JPH02278085A - Multistage pressure reducing device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of cavitation and erosion by a method wherein fluid pass holes opened and closed through expansion and contraction of a spring resiliently mounted between adjoining two plates of valve plates and a fixing plate are formed in the valve plates and the fixing plate. CONSTITUTION:A fixing plate 16 is located to a staged part 13c of a valve body 11 to close a flow passage 13b. Valve plates 17 and 18 are laminated forward and backward movably in the axial direction of the fixing plate 16. Springs 22 and 23 resiliently mounted between adjoining two plates of the valve plates 17 and 18 and the fixing plate 16 are provided. Fluid pass holes 19 - 21 opened and closed through expansion and contraction of the spring 22 and 23 are formed in the valve plates 17 and 18 and the fixing plate 16. The constitution reliably prevents the occurrence of cavitation and erosion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multistage pressure reducing device suitable for use in a pump water supply system.

[Conventional technology]

Generally, water supply systems found in many industrial power stations are known to supply water from a tank to a boiler using a water supply pump.

Conventionally, in this type of water supply system, as shown in Fig. 4, an overheating prevention valve 2 is connected to the boiler delivery side of the water supply pump 1, which returns a portion of the supplied water to the tank 3 and prevents the water from flowing during startup. Efforts are being made to prevent overheating of water pumps l.

By the way, a differential pressure corresponding to the pressure increase of the water supply pump 1 acts on this type of valve, causing cavitation to occur in the throttle portion. For this reason, in the conventional water supply system, a multistage pressure reducing device 5 consisting of a plurality of fixed orifices 4 connected to an overheating prevention valve 2 is used.
is provided.

(Problem to be Solved by the Invention) However, the fixed orifice 4 in the conventional multistage pressure reducing device is designed to function properly for a predetermined amount of fluid passing through the superheat prevention valve 2; When the amount of passing fluid changes, the differential pressure generated between the upstream side of the desuperheating valve 2 and the downstream side of the fixed orifice 4 does not act on both members 2.4 in an evenly distributed manner, and either There was a problem in that cavitation and erosion were likely to occur in one of the members (overheat prevention valve 2 or fixed orifice 4).In other words, if the differential pressure acting on the fixed orifice 4 was small, the differential pressure acting on the overheat prevention valve 2 If the differential pressure acting on the overheat prevention valve 2 is small, the differential pressure acting on the fixed orifice 4 becomes large.

The present invention was made in view of these circumstances, and it is possible to evenly disperse the differential pressure generated between the upstream and downstream sides of the flow path according to the number of valve plates, thereby preventing the occurrence of cavitation and erosion. The purpose of the present invention is to provide a multistage depressurization device that can reliably prevent such problems.

[Means to solve the problem]

The multi-stage pressure reducing device according to the present invention includes a fixed plate provided in a valve body so as to close a flow path, a plurality of valve plates laminated so as to be movable forward and backward in the axial direction of the fixed plate, and these valve plates and The valve plate and the fixed plate are provided with a spring elastically loaded between two adjacent plates of the fixed plate, and fluid passage holes that are opened and closed by the expansion and contraction of these springs are provided in the valve plate and the fixed plate.

[For production]

In the present invention, the plurality of valve plates can be simultaneously moved along the axis of the flow path by the elastic force of the spring, and the fluid can be passed from the upstream side to the downstream side of the fluid passage hole.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, the structure etc. of this invention will be explained in detail by the Example shown in the figure.

FIG. 1 is a sectional view showing the entire multistage pressure reducing device according to the present invention. In the same figure, inside the valve body indicated by reference numeral 11,
Two channels 12 and 13 are provided, each of which is orthogonal to each other. Both channels 12 and 13 are formed by wave channels each having a circular cross-section and an axis extending in the horizontal and vertical directions. Consists of two channels 13a and 13b,
A stepped portion 13c consisting of an annular flat surface is provided between these flow paths 13a and 13b. In addition, this flow path 13
is open upward along the axis. 14 is a flange 14 that is in contact with the upper opening periphery of both flow paths 12.1.3.
The lid is fixed to the valve body 11, and has an insertion hole 15 opening in the axial direction in the center.

Reference numeral 16 denotes a fixing plate having a circular shape in a plan view, and is provided in the stepped portion 13c in the valve body 11 so as to close the flow path 13b. Valve plates 17 and 18 are circular in plan view, and are stacked so as to be movable forward and backward in the axial direction of the fixed plate 16, and are provided in the flow path 13. Both valve plates 1.7.1.
8 and the fixed plate 16 are provided with a large number of fluid passage holes 19 to 21, each of which opens in the axial direction. These fluid passage holes 19 to 21 are configured to be opened and closed by expansion and contraction of a spring, which will be described later. Also,
The number of these fluid passage holes 19 to 21 is set to gradually increase from the upstream side to the downstream side. That is, the number of fluid passage holes 19 at the bottom is the minimum, and the number of fluid passage holes 21 at the top is the maximum. 2
2 and 23 are compression springs, which are connected to the valve plate 17.
18 and the fixed plate 16 are each mounted between two adjacent plates. 24 is the valve body 17.1
8 is a valve shaft that drives the valve plate 18, and is inserted into the insertion hole 15 via the packing 25 so as to be freely forward and backward, and has a threaded portion connected to an electric drive unit (not shown) at the externally exposed end. 26 are provided. Note that 27 is a seal retainer having a circular shape in plan view, and is fixed to the upper end surface of the lid 14, and an insertion hole 28 through which the valve shaft 24 is inserted is provided in the center.

In the multi-stage pressure reducing device configured in this way, the valve shaft 2
4 is driven upward, the bullet 18 of the spring 22.23
Since the force simultaneously moves the valve plates 17, 18 along the axis of the flow path 13, the fluid can pass from the upstream side to the downstream side of the fluid passage holes 19-21. In this case, when the valve body 17.1B changes from the valve closed state shown in FIG. 2(a) to the valve open state shown in FIG. and the dimension d between the valve body 18
2 is approximately equal to d (dt#dz=d),
Even if the amount of passing fluid changes, the differential pressure PI-P that occurs between the upper and lower flows of the flow path 13! can be evenly distributed in three parts. Here, the amount of movement of the valve plate 7 with respect to the fixed plate 16 and the amount of movement of the valve plate L8 with respect to the valve plate 17 are the same (d+=at
), the pressure drop ratio at each location is constant.

In addition, in this embodiment, since the number of fluid passing holes 19 to 21 is gradually increased from the upstream side to the downstream side of the channel 13, the opening area of the channel structure 3 when the fluid passing holes 19 to 21 are opened is is larger on the downstream side than on the upstream side, and the number of valve plates 17 and 18 required to prevent the occurrence of cavitation can be reduced by reducing the differential pressure acting on the downstream side from the upstream side.

Furthermore, in this embodiment, it is possible to function as a valve with a simple shape, and the fixing plate 16 and the valve plate 17.
Since the pitch adjustment of 18 is no longer necessary, the device can be manufactured simply.

Although this embodiment shows an example in which the valve stem 24 is driven by an electric drive unit (not shown), the present invention is not limited to this, and may be driven manually. The driving means can be changed as appropriate.

Further, the internal shape of the valve body 11 and the valve plate 17 in the present invention are
．． , 18, etc., are, of course, not limited to the above-mentioned embodiments.

〔Effect of the invention〕

As explained above, according to the present invention, there is provided a fixed plate provided in a valve body so as to close a flow path, a plurality of valve plates laminated so as to be movable back and forth in the axial direction of the fixed plate, and these valve plates. The valve plate and the fixed plate are equipped with a spring elastically loaded between two adjacent plates, and the valve plate and the fixed plate are provided with a fluid passage hole that opens and closes by the expansion and contraction of these springs.
The plurality of valve plates can be simultaneously moved along the axis of the flow path by the elastic force of the spring 1a, and the fluid can be passed from the flow side to the downstream side of the fluid passage hole. Therefore, the differential pressure generated between the upstream and downstream sides of the flow path can be evenly distributed according to the number of valve plates, so that cavitation and erosion can be effectively prevented.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the entire multistage pressure reducing device according to the present invention, FIG. 2 (al and (bl) are sectional views showing the valve closed state and valve open state of the multistage pressure reducing device, and FIG. Fig. 4 is a diagram showing an example of using a conventional multistage pressure reducing device in a water supply system. 11...Valve body, 12.13...・Flow path, 16・
... Fixed plate, 17.18... Valve plate, 19-21.
...Fluid passage hole, 22.23...Spring, 2
4...Valve shaft. Patent applicant: Yamatake Honeywell Co., Ltd.

Claims (1)

[Claims] a fixing plate provided in the valve body so as to close the flow path;
A plurality of valve plates are stacked so as to be movable in the axial direction of the fixed plate, and a spring is elastically loaded between two adjacent plates of these valve plates and the fixed plate. A multi-stage pressure reducing device characterized in that a fluid passage hole that opens and closes is provided in the valve plate and the fixed plate.