JP2527162B2 - Water supply device using constant pressure valve - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a water supply device in which a plurality of pumps, a constant pressure valve, and a small pressure tank are combined, and more particularly, to a pump without using a flow switch. The present invention relates to a water supply device equipped with a constant pressure valve suitable for controlling the number of units.

[Conventional technology]

Conventionally, for example, in Japanese Patent Publication No. 57-35483,
There is provided a water supply device that combines a pump, a constant pressure valve (including a pressure reducing valve), a small pressure tank, and the like to mechanically keep the pressure on the discharge side constant by the action of the constant pressure valve.

In addition, in recent years, while incorporating this constant pressure valve,
Controlling the number of pumps is also considered.

[Problems to be solved by the invention]

Now, in the water supply system incorporating the constant pressure valve, the discharge pressure is naturally kept constant regardless of the amount of demand water. Therefore, if the cheapest pressure switch is used to control the operation of the pump, the pressure on the discharge side will not rise unless the demand water amount decreases significantly. It runs for a long time and wastes power.
This causes a more serious problem when controlling the number of pumps by combining a plurality of pumps, and the timing of stopping the pump on the follower side that operates following the preceding pump is lost.

The problem can be solved by combining such a problematic pressure switch with a flow switch or a flow switch and detecting a decrease in the demand water amount, but such a detection device is generally expensive and maintenance is troublesome. Is.

Therefore, an object of the present invention is to make it possible to reliably stop the pump on the follower side in a water supply system incorporating a constant pressure valve, even if the demand water amount does not extremely decrease and an expensive flow rate sensor is not used. It is to provide a water supply device using a pressure valve.

[Means for solving problems]

In order to achieve the above object, in the present invention, at least two pumps, a constant pressure valve having a primary side connected to each discharge side of the pump, and a water supply pipe connected to the secondary side of the constant pressure valve, A pressure tank connected to this water supply pipe, an independent operation switching means that alternately switches two pumps one by one to enable operation, and two pumps are controlled, and one of the pumps is set in a preceding operation state. In some cases, in a water supply device having a parallel operation control unit that causes the other pump to perform follow-up operation, the parallel operation control unit is connected to the water supply pipe and the preceding operation and operation of one pump that operates in advance. A first pressure detecting means for issuing an operation command for stopping and a follow-up operation of the other pump which is connected to the water supply pipe, detects a pressure slightly lower than the preceding operation command of the one pump, and operates in a follow-up manner. Command A second pressure detecting means for issuing, connected to each of the primary side of the constant pressure valve, when the pressure rises along the pump characteristics with decreasing water demand,
A third pressure detection unit that detects a pressure higher than the operation command pressure of one pump and a follow-up operation command pressure of the other pump, and issues a stop command for the other pump, and a stop command for the third pressure detection unit. In response, a timer means for performing a timer operation for a predetermined time, and during the preceding operation of the one pump and the following operation of the other pump,
By the stop command of the other pump of the third pressure detecting means,
An operation control circuit for stopping the operation of the other pump when the timer means operates for a predetermined period of time.

[Action]

In the present invention, the discharge pressure is kept substantially constant on the secondary side of the constant pressure valve, but the primary side pressure gradually rises as the demand water volume decreases.

That is, when the water supply progresses while both pumps are stopped, the discharge pressure gradually decreases, and when the pressure drops to the pressure that issues the preceding operation command for one pump, the first pressure detection means detects this. This starts the operation of one pump.

At this time, when the demanded water amount is relatively small, the discharge pressure rises, and when the pressure at which one pump stops is restored, the pump is stopped by the first pressure detection means.

Further, when one of the pumps on the leading side is started in the above stage, the demand water amount increases, and when the pressure in the water supply pipe drops to the pressure at which the follow-up operation command of the other pump is issued, this is The other pump starts operating as a follow-up side, and both pumps are in parallel operation. When both pumps are operated in parallel, the discharge pressure of the water supply pipe is kept substantially constant within the range of the demand water volume by the action of the constant pressure valve.

On the other hand, when both pumps are in operation, the water demand gradually decreases,
Along with the decrease, the pump discharge pressure on the primary side of the constant pressure valve rises. At that time, when the pump discharge pressure rises to the pressure detected by the third pressure detecting means, a predetermined time period is set by the timer. To start the timer operation. Then, when the timer operation ends after the elapse of a certain time, the operation of the other pump can be stopped by the operation control means.

That is, when the demand water amount decreases during the operation of both pumps, the pressure on the primary side of the constant pressure valve associated therewith is detected by the third pressure detecting means, and therefore the pressure increase due to the decrease in the demand water amount is favorably suppressed. Can be detected. for that reason,
Even if the demand water amount does not decrease extremely, the stop timing of the pump on the follower side is not lost, the pump can be stopped reliably, and the follower pump can be controlled with high sensitivity.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. That is, FIG. 1 is a configuration diagram for explaining the overall configuration of the water supply device, and 11 and 12 are pumps having similar discharge characteristics, which are driven by a drive motor (not shown). Reference numerals 21 and 22 denote constant pressure valves connected to the discharge sides of the respective pumps 11 and 12, and the secondary sides of the constant pressure valves 21 and 22 are connected to the water supply pipe 4 via check valves 31 and 32, respectively. 5
Is a small pressure tank connected to the water supply pipe 4, 61 and 62 are the secondary side of the constant pressure valves 21 and 22, that is, the first and second connected to the water supply pipe 4.
The second pressure switches 63 and 64 are third pressure switches connected to the primary side of the constant pressure valves 21 and 22, that is, on the conduits connecting the discharge ports of the constant pressure valves 21 and 22 and the pumps 11 and 12, respectively. .

Next, the set pressures of the various pressure switches 61, 62, 63, 64 will be described with reference to FIGS.

That is, FIG. 2 shows the demand flow rate Q on the horizontal axis and the discharge pressure H on the vertical axis, and the characteristic curves A and B show the discharge characteristics and characteristic curves when the pumps 11 and 12 are operated independently and in parallel. A ′ and B ′ are discharge characteristics on the secondary side of the constant pressure valves 21 and 22 when the pumps 11 and 12 and the constant pressure valves 21 and 22 are combined and operated independently and in parallel. Also, FIG. 3 shows these pressure switches 61, 6
2 shows a relay sequence circuit which incorporates 2, 63 and 64 open / close contacts and controls the operation of the pumps 11 and 12. By the way, the first pressure switch 61 which issues the operation command for the preceding operation and the operation stop of the pump has the discharge pressure of P1.
When it drops to, it closes its contact PS1 and opens when the discharge pressure recovers to pressure P2.

Similarly, the second pressure switch 62, which issues a follow-up operation command for the pump, closes its contact PS2 when the discharge pressure drops to a pressure P3 slightly lower than the pressure P1, and recovers to a pressure P4 higher than this pressure P3. When open. In addition, the third pressure switch 6 that issues a stop command for the pump that follows
3,64 is the constant pressure valve 2 required to obtain the pressure P3 described above.
The contacts PS3, PS4 are closed at a pressure equal to or close to the primary side pressure P3 'of 1, 22 and open at a higher primary side pressure P5 of the constant pressure valves 21, 22, respectively. Note that the relationship between the operating pressure P4 of the second pressure switch 62 and the operating pressure P5 of the third pressure switches 63, 64 is the intersection of the demand water amount Q5 and the characteristic curve B'when the pressure P4 is the pressure P5. The pressure should be higher than P4 '.

Next, the relay sequence circuit for controlling the operation of the pumps 11 and 12 will be described in detail with reference to FIG. That is, P and N are control power supply bus lines, and MC1 and MC2 are pumps 11 and 12
An electromagnetic switch for operating the drive motors connected to each other, AL is an alternate relay having a contact mechanism ALC, and T is a timer having a contact Tb for performing a timer operation for a predetermined time. By the way, the alternate relay AL is a double electromagnetic switch MC
It is connected in series with the contacts MC1b and MC2b of 1 and MC2, and it operates every time both electromagnetic switches MC1 and MC2 are opened, and the contacts in the contact mechanism ALC of these are switched from the b side to the a side, or Switch from side a to side b. In other words, the contacts a and b inside the contact mechanism ALC of the alternate relay AL are respectively connected to each other, and each time the both electromagnetic switches MC1 and MC2 are opened, the pump selected as the leading or following side is selected. Switch.
Next, the contact PS1 of the first pressure switch 61 is connected to one contact c of the contact mechanism ALC.

The other contact c of the contact mechanism ALC is connected to a series circuit including the contacts MC1a and MC2a of the electromagnetic switches MC1 and MC2 and the contact Tb of the timer T. Further, the other contact c of the contact mechanism ALC is further connected to the contact PS2 of the second pressure switch 62 and the contact of the third pressure switch 63, 64.
The series circuit on the a side of PS3 and PS4 is connected. The a-sides of the contacts PS3, PS4 of the third pressure switches 63, 64 are connected in parallel, and the a-side contacts are the constant pressure valves 21, 22 described in FIG.
When the discharge pressure of the pumps 11 and 12 drops to a pressure equal to or close to the primary side pressure P3 ',
Open when the discharge pressure of pumps 11 and 12 is restored to P5.
At the same time, the b-side contact is also connected in parallel, and this b-side contact closes when the discharge pressure recovers to P5, contrary to the a-side contact, and the discharge pressure is equal to the pressure P3 'or It opens when the pressure drops to a near level.

A timer T is connected to the series circuit of the contacts PS3 and PS4 on the b side of the third pressure switches 63 and 64 connected in parallel and the contact PS2 of the second pressure switch 62. The timer operation of this timer T is the third pressure switch PS3, PS
It starts when the b-side contact of 4 is closed and is sufficient to suppress the starting frequency of each pump 11 and 12, and after a sufficient and necessary time so that meaningless simultaneous operation of both pumps does not occur. contact
Set to open Tb. In the embodiment, the timer operation time is set to about 3 to 5 minutes.

Next, the driving operation of the embodiment thus configured will be described. Now, the discharge pressure (water supply pressure on the water supply pipe 4 side) is pressure P2.
Thus, it is assumed that both pumps 11 and 12 are stopped in the state shown in FIG. When the water supply progresses in this state, the discharge pressure gradually decreases, and when it reaches the pressure P1, the contact PS1 of the first pressure switch 61 closes, the electromagnetic switch MC1 operates, and the pump 11 starts operating. At this time, when the demand water amount is relatively small, the discharge pressure rises, and when the pressure P2 is restored, the contact PS1 of the first pressure switch 61 is opened, so the pump 11 is stopped. Since the contact MC1b of the electromagnetic switch MC1 is closed by stopping the pump 11, the alternate relay AL operates and switches the contact in the contact mechanism ALC thereof from the b side to the a side.

By this switching operation, the pump 12 is subsequently selected as the preceding pump.

Despite the fact that the pump 11 on the preceding side started at the above stage, the demand water volume increased and the pressure in the water supply pipe 4 increased.
If it drops to P3 and the discharge pressure drops to P3 ',
Since the contact PS2 of the second pressure switch 62 and the contacts PS3 and PS4 of the third pressure switches 63 and 64 are closed one after another, the electromagnetic switch MC2 operates and the pump 12 on the following side operates. Beginning, the parallel operation of both pumps 11 and 12. At this time, the electromagnetic switch MC2 has its own contact MC2a and the electromagnetic switch M
It is self-held by a series circuit with the contact MC1a of C1 and the contact Tb of the timer T. Both pumps 11,12 like this
When the parallel movement is performed, the discharge pressure of the water supply pipe 4 is kept substantially constant within the demand water amount range Q1 to Q6 by the action of the constant pressure valves 21 and 22.

Now, when the demanded water volume gradually decreases and reaches the water volume Q5,
The discharge pressure of the primary side pumps of the constant pressure valves 21, 22 reaches the pressure P5 as the demand water amount decreases. When this pressure increase is detected by the third pressure switch 63, 64, its contact PS3, P
The b-side contact of S4 is closed, and the timer T starts the timer operation. As a result, the operation of the pump 12 on the following side is continued until the contact PS2 of the second pressure switch 62 is opened, the contacts PS3 and PS4 of the third pressure switches 63 and 64 are closed on the side b, and the contact Tb of the timer T is opened. The process is continued, and the process ends when the contact Tb opens.

Therefore, when the demand water amount decreases during the operation of both pumps, the pressure on the primary side of the constant pressure valves 21, 22 rises accordingly, but the pressure on the primary side is adjusted to the third pressure switch 63, 64.
Since it is detected by, it is possible to satisfactorily detect the pressure increase due to the decrease in the demand water amount. Therefore, even if the demanded water amount is not extremely reduced, the stop timing of the pump on the follower side is not lost, and the pump can be reliably stopped, and the follower pump can be controlled with high sensitivity.

Moreover, according to the embodiment, various signals necessary for operating / stopping the pump are obtained by the first to third pressure detecting means, the timer means, and the operation control circuit without using an expensive flow rate sensor. By appropriately selecting the parallel operation time of the following pumps, the starting frequency of the following pumps can be suppressed.

When the pumps 11 and 12 are in operation and the demand water amount increases again and the discharge pressure drops below the pressure P3 by the end of the timer operation, the contact PS3, PS4 of the third pressure switch 63,64
The a-side contact is closed again and the timer T is reset, so that both pumps 11 and 12 continue to operate in parallel.

Pump 11 on the leading side after the pump 12 on the trailing side stops
Since the independent operation of is as described above,
Description is omitted.

〔The invention's effect〕

As described above, according to the present invention, in the continuous operation of both pumps, when the demand water amount gradually decreases, the pressure on the primary side of the constant pressure valve rises accordingly, and the pressure on the primary side is adjusted to the third pressure. By detecting with the pressure detection means, it is possible to satisfactorily detect the pressure increase due to the decrease in the demand water amount, so that even if the demand water amount does not decrease extremely, the stop timing of the pump on the follower side is not lost. It has an effect that it can be surely stopped and the follow-up pump can be controlled with high sensitivity.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a water supply device for explaining an embodiment of the present invention, FIG. 2 is a diagram for explaining operating characteristics of the same embodiment, and FIG. 3 is a circuit showing a relay sequence of the embodiment. It is a figure. 4 ... Water supply pipe, 5 ... Pressure tank, 11, 12 ... Pump, 2
1,22 …… Constant pressure valve, 61 …… First pressure switch, 62 …… Second pressure switch, 63,64 …… Third pressure water soil, MC1, MC2
…… Electromagnetic switch, AL …… Alternating relay, T …… Timer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroshi Kunii 7-1-1 Higashi Narashino, Narashino City Narashino Factory, Hitachi Ltd. (72) Inventor Yukio Tagawa 7-1-1 Higashi Narashino, Narashino City Hitachi Ltd. Narashino Factory (72) Inventor Masanobu Inagaki 7-1-1 Higashi Narashino, Narashino City Hitachi Ltd. Narashino Factory (56) References JP-A-51-21201 (JP, A) Actual development Sho-59-146596 (JP) , U) Actual development Sho 57-150288 (JP, U) Japanese Patent Sho 57-35483 (JP, B2)

Claims (1)

(57) [Claims] 1. At least two pumps, a constant pressure valve having a primary side connected to each discharge side of the pump, a water supply pipe connected to the secondary side of the constant pressure valve, and a water supply pipe connected to the water supply pipe. The pressure tank and the independent operation switching means for alternately switching the two pumps so that they can be operated one by one, and the two pumps are controlled, and when one pump is in the preceding operation state, the other pump is operated. In a water supply device having a parallel operation control unit for following operation, the parallel operation control unit is connected to a water supply pipe, and outputs an operation command for preceding operation and operation stop of one of the pumps operated in advance. A second pressure that is connected to the water supply pipe and that detects a pressure slightly lower than the preceding operation command of the one pump and that issues a follow-up operation command of the other pump that operates in a follow-up manner. Detection means , Connected to each primary side of the constant pressure valve, when the pressure rises along the pump characteristics as the demand water volume decreases, a pressure higher than the operation command pressure of one pump and the follow-up operation command pressure of the other pump is set. Detect and
Third pressure detecting means for issuing a stop command for the other pump, timer means for receiving a stop command for the third pressure detecting means and performing a timer operation for a predetermined time, and preceding operation of the one pump. During the follow-up operation of the other pump, the operation of stopping the operation of the other pump at the time when the timer means operates for a predetermined period of time by the stop command of the other pump of the third pressure detecting means. A water supply device using a constant pressure valve, which is provided with a control circuit.