JP2541999Y2 - Pressure reducing valve for cold regions - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a backflow prevention type pressure reducing valve used in cold regions.

Conventionally, a pressure reducing valve used in a boiler or the like is usually provided with a backflow prevention device to prevent backflow of hot water.However, a pressure reducing valve for a cold region is provided with a drain plug to prevent freezing. After draining the water, the drain cock attached to the pressure reducing valve is opened to drain water from the pressure reducing valve.
According to this method, the water in the pressure reducing valve surely escapes.However, since the check valve closes the valve seat, the non-return valve freezes with the check valve closing the valve seat due to residual water droplets. This can lead to accidents such as no water coming out of the machine.

For this reason, as shown in FIG. 1, for example, after operating the water drain plug, the push rod b also serving as a water drain cock for accommodating the negative pressure operating valve a therein is pushed to open the check valve body c, and the pressure reducing valve is opened. In addition, a device has been put to practical use in which water is drained from the inside, and when the water drain plug is opened to discharge water, the pressing rod b is automatically depressed by the primary water pressure to prevent water leakage from the pressing rod b. Certainly, in the case of FIG. 1, the above-mentioned accident that the passage is closed by ice and water does not come out can be prevented, but the check valve c and the pressing rod b are arranged on the same axis. Therefore, after pressing, the spring d of the check valve body c and the water pressure due to the return water in the secondary pipe at the time of drainage act on the check valve body c and the push rod b as a descending force. When the head difference of the secondary side piping is large, a large descending force acts on the pressing rod b to push down the pressing rod b, and the check valve element c closes the valve seat. In order to prevent the check valve element c from closing the valve seat, the frictional force between the O-ring e and the pressing rod b is increased so that the pressing rod b does not easily descend. However, when the primary pressure is relatively low, the pressure rod b cannot be lowered with the water pressure, and an accident such as the ejection of water from the pressure rod b occurs.

In view of the above points, the present invention aims to provide a backflow prevention type pressure reducing valve that can reliably perform a drainage operation regardless of the level of the primary side water pressure. The body is not provided on the same axis, and the protrusion protruding toward the inflow side of the check valve body can be pressed from a right angle by a pressure rod having a conical tip so that the pressure rod and the first valve can be pressed. It is arranged so that it is perpendicular to the check valve body between the openings, so that the return force of the check valve body due to the spring or the water pressure of the return water at the time of drainage does not act as the return force of the pressing rod. is there.

Hereinafter, the present invention will be described with reference to the embodiment shown in FIGS.

In FIG. 2 and FIG. 3 which shows a cross-sectional view of the check valve portion in the right-angle direction of FIG. 2, reference numeral 1 denotes a valve box of the pressure reducing valve of the present invention, which has an inlet 2 at the left end and an outlet 3 at the right end. It arrange | positions and the 1st valve port 4 and the 2nd valve port 5 are opened in the intermediate part. A packing 9 of a check valve body 8 pressed upward by a spring 7 is pressed against a downward valve seat provided in the first valve port 4, and a first valve port bottom cover connected to the valve box 1. The check valve body 8 can forcibly close the valve seat 6 by raising the water blocking rod 11 screwed to 10. The upper end of the check valve 8 is the inlet 2
A protruding portion having a large-diameter protruding portion 12 formed on the side thereof and a tip 13 formed in a conical shape above the protruding portion 12 as shown in FIG.
A columnar pressing rod 14 having a diameter larger than 12 is arranged without contacting the protruding portion 12 in a normal state. In this state, the ring 15 fitted in the pressing rod 14 abuts on the plug 16 connected to the valve box 1 so as not to move further rightward. The part 17 is in contact with the plug 16 so as not to move further leftward. Reference numeral 18 denotes an O-ring for preventing water leakage. A pressure setting spring is provided on a downward valve seat 19 provided in the second valve port 5 through a diaphragm 21 with respect to a valve rod 20 penetrating the second valve port 5.
The packing 24 of the pressure reducing valve body 23 with the action of the valve 22 is disposed so as to be seated, and the bonnet 25 fixed to the upper end of the valve box 1 is provided.
The pressure is reduced by the downward pressing force of the pressure setting spring 22 locked by the adjusting screw 26 screwed into the diaphragm 21 and the upward pressing force applied to the diaphragm 21 by the secondary pressure in the secondary pressure chamber 27. I try to make it. The pressure reducing valve body 23 is provided with a communication hole 28 extending from the valve rod 20 to the lower end so that a secondary pressure can be introduced into the valve box bottom chamber 29. Numeral 30 denotes a one-way sealing packing which slides on the cylinder 32 of the second valve bottom cover 31 to prevent the high pressure water on the inlet 2 side from entering the valve box bottom chamber 29 and to remove the water at the time of draining. When both sides reach atmospheric pressure,
The secondary pressure on the outlet 3 side escapes to the inlet 2 side by pushing down the one-way sealing packing 30.

Next, the operation of the present invention will be described based on the embodiment shown in FIGS.

Example shows a state in which a negative pressure is generated on the main pipe side,
Since the secondary pressure on the outlet 3 side disappears, the pressure-reducing valve main body 23 opens the maximum by the pressure setting spring 22, but the packing 9 of the check valve body 8 comes into close contact with the valve seat 6 by the spring 7, and The backflow of water or hot water on the outlet 3 side to the pipe side is prevented. When the drainage operation is performed by a water drainage plug (not shown) provided in the upstream pipe of the inflow port 2 at the time of freezing or the like, the pressing rod 14 is pushed by hand from the state of FIG. Of the check valve body 8 comes into contact with the protruding portion 12 of the check valve body 8, and further lowers the check valve body 8 while compressing the spring 7.
The check valve body 8 stops descending in a state of contact with the valve 16. That is, since the packing 9 separates from the valve seat 6 and all the water in the pipe and the pressure reducing valve is drained to the drain port side, there is no possibility that the water will not flow out by freezing at the check valve 8 portion. The return water at the time of drainage and the lifting force of the check valve body 8 by the spring 7 are
In order not to act as a rightward moving force, it is preferable that the upper end of the protrusion 12 is ultimately brought into contact with the cylindrical portion instead of the conical tip 13 of the pressing rod 14, but If 13 is formed in a relatively gentle conical shape, it may be in contact with the conical portion. In any case,
The lifting force of the check valve body 8 acts as a force for pressing the pressing rod 14 against the inner wall surface of the plug 16 and increases the frictional force.
Even if the frictional force between the O-ring 18 of 14 and the plug 16 is reduced so that the pressure rod 14 operates smoothly even at relatively low pressure, the pressure rod 14 automatically turns on at the water pressure of the return water. The valve will not close.

When the drain valve is opened and water is discharged, the check valve body 8 further descends due to the water pressure, and the upward pressing force acting on the pressing rod 14 disappears, so that the pressing rod 14 automatically returns to the original state. .

In other words, even when the primary side is at a relatively low pressure, the accident that the pressure rod does not return due to the water pressure, a negative pressure is generated on the main pipe side in this state, and the hot water flows back to the main pipe side, Even if it does not occur, and even if a structure for draining water from the pressing rod 14 as shown in FIG. 1 is provided, an accident that water spouts from that part does not occur. When the water stop rod 11 is raised using a screwdriver or the like, the packing 9 of the check valve body 8 can be pressed against the valve seat 6 to select the water stop state.
This is convenient when repairing the packing or the diaphragm 21 or replacing the packing of the faucet.

FIG. 4 shows a horizontal hole 34 for drainage containing a negative pressure operating valve 33 therein.
2 and 3 show an embodiment in which the automatic valve closing is less likely to occur due to the water pressure at the time of draining water than that shown in FIGS. On the other hand, a locking groove 35 that fits into the protruding portion 12 of the check valve body 8 is drilled. When the check valve element 8 is lowered, the push rod can be moved rightward for the first time, so that the function as the push rod is not impaired even when the primary pressure is lower. .

In any case, the pressing rod 14 does not automatically close due to the restoring force of the spring 7 or the pressure of the return water at the time of draining, so that the operation of the pressing rod 14 can be made smooth,
Therefore, even when the primary pressure is low, when the water drainage stopper is opened, the pressing rod 14 does not automatically return, water is squirted from the pressing rod, or the check valve body does not close, and a backflow occurs. It can prevent accidents.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a conventional example, FIG. 2 is a longitudinal sectional view showing one embodiment of the present invention, and FIG. 3 is a longitudinal sectional view of a check valve body portion in FIG. FIG. 4 is a vertical sectional view showing a main part of another embodiment of the present invention. 1 is a valve box, 2 is an inlet, 3 is an outlet, 4 is a first valve port, 5
Is a second valve port, 6 is a valve seat, 7 is a spring, 8 is a check valve body, 9 is a packing, 12 is a protruding portion, 13 is a tip, 14 is a pressing rod, 19 is a valve seat, 20 is a valve rod, 21 is a diaphragm, 22 is a pressure setting spring,
Reference numeral 23 denotes a pressure reducing valve body.

Claims (1)

(57) [Scope of request for utility model registration] 1. A first valve port and a second valve port are opened between an inlet and an outlet of a valve box, and a check valve is pressed against a valve seat of the first valve port by a spring. In the valve seat, a pressure reducing valve in which a pressure reducing spring body in which a pressure setting spring is applied via a diaphragm to a valve rod is disposed so as to be seated, wherein a first valve port connected to and fixed to a bottom of the first valve port. The check valve, which moves up and down with the water stop rod screwed up and down inside the bottom lid as a guide, is installed at right angles to the inflow port and the outflow port, has one end flowing from the first valve port. A plug that is formed laterally between the inflow port and the first valve port of the valve box so as to form a large-diameter protrusion that protrudes largely at the inlet side and press the tip of the protrusion downward from above during drainage. A pressure rod that reciprocates with the inner wall as a guide, has a diameter larger than the protrusion of the check valve body, and has a conical tip, is orthogonal to the check valve. Cold climates for a pressure reducing valve which is formed by so that arrangement.