JPS6346275B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an automatic inspection device for pumps, especially fire pumps. Generally, fire extinguishing systems used in buildings have a water tank installed underground, and in the event of a fire, the water in the tank is pumped up to the highest floor of the building using a fire pump to supply fire extinguishing water to all floors of the building. I have to. For this reason,
In this type of equipment, it is necessary to check whether the fire pump maintains the ability to pump water from the water tank to the highest floor of the building, and as an example, the pump is shut off once a day. Conventionally, this type of equipment uses a pressure switch installed on the pump discharge side to detect the pressure of water discharged from the fire pump during test operation, and if the pressure switch is turned on at least once during the test, it is determined that there is no abnormality. Something like making a judgment is known. However, with this method, the cut-off pressure of the pump is reached at the time of start-up due to an aerodynamic system, etc., and even if the pressure switch is turned on, the pressure subsequently decreases, performance deteriorates, and the pressure switch is turned off, even if the pressure switch is turned off, it is not possible to say that there is no abnormality. The current situation is that we end up making judgments. The present invention provides pressure detection means such as a pressure switch.
Checks pump performance by constantly capturing ON/OFF status during pump operation and detecting ON/OFF changes in the pressure switch, making it more reliable by detecting pump performance abnormalities that could not be detected conventionally. The purpose of the present invention is to provide an automatic pump inspection device that has high-precision inspection ability at a low cost. The present invention provides a pump device having a discharge pressure detection means and a device for inspecting whether the pump capacity is maintained by pump cut-off operation, in which the detection means is turned on when the pressure exceeds a set pressure. A signal is output when the pressure is below the set pressure, and an OFF signal is output when the set pressure is lower than the set pressure. and in a state where the pump performance has slightly decreased,
Set lower than the instantaneous maximum pump discharge pressure that suddenly appears with respect to the ordinary pressure at or above the ordinary pressure with a small change lower than the pump discharge pressure at the time of aerodynamics or cavitation shown a predetermined time after the pump is started and started up. The patterns of the ON and OFF signals output by the detection means that occur during pump inspection operation, and the predetermined and memorized conditions until the pump performance deteriorates or the aerodynamic or cavitation conditions are determined. Pressure detection means ON during corresponding pump operation
-This is an automatic pump inspection device equipped with a function to compare with the OFF pattern and a control circuit that generates a signal to send the comparison results to the outside. Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram of an embodiment of the invention. A pump 2 and a motor 3 for driving the pump 2 are installed on the machine 1. The pump 2 pumps up water from a water tank 4 through a suction pipe 5 and discharges it to a discharge pipe 6 at increased pressure. A pipe 9 is connected to, for example, the roof of a building via a valve 7 and a gate valve 8.
A pressure switch 10 is attached to the discharge pipe 6 so as to detect the discharge pressure of the pump 2. Automatic inspection device 11 (not shown) when inspecting the fire pump device
When an operation command is given by a timer switch or manual switch in preparation for a fire, a start command is sent to the fire pump control panel 12, and the motor 3 is activated in the same way as the fire pump control panel 12 is operated by the fire signal FA in the event of a fire. The motor 3 starts and operates the pump 2, and the pump 2 pumps water from the water tank 4 through the suction pipe 5 and supplies it to the pipe 9 through the discharge pipe 6, check valve 7, and gate valve 8. Water is supplied. A signal indicating that the pressure switch 10 detects the discharge pressure of the pump 2 is sent to an automatic inspection device 11. The automatic inspection device 11 determines the operating state of the pressure switch 10 during a certain period of time for pump performance inspection, and outputs an inspection result IS. FIG. 2 is a diagram showing the pressure characteristics of a centrifugal pump, in which the horizontal axis shows the time after startup, and the vertical axis shows the pump discharge pressure after startup. In a normal pump, if the pump cut-off pressure is P1, the pump will rise after startup, and the pressure P1 will be slightly raised or lowered to maintain the normal pressure P1. This line is shown as a normal pressure characteristic line 13. The set pressure of the pressure switch 10 is selected to be a pressure P2 smaller than the cutoff pressure P1. Pump 2 during aerodynamics or cavitation
The pressure characteristics are as shown in the air disturbance pressure characteristic line 14. Air failure pressure characteristic line 14 is T1 after pump startup
At the time of startup, the set pressure P2 of the pressure switch 10 is exceeded and the pressure switch 10 is turned on, but there is a slight wave in the vicinity of the maximum pressure, which is lower than the cut-off pressure P1 when the normal pump 2 does not cause aerodynamics or cavitation. The pressure gradually decreases and reaches the pressure P2 at time T6 and further decreases, so the pressure switch 10 is turned OFF and the pressure gradually decreases until time T7 when the inspection operation ends. Next, the reduced performance pressure characteristic line of the pump 2 whose performance has slightly deteriorated and is likely to deteriorate further is indicated by 15. In this case, the pressure does not reach P2 by the time the pump starts up at time T1, and the pressure shows a normal pressure with a small change below pressure P2. At time T2, the pressure suddenly starts to rise rapidly, and at time T3, the pressure exceeds P2 and the pressure switch 10 is turned off. Further, the discharge pressure of the pump 2 increases rapidly, reaches the instantaneous maximum pump discharge force, and then rapidly decreases, exceeding the pressure P2 during time t1, and when the pressure switch 10 is turned OFF at the time of decrease, the pressure further decreases. The pressure suddenly decreases and remains at a normal pressure slightly lower than the set pressure P2 of the pressure switch 10, and for a period of time T
At time T5, t2 hours after the pressure switch 10 was turned OFF when the pressure decreased after the first pressure increase, the pressure switch 1 was turned off.
0 turns ON, and the pump pressure further rises rapidly, reaches the instantaneous maximum pump discharge pressure, and then rapidly decreases, and at t3
After a period of time, the pressure switch is turned off and the pressure remains at the normal pressure, which is slightly lower than P2. The operation pattern of the pressure switch 10 in which the pressure switch 10 is alternately turned ON and OFF as described above is common, and the position where the pressure increases may appear by the rising time T1 after startup, and the pump performance inspection end time T.
It may also appear in 7. In addition, if the decrease in pump performance is slight, the time t2 during which the pump pressure is lower than the set pressure P2 of the pressure switch 10 is small, and the time t1, t3, etc. during which the pump pressure is higher than the pressure P2 is longer. It is long. Therefore, pump performance can also be compared based on the value of t1/t2. As shown in the figure, some of the reduction performance pressure characteristic lines 15 have a clear maximum pressure and minimum pressure difference, but others have a small pressure difference. The pressure switch 10 exhibits similar pressure characteristics due to pressure fluctuations even when the pressure difference is small. In addition, the set pressure P2 of the pressure switch 10 that occurs during the pump performance inspection time
The condition of the pump can also be determined by the number of times the pump exceeds . As shown in the pressure characteristic line 16 when the performance decreases, when the pump performance decreases, the set pressure P2 of the pressure switch 10 is not reached at all during the pump inspection time, and the pressure switch 10 automatically inspects the pump at a time T7 from startup. It hasn't worked even once. If the pressure due to the shut-off operation of the pump 2 becomes about half of the normal value as shown in the pressure characteristic line 16, how much should the time from startup to time T7, that is, the operation time of the pump 2 for inspection, be extended? However, the set pressure P2 of the pressure switch 10 is not reached. Therefore, the operating time for the pump inspection should be set so that the pump is operated until a time after the time T6 when the line shown in the air failure pressure characteristic line 14 reaches the set pressure P2 of the pressure switch 10, or the pump is operated until the time T6 when the line shown in the air failure pressure characteristic line 14 reaches the set pressure P2 of the pressure switch 10, or It is preferable that the pump operation time for pump inspection be such that the pump passes through the set pressure P2 of the pressure switch 10 at least twice on the rising side and on the falling side, respectively. By knowing such pump operating conditions, it is possible to know the performance of the pump 2. Now, in cases like the above examples, the pressure switch 10
Describe the judgment of pump performance based on the ON/OFF pattern. The following table shows the ON/OFF judgment of the pressure switch 10.

[Table] In the above table, startup time is the time T1 after starting up after the pump is started for inspection in Figure 2.
The state of the pressure switch 10 is shown in FIG. "In operation" refers to the state of the pressure switch 10 from time T1 to immediately before stop time T7. Immediately before stopping is time T
7 or the state of the pressure switch 10 just before that. Case (1) In this case, the pressure switch 10 remains ON during the inspection operation of the pump 2, and the normal pressure line 13 in FIG. 2 indicates that the pump 2 is normal. Case (2) The pressure switch 10 is turned ON at startup, but afterwards the pressure switch 10 is turned OFF during operation, and the pressure switch 10 is turned ON at least once before stopping. This is the reduction performance pressure characteristic line 15 in Figure 2.
This is a case in which a pressure higher than the set pressure P2 of the pressure switch 10 first appears at the time of startup, indicating that there is a possibility that the pump performance will deteriorate. Case (3) At startup, the pressure switch 10 is in the OFF state,
During operation, the pressure switch 10 is turned ON and OFF, and immediately before stopping, the pressure switch 10 is either ON or OFF, which is shown by the reduced performance pressure characteristic line 15 in Fig. 2, and there is a risk of a decrease in pump performance. be. Case (4) Pressure switch 10 is turned ON at startup, and then turned OFF during operation. Then, just before stopping, the pressure switch 10 remains OFF and the inspection ends. This is indicated by the air failure pressure characteristic line 14 shown in FIG. 2, and the pump 2 is experiencing airlock or cavitation. Case (5) The pressure switch 10 does not operate and is in the OFF state from the start until just before the stop at time 7.
represents a decrease in performance. Therefore, turn on the pressure switch 10 illustrated above.
The OFF pattern is stored in the storage device of the automatic pump inspection device 11, and when a command for automatic pump inspection is issued from the automatic inspection device 11, the fire pump control panel 12 energizes the motor 3, and the motor 3 operates the pump 2 for a certain period of time (from startup to time T7) necessary for automatic inspection. During this time, the ON/OFF state of the pressure switch 10 is sent to the automatic inspection device 11. FIG. 3 shows a control flowchart of the automatic inspection device. In routine 101, it is determined whether the pressure switch 10 is ON or OFF immediately after startup, in routine 102, ON or OFF of the pressure switch 10 is memorized, and in routine 103, the pressure switch 10 during operation is determined.
It is determined whether the pressure switch is ON or OFF, and in routine 104 the ON or OFF state of the pressure switch during operation is memorized, and in routine 105 the pressure switch 10 is turned off immediately before stopping.
It is determined whether the pressure switch is ON or OFF, and in routine 106, the ON or OFF state of the pressure switch just before the stop is memorized. When pump 2 stops in routine 107, routine 1
Turn on pressure switch 10 during automatic inspection at 08.
The memorized OFF pattern is input to the automatic inspection device 11 in advance for the pressure switch 10.
It is compared with the ON/OFF pattern and the corresponding result is expressed as the inspection result IS on a readout device (not shown). The content of the automatic pump inspection device already mentioned is only the pattern of ON and OFF operation of the pressure switch, and the pattern is determined regardless of the ON length and OFF length. In such cases, it is possible to distinguish between when the pump is normal, when the pump pressure has decreased, when the pump is in an airlock or cavitation state, and when there is a risk of a decrease in pump performance. Therefore, if it can be determined that there is a risk of pump performance deterioration, the pressure switch ON time/
The value of the OFF time is calculated by the automatic inspection device 11, and it can be determined that the longer the pressure switch is ON, the better the pump performance. The status may be displayed. In addition, although a pressure switch was used in the embodiment, other pressure detection elements were used to set the set pressure P2 as a reference, and set it as ON when the set pressure P2 or above is detected, and OFF when the set pressure below is detected as shown in Fig. 2. The quality of the pump may be determined based on the pressure characteristics of the pump shown in FIG. As explained above, the present invention is equipped with an automatic inspection device for a fire pump device, and the automatic inspection device is configured to check the normal state of the pump, the state of degraded performance, and the like during a certain period of time during which the pump should be inspected after starting the pump. Conditions that affect pump performance, such as aerodynamics or cavitation, can be memorized in advance as patterns for the operation of the pressure switch installed in the pump, and used during automatic pump inspections and during automatic pump inspection operation periods. The operation of the pressure switch provided in the pump is sent to an automatic inspection device, and the system compares it with the already memorized pressure switch operation pattern corresponding to the pump condition to find a similar pattern and determines the pump condition corresponding to the pressure switch pattern. By displaying the fire pump in this manner, the condition of the fire pump can be known in detail and appropriate maintenance measures can be taken in a timely manner.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a pressure characteristic diagram of the pump, and FIG. 3 is a control flowchart of the present invention. 1... Machine base, 2... Pump, 3... Motor, 4
...Water tank, 5...Suction pipe, 6...Discharge pipe, 7...
... Check valve, 8 ... Gate valve, 9 ... Piping, 10
...Pressure switch, 11 ...Automatic inspection device, 12
...Fire pump control panel, 13...Normal pressure line, 1
4...Air failure pressure characteristic line, 15...Decrease performance pressure characteristic line, 16...Pressure characteristic line at performance decrease, 101
~108... Routine, P1... Cutoff pressure, P
2...Set pressure, T1-T7...Time, t1-t
4...time.

Claims (1)

[Scope of Claims] 1. In a pump device having a discharge pressure detection means and a device for inspecting whether the pump capacity is maintained by pump cut-off operation, the detection means is configured to detect discharge pressure exceeding a set pressure. When I'm there
Outputs an ON signal, and when the pressure is below the set pressure
In addition to outputting an OFF signal, the set pressure is the pump discharge pressure in an aerodynamic or cavitation state that is indicated a predetermined time after the pump has started up for pump inspection operation, and the pump performance has slightly decreased. , above the ordinary pressure with a small change lower than the pump discharge pressure at the time of aerodynamics or cavitation, which is shown a predetermined time after the pump is started and started up, than the instantaneous maximum pump discharge pressure that suddenly appears with respect to this ordinary pressure. A pattern of ON and OFF signals output by the detection means that occurs during pump inspection operation, and a predetermined and memorized state or aerodynamics or cavitation until the pump performance deteriorates. Pressure detection means ON during pump operation corresponding to the condition
An automatic pump inspection device equipped with a function to compare the OFF pattern and a control circuit that generates a signal to send the comparison results to the outside. 【table】