JP2003222083A - Variable speed water supply equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide variable speed water supply equipment that performs well-balanced actuation stop due to insufficient water, avoiding shut-off operation and frequent start-stop operation even in the simple and small economic water supply equipment. <P>SOLUTION: This equipment provided a pressure detection means 6 installed on the discharge side of a pump 1, a variable speed means 2 to change the numbers of rotation of the pump 1 and a control means 7 that controls the pump 1, and the control means 7 stops the pump 1 after the pressure monitor operation is done by using the pressure value on the discharge pressure and the lowest pressure value at the shut-off-operation when it becomes water insufficient condition. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple and small-sized variable speed water supply apparatus, and more particularly to a variable speed water supply apparatus having a small water quantity stop function for stopping a water supply pump when a load is a small amount of water.

[0002]

2. Description of the Related Art A variable speed water supply apparatus is a water supply apparatus capable of adjusting the flow rate and the discharge pressure by changing the rotational speed of a pump for supplying water according to a load by a variable speed means such as an inverter. FIG. 1 is an explanatory diagram showing the overall configuration of the variable speed water supply device. This variable speed water supply device sucks water from the suction port 11, pressurizes it with the water supply pump 1, and supplies the load 20 with water. On the discharge side of the water supply pump 1 of the flow path 10, a flow switch 3 that detects that the flow rate of the water flow is a small amount of water below a certain value, a check valve 4, and a pressure tank 5.
And pressure detecting means 6 for detecting the discharge side pressure of the pump (water pressure in the pressure tank). The pump 1 is driven by a frequency / voltage inverter which is a variable speed means 2 that changes its rotation speed, and the variable speed means 2 is controlled by a pump control means 7.

This pump control means 7 detects that the flow rate of the flow switch 3 is below a certain value, and generates a small water amount detection signal to maintain a constant small water amount detection time for a small amount of time. After confirming that the water quantity state has continued, the water tank 1 has a small water quantity stop function of stopping the water supply pump 1 after accumulating in the pressure tank 5 at a pressurizing pressure value or pressurizing frequency value for a certain period of time. Further, it has a pump starting pressure set value, and has a function of starting the water supply pump 1 when the pressure signal of the pressure detecting means 6 becomes equal to or lower than the pump starting pressure set value while the water supply pump is stopped.

Therefore, the operation of this variable speed water supply system is as follows. First, when the load 20 needs a medium water amount or a large water amount, the pump control means 7 uses the pressure signal S1 of the pressure detection means 6 to rotate the water supply pump 1 so that the pressure in the load 20 becomes constant. The means 2 is proportional-integral (PI) controlled. When the load is a small amount of water, the above-mentioned small amount of water stopping operation is performed in order to prevent heating due to the shutoff operation of the pump and to reduce wasteful operating time (energy saving). That is, the flow switch 3 detects a small amount of water and generates a detection signal, and after confirming that the small amount of water continues during a certain small amount of water detection time, the pressure tank 5 pressurizes for a certain time. Pressure is accumulated at a value or a pressurization frequency value, and then the water supply pump 1 is stopped. Then, when water is supplied from the pressure tank 5 to the load 20 and the pressure in the pressure tank 5 drops below a predetermined pump starting pressure set value, the water supply pump can be restarted to keep the water pressure in the load 20 at the predetermined pressure. Return to shifting operation.

[0005]

The purpose of the small water volume stop operation is to prevent heating by the pump shutoff operation and to reduce wasteful operation time. On the contrary, if the accumulated pressure during this small water volume stop operation is too high, A rapid pressure increase due to the accumulated pressure before the pump is stopped is frequently repeated, which causes a problem in the mechanical life of the water supply device and also causes a problem such as frequent pressure fluctuations on the load side. Also, if the pressure rise value due to accumulated pressure before stopping a small amount of water is suppressed to a low level, there will be no sudden pressure rise on the load side, which will improve the usability of the water supply device. You will not be able to earn money and the frequency of starting and stopping the pump will increase.

By the way, the present inventor et al.
In patent application No. 527, a variable speed water supply device having means for automatically setting operating parameters of a pump including a pressurizing pressure (frequency) value and a small water amount detection time in accordance with load or data of the most recent operating condition is provided. Disclosure. It also similarly discloses that the means for automatically setting the operating parameters is based on the fuzzy inference function. According to such a variable speed water supply device, while the original purpose of the small water volume stop function of preventing heating by the pump shutoff operation and reducing the wasteful operation time is satisfied, the frequency of starting and stopping the pump is reduced, and the pressure is accumulated before the small water volume stop. It is possible to achieve the contradictory objectives of reducing the rapid pressure rise to some extent in a well-balanced manner.

However, the above-mentioned variable speed water supply apparatus has the following problems when applied to a simple and small-sized water supply apparatus. The number of input element signals (information) used for control increases, and the cost of the control device increases. When the fuzzy inference function is used, the amount of data increases and the memory capacity increases exponentially. Therefore, a large-capacity memory and a CPU having a high processing speed are required, which increases the price of the control device.

The present invention has been made in view of the above-mentioned circumstances, and even in a simple and small-sized economical water supply device, a well-balanced small water amount stop can be performed by avoiding a deadline operation and avoiding frequent start-stop. It is an object of the present invention to provide a variable speed water supply device that can operate.

[0009]

In order to achieve the above-mentioned object, a variable speed water supply apparatus of the present invention comprises a pump, a pressure detecting means provided on the discharge side of the pump, and a rotation speed of the pump. Variable speed means for controlling, and control means for controlling the pump, the control means, when in a small water amount state, the pressure value based on the discharge pressure at that time and the minimum pressure value during deadline operation are used. After the monitoring operation, the pressure is accumulated and the pump is stopped.

According to one aspect of the present invention, the pressure monitoring operation monitors that the two pressure values are not lower than a predetermined time. According to one aspect of the present invention, the pressure value based on the discharge pressure is equal to the pressure on the pump discharge side when the small water amount state is reached. According to one aspect of the present invention, the pressure value based on the discharge pressure is a pressure slightly lower than the pressure on the discharge side of the pump at the time of the small water amount state.

The water supply apparatus of the present invention comprises a pump, pressure detecting means provided on the discharge side of the pump, variable speed means for changing the rotational speed of the pump, and control means for controlling the pump. When the amount of water is small, the control means fixes the rotation speed of the pump as it is, judges that the pressure detected by the pressure detection means does not fall below a predetermined pressure for a certain period of time, and controls the pump. It is characterized by stopping.

A preferred aspect of the variable speed water supply apparatus of the present invention is a water supply pump, variable speed means for changing the rotation speed of the water supply pump, a flow switch and a check valve provided on the discharge side of the water supply pump. A pressure tank and a pressure detection means provided on the downstream side of the check valve, and a pump control means, the pump control means, the flow switch generates a small water amount detection signal, a certain small water amount detection time After holding the pressure tank for a certain period of time, after accumulating at a certain pressurizing pressure value or pressurizing frequency value, it has a function of stopping the water supply pump, a pump starting pressure set value, and while the water supply pump is stopped. And a function of starting the water supply pump when the pressure signal becomes equal to or lower than the pump starting pressure set value by the pressure detecting means, and the small water amount detection time is the last pump stop time and the immediately preceding pump operation. And while, on the basis of the number of times of opening and closing of the flow switch, and a function of automatically setting.

Further, the control means starts a timer for detecting a small amount of water after the flow switch is closed, performs a pressure monitoring operation with the frequency fixed and slightly increased, and counts up the timer to perform the pressure accumulation operation. It is something that enters.

Further, the control means starts the timer for the small water amount detection time after the flow switch is closed, performs the pressure monitoring operation with the frequency fixed as it is, and enters the pressure accumulation operation by counting up the timer. It is a thing.

Further, the control means starts a timer for detecting a small amount of water and performs a pressure monitoring operation after the flow switch is closed, and the storage operation is started by counting up the timer.

The means for automatically setting the small water amount detection time is performed by fuzzy inference with reference to a data table.

According to the present invention, it is possible to reduce the wasteful operation time due to the pump shutoff operation, contribute to energy saving, and avoid a sudden rise in the discharge side pressure of the pump.
Provided is a comfortable water supply system which extends the mechanical life of the water supply system and has less pressure fluctuation on the load side.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the overall structure of a simple, compact and economical variable speed water supply system. As is clear from FIG. 1, a water feed pump 1, a variable speed means 2 for changing the rotation speed of the water feed pump 1, a flow switch 3 and a check valve 4 provided on the discharge side of the water feed pump, and a check valve. The configuration including the pressure tank 5 and the pressure detection means 6 provided on the downstream side is
This is similar to the variable speed water supply device described in the section of the related art.
In addition, the pump control means 7 causes the flow switch 3 to generate a small water amount detection signal S2 and hold it for a certain small water amount detection time, then accumulates pressure in the pressure tank 5 and then stops the water supply pump 1 And a pump starting pressure set value, and a starting function for starting the water feed pump 1 when the pressure signal S1 becomes less than or equal to the pump start pressure set value by the pressure detection means 6 while the water feed pump 1 is stopped. It is also the same as the above-mentioned conventional technique.

In the water supply system of this embodiment, the pump control means 7 is provided with an automatic setting means 15 for automatically setting an optimum value for the small water quantity detection time for confirming the continuation of the small water quantity state in accordance with the operating condition. . Here, the operating status is, for example, the immediately preceding water supply pump operating time, the previous pump stop time, the number of times the flow switch is opened and closed, and the like. The means for automatically setting the small water detection time is based on the fuzzy inference function, which has a fuzzy inference section and rules, and takes in various kinds of information on driving conditions and extracts the inference results according to the rules of fuzzy inference. The value is newly set as an operation parameter.

FIG. 2 shows a flow of the operation for stopping a small amount of water.
First, it is determined that the current pressure detected by the pressure detecting means 6 is equal to or higher than the minimum pressure PB during the deadline operation (ST.
1). If this is YES, it is determined whether the flow switch is closed or open (ST2). The fact that the flow switch is closed indicates that there is a small amount of water supplied to the load side. Yes
If that is the case, that is, if a small water quantity state is detected, the small water quantity detection time timer starts (ST3). Here, the timer value is automatically set from the data table by fuzzy inference. The details will be described later. Next, it is determined whether or not the timer has counted up (ST4). Whether or not the timer counts up is determined by whether or not a predetermined small water amount detection time has elapsed.

At this stage, if the answer is NO, the timer is not counting up, so the pressure monitoring operation is started (ST5). In this operation, the pump is operated at a constant frequency slightly higher than the frequency when the flow switch is closed. Then, the pressure monitoring delay timer starts (ST6). This timer is a short time timer of about several seconds, and it is judged whether or not the pressure monitoring delay timer has counted up (ST7). Since the current pressure can be read by counting up this timer, the current pressure is the pressure when the flow switch is closed (P
It is determined whether it is larger than F) (ST8). If the current pressure is equal to or higher than the pressure PF when the flow switch is closed, it is determined that the small water amount state is continuing, and S
Returning to T2, after that, ST3, ST4, ST5, ST6,
The loop of ST7 will be repeated.

In the pressure monitoring operation, the pump may be operated with the pressurizing frequency fixed when the flow switch is closed. In this case, the pressure value (PF) for comparison is slightly lowered, and is calculated as 95%, for example, and the pressure monitoring operation is performed, and then the pressure accumulation operation is started. Further, in the pressure monitoring operation, the variable speed (PI) control operation in which the supply non-end pressure is kept constant without fixing the pressurizing frequency may be continued.

Then, when the timer counts up in ST4 and becomes YES, it is confirmed that the small water amount state has continued for a certain period of time. Then, a pressure accumulating operation for pressurizing water in the pressure tank is started (ST9). That is, it means that the flow switch is never opened during this small amount of water detection time. The pressure accumulation operation is performed at a predetermined set pressure (or frequency).

In the step (ST8) of confirming the present pressure, the present pressure is the pressure PF when the flow switch is closed.
When it is lower than that, it is determined that the state is not a small water amount state, the flow switch detection timer and the pressure monitoring detection timer are reset, and the small water amount detection operation is canceled. Similarly, when the current pressure is lower than the minimum pressure PB at the shutoff operation in the pressure confirmation step (ST1) immediately after the start, it is similarly judged that the state is not the small water amount state,
The low water volume stop condition is canceled. Also, a step of detecting whether the flow switch is open or closed (ST2)
In, when the flow switch is open, it is similarly determined that the flow rate is not in the small water amount state, and the small water amount stop operation is canceled.

FIG. 3 is a time chart showing an example of the small water amount stopping operation. At time T1, the previous pressure accumulation operation started,
The pump operation is stopped at time T2. Then, at time T3, it is detected that the pressure has dropped below the starting pressure, the pump is restarted, and variable speed (PI control) is performed so as to keep the pressure in the terminal water supply device constant. The time from this time T2 to T3 is stored in the control device as the previous stop time. That is, the previous stop time is the stop time from when the pump operating speed becomes zero until restart and the frequency rises. When the closing of the flow switch is detected at time T4, a small water amount detection time timer for confirming that the small water amount state has continued for a certain time is started. Then, the pump enters the pressure monitoring operation at a frequency that is slightly higher than the frequency when the flow switch detects the small water amount state. During this period, the small water amount detection time is excluded, except when the small water amount condition disappears, such as when the flow switch is opened or the current pressure is lower than the pressure (PF) when the flow switch is closed. When is completed, the pump enters the pressure accumulation operation (ST9).

The small water amount detection time is a wait-and-see time for checking the continuation of the small water amount state, stopping the pump, and suppressing the starting frequency. If the small water amount detection time is lengthened, it is possible to avoid repeated useless starting and stopping of the pump when there is a large amount of water fluctuation, but when no water is supplied, useless operation is performed during this period. On the contrary, if the small water amount detection time is shortened, useless operation is reduced when the waterless state continues for a long time, but there is an adverse effect that the stop / start frequency increases when the water amount fluctuation is large.

That is, it is possible to achieve the following in an appropriate and balanced manner by automatically setting the small water amount detection time described above. Reduce the number of small water stop / starts (reduce the flow rate and pressure fluctuations by reducing the start frequency). Reduction of useless operating time (energy saving, prevention of heating due to pump deadline operation).

Here, the small water amount detection time is determined by fuzzy inference from the last stop time, the immediately preceding operation time, and the number of times the flow switch is opened and closed. The immediately preceding operation time is the time from when the pump is started to when the closing of the flow switch is detected, and is the time from T3 to T4 in FIG. still,
When the flow switch changes from the closed state to the open state during the pressure monitoring operation, the time from that point until the flow switch is closed again is added to the immediately preceding operation time. The number of times the flow switch is opened / closed is the number of times the flow switch has been opened / closed during the period from the time when the pressure accumulation operation was started last time (T1) until the small water amount detection time expires (T5). When the flow switch changes from closed to open during the pressure monitoring operation, the number of times of opening and closing is cumulatively counted.

For the small water amount detection time, referring to the data table, the data corresponding to the respective ranges of the three items of the previous stop time, the immediately preceding operation time, and the flow switch opening / closing number are selected. If the flow switch changes from closed to open during pressure monitoring operation, the small water flow stop operation is canceled, the timer is reset, and when the flow switch is closed again, a new small water flow detection time is selected. Restart the pressure monitoring operation based on the above.

FIG. 4 shows a data table for selecting a small water amount detection time. Few times to open and close the flow switch,
There are three categories, medium and many, the last stop time is two categories, short and long, and the last operation time is two categories, short and long. NA, NB,
NC, ND, NE respectively represent the length of the small water amount detection time for detecting the closed state of the flow switch. Where: NA short time NB slightly short time NC medium ND slightly long time NE long time

Therefore, for example, when the number of times the flow switch is opened and closed is small, the operating time immediately before the previous time is short, and the previous stop time is short, the small water amount detection time is NC (medium). As described above, the time for detecting that the flow switch is closed is obtained by referring to the table of the number of times the flow switch is opened / closed, the immediately preceding operation time, and the previous stop time.

Fuzzy inference with reference to this data table is supported by software using a general-purpose microcomputer. This method is a method in which the result of fuzzy inference is written in the ROM as discrete data in advance and the corresponding output value is referred at the time of input. The fuzzy inference rules this time have three inputs and one output, and the number of rules is relatively small, so there is no need for high-speed response, a relatively low-speed microcomputer is used, and the memory capacity is also small. Therefore, the manufacturing cost of the control circuit portion can be suppressed. The microcomputer used for fuzzy inference can be shared with the microcomputer because the microcomputer has already been adopted for the constant end pressure control.

A field test was conducted by applying the variable speed water supply system incorporating the above-mentioned fuzzy reasoning mechanism to a small-scale apartment house. As a result, when the data table of fuzzy inference is used, it is about 6 in comparison with the one which is not used.
It was confirmed that there was an effect of reducing the number of times a small amount of water stopped was about 0%. As for the small water stoppage time, the stoppage time per operation is about three times longer than that in the case where automatic setting by fuzzy reasoning is not used, and it can be seen that an appropriate small water stoppage is performed. The pressure setting value when accumulating is
In this embodiment, the pressure is set slightly higher than the required minimum pressure (PB). It is possible to obtain the pressurizing pressure during accumulating by fuzzy reasoning, but the setting range of the pressure during accumulating is narrow in comparison with the need for complicated calculation, so even if a fine setting is made within that range, it is large. This is because the effect cannot be expected. Therefore, by setting the pressure set value at the time of pressure accumulation to a predetermined fixed set value, it is possible to perform a sufficiently effective small water amount stopping operation.

In this embodiment, another fuzzy controller was used to perform inference in advance and the inference result was made into a data table to set the small water amount detection time. However, it is not limited to fuzzy inference, but fuzzy inference is possible. By using inference, it is possible to perform control so as to obtain a desired operating state for all load conditions, and to reflect empirical knowledge in the control content. Further, it goes without saying that the division of the data table may be increased more than in the above-described embodiment.

[0036]

According to the present invention, it is possible to reduce the frequency of operation stop (startup) with a simple and small water supply device while satisfying the purpose of the operation of stopping the small amount of water such as prevention of heating by the pump shutoff operation and reduction of the operation time. Can be achieved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a variable speed water supply device.

FIG. 2 is an explanatory diagram showing a flow of a small water amount stop operation.

FIG. 3 is a time chart showing an example of a small water amount stop operation.

FIG. 4 is an explanatory diagram showing an example of a table for inferring a small water amount detection time.

[Explanation of symbols]

1 water supply pump 2 Variable speed means 3 flow switch 4 Check valve 5 pressure tank 6 Pressure detection means 7 Pump control means 10 channels

[Procedure amendment]

[Submission date] March 24, 2003 (2003.3.2
4)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

In order to achieve the above-mentioned object, a variable speed water supply apparatus of the present invention comprises a pump, a pressure detecting means provided on the discharge side of the pump, and a rotation speed of the pump. Variable speed means for controlling, and a control means for controlling the pump, the control means, when in a small amount of water state, the pressure value based on the discharge pressure at that time and the minimum pressure value during deadline operation After the monitoring operation, the pressure is accumulated and the pump is stopped.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

According to one aspect of the present invention, the pressure monitoring operation monitors that the two pressure values are not lower than a predetermined time. According to one aspect of the present invention, the pressure value based on the discharge pressure is equal to the pressure on the discharge side of the pump when the amount of water is small . According to one aspect of the present invention, the pressure value based on the discharge pressure is a pressure slightly lower than the pressure on the discharge side of the pump when the amount of water is small .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

The water supply apparatus of the present invention comprises a pump, pressure detecting means provided on the discharge side of the pump, variable speed means for changing the rotational speed of the pump, and control means for controlling the pump. When the amount of water is small , the control means fixes the rotation speed of the pump as it is, judges that the pressure detected by the pressure detection means does not fall below a predetermined pressure for a certain period of time, and controls the pump. It is characterized by stopping.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

[0036]

According to the present invention, it is possible to reduce the frequency of operation stop (startup) with a simple and compact water supply device while satisfying the purpose of the operation of stopping a small amount of water such as prevention of heating by the pump shutoff operation and reduction of operation time. Can be achieved.

Continued front page    F-term (reference) 3H020 AA01 AA07 BA03 BA06 BA12                       CA02 CA05 DA04 DA30 EA02                       EA03 EA07 EA12                 3H045 AA01 AA09 AA12 AA23 BA07                       BA14 BA32 CA03 CA09 DA04                       DA43 DA48 EA13 EA17 EA34                       EA38 EA42

Claims (5)

[Claims] 1. A pump, a pressure detection means provided on the discharge side of the pump, a variable speed means for changing the rotational speed of the pump, and a control means for controlling the pump, the control means comprising: When a small water amount state is reached, a variable speed characterized by stopping the pump by accumulating pressure after performing a pressure monitoring operation using the pressure value based on the discharge pressure at that time and the minimum pressure value at the deadline operation Water supply device. 2. The variable speed water supply apparatus according to claim 1, wherein the pressure monitoring operation monitors whether the two pressure values are not lower than a predetermined time. 3. The variable speed water supply device according to claim 1, wherein the pressure value based on the discharge pressure is equal to the pressure on the discharge side of the pump when a small amount of water is reached. 4. The variable speed according to claim 1, wherein the pressure value based on the discharge pressure is a pressure slightly lower than the pressure on the discharge side of the pump when the amount of water is small. Water supply device. 5. A pump, a pressure detection means provided on the discharge side of the pump, a variable speed means for changing the rotational speed of the pump, and a control means for controlling the pump, the control means comprising: When the amount of water is small, the rotation speed of the pump is fixed as it is, and it is determined that the pressure detected by the pressure detecting means does not fall below a predetermined pressure for a certain period of time, and the pump is stopped. And water supply equipment.