JPS635737Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a fire extinguishing system equipped with a fire extinguishing pump that is activated when a sprinkler head is activated and supplies a pressurized extinguishing liquid.

Generally, this type of fire extinguishing equipment is equipped with a pressure tank that maintains the pressure inside the piping above a specified value under normal conditions. A pressure switch is connected, and when the pressure inside the pipe drops below the lower limit value due to the operation of the sprinkler head, the pressure switch is turned on and automatically starts the fire pump.

However, if pressure is left in the pipe, a small amount of water leaks from the pipe connections, etc.
Even when the pressure inside the pipe gradually drops and the pressure switch is activated due to this pressure drop due to natural water leakage, the fire pump is activated to maintain the pressure inside the pipe at a specified value.

However, in order to increase the pressure drop in the pipe due to natural water leakage to a predetermined specified value, it is only necessary to start the fire pump for a very short time, and therefore, the fire pump can be turned on within a very short time.・There will be a turn-off. Normally, when starting a fire pump motor, a star connection is used to generate strong torque when the power is turned on, and after the motor reaches a predetermined rotational speed, the motor is switched to a delta connection. On the other hand, in this type of motor, the current value reaches the maximum value at startup, and then the current value becomes steady after switching to the delta connection. For this reason, if the power supply is turned on and off near the maximum current value at startup, an excessive load will be placed on the motor, leading to problems such as damage to the contacts and damage to the motor tube motion control circuit.

This idea was made in view of the above, and aims to provide a fire extinguishing equipment that does not put an excessive burden on the motor circuit of the fire pump that is activated when pipe pressure decreases due to natural water leakage. purpose.

This invention will be explained below based on the drawings.

FIG. 1 is a diagram showing an example of fire extinguishing equipment to which this invention is applied. In Fig. 1, a fire pump 1 is installed in a basement or the like, and is connected to a pipe 4 that pumps fire extinguishing water from a water tank 2 and sends the water under pressure to a plurality of sprinkler heads 3 installed on each floor.
Connected via piping.

A pressure tank 5 is installed as a means for maintaining the pressure in the pipe line 4 so that, for example, a discharge pressure of 1 kg/cm ² or more is obtained at the sprinkler head farthest from the fire pump 1, and the pressure tank 5 is explained later. Air compressed by the pressure of the fire pump 1 is stored through a valve device 8, and the inside of the pipe is maintained at a specified pressure by this compressed air.

A pressure switch 6 is attached to the pressure tank 5.
An upper limit value and a lower limit value are set by giving a predetermined range to the specified starting pressure in , and it is set so that when it is above this upper limit value, it is turned off, and when it is below this lower limit value, it is set to be turned on.

The activation panel 7 of the fire pump 1 is for starting the fire pump 1 by manual operation or by a detection signal from the pressure switch 6 to perform pressurized water supply operation.

In addition, 9 is an elevated water tank used for filling the pipe 4 with water, etc., and 10 is a water tank that detects the initial operation of the sprinkler head 3 on each floor and controls the sprinkler head 3.
11 is a fire pump 1;
This is a test valve that is opened for a start-up test to create the same condition as when the sprinkler head 3 is activated on each floor.

FIG. 2 is a diagram showing details of the valve device 8. As shown in FIG.
In FIG. 2, the inlet 8A is connected to the pressure tank 5.
The outflow port 8B is connected to the discharge side of the fire pump 1. A valve seat 8C is formed on the inlet 8A side, and a lever 8G that is rotatable about a shaft 8F is attached to a valve plate 8D so as to come into contact with this valve seat 8C.
A hole 8E is formed in the valve plate 8D. Therefore, when the flow direction is in the direction of arrow A, most of this flow path is blocked by the valve plate 8D, and fluid flows into the inlet 8A only from the hole 8E.

On the other hand, when the fluid flow direction is in the direction of arrow B, this flow path is completely opened because the valve plate 8D is rotated in the direction of arrow C about the shaft 8F.

Next, the operation of the configuration shown in FIGS. 1 and 2 will be explained.

First, there is a difference in time change between the pressure drop in the pipe 4 when the sprinkler head 3 operates and the pressure drop due to natural water leakage, as shown in FIG. That is, when the sprinkler head is activated, the pipe pressure P suddenly drops as shown by curve A and falls below the lower limit within an extremely short period of time. On the other hand, the pressure drop due to natural water leakage is 1 kg/month per month.
Since the curve is extremely gradual at about cm ² , it takes a considerably long time to drop below the lower limit, as shown by curve B. When the pressure inside the pipe falls below the lower limit, the fire pump is activated and raises the pressure inside the pipe to the upper limit. However, when the sprinkler is activated, the pressure inside the pipe falls below the lower limit, as shown in curve A. When the pressure switch 6 goes down, the pressure switch 6 shows curve a.
The fire extinguishing pump 1 is activated to increase the pressure in the pipe line 4, and fire extinguishing liquid is discharged from the sprinkler head 3 as shown in FIG.

On the other hand, in the case of a pressure drop due to natural water leakage, when the pressure drop falls below the lower limit as shown by curve B, the pressure switch is turned on and the fire pump 1 is activated as shown by curve B. Here, the time from when the fire pump 1 is started until the pressure reaches the upper limit value is extremely short as shown by curve B' or curve b' if the valve device 8 is not provided as in the conventional system. The time becomes _t1 . However, in this invention, since the valve device 8 is provided, in other words, the small diameter hole 8E provided in the valve device 8 is provided, so that the pressure applied by the fire pump 1 is transferred to the pressure tank 5. As shown by curve B or curve b, a time t ₂ which is sufficiently longer than the above-mentioned time t ₁ is required until the pressure is transmitted to the provided pressure switch 6 . this time
If the opening area of the hole 8E is set so that t ₂ is greater than or equal to the area where excessive current occurs when starting the motor connected to the fire pump 1, power will not be applied to the excessive current area when starting the motor. It will no longer be turned on and off. Therefore, damage to the motor contacts and excessive load can be prevented.

Note that the upper and lower limits of the pressure switch 6 can be set arbitrarily depending on the number of sprinklers, the scale of the fire extinguishing equipment, etc., and the size of the hole 8E provided in the valve device 8 can also be set arbitrarily. ing. Moreover, it is of course possible to provide a bypass conduit instead of providing the hole 8E.

As explained in detail above, according to this invention, the configuration includes a pressure switch that is connected to a pressure tank and is turned on between a preset upper limit value and a lower limit value, and a fire pump activated based on the on output;
It is interposed between the discharge side of the fire pump and the pressure tank, and freely flows from the pressure tank side to the discharge side of the fire pump, and has a hole from the discharge side of the fire pump to the pressure tank side. By providing a valve device that flows through the fire pump, it is automatically activated when the sprinkler is activated, and when the fire pump is started due to natural water leakage, the contacts of the motor circuit connected to the fire pump and the motor This has the advantage of preventing accidents that could cause damage due to excessive load placed on the startup control circuit.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of this invention, FIG. 2 is a diagram showing details of the valve device, and FIG. 3 is a waveform diagram for explaining the operation. 1...Fire pump, 2...Water tank, 3...Sprinkler head, 4...Pipe line, 5...Pressure tank, 6...Pressure switch, 7...Start panel, 8...
Valve device, 9... elevated water tank, 10... alarm valve,
11...Test valve.

Claims (1)

[Scope of Claim for Utility Model Registration] A fire pump that pumps extinguishing fluid under pressure to multiple sprinkler heads connected via piping, and maintains the inside of the pipes under pressure during normal times when the sprinkler heads are not operating. In fire extinguishing equipment equipped with a pressure tank, a pressure switch is connected to the pressure tank and turns on between a preset upper limit value and a lower limit value, and is activated based on the on output of this pressure switch. a fire pump, which is interposed between the discharge side of the fire pump and the pressure tank, and which freely flows from the pressure tank side to the discharge side of the fire pump; A fire extinguishing equipment characterized in that it is equipped with a valve device for communicating through a hole on the side.