JP3737063B2 - Steam boiler decompression device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a decompression device for a steam boiler.
[0002]
[Prior art]
Conventionally, in a facility for supplying steam generated by a steam boiler (hereinafter simply referred to as “boiler”), as shown in FIG. A valve a and a pressure reducing valve b (in the illustrated example, a pilot actuated type) are provided, and a manual on-off valve and a pressure reducing valve are provided at appropriate locations in the piping to distribute and supply steam from the boiler B further downstream (not shown). It has been.
During the operation of the boiler B, the manual on-off valve a and the manual on-off valves at various places are opened as necessary, and steam is supplied to each equipment such as a water heater and a heater using steam heat provided downstream thereof. ing.
However, in the closed state of the manual on-off valve a shown in FIG. 6 or the manual on-off valves (hereinafter referred to as the manual on-off valve a) in various places in the pipe, that is, before the downstream steam supply, heat loss from the pipe surface Condensed water in which part of the steam is condensed in the pipe is retained in the pipe. If the manual open / close valve a or the like is suddenly opened from this state, the condensed water in the pipe prevents the steam from flowing to the boiler B. Heavy loads occur, or condensate is blown off at a stretch by the steam flow from the upstream and collides with the pipe wall, generating severe noise and vibration (water hammer). To alleviate these phenomena, downstream When the steam was supplied, it was necessary to slowly open the manual on-off valve a and the like over time.
[0003]
[Problems to be solved by the invention]
Therefore, when steam is supplied downstream in the steam supply facility, the operator must adjust the flow rate by opening the manual on-off valve a while looking at the pressure gauge, and this work is very troublesome.
Therefore, according to the present invention, the steam is supplied at a small flow rate from the initial stage of steam supply downstream until the steam rises to a predetermined pressure to reduce the occurrence of phenomena such as water hammer, and the steam pressure reaches a predetermined value. It is an object of the present invention to provide a decompression device that is automatically controlled so that the supply of steam continuously changes from a small flow rate to a normal flow rate (corresponding to a flow rate when the manual on-off valve a or the like is fully opened).
[0004]
[Means for Solving the Problems]
In view of the above problems, the present invention provides a pressure sensing valve that opens and closes the flow path between the pilot valve and the primary pressure chamber of the pressure reducing valve body, and the valve rod of the pressure sensing valve is partitioned from the flow path in an airtight manner. The pressure sensitive diaphragm can be moved forward and backward by a pressure sensitive diaphragm that is displaced by the pressure fluctuation of the fluid in the pressure chamber, and the pressure sensitive diaphragm is adjusted by an adjusting spring whose elastic force can be changed by an adjusting screw. A pilot-actuated mainstream pressure reducing valve provided with an operation valve biased in the valve closing direction of the pressure sensing valve, and a flow rate smaller than the mainstream pressure reducing valve body, and the set pressure is lower than the pilot valve set pressure And a tributary pressure reducing valve set higher than the set pressure of the operating valve in parallel with the steam supply pipe, and the pilot valve pressure control chamber is connected downstream of the main pipe with the main body interposed therebetween, and the operating valve The pressure chamber of the tributary is connected via the pressure reducing valve By connecting to the downstream side of the side pipe, the steam is supplied from the side pipe through the tributary pressure reducing valve from the initial stage of steam supply to the downstream until the pressure rises so as not to cause a phenomenon such as water hammer. When the operation valve senses that the downstream pressure has increased and reached a predetermined value, the main flow pressure reducing valve functions, and steam is also supplied from the main pipe, thus automatically adjusting the steam flow rate. This solves the above problem by reducing the occurrence of phenomena such as water hammer.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows a simplified piping system diagram of a steam boiler decompression device 1 according to the present invention.
This decompression device 1 comprises a steam supply pipe SG connected to the boiler B and a main flow decompression valve main body 1a and a branch flow decompression valve 1b connected in parallel, and the main body MP is branched into the main pipe MP branched from the steam supply pipe SG. The mainstream pressure reducing valve connected with 1a is provided with a pilot valve 2 for controlling the main body 1a and an operation valve 3 for sensing the steam pressure downstream of the branch pressure reducing valve 1b to control the main body 1a. .
In the present embodiment, the steam supply pipe SG provided with the decompression device 1 is shown to be continuous downstream of the boiler B, but the decompression device 1 has a header further downstream (not shown) of the steam supply tube SG. It is also provided in a separate steam supply pipe SG that distributes and supplies the steam through it.
The tributary pressure reducing valve 1b is a pressure reducing valve whose flow rate is smaller than that of the main flow reducing valve body 1a and whose set pressure is lower than the set pressure of the pilot valve 2 and higher than the set pressure of the operation valve 3. It branches from the steam supply pipe SG, and is intervened in the side pipe SP having a smaller diameter than the main pipe MP.
[0006]
The main flow reducing valve main body 1a has an inlet 5 and an outlet 6 opened on the left and right sides of the valve box 4, respectively, and the inlet 5 and the outlet 6 are partitioned vertically by partition walls 7 inside the valve box 4. The primary pressure chamber 8 and the secondary pressure chamber 9 communicate with each other.
The partition wall 7 is provided with a valve port 10 for communicating the primary side pressure chamber 8 and the secondary side pressure chamber 9, and a main valve 11 for opening and closing the valve port 10 is provided at the periphery of the upper opening of the valve port 10. It is provided on the seat 12 so as to be freely attached and detached.
A compression coil-shaped main valve spring 13 is interposed between the back of the main valve 11 and a spring receiver provided above the primary pressure chamber 8 to urge the main valve 11 in the valve closing direction.
The valve stem 14 of the main valve 11 is connected to a diaphragm 16 that is inserted through the valve port 10 and divides the secondary pressure chamber 9 into a diaphragm chamber 15 in the vertical direction. The secondary pressure chamber 9 slidably inserted and supported by a cylindrical valve rod guide 18 provided in a constricted portion 17 provided in the lower side of the side pressure chamber 9. It communicates with a communication hole 19 opened in the constricted part 17 in the vicinity.
[0007]
The pilot valve 2 is a flow path (conduit 20a, 20b, 20c) 20 for diverting from the primary side pressure chamber 8 communicating with the secondary side pressure chamber 9 and the diaphragm chamber 15 through the operation valve 3 assembled to the upper part of the main body 1a. An auxiliary valve 21 that is disposed inside and opens and closes the flow path 20 is provided.
In the valve box 22 of the pilot valve 2, a communication chamber 22 a that communicates with the operation valve 3 through a conduit 20 a, a directly upper flow path 23 that continues above the communication chamber 22 a, and a position above the directly upper flow path 23 An orthogonal flow path 24 that intersects perpendicularly and communicates with the diaphragm chamber 15 via the conduit 20b is provided, and an auxiliary valve is provided on the valve seat 25 provided at the periphery of the opening facing the communication chamber 22a of the directly upper flow path 23. 21 is provided so that it can be worn and detached.
The valve stem 26 of the auxiliary valve 21 is inserted through the directly upper flow path 23, and the front end side of the valve stem 26 can be moved forward and backward (moved up and down) in a pressure regulating chamber 27 that is provided in an airtight manner above the directly above flow path 23. The auxiliary valve spring 28 is externally fitted to the entry portion to urge the auxiliary valve 21 in the valve closing direction.
The pressure adjustment chamber 27 is partitioned from the internal space of the spring cover 29 by a pilot diaphragm 30 interposed between the spring cover 29 covered on the upper part of the valve box 22 and downstream (secondary) of the main body 1a via the detection tube 31. Side).
Inside the spring cover 29, an adjustment spring 33 that is elastically adjustable by an adjustment screw 32 that protrudes from the top of the spring cover 29 biases the pilot diaphragm 30 in the valve opening direction of the auxiliary valve 21, and from the secondary side, a detection tube 31 The valve rod 26 can be moved forward and backward by the contact and separation (contact and separation) of the pilot diaphragm 30 that is displaced by the pressure fluctuation of the steam flowing into the pressure regulation chamber 27 via the.
Further, the conduit 20b to which the orthogonal flow path 24 is connected connects the branch conduit 20c provided in the middle thereof to the orifice 34 provided in the secondary pressure chamber 9 of the main body 1a.
The set pressure of the pilot valve 2 adjusted by the adjusting screw 32 is equal to or higher than the set pressure of the tributary pressure reducing valve 1b, preferably the same pressure.
[0008]
The operation valve 3 is formed by integrally assembling the valve box 35 on the upper part of the main body 1a, and connects the pilot valve 2 and the primary pressure chamber 8 of the main body 1a (on the same line as the flow path 20). A pressure sensing valve 37 for opening and closing 36 is provided inside the valve box 35.
In the valve box 35, a directly upper flow path 38 that communicates with the primary pressure chamber 8 of the main body 1a, and a communication chamber of the pilot valve 2 that intersects perpendicularly above the directly upper flow path 38 and through the conduit 20a. The pressure sensing valve 37 is provided in the valve seat 40 provided at the crossing point of the orthogonal flow path 39 in the direct flow path 38, and the pressure sensing valve 37 is detachable. A pressure sensing valve spring 41 is externally fitted to 37 and urges the pressure sensing valve 37 in the valve opening direction.
The valve rod 42 of the pressure sensing valve 37 enters the pressure chamber 43 provided in the upper part of the directly upper flow path 38 so that the front end side of the valve rod 42 can be moved forward and backward (movable up and down). In addition to being crowned, the bottom of the bellows 44 is brought into contact with the tip of the corresponding valve stem 42, and the flow path 36 (directly upward flow path 38 and orthogonal flow path 39) between the primary pressure chamber 8 and the pilot valve 2 and pressure The periphery of the opening of the bellows 44 is fixed to the periphery of the lower opening of the insertion hole 45 of the valve rod 42 so as to isolate the chamber 43 in an airtight manner.
The pressure chamber 43 is partitioned from the internal space of the spring cover 46 by a pressure-sensitive diaphragm 47 interposed between the spring cover 46 covered on the top of the valve box 35, and downstream of the branching pressure reducing valve 1b of the side pipe SP. The pressure chamber 43 is connected to the via a connecting pipe 48.
Inside the spring cover 46, the pressure sensing diaphragm 47 is urged in the valve closing direction of the pressure sensing valve 37 by an adjustment spring 50 that allows the elastic force to be adjusted by an adjustment screw 49 that protrudes from the upper part of the spring cover 46. The valve rod 42 can be moved forward and backward by the contact and separation of a pressure-sensitive diaphragm 47 that is displaced by the pressure fluctuation of the steam .
The set pressure of the operation valve 3 adjusted by the adjusting screw 49 is set lower than the set pressure of the branch flow reducing valve 1b.
[0009]
Next, the operation of the decompression device for a steam boiler according to the present invention will be described.
In FIG. 1, in the separate steam supply pipe SG immediately after the start of the boiler B or the steam that distributes and supplies steam via a header (not shown), the steam is decompressed by the tributary pressure reducing valve 1b immediately after the steam is supplied downstream. The pressure is reduced to a predetermined pressure by the function, passes through the side pipe SP, and is supplied downstream thereof.
Further, since the vapor pressure in the pressure chamber 43 communicating with the downstream side of the side pipe SP is equal to or lower than the pressure set by the adjustment spring 50 of the operation valve 3, the pressure-sensitive diaphragm 47 and The pressure sensing valve 37 is pressed in the valve closing direction via the bellows 44 (valve rod 42), and the pilot valve 2 does not flow into the pilot valve 2. It does not operate and steam is not supplied to the diaphragm chamber 15, so the diaphragm 16 cannot be displaced in the valve opening direction of the main valve 11, and the elastic force and primary pressure of the main valve spring 13 acting in the valve closing direction of the main valve 11 Therefore, the main valve 11 is closed and no steam flows from the main pipe MP.
When the pressure of the steam in the pressure chamber 43 flowing in via the tributary pressure reducing valve 1b exceeds the set pressure of the operation valve 3 (elastic force of the adjusting spring 50), the pressure sensitive diaphragm 47 receiving the pressure is The pressure sensing valve 37 is opened by the primary pressure of the pressure sensing valve spring 41 and the primary pressure chamber 8 that are displaced in the valve opening direction of the pressure sensing valve 37 and consequently act in the valve opening direction of the pressure sensing valve 37. Then, the steam flows from the primary pressure chamber 8 to the communication chamber 22a of the pilot valve 2 through the flow path 36 and the flow path 20a.
In the pilot valve 2, since the auxiliary valve 21 is opened by the elastic force of the adjusting spring 33, the steam from the primary pressure chamber 8 side flows into the diaphragm chamber 15 from the flow paths 23 and 24 through the conduit 20b. At the same time, it flows into the secondary pressure chamber 9 through the branch conduit 20 c and the orifice 34.
When the flow rate through the flow passages 23 and 24 is greater than the flow rate through the orifice 34, the operating pressure in the diaphragm chamber 15 rises and overcomes the primary pressure on the back of the main valve 11 and the elastic force of the main valve spring 13. The main valve 11 is pushed open, and steam begins to flow from the primary side pressure chamber 8 to the secondary side pressure chamber 9.
Further, since the steam flowing into the secondary side pressure chamber 9 is guided to the pressure adjusting chamber 27 from the detection pipe 31, the pilot diaphragm 30 receives the secondary side pressure and balances with the adjusting spring 33 to increase or decrease the secondary side pressure. The pressure acting on the pilot diaphragm 30 and the adjustment spring 33 work together to increase or decrease the opening by the auxiliary valve 21, and change the inflow to the diaphragm chamber 15 to control the opening by the main valve 11, Set the side to the proper pressure.
When there is no load on the secondary side, the pressure in the pressure adjustment chamber 27 increases, the auxiliary valve 21 is closed by the auxiliary valve spring 28, and the operating pressure in the diaphragm chamber 15 passes through the orifice 34 to the secondary side. The main valve 11 is pushed by the main valve spring 13 and closes.
[0010]
【The invention's effect】
In short, the present invention is provided with a pressure sensing valve 37 that opens and closes the flow path 36 between the pilot valve 2 and the primary pressure chamber 8 of the pressure reducing valve main body 1a, and the valve rod 42 of the pressure sensing valve 37 is connected to the flow path 36. The pressure-sensitive diaphragm 47 is inserted into the pressure chamber 43 which is partitioned in an airtight manner, and can be moved forward and backward by the contact and separation of the pressure-sensitive diaphragm 47 which is displaced by the pressure fluctuation of the fluid in the pressure chamber 43. A pilot-actuated mainstream pressure reducing valve provided with an operation valve 3 biased in the closing direction of the pressure sensing valve 37 by an adjustment spring 50 whose elasticity is freely changeable, and a flow rate smaller than the main flow reducing valve main body 1a. And a tributary pressure reducing valve 1b whose set pressure is lower than the set pressure of the pilot valve 2 and higher than the set pressure of the operation valve 3 is connected in parallel to the steam supply pipe SG, and the pressure control chamber of the pilot valve 2 27 is connected downstream of the main pipe MP connected via the main body 1a, and the pressure chamber 43 of the operation valve 3 is connected. Since it is connected downstream of the side pipe SP connected to the diverting pressure reducing valve 1b, at the initial stage of supplying steam downstream, by supplying steam from the side pipe SP through the tributary pressure reducing valve 1b at a small flow rate, Etc., and the operation valve 3 senses that the downstream pressure of the side pipe SP has increased to reach the set pressure, so that the main body 1a of the mainstream pressure reducing valve functions, and the main pipe MP Also, it is possible to automatically supply steam, and the labor and time conventionally performed manually by the operator can be completely eliminated.
The set pressure of the operation valve 3 can be changed as appropriate by adjusting the elastic force of the adjusting spring 50 with the adjusting screw 49, so that it can be used according to the capacity of the boiler B. is there.
[Brief description of the drawings]
FIG. 1 is a simplified piping system diagram of a decompression device.
FIG. 2 is a cross-sectional view of a mainstream pressure reducing valve.
FIG. 3 is a side view of the pressure reducing valve.
FIG. 4 is an enlarged sectional view of a pilot valve and an operation valve.
FIG. 5 is an enlarged cross-sectional view of an operation valve.
FIG. 6 is a simplified piping system diagram of a conventional steam supply facility.
[Explanation of symbols]
1a Pressure reducing valve body
1b Tributary pressure reducing valve 2 Pilot valve 3 Operating valve 4 Valve box 8 Primary pressure chamber 9 Secondary pressure chamber
10 Valve
11 Main valve
13 Main valve spring
14 Valve stem
15 Diaphragm room
16 Diaphragm
20 channels
21 Auxiliary valve
26 Valve stem
27 Pressure control room
30 Pilot diaphragm
33 Adjusting spring
36 flow path
37 Pressure sensing valve
42 Valve stem
43 Pressure chamber
47 Pressure-sensitive diaphragm
49 Adjustment screw
50 Adjustment spring SG Steam supply pipe MP Main pipe SP Side pipe

Claims (1)

The main valve that opens and closes the valve port communicating with the primary side pressure chamber and the secondary side pressure chamber partitioned inside the valve box is energized in the valve closing direction by the main valve spring, and the secondary side pressure chamber is the diaphragm chamber. A pressure reducing valve main body formed by connecting a valve stem of a main valve to a diaphragm divided into two, and an auxiliary valve that opens and closes a flow path for branching from the primary pressure chamber to the secondary pressure chamber and the diaphragm chamber. The valve rod of the auxiliary valve enters into a pressure control chamber that is airtightly defined with the flow path that opens and closes the auxiliary valve, and the pilot diaphragm that is displaced by the pressure fluctuation of the fluid in the pressure control chamber makes contact and separation. Providing a pilot valve that can be moved forward and backward, energizing the pilot diaphragm in the opening direction of the auxiliary valve with an adjustment spring, and a pressure sensing valve that opens and closes the flow path between the pilot valve and the primary pressure chamber The valve stem of the pressure sensing valve is connected to the pilot valve. The pressure sensor is inserted into a pressure chamber partitioned in a gastight manner with a flow path between the valve and the primary pressure chamber, and can be moved forward and backward by a pressure-sensitive diaphragm that is displaced by pressure fluctuations of the fluid in the pressure chamber. The main flow pressure reducing valve is composed of an operation valve that is urged in the valve closing direction of the pressure sensing valve by a separate adjusting spring whose elastic force can be freely changed by an adjusting screw, and a flow rate smaller than that of the main pressure reducing valve body. And a tributary pressure reducing valve whose set pressure is less than or equal to the set pressure of the pilot valve and higher than the set pressure of the operation valve is connected in parallel to the steam supply pipe, and the pressure control chamber of the pilot valve is interposed in the main body A steam boiler decompression device, wherein the steam chamber is connected to a downstream side of a connected main pipe, and a pressure chamber of the operation valve is connected to a downstream side of a side pipe connected to the tributary decompression valve.

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