JPH01234910A - Multistage pressure reducing device for pressure reducing valve - Google Patents

Abstract

PURPOSE:To attain efficient pressure reduction balanced as a whole by finding out the optimum set pressure value of each pressure reducing valve in a control part only by inputting primary side pressure and a set pressure value and controlling a driving part for each pressure reducing valve based on the set pressure value. CONSTITUTION:In case of executing secondary pressure reduction, a primary side pressure (P0') detecting means 71, a 1st pressure reducing valve (R1) 72, a 1st-stage pressure (P1') detecting means 73, a 2nd pressure reducing valve (R2) 74, a secondary side pressure (P2') detecting means 75, and controllers 76, 77 for controlling respective pressure reducing valves are prepared. Since the flow rates of respective pressure reducing valves and relational data for finding out the optimum set pressure of the 1st pressure reducing valve 72 from data in a settable range are stored in a storage means of the controller 77, the optimum set pressure values of respective pressure reducing valves are found out in the controller 77 and the driving parts of respective pressure reducing valves are controlled based on the set pressure values. Consequently, accurate, stable and efficient multistage pressure reduction can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a pressure reducing valve that is attached to piping for steam, compressed air, etc. to maintain fluid pressure on the secondary side at a constant set pressure.

Prior Art A conventional pressure reducing valve is shown in FIG. In the figure, reference numeral 2 denotes a pressure setting spring, and a spring receiver 26 that contacts the diaphragm is attached to one end of the spring, and a spring receiver 4 is attached to the other end. This spring receiver 4 is in contact with the tip of an adjusting screw 8 via a ball 6. A male thread 10 is formed on the peripheral edge of the distal end of the adjustment screw 8, and is screwed into a fixedly provided female thread 12. A midway portion of the adjustment screw 8 is supported by a thrust bearing 14, and a hole is cut from the other end toward the inner depth. A retainer 16 and a pawl 18 are provided within this hole to form a spline hole.

A spline l[1I20 is spline-fitted into this spline hole, and this spline shaft 20 is connected to the rotating shaft of a motor 24 via a speed reducer 22.

When the rotation shaft of the motor 24 is rotated in one direction, the spline shaft 20 rotates, and this rotation is transmitted to the adjustment screw 8, causing it to rotate. At this time, since the male threaded portion 10 of the adjustment screw 8 is screwed into the female thread 12 that is fixedly installed,
The adjusting screw 8 descends downward, and the spring receiver 4 compresses the pressure setting spring 2, allowing the set pressure to be increased. When the rotating shaft of the motor 24 is reversely rotated, the adjustment screw 8 is raised in the same manner as described above, and the pressure setting spring 2 is extended, so that the set pressure can be reduced.

The diaphragm 28 is compressed via the spring receiver 26 provided at the other end of the pressure setting spring 2, and the pilot guide 3
0 is lowered, and the pilot valve 32 is pushed down against the acting force of the coil spring 34.

In this state, primary pressure fluid, for example -
When sub-pressure steam is introduced, a portion of this sub-pressure steam is
enters the lower chamber of the pilot valve 32 through a passage 38 and enters the upper chamber of the piston 42 through the opened pilot valve 32 and the second passage 40, whereby the piston 42 is moved by the action of the coil spring 44. The main valve body 46 opens. Most of the primary pressure steam introduced from the inlet 36 is sent out from the outlet 48 as secondary pressure steam via the opened main valve body 46. A portion of this secondary pressure steam is sent into the chamber below the diaphragm 28 via the third passage 50.

When the secondary pressure is higher than the pressure set by the pressure setting spring 2, the diaphragm 28 is pushed up against the force of the pressure setting spring 2, reducing the opening degree of the pilot valve 32,
Therefore, the opening degree of the main valve body 46 is reduced, the secondary pressure is reduced, and the pressure is maintained at the set pressure. On the other hand, if the secondary pressure is lower than the set pressure, the steam reverses the action to increase the secondary pressure and maintain it at the set pressure. In addition, 52 is the main valve body frame 54 of the main valve body 46.
of! It is a cylinder for stirring speech and movement, and is supported by an open state 56 provided within the main body 2.

For controlling this pressure reducing valve, a pressure sensor 60 is installed on the secondary side.
and sends the signal to the control section 62.

The control unit 62 compares the set pressure value inputted from the setting unit 64 with the secondary side pressure value, and applies a drive signal to the motor 24 so that the secondary side pressure becomes the same as the set pressure value. It is.

Problems to be Solved by the Invention Generally, in businesses that use steam, high-pressure steam is generated in a central boiler, and the high-pressure steam is reduced to the working pressure of each factory and the pressure required for each steam-using device. and supply it. However, when this pressure is reduced, the pressure reduction ratio is within a relatively small range, for example - next pressure 10 Kg/CfI! 5
When reducing the pressure to K'j/ctrt, it is possible to stably reduce the pressure within the specification range of one pressure reducing valve, but for example, when reducing the pressure from 16 Kg/cm to 2'j/cr/l, the pressure can be reduced stably within the specification range of one pressure reducing valve. Chattering occurs because the ratio is too large.

This chattering phenomenon is a phenomenon in which the members of the pressure reducing valve move significantly together with a loud noise, making settings impossible and eventually damaging the valve.

As a pressure reduction method to prevent this, for example, there is a multi-stage pressure reduction method using two pressure reduction valves. In other words, the high primary pressure is reduced twice to the desired value. However, the problem here is how many kg/ctrt should be set for the first pressure reducing valve in order to perform the most efficient pressure reducing action without undue stress. - Next pressure is PO11th pressure reducing valve is old, - stage setting pressure is Pl, second pressure reducing valve is R2,
If the target set pressure is R2, then PO, R2
The Pl that can be set is determined within a certain range from the relationship, but
If Pl is set at any pressure within that range, the rated flow rate may decrease.

Furthermore, since the flow rate from PO to Pl is not balanced with the flow rate from Pl to R2, one of the pressure reducing valves may be accompanied by insufficient capacity or abnormal imaging. In order to prevent this, Pl should be determined by X without checking the specifications of each pressure reducing valve, but in reality, Pl is determined empirically by workers at the workplace.

Therefore, the technical problem of the present invention is that anyone can automatically determine the optimum Pl and perform an efficient pressure reduction action without requiring any experience by simply inputting the primary pressure PO and any set pressure P2. The object of the present invention is to provide a multi-stage decompression device that performs the following steps.

Means for solving the problems The technical means of the present invention taken to solve the above problems are as follows:
A pressure reducing valve, a means for adjusting the set pressure of the pressure reducing valve, a means for driving the adjusting means, a setting section for inputting a set pressure value to the driving means, and a pressure detection device provided on the secondary side of the pressure reducing valve. In a pressure reducing valve comprising a means and a control section that provides a drive signal to the drive means so that the detected pressure on the secondary side becomes the same as the above-mentioned 82 constant pressure value, a plurality of these pressure reducing valves are used to control high pressure. When setting the primary pressure to a low pressure by reducing the pressure in multiple stages,
The storage means of the control unit records related data for determining the optimal set pressure of each pressure reducing valve from the data of the setting range of each pressure reducing valve, and the primary side pressure and set pressure value. The optimum set pressure value for each pressure reducing valve is determined within the control section simply by manual operation, and the drive section of each pressure reducing valve is controlled based on this set pressure value.

For example, when performing two-stage pressure reduction, the storage means of the control unit stores the flow rate of each pressure reducing valve and related data for determining the optimal setting pressure of the first pressure reducing valve from the data in the settable range. Therefore, by manually inputting the primary pressure and the target secondary side set pressure to the setting section, the optimum first stage set pressure is determined from the above data in the control section, and this set pressure drives the first pressure reducing valve. Input as a signal. The first pressure reducing valve reduces the pressure in the first stage according to this signal, and the second pressure reducing valve receives the target set pressure as it is and reduces the pressure, thereby achieving overall harmonious and efficient pressure reduction.

Example An example showing a specific example of the above technical means will be described.

Since the pressure reducing valve is the same as that shown in FIG. 6, detailed explanation will be omitted.

In this embodiment, a case where the pressure is reduced in two stages as shown in FIG. 1 will be explained. In the figure, 71 is the primary side pressure (PO') detection means, 72 is the first pressure reducing valve (R1), 73 is the first stage pressure (PI") detection means, and 74 is the second pressure reducing valve (R1). R2)
, 75 is a secondary side pressure (P2°) detection means. 76.
77 is a controller for controlling each pressure reducing valve, and the controller 76 includes R1 and Plo, and the controller 7
7, connect R2 and P2°. Also, controller 7
As will be described later, the recording/polishing means in 7 records the optimum set pressure P1 of R1 from the data of the flow rates of R1 and R2 and the set pressure range.
Store it in the relationship data to find it. Therefore, go to controller 77.

When PO and Pl are input, the optimum set pressure P1 is determined and sent to the controller 76. R1 receives this signal and turns Pl”
A depressurizing action is performed so that P becomes Pl, Pl is input as is to R2, and a depressurizing action is performed so that P2' becomes Pl.

On the other hand, the related data for determining Pl stored in the storage means of the controller 77 is created in the following procedure.

Figure 3 shows a graph of the relationship between the primary side pressure and set pressure, and Figure 4 shows a graph of the possible setting range of the pressure reducing valve. Create relational data to find Pl from the indicated PO and Pl.

First, when selecting the rated flow rate υ2 of Pl from Pl to the maximum Pl in the range of Pl that can be set from PO to Pl,
When the rated flow rate Q1 from po to Pl is Q2>Ql, Pl is set so that Q2 and 01 are approximately equal. (5th
Figure X part) When the above is 02 < Ql, set pressure is Pl where the rated flow rate Q2 from Pl to Pl is maximum and Pl is minimum. (Part Y in FIG. 5) When Pl at which Q2 becomes maximum is smaller than the minimum value of the PO pressure setting range, Pl of the lowest settable pressure is set as the set pressure. (FIG. 5, Section Z) The graph shown in FIG. 5 is a graph that summarizes the above procedure for each pressure, and is stored in the recorder means in the controller 77. For example, Po is 16Kg/car and Pl is 7Kg/crtr
When you want to set Pl to about 12KFi/cm (point Al>,
When you want to set Pl to 5'j/cri, approximately 10Kg/-d
(Point A2), if you want the same < 2 Kg/cti, it is about 8 匈/cri < point 3).

In Figure 1, two controllers 1 to 01 are supported, but the
As shown in the figure, a single controller can also be used. Further, based on the above idea, multistage decompression such as three or four stages is also possible in addition to two stages.

Effects of the Invention According to the present invention, there is no need to calculate and set the respective pressures of Pl and P2 based on specifications such as catalogs, but by simply inputting PO and P2, Pl is automatically determined and even set. Therefore, accurate, stable, and efficient multi-stage depressurization is possible.

Further, as for the related data for determining Pl, a Pl as low as possible is selected so that the rated flow rate is maximized, or when the flow rates are the same, in order to reduce heat radiation loss, economical operation is possible.

[Brief explanation of the drawing]

Fig. 1 is a piping system diagram of an embodiment of the present invention, Fig. 2 is a piping system diagram of another embodiment, Fig. 3 is a flow rate graph of a pressure reducing valve, and Fig. 4 is a piping system diagram of an embodiment of the present invention.
The figure shows the setting range of the pressure reducing valve, and Figure 5 shows the PO and P
FIG. 6 is a cross-sectional view of a conventional pressure reducing valve. 36: Inlet 48; Outlet 24: Motor 62: Control section

Claims (1)

[Claims] 1. A pressure reducing valve, a means for adjusting the set pressure of the pressure reducing valve, a means for driving this adjusting means, a setting section for inputting a set pressure value to this driving means, and a setting section provided on the secondary side of the pressure reducing valve. In a pressure reducing valve consisting of a pressure detecting means and a control section that provides a drive signal to the driving means so that the detected pressure on the secondary side becomes the same as the set pressure value, a plurality of these pressure reducing valves are used to control high pressure. When setting the primary pressure to a low pressure by reducing the pressure in multiple stages, the control unit stores related data for determining the optimal setting pressure for each pressure reducing valve from the flow rate of each pressure reducing valve and data on the settable range of the pressure reducing valve. By simply inputting the primary side pressure and the set pressure value, the optimum set pressure value for each pressure reducing valve is determined in the control section, and the drive section of each pressure reducing valve is controlled based on this set pressure value. A multi-stage pressure reducing device featuring a pressure reducing valve.