JPH10220360A - Pump inlet pressure reducing valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent high pressure from being applied to a downstream side pump when pumps are connected in tandem and water is discharged. SOLUTION: When a plurality of pumps is connected in tandem, an inlet pressure reducing valve 10 is connected to the inlet side of a downstream side pump, thereby, at the time of discharge work, pressure on the inlet side of the downstream pump can be retained to the same as the pressure of a first space 24, and high pressure is prevented from being applied to the downstream side pump. Also, when the downstream side pump and a discharge valve at the end of a drain hose are disconnected so as to stop discharge, a valve element 26 is seated on a valve seat 27, thereby pressure can be prevented from being applied from an upstream side pump to the downstream side pump, and a failure accident can be prevented, which is caused that abnormally high pressure is applied to the downstream side pump and the end of the discharge hose when discharge is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure reducing valve for a pump for reducing the pressure acting on the inlet of a pump for fire fighting or the like.

[0002]

2. Description of the Related Art Conventionally, in a fire extinguishing operation using a fire fighting pump, when a fire site is far from a water source or at a high place, high pressure is required to send water with one pump, and large A prime mover, a pump and a hose with high pressure resistance are required, and the weight becomes heavy and handling becomes difficult.

In order to solve these problems, a method is generally adopted in which a plurality of pumps are connected in series and water is supplied by sequentially increasing the pressure from a pump close to a water source. However, when the pumps are connected in series and operated, the pressure applied to the inlet of the upstream pump is added to the pressure generated by the pump, and the added pressure acts on the inlet of the downstream pump. Therefore, as the number of connected pumps increases, the pressure acting on the inlet of the downstream pump gradually increases.

For this reason, when the pressure of the upstream pump is acting on the inlet of the downstream pump, the downstream pump is operated at a high pressure, the water discharge valve of the downstream pump is closed, or the fire extinguishing worker is operated. If the water discharge valve at the end of the water discharge hose is closed, the pump pressure of the downstream pump will rise abnormally, and the pump or hose will be damaged, making it impossible to extinguish the fire. An operator may be injured by being swung by the reaction force of water discharge.

Conventionally, in response to such a problem, the valve provided at the inlet of the upstream pump is manually operated to adjust the pressure, or the output of the prime mover for driving the upstream pump is manually operated. Was.

Further, as described in Japanese Patent Publication No. 6-98197, a method is known in which a relay water control valve is provided near the inlet of a pump to automatically adjust the inlet pressure of the pump.

[0007]

In the method of manually operating the valve and adjusting the output of the prime mover, there is a situation where the above-mentioned accidents are continually caused due to delays or mistakes in the operation. Moreover, under the condition that there is a distance between pumps and a height difference, difficulty in information transmission is added, and the frequency of the above-mentioned accidents is doubled.

In order to prevent the adverse effects of such a manual operation, an automatic operation device such as Japanese Patent Publication No. Hei 6-98197 has been proposed. However, according to this method, when the downstream pump discharges water, Inlet pressure can be adjusted automatically. However, when the downstream pump and the water discharge valve at the end of the water discharge hose are shut off and the water discharge is stopped while the upstream pump is driven, the pressure applied to the upstream side of the pressure control valve increases,
As the pressure regulating valve is pushed open, the high pressure of the upstream pump acts on the inlet of the downstream pump, and the pressure of the downstream pump, which has just been high due to the cutoff operation, further increases, and the pump and hose are damaged. There is a significant disadvantage of doing so.

Accordingly, the present invention provides a method for controlling the pressure of an upstream pump when a plurality of pumps are connected in series and the discharge of water is stopped by shutting off a water discharge valve at a downstream pump or a discharge hose tip. Pump inlet that can prevent water from acting on the downstream pump and prevent the downstream pump and hose from being damaged due to large pressure and the fire extinguishing operator from being swung by the reaction force of water discharge. It is an object to provide a pressure reducing valve.

[0010]

According to the first aspect of the present invention,
A pressure reducing valve case having a flow path formed therein and connected to the inlet side of the pump; a movable shaft provided in the pressure reducing valve case and slidable along the flow axis direction of the flow path; A first pressure receiving member fixed to the upstream end of the first pressure receiving member, an inner wall fixed in the pressure reducing valve case and surrounding the first pressure receiving member, and partitioned by the first pressure receiving member inside the inner wall. The first space and the second space, the valve body fixed to the downstream end of the movable shaft, and the movable shaft formed on the inner peripheral surface of the flow path and slid upstream to a predetermined position. A valve seat on which the valve element is seated, a second pressure receiving member fixed to the movable shaft and located upstream of the valve seat, and a first communication passage communicating the first space with the atmosphere. And a second communication passage that communicates the second space with a portion of the flow passage downstream of the valve seat.

Therefore, a plurality of pumps are connected in series,
When an inlet pressure reducing valve is installed at the inlet side of each downstream pump to perform a water discharge operation, water sent from the upstream pump flows through the flow path in the pressure reducing valve case and flows into the inlet of the downstream pump. At this time, the downstream portion of the valve seat in the flow path and the second space communicate with each other through the second communication passage, and the pressure in the second space communicates with the atmosphere through the first communication passage. Since the pressure is automatically adjusted to be equal to the pressure in the first space, when the pressure of the upstream pump becomes higher than the pressure in the first space, the pressure acts on the second space and the first pressure receiving member, the movable shaft, and the valve The body slides integrally to the upstream side, the gap between the valve body and the valve seat decreases, the amount of water flowing to the downstream pump side decreases, and the pressure acting on the inlet of the downstream pump decreases. It falls until it becomes the same value as the pressure of one space.

On the other hand, the pressure on the inlet side of the downstream pump
When the pressure becomes lower than the pressure in the space, the first pressure receiving member, the movable shaft and the valve element slide integrally to the downstream side, the gap between the valve element and the valve seat increases, and the pressure increases toward the downstream side pump side. As the amount of flowing water increases, the pressure acting on the inlet of the downstream pump increases until it becomes the same value as the pressure in the first space. By providing the inlet pressure reducing valve in this manner, even if the pressure of the upstream pump fluctuates during the water discharging operation, the pressure of the inlet of the downstream pump is maintained at the same pressure as the first space.

When the downstream pump or the water discharge valve at the end of the water discharge hose is closed to stop water discharge while the upstream pump is driven, the pressure from the upstream pump acts on the valve element and the second pressure receiving member. The first pressure receiving member, the movable shaft, and the valve do not slide due to the pressure from the upstream pump. On the other hand, when the water discharge is stopped, a pressure higher than the pressure of the first space leaked from the high-pressure portion of the downstream pump acts on the downstream portion of the valve seat, and the pressure is applied to the second space via the second communication passage. Acting, the first pressure receiving member, the movable shaft and the valve element slide integrally on the upstream side, and the valve element is seated on the valve seat. Therefore, when the downstream pump and the water discharge valve at the end of the water discharge hose are closed and the water discharge is stopped while the upstream pump is driven, the pressure of the upstream pump does not act on the downstream pump and the water discharge hose end, etc. Abnormally high pressure does not act on the pump or the end of the water discharge hose.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows a state in which three pumps (a first pump 2, a second pump 3, and a third pump 4) are connected in series in order to discharge water to a fire site remote from the water source 1. A water suction pipe 5 is connected to the inlet side of the first pump 2, a relay hose 6 is connected between the discharge side of the first pump 2 and the inlet side of the second pump 3, and the discharge side of the second pump 3 A relay hose 7 is connected between the first pump 4 and the inlet side of the third pump 4, and a water discharge hose 8 is connected to a discharge side of the third pump 4. The discharge side of each of the pumps 2 to 4 is provided with a water discharge valve 2 a, 3 a, 4 a that can be freely opened and closed.
A water discharge valve 9 is also provided at the tip of the.

An inlet pressure reducing valve 10 is connected to the inlet side of the second pump 3, and an inlet pressure reducing valve 11 is connected to the inlet side of the third pump 4. These inlet pressure reducing valves 10,
Reference numeral 11 denotes the same structure, and the structure will be described with reference to FIG. Each of the inlet pressure reducing valves 10 and 11 has an inlet 12 formed at one end, an outlet 13 formed at the other end, and a flow path 14 formed between the inlet 12 and the outlet 13. 15. The pressure reducing valve case 15 includes a first case 15a and a second case 1 each having a cylindrical shape.
5b is connected by a plurality of bolts 16. An O-ring 17 for connecting the relay hose 6 and a hose connection fitting 18 are attached to the first case 15a. A screw 19 for connecting the inlet pressure reducing valves 10 and 11 to the inlet of the second pump 3 or the third pump 4 is formed on the inner peripheral surface of the second case 15b, and further, airtightness is secured during this connection. Gasket 20 is attached. Also, on the outer peripheral portion of the second case 15b,
The inlet pressure reducing valves 10 and 11 are connected to the second pump 3 or the third pump 4
A handle 15c that is operated when connected to the entrance of the camera and that also serves as a handle for carrying is integrally formed.

A pressure reducing valve shaft 21 slidably movable along the flow axis direction of the flow path 14 in the pressure reducing valve case 15.
Is provided. An inner peripheral end of a flexible diaphragm 22, which is a first pressure receiving member, is fixed to an upstream end of the pressure reducing valve shaft 21, and an outer peripheral end of the diaphragm 22 is connected to the first case 15a and the first case 15a. It is sandwiched between the two cases 15b. Further, inside the pressure reducing valve case 15, an internal wall 23 surrounding the upstream end of the pressure reducing valve shaft 21 and the diaphragm 22 is provided at a fixed position, and the inside of the internal wall 23 is defined by the diaphragm 22. First space 2
4 and a second space 25.

A pressure reducing valve 26 as a valve is fixed to the downstream end of the pressure reducing valve shaft 21. The second case 1
A pressure reducing valve seat 27, which is a valve seat on which the pressure reducing valve body 26 is seated when the pressure reducing valve shaft 21 slides upstream to a predetermined position, is formed on the inner peripheral surface of 5b. The pressure reducing valve shaft 21
A pressure receiving piston 28, which is a second pressure receiving member located upstream of the pressure reducing valve seat 27, is integrally formed between the pressure reducing valve body 26 and the diaphragm 22. The diameter of the pressure receiving piston 28 is formed to be the same as the diameter of the pressure reducing valve seat 27. A guide hole 29 is formed in the inner wall 23, and the outer periphery of the pressure receiving piston 28 is slidably fitted in the guide hole 29. An O-ring 30 is attached to the outer peripheral surface of the pressure receiving piston 28.

The first space 24 is provided with the pressure reducing valve case 1
5 communicates with the atmosphere through a first communication passage 31. The second space 25 is communicated with a portion of the flow path 14 downstream of the pressure reducing valve seat 27 by a second communication passage 32 formed in the pressure reducing valve case 15.

In such a configuration, three pumps 2 to 4 are connected in series as shown in FIG.
Is driven and the water discharge valves 2a to 4a, 9 are opened, so that the water sucked from the water source 1 is supplied to the relay hose 6,
Water is discharged from the distal end of the water discharge hose 8 via the pump 7 and the water discharge hose 8 and the pumps 2 to 4 and the inlet pressure reducing valves 10 and 11.

Here, the operation of the inlet pressure reducing valves 10 and 11 will be described. Since the operation of the inlet pressure reducing valves 10 and 11 is the same, the operation of one of the inlet pressure reducing valves 10 will be described.

First, the operation during the water discharging operation will be described. Water sucked from a water source by driving the first pump 2 flows into the second pump 3 via the flow path 14 of the inlet pressure reducing valve 10. At this time, the pressure generated by driving the first pump 2 acts on the second space 25 through the flow path 14 and the second communication path 32. Here, the atmospheric pressure acts on the first space 24, and when the pressure generated by driving the first pump 2 is higher than the atmospheric pressure, the pressure reducing valve shaft 21 is moved upstream together with the diaphragm 22 and the pressure reducing valve body 26. Side, the pressure reducing valve body 26 approaches the pressure reducing valve seat 27. And the pressure reducing valve body 26
The gap between the pressure reducing valve seat 27 and the pressure reducing valve seat 27 becomes small, the amount of water flowing to the second pump 3 side decreases, the pressure acting on the downstream side of the pressure reducing valve seat 27 gradually decreases, and this pressure is reduced to the first space 24. Pressure reducing valve shaft 21 until it becomes the same as the atmospheric pressure acting on
When the slider slides, it stops at that position.

On the other hand, when the pressure on the downstream side of the pressure reducing valve seat 27 or on the inlet side of the second pump 3 becomes lower than the atmospheric pressure due to a decrease in the amount of water supplied from the first pump 2, the pressure in the second space 25 also increases. Since the pressure is lower than the atmospheric pressure, the pressure reducing valve shaft 21 slides downstream together with the diaphragm 22 and the pressure reducing valve body 26, and the gap between the pressure reducing valve body 26 and the pressure reducing valve seat 27 increases. Then, the gap between the pressure reducing valve body 26 and the pressure reducing valve seat 27 increases, and the amount of water flowing toward the second pump 3 increases, which acts on the downstream side of the pressure reducing valve seat 27 and the inlet of the second pump 3. The pressure gradually increases, and the pressure reducing valve shaft 21 slides to a position where the pressure becomes equal to the atmospheric pressure acting on the first space 24,
Stop at that position. By providing the inlet pressure reducing valve 10 on the inlet side of the second pump 3 in this manner, even if the pressure of the first pump 2 fluctuates during the water discharging operation, the pressure at the inlet of the second pump 3 is maintained at the atmospheric pressure. Can be kept the same.

Since the inlet of the third pump 4 is also connected to the inlet pressure reducing valve 11, the pressure at the inlet of the third pump 4 can be maintained at the same level as the atmospheric pressure. Therefore, even if a large number of pumps 2, 3, and 4 are connected in series as shown in FIG.
The pressure at the inlet of the pump can be maintained at the same level as the atmospheric pressure, preventing the pressure acting on the downstream pumps 3 and 4 from becoming abnormally high. Can be prevented. The water pressurized by the third pump 4 is discharged from the distal end of the water discharge hose 8 in a high pressure state.

Next, the operation of the inlet pressure reducing valve 10 when the water discharge valve 3a of the second pump 3 is closed during the water discharge operation will be described. The pressure of the first pump 2 enters the inlet pressure reducing valve 10 and acts to increase the gap between the pressure reducing valve body 26 and the pressure reducing valve seat 27 by pushing the pressure reducing valve body 26 downstream. It also acts in the direction of pushing to the side to reduce the gap between the pressure reducing valve body 26 and the pressure reducing valve seat 27. Accordingly, both forces cancel each other to zero, and the inlet pressure reducing valve 10
Is negligible.

On the other hand, if the driving of the second pump 3 is continued while the water discharge valve 3a is closed, a pressure higher than the atmospheric pressure leaks from the high-pressure portion in the second pump 3 to the inlet side of the second pump 3, and
The inlet side of the pump 3 and the downstream side of the pressure reducing valve seat 27, and further,
The pressure in the second space 25 communicated with the second communication passage 32 becomes higher than the atmospheric pressure. Then, by the action of this pressure, the pressure reducing valve body 26 slides upstream together with the pressure reducing valve shaft 21 and the diaphragm 22 to be seated on the pressure reducing valve seat 27, and the flow path 14 is shut off. For this reason, the pressure of the first pump 2 does not act on the inlet of the second pump 3, and it is possible to prevent the abnormally high pressure from acting on the second pump 3 to damage the second pump 3.

During the water discharge operation, the water discharge valve 9 at the tip of the water discharge hose 8
When the water is stopped by closing the pump, the upstream pump 2,
The pressure of 3 does not act on the downstream pumps 3 and 4 and the tip of the water discharge hose 8, but the abnormally high pressure acts on the downstream pumps 3 and 4 and the tip of the water discharge hose 8, and the pumps 3 and 4 and the The breakage of the hose 8 is prevented.

Here, since the components of the inlet pressure reducing valves 10 and 11 are all arranged linearly in the flow path 14, the flow axis of the water flowing through the inlet pressure reducing valves 10 and 11 is also linear, Road resistance is reduced and water can be sent efficiently.

Further, since the inlet pressure reducing valves 10 and 11 can be easily attached to and detached from the relay hoses 6 and 7 and the pumps 3 and 4,
When the pumps 2 to 4 are used independently without being connected in series, the inlet pressure reducing valves 10 and 11 can be easily removed.

In this embodiment, the case where the diaphragm 22 is used as the first pressure-receiving member and the pressure-receiving piston 28 is used as the second pressure-receiving member has been described as an example. It may be either a piston or a pressure receiving member having another structure.

Further, in the present embodiment, the case where only the atmospheric pressure is applied to one surface on the upstream side of the diaphragm 22 by communicating the first space 24 with the atmosphere has been described as an example. A spring or the like may be provided inside 24 to adjust the magnitude of the force acting on one surface on the upstream side of the diaphragm 22.

[0031]

According to the first aspect of the present invention, by connecting the inlet pressure reducing valve to the inlet side of the downstream side pump of the serially connected pump, the pressure of the inlet side of the downstream side pump is reduced during water discharge. It is possible to maintain the same pressure as the pressure in the first space, and therefore, it is possible to prevent the downstream pump and the hose connected to the downstream pump from being damaged due to abnormally high pressure acting on the downstream pump, Further, it is possible to prevent the fire extinguishing worker from being injured by being swung by the reaction force of the water discharge. Furthermore, when water is stopped by closing the downstream pump or the water discharge valve at the end of the water discharge hose during water discharge work, the pressure of the upstream pump can be prevented from acting on the downstream pump by the inlet pressure reducing valve. Damage accidents caused by abnormally high pressure acting on the downstream pump, the end of the water discharge hose, etc. can be prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing an embodiment of the present invention.

FIG. 2 is an explanatory view showing a state in which a plurality of pumps are connected in series during a fire extinguishing operation.

[Explanation of symbols]

 3, 4 Pump 14 Flow path 15 Pressure reducing valve case 21 Movable shaft 22 First pressure receiving member 23 Inner wall 24 First space 25 Second space 26 Valve element 27 Valve seat 28 Second pressure receiving member 31 First communication passage 32 Second connection aisle

Claims (1)

[Claims] 1. A pressure reducing valve case having a flow path formed therein and connected to an inlet side of a pump, and a movable shaft provided in the pressure reducing valve case and slidable along a flow axis direction of the flow path. When,
A first pressure receiving member fixed to the upstream end of the movable shaft;
An inner wall fixed in the pressure reducing valve case and surrounding the first pressure receiving member; a first space and a second space partitioned by the first pressure receiving member inside the inner wall; and a downstream of the movable shaft. A valve body fixed to a side end, a valve seat formed on an inner peripheral surface of the flow passage, and the valve body seated when the movable shaft slides upstream to a predetermined position; and the movable shaft. A second pressure-receiving member fixed to the valve seat and located upstream of the valve seat; a first communication passage communicating the first space with the atmosphere;
An inlet pressure reducing valve for a pump, comprising: a second communication passage which communicates the second space with a downstream portion of the flow passage from the valve seat.