Vacuum sprinkler system

Abstract

To enable notification that fire fighting is being performed and enable a fire extinction water discharge operation immediately, without waiting for the pressure to rise to a predetermined value at which a pressure sensor monitoring the pressure in a secondary-side piping generates a pressure change signal during fire breaking in a vacuum sprinkler system.SOLUTION: In a negative-pressure sprinkler system comprising a primary-side piping 32, a secondary-side piping 34, a fire detector 40, a negative-pressure device (54, 48, 52) that maintains the secondary-side piping in a negative-pressure state under normal conditions, a pressure sensor 42 that detects the pressure in the secondary-side piping, and a control unit 50 that receives signals from the fire detector 40 and the pressure sensor 42 and controls operation of the negative-pressure device, the control unit 50, upon receiving a fire detection signal from the fire detector 40, stops the operation of the negative-pressure device to allow the pressure in the secondary-side piping 34 to rise, calculates an increment (increasing rate) of a pressure value for each predetermined time, and permits water supply from the primary-side piping 32 to the secondary-side piping 34 when the increasing rate exceeds a predetermined value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vacuum sprinkler system, and more particularly to a vacuum sprinkler system that starts fire extinguishing water discharge based on two signals: a fire detection signal from a fire detector and a pressure change signal from a pressure sensor in a secondary pipe.

Background Art

[0002] Sprinkler systems are classified into wet and dry types depending on whether the secondary pipe is filled with water under normal conditions, and are also classified into vacuum and pressurized types depending on whether the secondary pipe is under negative pressure or pressurized under normal conditions, and there are various types of sprinkler systems. Among them, a vacuum wet sprinkler system (see Patent Document 1) and a vacuum dry sprinkler system (see Patent Document 2) that solve the problem of water damage caused by malfunction of the sprinkler head etc. have attracted attention.

[0003] In a vacuum wet sprinkler system and a vacuum dry sprinkler system (collectively referred to as a vacuum sprinkler system), when a fire occurs, a fire detector detects the fire and transmits a fire detection signal to a control unit. The control unit stops the operation of the negative pressure device in the secondary pipe and allows the pressure in the secondary pipe to rise. Then, since the sprinkler head melts due to heat, the pressure in the secondary pipe rises. The pressure sensor (switch) transmits a pressure change signal to the control unit when the pressure in the secondary pipe reaches a predetermined pressure. The control unit is configured to start fire extinguishing water discharge, for example, operate a water supply pump, when it receives the above two signals: the fire detection signal and the pressure change signal.

[0004] The method of using two signals, a fire detection signal and a pressure change signal, is called a double-action method. Here, it is possible to start fire extinguishing water discharge only with the fire detection signal of the fire detector, but the fire detector has many malfunctions, and it is risky to perform fire extinguishing water discharge only with the fire detector. Also, it is possible to start fire extinguishing water discharge only with the pressure change signal in the secondary pipe, but in this case, it is impossible to distinguish between a failure of the sprinkler head and an actual fire.

[0005] Hitherto, a pressure value has been defined at which a pressure sensor (switch) transmits a pressure change signal according to an initial pressure value. When the initial pressure value is low, the curve of the pressure change is steep, whereas when the initial pressure value is high, the curve of the pressure change is gentle.

[0006] In addition, when the water supply pump is operating and water flows from the primary pipe to the secondary pipe through the on-off valve for a predetermined time, for example, notification (fire notification) that fire extinguishing activities are being carried out is performed by a flowing water detection device.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Disclosure of the Invention

Problems to be Solved by the Invention

[0008] In a vacuum sprinkler system, in order for the control unit to start fire extinguishing water discharge, it is necessary to receive two signals, a fire detection signal and a pressure change signal (double action method). The fire detection signal can transmit the fire detection signal as soon as a fire occurs, whereas the pressure change signal is emitted when the pressure in the secondary pipe rises from the initial value to a predetermined pressure. This predetermined pressure is set to a value that is not affected by errors from the initial value in order to prevent malfunction.

[0009] Therefore, it takes a long time until the pressure in the secondary pipe reaches the predetermined pressure value. For this reason, there has been a problem that the time until notification (fire notification) that fire extinguishing activities are being carried out and the time until the start of fire extinguishing water discharge take a long time.

[0010] The present invention has been made in view of the above problems, and its object is to provide a vacuum sprinkler system that can notify (fire notification) that fire extinguishing activities are being carried out immediately and start a fire extinguishing water discharge operation without waiting for a pressure sensor that monitors the pressure in the secondary piping to rise to a predetermined value at which it issues a pressure change signal when a fire occurs.

Means for Solving the Problems

[0011] To achieve the above object, the vacuum sprinkler system according to claim 1 A primary pipe that extends vertically across each floor and receives the supply of fire extinguishing water from a fire extinguishing water tank, A secondary pipe branched from the primary pipe on each floor and piped to a sprinkler head for discharging fire extinguishing water, A fire detector disposed on each floor for detecting the occurrence of a fire and transmitting a fire detection signal, A negative pressure device for maintaining a negative pressure in the secondary pipe under normal conditions, A pressure sensor for detecting the pressure in the secondary pipe, In a negative pressure sprinkler system having a control unit that receives signals from the fire detector and the pressure sensor and controls the supply of the fire extinguishing water from the primary pipe to the secondary pipe and the operation of the negative pressure device, The control unit When receiving a fire detection signal from the fire detector, stops the operation of the negative pressure device to allow the pressure in the secondary pipe to rise, Based on the signal from the pressure sensor after the operation of the negative pressure device is stopped, calculates the increase in the pressure value (increase rate) of the secondary pipe at each predetermined time, and when the increase rate exceeds a predetermined value, allows the supply of water from the primary pipe to the secondary pipe.

[0012] With this configuration, when the fire detector senses a fire and transmits a fire detection signal to the control unit, the control unit stops the operation of the negative pressure device in the secondary pipe and allows the pressure in the secondary pipe to rise. At this time, the sprinkler head is activated by the fire, that is, the sprinkler head is opened, and the pressure in the secondary pipe rises. After the operation of the negative pressure device is stopped, the control unit calculates the increase in the pressure value, that is, the increase rate, every predetermined time based on the pressure value information in the secondary pipe from the pressure sensor. When this increase rate exceeds a predetermined value, the control unit assumes that the pressure in the secondary pipe will surely rise to a predetermined pressure value at which conventional fire extinguishing water discharge is started, starts the fire extinguishing water discharge, and also notifies (fires notification) that the fire extinguishing activity is being carried out.

[0013] Therefore, it is possible to start the fire extinguishing water discharge in a set short time without waiting for the pressure in the secondary pipe to rise to a predetermined pressure value. As a result, the start of the fire extinguishing activity is accelerated and more effective fire extinguishing is possible. Also, the notification (fire notification) that the fire extinguishing activity is being carried out is earlier.

[0014] The vacuum sprinkler system according to claim 2 is the vacuum sprinkler system according to claim 1, wherein the predetermined time is characterized by being 3 to 5 seconds.

[0015] Generally, there are minute changes in the pressure in the secondary pipe, and there is a risk of picking up a change that is not based on a fire as a fire with only one confirmation in a short time. Therefore, by performing the confirmation within 3 to 5 seconds, it is possible to exclude changes not caused by a fire as described above, and accurate early detection of a fire and avoidance of misrecognition are achieved.

[0016] The vacuum sprinkler system according to claim 3 is the vacuum sprinkler system according to claim 1 or 2, wherein the predetermined increase rate is characterized by being set to vary depending on the initial pressure value in the secondary pipe when the operation of the negative pressure device stops.

[0017] In a vacuum sprinkler system, the initial pressure value at the time of the operation stop of the negative pressure device varies depending on the diameter, length, bending condition, etc. of the secondary piping. Also, the pressure rise curve after the operation stop of the negative pressure device is different.

[0018] Therefore, if a predetermined increase rate is made constant regardless of the initial pressure value at the time of the operation stop of the negative pressure device, there is a risk that the fire extinguishing water discharge timing will be delayed in a vacuum sprinkler system with a high initial pressure. Thus, by changing and setting the predetermined increase rate according to the initial pressure value, even in a vacuum sprinkler system with a low initial pressure value or in a vacuum sprinkler system with a high initial pressure value, it is possible to start the fire extinguishing water discharge in a set short time without waiting for the pressure in the secondary piping to rise to a predetermined pressure value. Thereby, the start of the fire extinguishing activity is accelerated and more effective fire extinguishing becomes possible.

[0019] The vacuum sprinkler system according to claim 4 is the vacuum sprinkler system according to claim 3, wherein the setting of the predetermined increase rate is characterized in that it is set to be smaller as the initial pressure value is higher and larger as the initial pressure value is lower.

[0020] Thereby, when the initial pressure value is low, after the operation of the negative pressure device is stopped, since the pressure rise in the secondary piping is small with respect to time, by making the set value of the predetermined increase rate small, the action of the invention described in claim 1 can be accurately brought out.

Effect of the Invention

[0021] According to the vacuum sprinkler system of the present invention, after a fire detector transmits a fire detection signal to the control unit, it is possible to start the fire extinguishing water discharge in a set short time without waiting for the pressure in the secondary piping to rise to a predetermined pressure value. The start of the fire extinguishing activity is accelerated and more effective fire extinguishing becomes possible. Also, the notification (fire notification) that the fire extinguishing activity is being carried out is earlier.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0023] The vacuum sprinkler system of the present invention will be described in detail below with reference to the following drawings. FIG. 1 shows a schematic configuration of a vacuum dry sprinkler system 10 according to an embodiment of the vacuum sprinkler system of the present invention. However, only the main configuration for one floor is shown.

[0024] In the vacuum dry sprinkler system 10, the water stored in the fire extinguishing water tank 44 is discharged via the water supply pump 35, the primary piping 32, the partition valve 36, the secondary piping 34, and the sprinkler head 33. The partition valve 36 is connected to the base end of the secondary piping 34 branched on each floor so as to allow water to pass through, and is composed of an on-off valve 36a and an alarm device (flow water detection device) 36b. In normal times (normal state), the on-off valve 36a is maintained in a closed state, and is opened by the detection signal of the fire detector 40 attached to each floor. This operation of opening is performed by the control unit 50. The flow water detection device 36b detects the flowing water and gives an alarm when the on-off valve 36a is opened and water supply is performed for a predetermined time. This alarm is an important notification (fire notification) indicating that fire extinguishing activities are being carried out.

[0025] One end of the secondary-side pipe 34 is communicatively connected to the shut-off valve 36. After extending substantially parallel to the ceiling for each floor, it further branches to form a downspout pipe that hangs vertically downward. At the tip thereof, a sprinkler head 33 is attached in a state of being exposed from the ceiling portion of each floor. A test valve 38 is provided at the other end of the secondary-side pipe 34 to open the inside of the secondary-side pipe 34 after flowing water therein experimentally or after water has flowed into the secondary-side pipe 34 due to a malfunction of the system.

[0026] Here, under normal conditions, the inside of the secondary-side pipe 34 is not filled with water, and the suction solenoid valve 54 is opened, and the air inside the suction pipe 48 and the secondary-side pipe 34 is sucked by the vacuum pump 52. The suction solenoid valve 54, the suction pipe 48, and the vacuum pump 52 constitute a negative pressure device. This negative pressure device is controlled by the control unit 50. Under normal conditions, the inside of the secondary-side pipe 34 is in a negative pressure state below atmospheric pressure corresponding to the suction of the vacuum pump 52.

[0027] When the sprinkler head 33 is damaged during a non-fire situation, air flows into the secondary-side pipe 34 and the pressure increases. This pressure increase is detected by the pressure sensor 42 attached to the secondary-side pipe 34, and the control unit 50 calculates the pressure increase rate for a predetermined time. However, since there is no fire detection signal from the fire detector 40, a failure of the sprinkler head 33 is notified.

[0028] The pressure sensor 42 attached to the secondary-side pipe 34 is configured to always measure the pressure inside the secondary-side pipe 34, and the measured value is sent to the control unit 50. As will be described below, when a pressure change occurs, the pressure change rate is calculated.

[0029] In the vacuum dry-type sprinkler system up to now, when the control unit 50 received a fire detection signal from the fire detector 40 and a pressure change signal from the pressure sensor 42, it started the water supply pump 35. The pressure change signal was transmitted to the control unit 50 when the pressure inside the secondary-side pipe 34 rose to -0.06 Mpa, for example, assuming the initial pressure value inside the secondary-side pipe 34 when the operation of the negative pressure device stopped was -0.08 Mpa.

[0030] Figure 2 shows the change in pressure within the secondary pipe 34 immediately after a fire has occurred and the control unit 50 has stopped the operation of the negative pressure device. An example is shown. The horizontal axis represents time (seconds), and zero seconds indicates the time when the control unit 50 stopped the operation of the negative pressure device. At this time, since the sprinkler head 33 has melted, the pressure within the secondary pipe 34 will increase. The vertical axis represents pressure (Mpa), and the initial pressure is -0.08 Mpa.

[0031] In this state, since the fire detector 40 has detected a fire and transmitted a fire signal to the control unit 50, the on-off valve 36a of the partition valve 36 is in the open state. At the same time, the suction solenoid valve 54 is closed, and the suction of the interior of the secondary pipe 34 by the vacuum pump 52 has stopped, and the pressure within the secondary pipe 34 is in a state where an increase is permitted. At this point, the water supply pump 35 has not yet been started.

[0032] Since the suction of the interior of the secondary pipe 34 by the vacuum pump 52 has stopped, air is sucked from the melted sprinkler head 32, and the pressure within the secondary pipe 34 increases from the initial pressure of -0.08 MPa as shown by curve B.

[0033] In Figure 2, if the water supply pump 35 is not started, curve B gradually rises further beyond point P. In the vacuum dry type sprinkler system up to this point, when the pressure within the secondary pipe 34 reached approximately -0.06 Mpa (point P, time T1 seconds), the pressure sensor 42 transmitted a pressure change signal to the control unit 50, the water supply pump 35 was started, and water was supplied from the primary side pipe 32 to the secondary side pipe 34.

[0034] When the water supply pump 35 is started, the pressure in the secondary piping 34 rapidly rises from point P as shown by the straight line A in Fig. 2 (point P is referred to as the operating point). That is, conventionally, when the pressure in the secondary piping 34 reaches this point P, the pressure sensor 42 transmits a pressure change signal to the control unit 50, and the control unit 50 starts the water supply pump 35 based on the fire detection signal it has already received and this pressure change signal (double action method).

[0035] It takes about 40 seconds until this water supply pump 35 is started (up to point P in Fig. 2). This is a very long time and leads to a problem of delaying the fire extinguishing activities. In order to avoid this, by making the pressure value at which the pressure change signal is issued closer to the initial pressure value, that is, by bringing the operating point P closer to the origin, this time can be shortened. However, as can be seen from Fig. 2, the measured pressure value vibrates and includes errors, so it cannot be brought too close to the initial pressure value. That is, there was a risk of malfunction when the pressure value at which the pressure change signal is issued is brought closer to the initial value.

[0036] Fig. 3 shows the actual data of the curve B shown in Fig. 2. The first column is the time (seconds), and the second column is the measured pressure value (KPa). The third, fourth, and fifth columns show the increments every 1 second, every 2 seconds, and every 5 seconds, respectively. The measured value -80.116 (KPa) at time 0 seconds is the initial value. The P point in Fig. 2 corresponds to the time 40 seconds in Fig. 3. However, in this figure, the increment every 5 seconds shows, for example, the increment from 0 to 5 seconds at time 5 seconds and the increment from 1 to 6 seconds at time 6 seconds. Similarly, the increment every 2 seconds shows the increment from 1 to 2 seconds at time 2 seconds and the increment from 2 to 3 seconds at time 3 seconds.

[0037] In the vacuum dry sprinkler system of the present embodiment, instead of waiting for the pressure to rise to the operating point P, when the increase (increase rate) in the pressure change per a predetermined time exceeds a predetermined value, the fire extinguishing water supply is started. In the present embodiment, the predetermined time is set to 5 seconds. As shown in FIG. 3, at time 5 seconds, the increase (total sum) in the past 0 to 5 seconds is 3.428 KPa. From this, the increase rate is 0.6856 KPa / second respectively, which exceeds the predetermined increase rate of 0.5 KPa / second. Therefore, assuming that the pressure value in the secondary pipe 34 will surely reach -0.06 MPa, the control unit 50 starts the water supply pump 50 to start the fire extinguishing activity.

[0038] With this configuration, without waiting for the pressure to rise to a predetermined pressure value (P point) as in the prior art, it is possible to immediately start the water supply pump 35 after a change in the pressure in the secondary pipe 54 occurs. Since the start of the water supply pump 35 is accelerated, it is also possible to quickly notify (fire notification) that the fire extinguishing activity is being carried out by the alarm device 36b.

[0039] Furthermore, it is important that the above-mentioned predetermined value is changed according to the initial pressure value. For example, when the initial pressure value is higher, the increase in the curve of the pressure change in the secondary pipe 34 with respect to time is small, so the predetermined value is set small. When the initial pressure value is low, since the increase in the curve is large, the predetermined value is set large.

[0040] Assuming that when the increase rate of the pressure in the secondary pipe 34 exceeds a predetermined value, the pressure in the secondary pipe 34 will surely rise to the operating point, this predetermined value can be changed according to the initial pressure value in the normal state of the secondary pipe 34, so that the present invention can be applied to vacuum sprinkler systems with different initial pressure values (pressure values when the operation of the negative pressure device is stopped). That is, the initial pressure value of the secondary pipe 34 varies depending on the diameter, length, degree of bending, etc. By changing the above-mentioned predetermined value corresponding to this initial pressure value, it can be applied to various sprinkler systems.

[0041] Note that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. For example, although the vacuum dry sprinkler system has been described, it goes without saying that the present invention can also be applied to a vacuum wet sprinkler system.

Explanation of Reference Numerals

[0042] 10 Vacuum dry sprinkler system 32 Temporary side pipe 33 Sprinkler head 34 Secondary side pipe 35 Water supply pump 36 Partition valve 36a On-off valve 36b Alarm device (flow detection device) 38 Test valve 40 Fire detector 42 Pressure sensor 44 Fire extinguishing water tank 48 Suction pipe 50 Control unit 52 Vacuum pump 54 Suction solenoid valve

Claims

1. A primary pipe that extends vertically across each floor and receives the supply of fire extinguishing water from a fire extinguishing water tank, a secondary pipe branched from the primary pipe on each floor and piped to a sprinkler head for discharging fire extinguishing water, a fire detector disposed on each floor for detecting the occurrence of a fire and transmitting a fire detection signal, a negative pressure device for maintaining a negative pressure in the secondary pipe under normal conditions, a pressure sensor for detecting the pressure in the secondary pipe, a control unit that receives signals from the fire detector and the pressure sensor and controls the supply of fire extinguishing water from the primary pipe to the secondary pipe and the operation of the negative pressure device. In a negative pressure sprinkler system having the above components, the control unit, when receiving a fire detection signal from the fire detector, stops the operation of the negative pressure device to allow the pressure in the secondary pipe to rise, calculates the rate of increase of the pressure value in the secondary pipe at each predetermined time based on the signal from the pressure sensor after the stop operation of the negative pressure device, and when the rate of increase exceeds a predetermined value, allows the supply of water from the primary pipe to the secondary pipe. A vacuum sprinkler system characterized by this.

2. The vacuum sprinkler system according to Claim 1, wherein the predetermined time is 3 to 5 seconds.

3. The vacuum sprinkler system according to Claim 1 or 2, wherein the predetermined rate of increase is set to vary depending on the initial pressure value in the secondary pipe when the operation of the negative pressure device stops.

4. The vacuum sprinkler system according to Claim 3, wherein the setting of the predetermined rate of increase is such that the higher the initial pressure value, the smaller the rate, and the lower the initial pressure value, the larger the rate.

Images