the pressure from the secondary side and presses the second spring body. and a valve-closing force applying member that is retracted in the valve-closing direction against the valve-closing force applying member. Further, a second valve drive section is provided for receiving the pressure of the outflow passage to open the main valve body, and the inflow passage communicates with the primary side of the main passage.

A pressure-reducing valve according to a second configuration of the present invention is a pressure-reducing valve that is disposed in a main fluid passage and reduces the pressure on the primary side to the pressure on the secondary side. an automatic cleaning mechanism, a shaft member that presses the valve body and the valve body in a valve-opening direction, and a valve drive section that presses the shaft member in the valve-opening direction to separate the valve body from the valve seat. ing. The valve drive unit includes a second spring body that advances and pushes the shaft member in a valve opening direction, and a second spring body that receives pressure from the secondary side and moves the second spring body against the spring force. and a valve closing force application member that retracts in the valve closing direction. The primary and secondary sides of the main passage form the inflow and outflow, respectively.

According to the pressure reducing valves of the first and second configurations described above, it is possible to prevent clogging of the screen and reduce the frequency of maintenance.

According to the automatic screen cleaning mechanism of the present invention and the pressure reducing valve using the same, it is possible to effectively prevent foreign matter from depositing on the screen.

1 is a longitudinal sectional view showing the basic configuration of a pressure reducing valve, which is the object of the present invention; FIG. FIG. 4 is a vertical cross-sectional view schematically showing a state of the pressure reducing valve before pressure reduction; It is a longitudinal cross-sectional view which shows typically the pressure adjustment state of the same pressure-reduction valve. It is a longitudinal cross-sectional view which shows typically the pressure reduction holding state of the same pressure-reduction valve. FIG. 4 is a vertical cross-sectional view of the main part showing the operating state of the brush unit when the valve of the automatic screen cleaning mechanism according to the first embodiment of the present invention is closed. FIG. 10 is a vertical cross-sectional view of the main part showing the operating state of the brush unit when the valve of the automatic screen cleaning mechanism is open. FIG. 4 shows a front cross-sectional view of a brush unit used in an automatic screen cleaning mechanism. It is front sectional drawing which shows the modification of the same brush unit. FIG. 7 is a longitudinal sectional view showing a pressure reducing valve employing an automatic screen cleaning mechanism according to a second embodiment of the present invention; It is an enlarged vertical cross-sectional view showing the main part of the automatic cleaning mechanism of the same screen.

Prior to describing embodiments of the present invention, a pressure reducing valve used in a steam passage will be described. In various industries, steam is used as a heat carrier from the viewpoint of cost, convenience and safety. The greatest advantage is that the latent heat per unit weight is large, and the temperature can be kept constant by controlling the pressure.

When using steam, instead of generating steam at each required pressure, a boiler generates high-pressure steam, and the steam is lowered to the required pressure according to the product or application. In that case, the automatic valve that keeps the steam pressure substantially constant is the pressure reducing valve. The purpose of lowering the pressure is to lower the steam temperature and keep it at the desired heating temperature.

The basic principle of decompression is called the throttling phenomenon. When steam flows through a pipe, if the passage through which the steam flows is throttled, the steam pressure on the downstream side becomes lower than the throttled point. This is the depressurization of steam. If it is just to throttle, there is a method of fixing the valve at an intermediate opening or providing an orifice plate, but this method has the problem that the pressure also changes when the flow rate changes. Therefore, even if the flow rate or the primary pressure (upstream pressure of the throttling point) changes, the secondary pressure (downstream pressure of the throttling point) does not fluctuate. A pressure reducing valve is a valve that is set to automatically change the valve opening by directly using .

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows the basic configuration of a pilot-operated pressure reducing valve as one type of pressure reducing valve, which is the subject of the present invention. In FIG. 1, the pressure reducing valve is arranged in a main passage 1 through which steam S, which is a type of fluid, flows. A casing 2 of the pressure reducing valve PRV is formed by connecting a body case 4, an upper case 6 and a lower case 8. As shown in FIG. A primary side passage 10 , a secondary side passage 12 , and a valve chamber 14 therebetween are formed inside the body case 4 . The primary passage 10 and the secondary passage 12 form part of the main passage 1 through which the steam S flows. A valve holder 16 and a main valve element 18 that slides inside the valve holder 16 are arranged in the valve chamber 14 . The upper portion of the valve holder 16 is supported by the main body case 4 by screw connection.

The main valve body 18 contacts a main valve seat 22 formed in the valve holder 16 by a main spring body 20 made of a coil spring, and spring force is applied in the direction of closing the valve. A main valve driving section 24 for driving the main valve body 18 is arranged above the valve chamber 14 . The main valve driving portion 24 has a piston 26 that contacts the main valve element 18 and is slidably inserted into a cylinder 28 that is supported by the main body case 4 . Above the piston 26 is a main valve body driving chamber 27, which will be described later. The piston 26 is provided with a release hole 29 for releasing the pressure in the main valve body drive chamber 27 .

A pilot valve unit 30 is arranged above the upper case 6 . That is, the upper case 6 forms a casing of the pilot valve unit 30. As shown in FIG. The pilot valve unit 30 has a valve device 34 including a ball-shaped valve body 32 and a valve driving section 36 for opening and closing the valve device 34 . The valve device 34 has a valve seat block 37, and a valve seat 40 is formed at its tip (left end in FIG. 1). A valve opening 41 that is opened and closed by the valve body 32 is opened in the central portion of the valve seat 40 .

A shaft member 42 is inserted through the valve seat block 37 in the front-rear direction (left-right direction in FIG. 1). A tip portion 42a of the shaft member 42 contacts the valve body 32, and a rear end portion 42b faces a tip plate 38 of the valve drive portion 36, which will be described later. The valve body 32 is pressed against the valve seat 40 by a first spring body 44 made of a coil spring. The first spring body 44 is interposed between a first spring bearing 48 provided on the upper case 6 .

A tip plate 38 at the tip (the left end in FIG. 1) of the valve driving portion 36 extends from the rear (right in FIG. 1) to the front (left in FIG. 1) to form a second spring body 54 made of a coil spring. is pressed by The second spring body 54 is interposed between a tip member 56 that contacts the tip plate 38 and a second spring retainer 58 that is arranged inside the cover member 50 . The cover member 50 is screwed to the upper case 6 (casing). A push rod 60 is arranged between the cover member 50 and the tip member 56 and passes through the inner space of the second spring body 54 .

The valve driver 36 has a pressure regulating means 49 . The pressure adjusting means 49 has the tip plate 38 and the bellows 43, and retracts the second spring body 54 in the valve closing direction (rightward direction). That is, the pressure adjusting means 49 constitutes a valve closing force applying member that retracts the second spring body 54 in the valve closing direction against the spring force.

A distal end portion 43 a of a bellows 43 is connected to the distal end plate 38 , and a proximal end portion 43 b of the bellows 43 is fixedly supported between the upper case 6 and the cover member 50 . An adjustment handle 52 for adjusting pressure is rotatably connected to the cover member 50 by screws.

A pilot chamber 62 that houses the first spring body 44 is arranged on the front side (left side) of the valve device 34 . The pilot chamber 62 communicates with the primary side passage 10 via a primary conduction passage 64 . A screen 66 for removing foreign matter is arranged in the pilot chamber 62 . A through passage 68 communicating with the valve port 41 is formed downstream of the valve body 32 in the valve device 34 . The pilot chamber 62 and the through passage 68 form an inflow passage and an outflow passage for the pilot valve unit 30, respectively. On the other hand, the secondary passage 12 communicates with the pressure introduction chamber 70 housing the pressure application means 49 via the secondary conduit 72 .

Next, the operation of the above configuration will be explained.
[Before decompression]
FIG. 2 shows the state before the start of the pressure reducing operation, in which the main valve body 18 is in the closed state. When the steam S is passed through the pressure reducing valve, the steam S reaches the pilot chamber 62 from the primary passage 10 through the primary conduit 64 .

[Pressure adjustment]
When the adjustment handle 52 is rotated in the pressure reducing direction (counterclockwise), the push rod 60 of the pressure application means 49 moves forward (leftward) as shown in FIG. As a result, the bellows 43 expands and the tip plate 38 moves the shaft member 42 forward (to the left) to open the valve body 32 . As a result, the steam S flows into the outflow passage (through passage) 68 and pushes down the piston 26 to open the main valve body 18 . At this time, a slight gap G exists between the pressing plate 38 at the tip of the pressure applying means 49 and the back surface of the valve seat block 37 . By opening the main valve body 18, the steam S in the primary side passage 10 flows into the secondary side passage 12 and is decompressed.

[Holding of reduced pressure]
Part of the steam S that has flowed into the secondary passage 12 reaches the pressure introduction chamber 70 through the secondary conduit 72 as shown in FIG. The bellows 43 of the pressure application means 49 is compressed by the steam pressure in the pressure introduction chamber 70, and the tip plate 38 retreats rightward. As a result, the shaft member 42 is allowed to move rearward (rightward), and the valve body 32 is moved in the valve closing direction. By adjusting the pressure in the main valve drive chamber 27 in this manner, the degree of opening of the main valve 18 is adjusted, and the pressure in the secondary passage 12 is kept constant.

Next, an automatic cleaning mechanism, which is a main part of one embodiment of the present invention, will be described with reference to FIGS. 5 to 8. FIG. In this embodiment, as shown in FIGS. 5 and 6, a pilot chamber 62 is arranged vertically with respect to the horizontally oriented valve device 34, and a cylindrical screen 66 for removing foreign matter is arranged inside the pilot chamber 62. It is The screen 66 has a large number of meshes or small holes on its peripheral wall. Here, FIG. 5 shows the operating state of the brush unit when the valve of the automatic screen cleaning mechanism is closed, and FIG. 6 shows the operating state of the brush unit when the valve of the automatic screen cleaning mechanism is open.

As shown in FIG. 5, a plurality of, for example, four, straight rod-shaped guide members 97 are arranged at regular intervals in the circumferential direction outside the screen 66 arranged in the pilot chamber 62 in the axial direction of the screen 66. An annular brush unit 90 is vertically movably supported by the guide member 97 to remove foreign matter adhering to the screen 66 . The upper end 97a of the guide member 97 is press-fitted into the insertion hole of the retaining ring 101 arranged on the lower peripheral edge of the plug 92, and the lower end 97b of the guide member 97 is pressed into the top surface of the upper case 6 constituting the casing 2 of the pressure reducing valve PRV. It is inserted into the provided insertion hole. The retaining ring 101 is welded or press-fitted to a stepped portion 110 provided on the lower side of the plug screwing screw hole 103 of the upper case 6 . The brush unit 90 includes a holding member 90a, a brush 90b that protrudes radially inward and contacts the screen 66, and an annular pedestal 90c that holds the holding member 90a and slides up and down on the guide member 97. .

FIG. 7 shows the brush unit 90 in more detail. The overall shape of the brush unit 90 is annular when viewed from the front. 90b is flocked. In addition, on one side surface 90aa below the holding member 90a, the brush unit 90 is rotated about its axis by the flow of steam that flows into the primary conduction path 64 from the inflow path (primary side path 10) when the valve is opened. A plurality of grooves 93 (12 in the figure) are arranged in the circumferential direction and move upward in the axial direction. This groove 93 extends in a direction inclined with respect to the radial direction from the inside to the outside of the holding member 90a. The holding member 90a is rotatably supported on the pedestal 90c by a dovetail groove structure. A plurality of (for example, four) through-holes 98 are evenly formed in the pedestal 90c in the circumferential direction. During assembly, the guide member 97 is inserted into the through hole 98 of the base 90c in such a direction that the tip of the brush 90b of the brush unit 90 contacts the screen 66, and the lower end portion 97b of the guide member 97 is pushed as described above. It is set by fitting it into an insertion hole provided on the top surface of the upper case 6 .

FIG. 6 shows the position of the brush unit 90 when the valve is open. When the valve is opened, the fluid S that has entered the pilot chamber 62 from the primary passage 10 (FIG. 1) through the primary conduction passage 64 is introduced into the groove 93 (FIG. 7) of the holding member 90a of the brush unit 90. The swirling fluid S turns into a swirling flow, and the brush unit 90 moves upward in the axial direction while rotating about its axis (R1 direction). That is, the brush unit 90 is lifted up to near the upper end of the guide member 97 shown in FIG. In the process in which the brush unit 90 rotates and moves upward from the lower end position of the guide member 97 shown in FIG. Such foreign matter 80 is scraped off, and the foreign matter is forcibly scraped off from the screen 66 . When the valve is closed, the flow of the fluid S ceases and dynamic pressure of the fluid is not applied, so the brush unit 90 descends along the guide member 97 due to its own weight and returns to its original position shown in FIG. The foreign matter 80 on the screen 66 is also scraped off when the brush unit 90 descends due to its own weight.

FIG. 8 shows a modification of the brush unit. In the case of this modification, instead of the groove 93 provided in one side surface 90aa of the holding member 90a of the brush unit 90 of FIG. In the case of this modified example, the same operation as the brush unit 90 provided with the grooves 93 described above is performed, and the same effect can be expected. Like the grooves 93, the blades 95 are oriented and angled so that the holding member 90a rotates around the axis (rotational direction R1) by the action of the fluid S such as steam introduced when the valve is opened. there is

As the screen 66 is automatically and repeatedly cleaned in this manner, the foreign matter adhering to the screen 66 is smoothly rubbed off in a relatively small stage. Further, when replacing the brush 90b of the brush unit 90 due to deterioration over time due to use, since the brush 90b is a set with the holding member 90a and the pedestal 90c, it can be removed together with the screen 90 by loosening the plug 92. can be easily performed, and maintenance work can be performed quickly.

The present invention is applicable not only to the pilot-operated pressure reducing valve PRV1 but also to the direct-acting pressure reducing valve PRV1 shown in FIG. In this pressure reducing valve PRV1, the same reference numerals are assigned to the portions that are the same as or correspond to those of the pilot valve unit 30 of FIG. The pressure reducing valve PRV1 uses the valve device 34 employing the automatic cleaning mechanism of the first embodiment shown in FIG. As shown in FIG. 10, which is an enlarged view of the essential part of FIG. 9, an annular brush unit 90 is axially movably supported by a guide member 97 attached between the housing 5 and a plug 92A closing the bottom thereof. ing. Specifically, the support plate 105 is sandwiched between the spring bearing 48A of the first spring body 44 and the plug 92A, and the upper end portion 97a of the guide member 97 is press-fitted into the insertion hole provided in the housing 5, thereby The guide member 97 is set by inserting the lower end portion 97b of the support plate 105 into an insertion hole provided in the support plate 105 . A lower side surface 90aa of the holding member 90a of the brush unit 90 is formed obliquely so as to deviate upward in a radially outward direction. .

In the case of this direct-acting type, the fluid S passes through the screen 66 from the primary passage 10 and goes toward the valve body 32 through the plurality of steam passage holes 99 . At this time, part of the fluid S is introduced into the grooves 93 or the blades 95, causing the brush unit 90 to rotate and move upward in its axial direction. At this time, since the one side surface 90aa is obliquely formed, the surface area that receives the pressure of the inflowing fluid S is increased, and the size of the groove 93 or the vane 95 can be secured to be large. As a result, when the valve is opened, sufficient rotational force and rising force can be applied to the brush unit 90 sliding along the guide member 97 . In FIG. 9, the pressure in the primary side passage 10, which is an inflow passage, is reduced by opening the valve body 32, and the fluid flows out from the secondary side passage 12, which is an outflow passage.

The operation of the direct acting pressure reducing valve PRV1 is as follows.
[Before decompression]
The valve body 32 is pressed against the valve seat 40 by the first spring body 44 and is in the closed state.

[Pressure adjustment]
When the handle 52 is turned to the left, the second spring body 54 included in the pressure adjusting means 49 of the valve drive section 36 is extended to push down the shaft member 42 and open the valve body 32 . Thereby, the steam S in the primary side passage 10 flows to the secondary side passage 12 .

[Holding of reduced pressure]
When the pressure in the secondary passage 12 increases, the bellows 43 contracts, allowing the shaft member 42 to rise, and the valve body 32 moves in the valve closing direction (upward). Thereby, the opening degree of the valve body 32 is adjusted.

The present invention is not limited to the above embodiments, and various additions, changes, or deletions are possible without departing from the scope of the present invention. For example, in each of the above embodiments, the automatic cleaning mechanism is used for the pressure reducing valve PRV, but it is not limited to the pressure reducing valve PRV, and can also be used for, for example, a steam trap. Accordingly, such are also included within the scope of this invention.

18 Main valve disc 24 Main valve drive unit 30 Pilot valve unit 32 Valve disc 34 Valve device 36 Valve drive unit (first valve drive unit)
37 valve seat unit 40 valve seat 42 shaft member 44 first spring body (coil spring)
49 Pressure adjusting means (valve closing force applying member)
54 Second spring body 62 Pilot chamber (inflow path)
68 through passage (outflow passage)
90 brush unit 90a holding member 90b brush 90c pedestal 93 groove 95 blade 97 guide member PRV, PRV1 pressure reducing valve
S fluid (steam)

Claims (4)

a valve body that opens and closes between the inflow path and the outflow path of the fluid;
a cylindrical screen disposed in the inflow channel for removing foreign matter in the fluid;
an annular brush unit for removing foreign matter adhering to the screen;
The brush unit has an axial center arranged in the vertical direction,
The brush unit is provided with grooves or vanes that cause the brush unit to rotate about its axis and move in the axial direction by the flow of the fluid through the inflow passage when the valve is opened. cleaning mechanism. 2. The automatic screen cleaning mechanism according to claim 1, further comprising a guide member for supporting said brush unit movably in its axial direction. A pressure reducing valve arranged in a main fluid passage to reduce the pressure on the primary side to the pressure on the secondary side,
a main valve body that opens and closes the main passage;
A pilot valve unit that opens and closes the main valve body,
wherein the pilot valve unit is an automatic screen cleaning mechanism according to claim 1 or 2;
a shaft member that presses the valve body in a valve-opening direction; and a first valve drive section that presses the shaft member in the valve-opening direction to separate the valve body from a valve seat,
The first valve drive unit includes a second spring body that advances and pushes the shaft member in the valve opening direction, and a spring force that receives the pressure from the secondary side and pushes the second spring body. a valve-closing force applying member that retracts in the valve-closing direction against the
Furthermore, a second valve drive section is provided for receiving the pressure of the outflow passage and opening the main valve body,
A pressure reducing valve in which the inflow passage communicates with the primary side of the main passage. A pressure reducing valve arranged in a main fluid passage to reduce the pressure on the primary side to the pressure on the secondary side,
The automatic screen cleaning mechanism according to any one of claims 1 and 2, which opens and closes the main passage;
a shaft member that presses the valve body in a valve-opening direction; and a valve drive section that presses the shaft member in the valve-opening direction to separate the valve body from a valve seat,
The valve drive unit includes a second spring body that advances and pushes the shaft member in a valve opening direction, and a second spring body that receives pressure from the secondary side and moves the second spring body against the spring force. and a valve closing force application member that retracts in the valve closing direction,
A pressure reducing valve in which a primary side and a secondary side of the main passage form the inflow passage and the outflow passage, respectively.

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