JPS58210387A - Automatic inspection apparatus for pump - Google Patents

Abstract

PURPOSE:To permit whether pumping impossibility is due to air-lock phenomenon or not to be correctly judged by installing a pressure detecting means onto a pump and detecting the variation of the pump discharge pressure with lapse of time. CONSTITUTION:A pressure detector 10 detects the discharge pressure of a pump 2 and transmits a signal to a control circuit 12 which is provided with the automatic inspection function for pump and the operation control function for motor, through A/D conversion by means of a signal converter 11, and the output of the control circuit 12 is sent into a motor 3. When the pump 2 itself is in the trouble such as water leak and increase of resistance in water suction pipe, a constant pressure lower than the pressure shown by a normal discharge pressure line 13 is generated. When the pump 2 is put into shut-off operation and started at a time T1, the discharge pressure is varied as shown by a curve 15, if air-lock phenomenon is generated in the pump. Therefore, whether the pumping impossibility is due to air-lock or not can be correctly judged.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides pump 4? This relates to an automatic inspection device for fire pumps.

Generally, fire extinguishing systems used in buildings have a water tank buried underground, and when a fire occurs, the water in the tank is pumped up to the top floor of the building using a fire pump, supplying fire extinguishing water to all floors of the building. ing. Furthermore, if air gets mixed into the suction pipe of a fire pump, the pump's water pumping capacity will be significantly reduced due to the aerodynamic phenomenon. For this reason, it is necessary to use this inspection device to check whether the fire pump maintains its ability to pump water from the water tank to the top floor of the building, and the pump must be operated once a day. It is being said.

Conventionally, this inspection device has been known to use a pressure switch to detect the pressure of water discharged from a fire pump during a test operation, and to check whether or not the fire pump is pumping water sufficiently. ing.

However, if the discharge pressure of the pump is determined by the pressure switch I, it is currently impossible to determine the cause of the pump's inability to pump water when it becomes unable to pump water. If it is determined that the pump is the cause of the inability to pump water, the pump is removed and disassembled for inspection. And if it's an aerodynamic, it won't be removed when reassembling, so I'll have to figure out the cause of the problem.
This may result in unnecessary work.

The invention is equipped with a pressure detection means in the pump, and by detecting changes in the pump discharge pressure over time, it is determined whether or not the cause of the inability to pump water is due to an aerodynamic phenomenon. The purpose is to provide an automatic inspection function for pumps that has inspection capabilities of

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 motor 3 for driving pump= and pump- is provided on the machine base/top, and pump 2 pumps up water from the water receiving station through the suction pipe S and discharges the water at increased pressure to the discharge pipe 6. Piping is connected to, for example, the roof of a building via a check valve 7 and a gate valve g. A pressure detector io, such as a semiconductor whose electric resistance changes depending on pressure, is attached to the pump 2 so as to measure the discharge pressure of the pump 2. The pressure detector io detects the discharge pressure of the pump, A/D converts it through the signal converter //, and sends a signal to the control circuit l.

The control circuit /J has a pump automatic inspection function, which will be described later, as well as a normal motor operation control function. The output of the control circuit 1 is sent to the motor 3.

Figure 2 shows when the pump is started when an aerodynamic phenomenon occurs.
It is a diagram showing changes in starting current and changes in pump discharge pressure, where the horizontal axis shows time, and the vertical axis shows motor input current and pump discharge pressure. In the figure, when the pump 2 is in a shut-off operation, reference numeral 13 is a curve showing the discharge pressure when the pump is normal. When the motor 3 is started at T/time, the starting current /41 increases rapidly, overcomes the inertia of the rotor of the motor 3, self-rust induction, and the resistance of the pump, rotates, reaches a constant speed, and then rotates at a constant speed. do. Pump 2 has normal discharge pressure #! 13
The height of the horizontal line P. After that, the pressure becomes constant P0
keep it. If the pump itself has a problem such as water leakage or increased water suction pipe resistance, the pressure will be a constant pressure lower than the pressure indicated by the normal discharge pressure iIA/J. Pump 2 is operated for a period of time T.
When the pump is started at 2, the pump discharge pressure changes as shown by the curve is when an aerodynamic phenomenon occurs in pump 2.

The discharge pressure is positive after time TL, and the discharge pressure is also low when it is normal.
It has become 1. Then, the discharge pressure of pump 2 gradually decreases until 1 to 2 seconds after the time T2 when the pressure reaches the maximum, and reaches the pressure P at time T''3.

FIG. 3 is a block diagram of the control circuit.

When the motor 3 is started, the starting signal generator 16 sends a signal to the timer 17 and the gate at time T to open the gate at of the memory circuit λl.

Then, the timer 17 is started, the trigger gate circuit 1 is opened, and the pressure sensor 10 detects the pump 2 time T.
The pressure signal at / is sent to the A/D converter 20 through gate /q, A/D converted and stored in the memory circuit col through gate lza. Timer 17 after time-varying T
Since the time-up occurs, the trigger gate circuit 19 is opened again, so the pressure signal of pressure P2 passes from the pressure detector io to the trigger gate circuit 19 and is converted to A at the A/D converter -〇.
/ D-converted and sent to two arithmetic units, then stored in the memory circuit 21
The contents of are called and P□-p, = ΔP is executed, and if ΔP is larger than a certain value preset in the setting device Ko3, a signal is sent to the alarm generator Koda such as a display and a warning is issued. . Alternatively, the signal of the computing unit =- is amplified and sent to the automatic valve S, as shown by the two-dot S line in Fig. Pump 2 may be vented automatically.

Although the above explanation is based on the difference in the pressure drop over time during the aerodynamics, it is also possible to detect the speed at which the pressure decreases.

The present invention uses a pressure detector to detect pressure when checking the pumping capacity of a fire pump automatic inspection device, and detects temporal changes in the pump discharge pressure, thereby determining whether or not the cause of pumping failure is due to aerodynamics. This allows the pump to be kept in normal condition by venting air.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a diagram illustrating the aerodynamic phenomenon of the pump, and FIG. 3 is a control block diagram. l...Machine base Co...Pump 3...Motor...Water receiving @
s...Suction pipe 6...Discharge pipe 7...Check valve Z...
Partition box...Piping 10...Pressure detection device IT...Signal converter l...Control circuit 13...Normal discharge pressure line/4''...Starting current is...Track 1)/l-...・Start signal generator lli・・Timer 7g−・Gate
/ q ・ ・ Trigger gate circuit, λO・ ・A
/ D converter / Memory circuit = / Computing unit 2
3... Setting device Koda... Alarm generator = 5... Automatic valve Colo... Piping P.・・Normal discharge pressure p, + p2
...Discharge pressure T, T/, 'L"J. T3 ... Time. Patent applicant Ebara Corporation Agent Arai - Department

Claims (1)

[Claims] l Do you also have a device to test the discharge pressure of the pump? In a pump device according to the present invention, a detection means for obtaining a detection signal corresponding to the magnitude of pressure when the pump is activated; An automatic dosing device for a pump characterized by comprising a control circuit that generates a signal when there is a pressure drop greater than the pressure drop value indicating an aerodynamic condition! .