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 discharging fire water in response to two signals: a fire detection signal from a fire detector and a pressure change signal from a pressure sensor in the secondary piping. [Background technology]

[0002] Sprinkler systems are divided into wet and dry types depending on whether the secondary piping is normally filled with water, and into vacuum and pressure types depending on whether the secondary piping is normally under negative or pressurized pressure. Among these, vacuum wet sprinkler systems (see Patent Document 1) and vacuum dry sprinkler systems (see Patent Document 2) have attracted attention because they solve the problem of water damage caused by sprinkler head malfunctions.

[0003] In vacuum wet sprinkler systems and vacuum dry sprinkler systems (collectively referred to as vacuum sprinkler systems), when a fire breaks out, a fire detector detects the fire and sends a fire detection signal to the control unit. The control unit then stops the operation of the negative pressure device in the secondary piping and allows the pressure in the secondary piping to increase. The sprinkler head then melts due to heat, causing the pressure in the secondary piping to increase. When the pressure in the secondary piping reaches a predetermined pressure, the pressure sensor (switch) sends a pressure change signal to the control unit. Upon receiving both the fire detection signal and the pressure change signal, the control unit begins discharging water to extinguish the fire, for example, by operating a water pump.

[0004] A system that uses two signals, a fire detection signal and a pressure change signal, is called a double-action system. It is possible to start a fire extinguishing water discharge based on just the fire detection signal from the fire detector, but fire detectors often malfunction, so using just the fire detector to discharge water is risky. It is also possible to start a fire extinguishing water discharge based on just the pressure change signal in the secondary piping, but in this case, it is impossible to distinguish between a sprinkler head malfunction and an actual fire.

[0005] Until now, the pressure value at which the pressure sensor (switch) sends a pressure change signal was determined according to the initial pressure value. When the initial pressure value is low, the pressure change curve is steep, whereas when the initial pressure value is high, the pressure change curve is gentle.

[0006] In addition, when the water supply pump is operating and water flows from the primary piping to the secondary piping through the on-off valve for a predetermined period of time, an alarm (fire alarm) is issued by, for example, a water flow detection device to indicate that firefighting activities are underway. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 3264939 [Patent Document 2] Patent No. 5054789 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0008] In a vacuum sprinkler system, the control unit must receive two signals to start discharging water to extinguish a fire: a fire detection signal and a pressure change signal (double action system). The fire detection signal can be sent as soon as a fire occurs, but the pressure change signal is sent when the pressure in the secondary piping rises from an initial value to a specified pressure. This specified pressure is set to a value that is not affected by errors from the initial value to prevent malfunctions.

[0009] Therefore, it takes a long time for the pressure in the secondary piping to reach the specified pressure value, which causes problems such as a long time required for an alarm to be issued that firefighting activities are underway (fire alarm) and for the start of firefighting water spraying.

[0010] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a vacuum sprinkler system that can immediately issue an alert that fire extinguishing activities are underway (fire alarm) and begin fire extinguishing water discharge operations, without waiting for the pressure sensor that monitors the pressure in the secondary piping when a fire occurs to rise to a predetermined value at which it will emit a pressure change signal. [Means for solving the problem]

[0011] To achieve the above objectives, The present invention Vacuum sprinkler systems are A primary piping that extends vertically across each floor and receives fire water from the fire water tank; A secondary piping that branches off from the primary piping on each floor and is routed to a sprinkler head for discharging fire water; A fire detector is installed on each floor and detects the occurrence of a fire and transmits a fire detection signal. a negative pressure device that normally creates a negative pressure in the secondary side piping; a pressure sensor that detects the pressure in the secondary piping; 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 piping to the secondary piping and the operation of the negative pressure device, The control unit When a fire detection signal is received from the fire detector, the operation of the negative pressure device is stopped to allow the pressure in the secondary piping to increase, The increase (increase rate) in the pressure value in the secondary piping for each predetermined time is calculated based on the signal from the pressure sensor after the operation of the negative pressure device has stopped, and when the increase rate exceeds a predetermined value, water is allowed to be sent from the primary piping to the secondary piping.

[0012] With this configuration, when the fire detector detects a fire and sends a fire detection signal to the control unit, the control unit stops the operation of the negative pressure device in the secondary piping and allows the pressure in the secondary piping to increase. At this time, the sprinkler head is activated by the fire, i.e., the sprinkler head is opened, and the pressure in the secondary piping increases. After the operation of the negative pressure device is stopped, the control unit calculates the increase in the pressure value per predetermined time, i.e., the increase rate, based on the pressure value information in the secondary piping from the pressure sensor. If this increase rate exceeds a predetermined value, the control unit assumes that the pressure in the secondary piping will definitely increase to the predetermined pressure value that initiates conventional fire extinguishing water discharge, and begins fire extinguishing water discharge and also issues a fire alarm, indicating that firefighting activities are underway.

[0013] Therefore, it is possible to start fire extinguishing water discharge within a set short time without waiting for the pressure in the secondary piping to rise to a predetermined pressure value. This allows firefighting activities to start sooner and more effectively extinguishes the fire. It also allows for earlier notification that firefighting activities are underway (fire alarm).

[0014] Furthermore, the present invention Vacuum sprinkler systems are The aforementioned In vacuum sprinkler systems, The predetermined time is characterized by being 3 to 5 seconds.

[0015] Generally, there are small changes in the pressure in the secondary piping, and if you check it only once in a short time, there is a risk that changes that are not caused by a fire will be detected as a fire. Therefore, by checking for 3 to 5 seconds, it is possible to exclude changes that are not caused by a fire, such as those mentioned above, and accurate early detection of a fire can be achieved and false recognition can be avoided.

[0016] Furthermore, the present invention Vacuum sprinkler systems are The aforementioned In vacuum sprinkler systems, The predetermined increase rate is set by varying it depending on the initial pressure value in the secondary pipe when the operation of the negative pressure device is stopped.

[0017] In a vacuum sprinkler system, the initial pressure value when the negative pressure device stops operating varies depending on the diameter, length, and degree of bending of the secondary piping. The pressure rise curve after the negative pressure device stops operating also differs.

[0018] Therefore, if the specified increase rate were set constant regardless of the initial pressure value when the negative pressure device stopped operating, there would be a risk that the timing of fire extinguishing water discharge would be delayed in vacuum sprinkler systems with high initial pressure. Therefore, by setting the specified increase rate to vary depending on the initial pressure value, fire extinguishing water discharge can be initiated within a set short time, regardless of whether the vacuum sprinkler system has a low initial pressure value or a high initial pressure value, without waiting for the pressure in the secondary piping to rise to the specified pressure value. This allows firefighting activities to start earlier, resulting in more effective firefighting.

[0019] Furthermore, the present invention Vacuum sprinkler systems are The aforementioned In vacuum sprinkler systems, The predetermined increase rate is set to be smaller as the initial pressure value is higher and larger as the initial pressure value is lower.

[0020] As a result, when the initial pressure value is low, the increase in pressure in the secondary piping is small over time after the operation of the negative pressure device is stopped, so by setting a small value for the specified increase rate, the effect of the invention described in claim 1 can be accurately achieved. [Effects of the Invention]

[0021] The vacuum sprinkler system of the present invention can start discharging fire water within a set short time after the fire detector sends a fire detection signal to the control unit, without waiting for the pressure in the secondary piping to rise to a predetermined pressure value, which allows for a faster start of firefighting activities and more effective firefighting.It also allows for a faster notification that firefighting activities are underway (fire alarm). [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic diagram illustrating the main configuration of a vacuum dry sprinkler system according to one embodiment of the vacuum sprinkler system of the present invention. [Figure 2] 2 is an explanatory diagram showing a change in pressure in the secondary piping from the time when the negative pressure device in the vacuum dry sprinkler system shown in FIG. 1 stops operating. FIG. [Figure 3] An example of measurement data of the pressure change in FIG. 2 is shown. DETAILED DESCRIPTION OF THE INVENTION

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

[0024] In the vacuum dry sprinkler system 10, water stored in the fire water tank 44 is discharged via the water supply pump 35, the primary piping 32, the gate valve 36, the secondary piping 34, and the sprinkler head 33. The gate valve 36 is connected to the base end of the secondary piping 34, which branches off on each floor, so that water can flow through it. The gate valve 36 is composed of an on-off valve 36a and an alarm device (water flow detection device) 36b. Under normal circumstances (normal conditions), the on-off valve 36a is kept closed and is opened in response to a detection signal from a fire detector 40 installed on each floor. This opening operation is performed by the control unit 50. The water flow detection device 36b detects water flow when the on-off valve 36a is open and water has been supplied for a predetermined period of time, and issues an alarm. This alarm is an important notification (fire alarm) indicating that firefighting activities are underway.

[0025] One end of the secondary piping 34 is connected in communication with a gate valve 36, extends approximately parallel to the ceiling on each floor, and then branches off to form vertically hanging down pipes, the ends of which are fitted with sprinkler heads 33 exposed from the ceiling of each floor. A test valve 38 is provided at the other end of the secondary piping 34 to open the interior of the secondary piping 34 after a test water flow or after the system malfunctions and water flows into the secondary piping 34.

[0026] Here, in a normal state, the inside of the secondary-side piping 34 is not filled with water, and the suction solenoid valve 54 is opened to suck air from the inside of the suction pipe 48 and the inside of the secondary-side piping 34 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. In a normal state, the inside of the secondary-side piping 34 is at a pressure below atmospheric pressure and is in a negative pressure state corresponding to the suction of the vacuum pump 52.

[0027] If the sprinkler head 33 is damaged when there is no fire, air will flow into the secondary piping 34 and the pressure will rise. This pressure rise will be detected by the pressure sensor 42 attached to the secondary piping, and the control unit 50 will calculate the rate of pressure increase over a specified period of time. However, since there is no fire detection signal from the fire detector 40, a malfunction of the sprinkler head 33 will be reported.

[0028] The pressure sensor 42 attached to the secondary piping 34 is configured to be able to measure the pressure inside the secondary piping 34 at all times, and the measurement value is sent to the control unit 50. As will be explained below, if a pressure change occurs, the rate of pressure change is calculated.

[0029] In the conventional vacuum dry sprinkler system, the control unit 50 starts the water pump 35 when it receives a fire detection signal from the fire detector 40 and a pressure change signal from the pressure sensor 42. For example, if the initial pressure value in the secondary piping 34 when the operation of the negative pressure device stops is -0.08 MPa, the pressure change signal is sent to the control unit 50 when the pressure in the secondary piping 34 rises to -0.06 MPa.

[0030] Figure 2 shows the change in pressure inside the secondary piping 34 immediately after a fire breaks out and the control unit 50 stops the operation of the negative pressure device. An example is shown. The horizontal axis is time (seconds), with zero seconds indicating the time when the control unit 50 stops the operation of the negative pressure device. At this time, the sprinkler head 33 has melted, so the pressure inside the secondary piping 34 will rise. The vertical axis is pressure (Mpa), with the initial pressure being -0.08 Mpa.

[0031] In this state, the fire detector 40 detects a fire and sends a fire signal to the control unit 50, so the on-off valve 36a of the gate valve 36 is open, and at the same time, the suction solenoid valve 54 is closed, stopping the suction of the inside of the secondary piping 34 by the vacuum pump 52 and allowing the pressure inside the secondary piping 34 to rise. At this point, the water pump 35 has not yet started.

[0032] Since the suction of the secondary piping 34 by the vacuum pump 52 is stopped, air is sucked out of the melted sprinkler head 32 and the pressure in the secondary piping 34 rises from the initial pressure of -0.08 MPa as shown by curve B.

[0033] 2, if the water pump 35 is not started, the curve B continues to gradually rise beyond point P. In conventional vacuum dry sprinkler systems, when the pressure in the secondary piping 34 reaches approximately -0.06 MPa (point P, time T1 second), the pressure sensor 42 sends a pressure change signal to the control unit 50, the water pump 35 is started, and water is sent from the primary piping 32 to the secondary piping 34.

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

[0035] It takes about 40 seconds for the water pump 35 to start (to point P in Figure 2). This is an extremely long time, which leads to delays in firefighting activities. To avoid this, this time can be shortened by bringing the pressure value emitted by the pressure change signal closer to the initial pressure value, i.e., by bringing the operating point P closer to the origin. However, as can be seen from Figure 2, the measured pressure value fluctuates and contains errors, so it is not possible to bring it too close to the initial pressure value. In other words, bringing the pressure value emitted by the pressure change signal closer to the initial value could cause malfunctions.

[0036] Figure 3 shows actual data for curve B shown in Figure 2. The first column is time (seconds), and the second column is the measured pressure (KPa). The third, fourth, and fifth columns show the increments every 1, 2, and 5 seconds, respectively. The measured value of -80.116 (KPa) at time 0 seconds is the initial value. Point P in Figure 2 corresponds to time 40 seconds in Figure 3. However, in this figure, the increments every 5 seconds represent, 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 increments every 2 seconds represent 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 this embodiment, fire extinguishing water supply is initiated when the increment (increase rate) of pressure change over a predetermined time period exceeds a predetermined value, rather than waiting for the pressure to rise to operating point P. In this embodiment, the predetermined time period is 5 seconds. As shown in FIG. 3, the increment (sum) from 0 to 5 seconds in the past is 3.428 KPa at 5 seconds. From this, the increase rate is 0.6856 KPa / sec, which exceeds the predetermined increase rate of 0.5 KPa / sec. Therefore, it is assumed that the pressure value in the secondary piping 34 will definitely reach -0.06 MPa, and the control unit 50 starts the water supply pump 50 to commence fire extinguishing activities.

[0038] With this configuration, it is possible to start the water pump 35 instantly after a change in pressure occurs in the secondary piping 54, without having to wait for the pressure to rise to a predetermined value (point P) as in the past. Because the water pump 35 starts quickly, it is also possible to quickly issue a notice (fire alarm) by the alarm device 36b that firefighting activities are underway.

[0039] Furthermore, it is important to change the predetermined value according to the initial pressure value. For example, if the initial pressure value is higher, the increase in the curve of the pressure change in the secondary pipe 34 over time is small, so the predetermined value is set small. If the initial pressure value is low, the increase in the curve is large, so the predetermined value is set large.

[0040] When the rate of increase in pressure in the secondary piping 34 exceeds a predetermined value, it is assumed that the pressure in the secondary piping 34 will always rise to the operating point. This predetermined value can be changed depending on the initial pressure value in the normal state of the secondary piping 34, so that the present invention can be applied even to vacuum sprinkler systems with different initial pressure values ​​(pressure value when operation of the negative pressure device is stopped). In other words, the initial pressure value of the secondary piping 34 varies depending on the diameter, length, degree of bending, etc., and by changing the above predetermined value in accordance with this initial pressure value, the present invention can be applied to various sprinkler systems.

[0041] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, although the description has been given of a vacuum dry sprinkler system, it goes without saying that the present invention can also be applied to a vacuum wet sprinkler system. [Explanation of symbols]

[0042] 10. Vacuum dry sprinkler system 32 Primary side piping 33 Sprinkler Head 34 Secondary piping 35 Water pump 36 Gate valve 36a On-off valve 36b Alarm device (flow detection device) 38 Test valve 40 Fire detector 42 Pressure Sensor 44 Fire Water Tank 48 Suction tube 50 control section 52 Vacuum pump 54 Suction solenoid valve

Claims

1. A primary piping that extends vertically across each floor and receives fire water from the fire water tank; A secondary piping that branches off from the primary piping on each floor and is routed to a sprinkler head for discharging fire water; A fire detector is installed on each floor and detects the occurrence of a fire and transmits a fire detection signal. a negative pressure device that normally creates a negative pressure in the secondary side piping; a pressure sensor that detects the pressure in the secondary piping; 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 piping to the secondary piping and the operation of the negative pressure device, The control unit When a fire detection signal is received from the fire detector, the operation of the negative pressure device is stopped to allow the pressure in the secondary piping to increase, a rate of increase in the pressure value in the secondary piping for each predetermined time period based on a signal from the pressure sensor after the operation of the negative pressure device has been stopped; and when the rate of increase exceeds a predetermined value, water is allowed to be sent from the primary piping to the secondary piping; A vacuum sprinkler system characterized in that the predetermined increase rate is set by changing it depending on the initial pressure value in the secondary side piping when the operation of the negative pressure device is stopped.

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

3. 3. The vacuum sprinkler system according to claim 1, wherein the predetermined increase rate is set to be smaller as the initial pressure value is higher and set to be larger as the initial pressure value is lower.

Images