JP7325118B2 - Pressure reducing valve with automatic cleaning function - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure reducing valve equipped with an automatic cleaning mechanism for cleaning a screen provided in a fluid passage for removing foreign matter from the passage.

In a pressure reducing valve used in connection with a fluid passage such as a steam pipe, a filter-like mechanical component called a screen is attached to an inflow path to a valve device that opens and closes the passage. If this screen is not cleaned, it will become clogged with foreign matter such as scale (e.g. iron oxide) and cause problems such as a decrease in the flow rate of fluids such as steam, so regular maintenance is required. . Opportunity loss occurs because the flow of fluid is stopped during maintenance. The prior art of the pressure reducing valve includes the following.

JP 2020-029872 A

SUMMARY OF THE INVENTION An object of the present invention is to provide a pressure reducing valve having an automatic screen cleaning mechanism that prevents such buildup of scale.

In order to achieve the above object, a pressure reducing valve of the present invention is a pressure reducing valve arranged in a main fluid passage to reduce pressure on the primary side to pressure on the secondary side, the main valve opening and closing the main passage. and a pilot valve unit that opens and closes the main valve body. The pilot valve unit includes a pilot valve body that opens and closes between an inflow path and an outflow path of a fluid, a screen that is disposed in the inflow path and removes foreign matter in the fluid, and a screen that removes foreign matter adhering to the screen. an automatic cleaning mechanism for the screen; a shaft member for pressing the pilot valve body in the valve opening direction; and a shaft member for pressing the pilot valve body in the valve opening direction to remove the pilot valve body from the valve seat. and a spaced apart pilot valve drive. The pilot valve driving portion includes a second spring body that advances and presses the shaft member in the valve opening direction, and a second spring body that receives pressure from the secondary side and resists the spring force. and pressure adjusting means for retracting in the valve closing direction. The automatic cleaning mechanism includes a first brush that receives a difference between the primary side pressure and the secondary side pressure when the valve is closed, and moves the brush unit in a first direction along the axis of the screen. It has a drive section and a second brush drive section for moving the brush unit in a second direction opposite to the first direction when the valve is opened. Further, a main valve driving portion 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.

According to this configuration, the pressure in the pilot chamber (primary side pressure) is high when the pilot valve body that opens and closes between the inflow path and the outflow path of the fluid is closed, and is low when the pilot valve body is open. Using this pressure difference, the automatic cleaning mechanism functions. When the side pressure is low, the second brush drive moves the brush unit in a second direction opposite to the first direction. In this manner, the brush unit moves back and forth along the axis of the screen due to changes in the pressure in the pilot chamber, thereby rubbing the screen and automatically scraping off foreign matter adhering to the screen. As a result, the screen is not clogged with foreign matter, and the number of times of maintenance can be reduced.

In the pressure reducing valve of the present invention, the first brush driving portion includes a pilot chamber in which the brush unit is housed and the primary side pressure of the main passage is introduced, and a pressure chamber into which the secondary side pressure of the main passage is introduced. The brush unit may include a communication passage communicating with the introduction chamber, a piston inserted into the communication passage, and a link unit connecting the piston and the brush unit.

According to this configuration, since the pressure reducing valve is of a pilot-operated type, due to its structure, the communication passage communicating between the pilot chamber and the pressure introduction chamber into which the secondary side pressure of the main passage is introduced is provided by the first brush. It can be secured as an installation space for the drive unit. In addition, since the first brush drive section is a simple means consisting of a piston and a link unit that connects the piston and the brush unit, it can be installed easily and at a low cost.

In the pressure reducing valve of the present invention, a brush spring body may be provided that applies a spring force in the second direction to the second brush driving portion brush unit. In this case, the structure can be simplified.

The pressure reducing valve of the present invention includes a first magnet body that magnetically holds the brush unit moved in the first direction and a second magnet body that magnetically holds the brush unit moved in the second direction. You may do so. In this case, even if the brush unit moves in either the first direction or the second direction, it is stably held by the first magnet or the second magnet. Further, when the brush unit moves in the first direction or the second direction, foreign matter such as iron oxide adhering to the screen scraped off by the movement of the brush unit is removed by the first magnet or the second magnet. 2, clogging of the screen with foreign matter is suppressed. As a result, it is possible to avoid a phenomenon in which the flow rate of fluid such as steam is reduced, reduce the frequency of maintenance, and reduce opportunity loss.

In the pressure reducing valve of the present invention, the screen may be cylindrical and the brush unit may be annular. In this case, considering that the screen disposed in the pilot chamber is usually cylindrical in this kind of pilot-operated pressure reducing valve, by making the brush unit ring-shaped, it is easy to mount on the screen during assembly. The effect of removing foreign matter adhering to the surface is also improved.

According to the pressure reducing valve of the present invention, the foreign matter adhering to the screen can be efficiently scraped off with a simple structure, and a reduction in the fluid flow rate due to clogging of the foreign matter can be prevented, so the frequency of maintenance can be reduced. , the opportunity loss is also reduced.

1 is a longitudinal sectional view showing the basic configuration 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 essential parts showing the operation of the brush unit when the pressure reducing valve according to the first embodiment of the present invention is closed; FIG. 4 is a vertical cross-sectional view of a main part showing the operation of the brush unit when the pressure reducing valve according to the same embodiment is opened;

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 decompression of steam. If it is just to throttle, there are methods such as fixing the valve at an intermediate opening or providing an orifice plate, but these methods have 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 according to a first embodiment of the present invention. In FIG. 1, a pressure reducing valve PRV 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. Above the valve chamber 14, a main valve driving section 24 is arranged to open the main valve body 18 by receiving the pressure of the outflow passage. 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 pilot valve body 32 and a pilot 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 a pilot valve element 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 pilot valve body 32, and a rear end portion 42b faces a tip plate 38 of the pilot valve driving portion 36, which will be described later. The pilot 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 (left end in FIG. 1) of the pilot valve driving portion 36 is a second spring body made of a coil spring that extends from the rear (right in FIG. 1) to the front (left in FIG. 1). 54 is pressed. 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 pilot valve driving section 36 has pressure adjusting 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) against the spring force. 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 pilot 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 pressure introduction chamber 70 in which the pressure adjusting means 49 is housed is communicated with the secondary passage 12 via a secondary conducting passage 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 adjusting handle 52 is rotated in the pressure reducing direction (counterclockwise), the push rod 60 of the pressure adjusting 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 tip plate 38 at the tip of the pressure adjusting 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 adjusting 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 pilot 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 screen cleaning mechanism, which is a main part of the first embodiment of the present invention, will be described with reference to FIGS. 5 and 6. FIG. Here, FIG. 5 shows the operation of the brush unit when the valve of the automatic screen cleaning mechanism is closed, and FIG. 6 shows the operation of the brush unit when the valve of the automatic screen cleaning mechanism is opened.

As shown in FIG. 5, a cylindrical screen 66 is horizontally arranged in the pilot chamber 62, and an annular brush unit 90 for brushing off foreign matter 80 adhering to the screen 66 extends along the axial direction of the screen 66 ( 5) is movably supported. The brush unit 90 has a holding member 90a and brushes 90b. The brushes 90b are arranged at regular intervals so that their tips protrude radially inward from the inner peripheral surface of the holding member 90a so as to come into contact with the outer peripheral surface of the screen 66. The book is flocked. This brush unit 90 is configured to perform a constant operation by an automatic cleaning mechanism.

The automatic cleaning mechanism detects the difference between the pressure on the primary side and the pressure on the secondary side when the valve is closed, that is, the pressure P1 in the primary conduit 64 communicating with the primary side passage 10 and the pressure P1 communicating with the secondary side passage 72. a first brush driving portion 74 that receives the pressure difference of the pressure P2 in the introduction chamber 70 and moves the brush unit 90 in a first direction (right side in FIG. 5) X1 along the axis of the screen 66; and a second brush driving section 75 for moving the brush unit 90 in a second direction (left side in FIG. 5) X2 opposite to the first direction X1. A first magnet body 93 that holds the brush unit 90 when it moves in the first direction X1 is supported by the upper case 6 in close proximity to one end of the screen 66 near the pilot valve body 32. A second magnet 94 that holds the brush unit 90 when moved in the second direction X2 is supported by the upper case 6 in close proximity to the other end of the screen 66 . Both magnet bodies 93 and 94 are provided in an annular shape like the holding member 90a made of a magnetic iron material.

The first brush driving portion 74 includes a pilot chamber 66 in which the brush unit 90 is housed and the primary side pressure of the main passage 1 is introduced, and a pressure introduction chamber 70 into which the secondary side pressure of the main passage 1 is introduced. A communication passage 77 communicating between them, a piston 78 inserted into the communication passage 77, and a link unit 79 connecting the piston 78 and the brush unit 90 are provided. The link unit 79 is formed by connecting two link knittings 79a and 79b with a connecting pin 79c so as to be relatively rotatable. On the other hand, the second brush driving portion 75 is composed of a spring body (for example, a coil spring) and is biased to press the brush unit 90 in the first direction X1 when the valve is opened.

In the pressure reducing valve PRV configured as described above, the pressure in the pilot chamber 62 ( The primary side pressure P1 is sufficiently higher than the pressure P2 in the pressure introduction chamber 70 (P1>>P2), and becomes slightly higher than the pressure P2 in the pressure introduction chamber 70 when the pilot valve element 32 is opened ( P1>P2). Using this pressure difference, the automatic cleaning function functions, and when the pressure P1 on the primary side when the valve is closed is high, the brush unit 90 is moved in the first direction (toward the pilot valve body 32) by the first brush driving section 74. ) Move to X1.

When the pressure P1 on the primary side when the valve is opened is low, as shown in FIG. It moves in the second direction X2. In this manner, the brush unit 90 moves left and right on the screen 66 due to the pressure change in the pilot chamber 62 , thereby rubbing the screen 66 and automatically scraping off the foreign matter 80 adhering to the screen 66 . As a result, the screen 66 is prevented from being clogged with foreign matter, and the frequency of maintenance can be reduced.

Further, since the pressure reducing valve PRV is of a pilot-operated type, due to its structure, the communication passage 77 communicating between the pilot chamber 62 and the pressure introduction chamber 70 into which the pressure on the secondary side of the main passage 1 is introduced is replaced by a piston 78. and can be secured as an installation space for the link unit 79, and can be formed relatively easily. Since the first brush driving portion 74 is a simple means consisting of the piston 78 and the link unit 79 connecting the piston 78 and the brush unit 90, it can be installed easily and at a low cost.

Furthermore, since the second brush driving portion 75 can adopt the brush spring body 76 that applies a spring force to the brush unit 90 in the second direction X2, the structure can be simplified.

Further, in the pressure reducing valve PRV of the present invention, the first magnet body 93 that holds the brush unit 90 that has moved in the first direction X1 and the second magnet that holds the brush unit 90 that has moved in the second direction X2. body 94, the brush unit 90 is stably held by the first magnet body 93 or the second magnet body 94 even if the brush unit 90 moves in either the first direction X1 or the second direction X2. be done. Furthermore, since the foreign matter 80 rubbed off by the movement of the brush unit 90 adheres to the first magnet body 93 or the second magnet body 94, clogging of the screen 66 by the foreign matter 80 is suppressed, and steam is generated. Such a phenomenon that the flow rate of the fluid S is reduced can be avoided. Therefore, the number of times of maintenance can be suppressed, and opportunity loss can be reduced.

Furthermore, in view of the fact that the screen 66 disposed in the pilot chamber 62 is usually cylindrical in this type of pilot-operated pressure reducing valve, the brush unit 90 is made annular so that it can be easily mounted on the screen 66 during assembly. The effect of scraping off the foreign matter 80 adhering to the surface can be further expected.

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 body 24 main valve driving part 30 pilot valve unit 32 pilot valve body 32a cylindrical part 32b truncated cone part 34 valve device 36 pilot valve driving part 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)
70 pressure introduction chamber 74 first brush driving portion 75 second brush driving portion 77 communication passage 78 piston 79 link unit 90 brush unit 90a holding member 90b brush 93 first magnet body 94 second magnet body PRV pressure reducing valve
S fluid (steam)
X1 first direction X2 second direction

Claims (5)

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,
The pilot valve unit includes a pilot valve body that opens and closes between an inflow path and an outflow path of a fluid, a screen that is disposed in the inflow path and removes foreign matter in the fluid, and a screen that removes foreign matter adhering to the screen. an automatic cleaning mechanism for the screen; a shaft member that presses the pilot valve body in the valve opening direction; and a shaft member that presses the pilot valve body in the valve opening direction to separate the pilot valve body from the valve seat. and a pilot valve drive unit that allows
The pilot valve driving portion includes a second spring body that advances and presses the shaft member in the valve opening direction, and a second spring body that receives pressure from the secondary side and resists the spring force. and pressure adjusting means for retracting in the valve closing direction,
The automatic cleaning mechanism includes a first brush that receives a difference between the primary side pressure and the secondary side pressure when the valve is closed, and moves the brush unit in a first direction along the axis of the screen. a drive section; and a second brush drive section for moving the brush unit in a second direction opposite to the first direction when the valve is opened,
Furthermore, a main 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. 2. A pressure reducing valve according to claim 1, wherein said first brush driving portion includes a pilot chamber in which said brush unit is housed and into which primary side pressure of said main passage is introduced, and a secondary side pressure of said main passage is introduced thereinto. A pressure reducing valve comprising: a communication passage communicating with a pressure introducing chamber, a piston inserted in the communication passage, and a link unit connecting the piston and the brush unit. 2. The pressure reducing valve according to claim 1, wherein said second brush driving portion is a brush spring body for applying a spring force to said brush unit in a second direction. 2. The pressure reducing valve according to claim 1, comprising a first magnet holding said brush unit moved in the first direction and a second magnet holding said brush unit moved in said second direction. pressure reducing valve. 2. The pressure reducing valve of claim 1, wherein said screen is cylindrical and said brush unit is annular.

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