JPH0578714B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a pressure reducing valve that is attached to a steam pipe to maintain fluid pressure on the secondary side at a constant pressure, and in particular, an actuator is used to move an adjusting screw forward and backward. This invention relates to an automatic setting pressure reducing valve.

2. Description of the Related Art A conventional automatic setting pressure reducing valve is shown in FIG. A pressure setting spring 24 is housed in a spring case 25, and a spring receiver 26 that contacts a diaphragm 28 is attached to one end of the spring, and a spring receiver 22 is also attached to the other end. This spring receiver 22 is in contact with the tip of the adjusting screw 10 via the ball 20. A male thread 16 is formed on the peripheral edge of the distal end of the adjusting screw 10, and is screwed into a fixedly provided female thread 18. A midway portion of the adjusting screw 10 is supported by a thrust bearing 15, and a hole is cut inwardly from the other end. A retainer 12 and balls 14 are provided within this hole to form a spline hole. A spline shaft 8 is spline-fitted into this spline hole, and this spline shaft 8 is connected to the rotating shaft of the motor 4 via a speed reducer 6.

When the motor shaft is rotated in one direction,
The spline shaft 8 rotates, and this rotation is controlled by the adjusting screw 1.
0 and rotates. At this time, the male threaded portion 16 of the adjusting screw 10 is fixedly provided on the female thread 1.
8 are screwed together, the adjusting screw 10 descends downward, the spring receiver 22 compresses the pressure setting spring 24, and the set pressure can be increased. When the rotating shaft of the motor 4 is rotated in the opposite direction, the adjusting screw 10 is raised in the same manner as described above, and the pressure setting spring 24 is extended to reduce the set pressure.

There is a functional relationship between the value representing the position of the tip of the adjusting screw 10 from the reference position (screw position) and the degree of compression of the pressure setting spring 24, and thus the set pressure, and the motor 4 is rotated. By causing the adjustment screw 10 to take a predetermined screw position,
A predetermined set pressure can be set.

In addition, as a method of controlling the adjusting screw 10 so that it takes a predetermined screw position, for example, a screw position detection device such as a potentiometer is provided, and the motor is operated until the output from this generates a signal indicating that the predetermined screw position is detected. Alternatively, a stepping motor for which it is known how many times it will rotate when one pulse is supplied is used as the motor 4, and the number of pulses supplied to the stepping motor is controlled. .

As mentioned above, there is a functional relationship between the screw position and the set pressure, so this relational expression is stored in the microcomputer in the adjustment system, the set pressure is input to the microcomputer, the screw position is calculated, A microcomputer controls the motor 4 so that the adjustment screw 10 takes this screw position.

Then, the actual secondary pressure is detected by a pressure sensor (not shown) installed on the secondary side of the pressure reducing valve, and the screw position is adjusted so that the deviation between this secondary pressure and the set pressure becomes 0. Adjust.

When the diaphragm 28 is compressed via the spring receiver 26 provided at the other end of the pressure setting spring 24, the pilot guide 30 descends, pushing down the pilot valve 32 against the force of the coil spring 34. In this state, when primary pressure steam is introduced from the inlet 36, a part of this primary pressure steam enters the chamber below the pilot valve 32 via the first passage 38, and enters the opened pilot valve 32. , enters the chamber above the piston 42 via a second passage 40.

As a result, the piston 42 descends against the force of the coil spring 44 and opens the main valve body 46. Most of the primary pressure steam flowing in from the inlet 36 passes through the opened main valve body 46 and is transferred to the outlet 48 as secondary pressure steam.
sent from. A part of this secondary pressure steam is
is fed into the lower chamber of the diaphragm 28 through a passage 50.

When the secondary pressure is higher than the pressure set by the pressure setting spring 24, the diaphragm 28
4, the opening degree of the pilot valve 32 is reduced, and therefore the opening degree of the main valve body 46 is reduced, and the secondary pressure is reduced and maintained at the set pressure. On the other hand, if the secondary pressure is lower than the set pressure, the secondary pressure is increased and maintained at the set pressure by the reverse operation. Note that 52 is a cylinder for sliding the main valve rod 54 of the main valve body 46, and is supported by the cylindrical body 56.

Problems to be Solved by the Invention In order to control the above-mentioned pressure reducing valve, in addition to external control equipment such as a microcomputer, an actuator case (not shown in Fig. 2) is required. A printed circuit board with electronic components attached is housed inside.

During operation of the pressure reducing valve, hot steam is present under the diaphragm 28, and heat is transferred through the spring case to the actuator housing the electronic components. As a result, the heat had a negative effect on electronic components, causing the motor to malfunction and become uncontrollable.

The spring case 25 has a cylindrical shape, and the inside thereof is in a substantially sealed state, and the air inside the case does not move, so that the heat dissipation effect of the spring case is hindered. Therefore, it is possible to install a ventilation hole, but the current one has only one small hole in the horizontal direction to prevent rainwater from entering, so the effect could not be expected.

Therefore, the technical problem of the present invention is to provide a heat dissipation structure for an automatically setting pressure reducing valve that solves the above-mentioned problems.

Means for Solving the Problems The technical means of the present invention taken to solve the above-mentioned problems is to apply the elastic force of a pressure setting spring to one surface and apply the fluid pressure on the secondary side to the other surface of the diaphragm. A pressure reducing valve that drives a main valve body by displacement, and is configured to adjust the set pressure of the valve by applying rotation to an adjusting screw and moving it forward and backward to change the biasing state of the pressure setting spring. In the automatic setting pressure reducing valve in which the adjustment screw is moved forward and backward by an actuator, a vent hole is provided in the side wall of the spring case that houses the pressure setting spring from the inside to the outside and diagonally downward. A plurality of vents are opened, and only the uppermost vent is opened diagonally upward from the inside to the outside, and cooling fins are provided between the vents.

Function When the air inside the housing that houses the pressure setting spring is heated by the heat from the main body, it becomes lighter and rises. Then, fresh air from outside is sucked into the housing from the vent opening at the top that opens diagonally upward from the inside to the outside, and at the same time, from the vent opening below that opening diagonally downward from the inside to the outside. The housing is cooled by air.

Example An example showing a specific example of the above technical means will be described. (See FIG. 1) This embodiment will be explained by improving a part of the automatic setting pressure reducing valve shown in FIG. 2, and a detailed explanation of the pressure reducing valve as a whole will be omitted.

A pressure setting spring 24 is housed in a spring case 60, and vent holes 61 to 68 are opened diagonally downward from the inside to the outside in the side wall of the spring case 60. In this embodiment, the openings are symmetrically opposed to each other, but the openings may be opened in other three directions. Then, vent holes 69 and 70 are opened diagonally upward from the inside to the outside at the top of the above-mentioned ventilation holes. Disc-shaped cooling fins 71 to 74 are provided diagonally downward between the respective vent holes.

The heated air inside the spring case 60 becomes lighter, rises, and exits from the vents 69 and 70. At the same time, fresh air from the outside flows in from the vents 61 to 68, and the spring case 60 is constantly cooled. The heat of the spring case 60 is also radiated from the cooling fins 71 to 74.

Since the cooling fins 71 to 74 are installed diagonally downward, they have a heat dissipation effect and the ventilation holes 6
It also serves to prevent rainwater from entering the spring case 60 from the springs 1 to 68. Although the vents 69 and 70 open diagonally upward, they are covered by a flange 75 immediately above, so that rainwater does not enter.

Effects of the Invention According to the present invention, since the spring case is cooled using air convection, the spring case can be cooled more efficiently than heat dissipation using only cooling fins. The cooling fins can also be efficiently cooled by air convection. Therefore, no heat is transferred to the actuator, the electronic components are protected, and normal control operation continues indefinitely.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main part of the embodiment of the present invention, Fig.
The figure is a sectional view of a conventional automatic setting pressure reducing valve. 4... Motor, 10... Adjustment screw, 24... Pressure setting spring, 28... Diaphragm, 36... Inlet, 48... Outlet, 25, 60... Spring case,
61 to 70...Vent holes, 71 to 74...Cooling fins.

Claims (1)

[Claims] 1 A pressure reducing valve that drives the main valve body by the displacement of a diaphragm with the elastic force of a pressure setting spring acting on one side and fluid pressure on the secondary side acting on the other side, which rotates the adjustment screw to move it forward or backward. The automatic setting pressure reducing valve is configured to adjust the set pressure of the valve by moving the pressure setting spring to change the biasing state of the pressure setting spring, and the adjustment screw is moved forward and backward by an actuator. In the side wall of the spring case housing the pressure setting spring, a plurality of vents are opened from the inside to the outside and diagonally downward, and only the uppermost vent is opened from the inside to the outside and diagonally upward. 1. A heat dissipation structure for an automatically setting pressure reducing valve, characterized in that cooling fins are provided between the respective vents.