JPH02112694A - Feed water supply system - Google Patents

Abstract

PURPOSE:To prevent frequent sudden variation of water pressure by restarting a pump when a pressure switch is turned on within the specified time after the stop instruction is issued to the pump. CONSTITUTION:The signals from a timer 9 and a pressure switch 6 are constantly outputted to a controller 7 to detect if the pressure switch 6 is turned on before the timer 9 finishes counting of the set time. Once it is detected that the pressure switch 6 is turned on before the timer 9 finishes the counting of the set time, a change-over means 8 is controlled to prevent the change-over of a pump 1 or 2 started up, that is, to restart the latest running pump 1 or 2. If the pressure switch 6 is turned on after the timer 9 finishes the counting, the change-over of a pump selectively started up is executed by the change-over means 8 to control such the operation that the latest running pump 1 or 2 is switched to the other pump 1 or 2. So the pressure in a mixing pipe 3 may be prevented from sudden reduction.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a water supply device used for supplying water to housing complexes and the like.

2. Description of the Related Art An example of a conventional water supply device will be described below with reference to FIGS. 4 and 5.

In Figure 4, 1.2 is a pump, 3 is a confluence pipe that connects the outlet of pump 1.2 and the water supply pipe 4 to each home, and 5 is a branched pipe installed in the middle of this confluence pipe 3. pressure tank,
Reference numeral 6 denotes a pressure switch provided in the merging pipe 3, which is turned on and off according to pressure fluctuations within the merging pipe 3. 7
pump 1.2 according to the output from this pressure switch 6.
It is a control unit that controls the driving of the pumps 1 and 2, and has a built-in delay timer 7a in order to reduce the frequency of activation of the pumps 1 and 2. Reference numeral 8 denotes a switching means for alternately switching the pumps to be started according to commands from the control section 7.

In addition, FIG. 5 is a diagram showing the relationship between the amount of water used and the pressure inside the merging pipe 3. In the diagram, the region A is the intermittent operation region of the pump, and the regions B and C are the continuous operation region. .

Next, the operation will be explained.

With the use of water, the pressure inside the confluence pipe 3 decreases while the pump is stopped, and when the pressure reaches the on pressure of the pressure switch 6, the pressure switch 6 is turned on. Then, the control section 7 detects the output from this pressure switch, operates an internally provided delay timer 78, and starts one of the pumps. Until the predetermined time set in the delay timer 78 has elapsed, the pump is operated regardless of whether the pressure switch 6 is turned off. Further, if the pressure switch 6 is on when the delay timer 73 is turned off, the control section stops the pump at the same time as the pressure switch 6 is turned off. Further, in order to extend the product life of the pumps 1 and 2, the control section 7 controls the switching means 8 so that the pumps 1 and 2 are operated alternately each time the pumps are started.

FIG. 6 is a timing chart showing the timing of the above operations.

Note that the pressure tank 5 performs a pressure maintenance function to keep the pressure inside the pipe constant when the pump is stopped by accumulating pressure.

Problems to be Solved by the Invention By the way, in a water supply system having the above configuration, the pressure tank occupies a considerable size, so in order to downsize the overall shape of the water supply system, it is necessary to downsize this pressure tank. There is a need.

As mentioned above, in a system in which two pumps are operated alternately, the following problems occur when the pressure tank is downsized.

In other words, if the pressure tank is large, the pressure accumulation effect is large, so even if the amount of water used is large, there will not be a sudden drop in water pressure until the pressure switch is turned on and the pump starts pressurizing. As the pressure tank becomes smaller, the pressure accumulation effect also decreases accordingly, so when the amount of water used is large, it takes a short time (usually 1 hour) for the pressure switch to be turned on and the pump to pressurize. This is a problem in that the water pressure rapidly decreases over a period of time (hereinafter referred to as a time lag), and the pressure within the water supply pipe also decreases rapidly. Therefore, when a water heater or the like is connected to this water supply pipe, this rapid pressure drop causes a rapid change in the temperature of the hot water discharged from the water heater, making it extremely difficult to use.

In view of this problem, it is an object of the present invention to prevent the above-described rapid changes in water pressure from occurring frequently in a water supply device equipped with a plurality of pumps.

Means for Solving the Problems To achieve the above object, the water supply device of the present invention includes means for restarting the pump when the pressure switch is turned on within a predetermined time after outputting a stop command to the pump. .

If the pump is started while the impeller of the working pump is rotating, the above-mentioned time lag can be kept small.

Embodiment Hereinafter, one embodiment of the water supply device of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a water supply device according to an embodiment, and in the figure, components having the same configuration as the conventional one are given the same numbers as the conventional one, and the explanation thereof will be omitted.

The configuration is different from the conventional one in that a second timer 9 is added that starts timing operation at the same time as the control unit 7 outputs a stop command to the pump, and the control unit 7 uses this second timer 9 and a pressure switch. The point is that the switching means 8 is configured to be controlled according to the output of the switch 6. In this embodiment, the second timer 9 completes the timing operation in a time shorter than the time from when the control section 7 issues a stop command to the pump until the impeller of the pump actually stops, that is, turns off. is designed to.

Moreover, the specific operation control of this control section 7 is as follows. That is, the outputs from the timer 9 and the pressure switch 6 are input to the control section 7, and the control section 7 determines whether the pressure switch 6 is turned on before the timer 9 expires. If it is determined that the pressure switch has been turned on before the timer 9 expires, the switching means 8 is controlled to prevent the pump to be started from being switched, that is, to restart the pump that has been operating until recently. put on. Further, when the pressure switch 6 is turned on after the timer 9 expires, the switching means 8 executes a starting pump switching operation, and the operation is controlled so as to start a pump different from the pump that has been operating until recently.

Next, the operation of the water supply device of this embodiment configured as described above will be explained with reference to the flowchart of FIG. 2.

First, when the pressure in the confluence pipe 3 decreases, the pressure switch 6 is turned on, and at the same time, the first pump 1 is activated (steps (a) and (b)). The delay timer 78 built into the control unit 7 is turned on when the pressure switch 6 is turned on (step (c)), and even if the pressure switch 6 is turned off while the delay timer 7a is turned on, it will not be affected. (The operation of the pump 1 continues (steps (d), steps (e)). Then, when the delay timer turns off, the control unit 7 stops the startup of the pump 1 and controls the second timer 9 to start the timing operation. (step (
fart)). If the pressure switch 6 is not turned on until the timer 9 expires, the process proceeds from step (G) to step (H) to step (S), and the control section 7 controls the switching means 8 to perform the next operation. The pump to be started is switched to the second pump 2, and the process returns to step (b), and the second pump 2 is started at the same time as the pressure switch is turned on. Further, if the pressure switch 6 is on when the delay timer 7a is turned off, the pump 1 continues to operate, and when the pressure switch 6 is turned off, the pump 1 is stopped. Also, while the first pump 1 is operating, the oil pump 1 stops operating due to the delay timer being turned off, the second timer 9 starts timing operation, and before the timer 9 turns off, the pressure switch 6 is turned off. If it is turned on, the control unit 7 controls the first pump l that has been operating until then to be started again without performing a pump switching operation (step (H)).

If the pressure switch turns on immediately after the delay timer turns off, restart the pump that has been operating until recently, i.e., the pump that has an impeller that continues to rotate due to inertia. As a result, the time required from the activation of the pump until the pressure within the confluence pipe 3 rises can be shortened.

Note that the above-mentioned timer means can be easily realized by an RC timer using a resistor and a capacitor.

Further, FIG. 3 is a timing chart showing the timing of the above operations.

As described in detail of the invention, in the water supply system of the present invention that operates by switching a plurality of pumps, if the pressure switch is turned on within a predetermined time after outputting a stop command to the pump in operation, the By providing a means for restarting the pump, it is possible to prevent a sudden drop in the pressure inside the pipe compared to the conventional water supply system, which is very effective in practice.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a water supply device according to an embodiment of the present invention, FIG. 2 is a flowchart showing the flow of operation of the water supply device according to the same embodiment, and FIG. 3 is a timing chart showing the timing of operation of the same embodiment. , Figure 4 is a configuration diagram of a conventional water supply device, Figure 5
The figure is a characteristic curve diagram showing the relationship between the amount of water used and the pressure in the confluence pipe, and FIG. 6 is a timing chart showing the timing of the operation of the conventional example. 1.2... Pump, 3... Merging pipe, 4... Water supply pipe, 5... Pressure tank, 6... Pressure switch. , 7...Control unit, 7a...Delay timer 8...Switching means, 9...Second timer

Claims (2)

[Claims] (1) Multiple pumps connected to the same water supply pipe, a pressure tank, and a pressure switch installed in the discharge pipe of the pump to detect the pressure inside the pipe and output a detection signal when a predetermined pressure is reached. , a water supply device comprising a switching means for switching the pump to be started, and a control section for controlling the switching means according to an output from the pressure switch, wherein the control section is configured to control the pump in operation. The pump is provided with a means for restarting the pump that has been operating until then without performing a switching operation by the switching means when a detection signal is output from the pressure switch within a predetermined time after issuing a stop command. Characteristic water supply device. (2) The predetermined time according to claim (1) is set to be shorter than the time from when the control section instructs the pump to stop until the impeller of the pump stops. water supply equipment.