JPS60208677A - Adjuster for electrically driven opening and closing valve - Google Patents

Abstract

PURPOSE:To provide the function for softening water hammering phenomenon and maintaining a prescribed opening degree by installing an adjusting system for intermittently increasing or reducing the opening-degree of an electrically driven valve within a range of the effective opening-degree of 30% or less, onto an electromagnetic switch. CONSTITUTION:The power source circuits 19 and 20 for opening or closing an electrically driven valve are equipped with electromagnetic switches 21 and 22, which is equipped with an adjusting system 23 for intermittently increasing or reducing the opening-degree of the electrically driven valve only in the range of the effective opening-degree of the opening and closing valve in 0% or more, at least 30% or less. Therefore, water hammering phenomenon can be softened markedly without deteriorating the rapid opening and closing operation. Further, the function for maintaining the prescribed opening-degree without changing the constitution of the electrically driven valve body or electrical circuits by adjusting the number of times of intermittence or the intermittence time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for an electric on-off valve that opens and closes a flow path at a constant speed. In addition to alleviating the sudden pressure fluctuations that occur when an electric on-off valve closes or opens, which is usually called the water hammer phenomenon, the electric on-off valve, which previously had a structure that could only maintain a fully open or fully closed opening, can be maintained at a predetermined opening. This makes it possible to easily add maintenance functions.

[Prior art]

FIGS. 1A to 1) show an example of the basic structure of a valve body used in an electromagnetic on-off valve, and the hatched part in the figure is the valve body. In the figure, numerals 1 and 2 open and close the flow passages by rotating a valve body, and the one corresponding to 1 is usually called a ball pulp valve, and the one corresponding to 2 a butterfly valve. In addition, 3 and 4 in the figure open and close the flow passage by parallel movement of the valve body, and the one corresponding to 3 is sluice pulp, and the one corresponding to 4
This type of pulp can be called stop pulp, and diaplum pulp is also included in this category. In addition, when operating the valve body having the structure shown in 1 and 2 in the figure at a constant rotation speed, the flow passage opening cross-sectional area is at least about the same as when the valve is fully opened at about 50% of the effective opening, and The rate of change of the cross-sectional area of the valve opening over time is not constant, and increases rapidly at the beginning of opening and at the end of closing. Further, a valve having the structure shown in 4 in the figure, in which the valve body shape is needle-shaped or the like, and the time change rate of the opening cross-sectional area is approximately constant, is usually called a control valve.

Further, in the case of the ball valve shown in 1 in the figure, the flow path does not actually open until the valve opening degree is about 30%, so the operating time required for opening is about 30% shorter than the valve operating time.

Next, FIG. 2 shows an example of the basic configuration of the valve body drive unit electric circuit. In the figure, numeral 5 schematically shows the basic electric circuit of the main body of the drive unit, and 6 is a motor for driving the valve body, and its rotation direction. The valve body is switched from open to closed or from closed to open by rotating the valve in the forward and reverse directions. Reference numerals 7 and 8 indicate drive coils for the motor 6, where 7 is an opening coil and 8 is an opening coil. 9 and IO are open and open internal switches, respectively, whose purpose is to cut off the power to the coils 7 and 8 at the end of their respective operations. 11
is a capacitor, which absorbs electrical noise generated from coils 7 and 8 when switches 9 and IO operate.

Next, a conventional external circuit that supplies power to the drive unit main body will be described. Reference numeral 12 indicates a power source, and a single phase of 100 volts or 200 volts is usually used in many cases. 13 is an open power supply circuit, 14 is an open power supply circuit, and 15 is an on/off changeover switch, in which an electromagnetic switch may be used. 16 is the part to which the present invention is introduced.

The operating state of the above electric valve according to the conventional method will be described below.

When the open/close switch 15 is operated, the power supply circuit 13
or via 14 and internal switch 9 and lO,
Power is supplied to the motor drive coil 7 or 8,
The valve body driving motor 6 rotates, and the valve body begins to open or close. When the valve body or valve body driver operates to the fully open or fully closed position, the internal switch 9 or lO
operates to cut off the power supply to the motor drive coil 7 or 8, and the operation stops. During this time, the valve body or the valve body driver moves at a constant speed. The above is the operating state of the electric on-off valve using the conventional adjustment method, and the operating time is 2 seconds or more.
Seconds or less are most commonly used.

[Problems with conventional technology]

Next, top! P# Describe various problems that have arisen under the previous law.

Normally, when opening and closing flow paths for incompressible fluids such as water, the problem is the water hammer phenomenon, which is particularly noticeable when the valve is closed, and the same problem occurs when opening and closing electric on-off valves using conventional methods. This phenomenon has become a problem. The water hammer phenomenon occurs when the velocity energy of water changes to pressure energy, which is then converted to elastic strain energy of the water and piping, resulting in a pressure wave generated upstream of the valve that travels back and forth between the valve and the detection port or pump discharge port. This is a phenomenon of severe pressure fluctuations caused by The above case occurs when a valve is closed, but a similar mechanism causes water hammer when pressurized water is rapidly released. Although it is smaller than when the valve is closed, it is equivalent in that vibrations occur. The water hammer phenomenon becomes more pronounced as the valve closing and opening times become shorter, but when operating an electric on-off valve using the conventional method, the effective valve opening is about 50% and the flow passage opening cross-sectional area is almost the same as when it is fully open. Therefore, the effective operating time is reduced from about 2 seconds to about 1 second to about 5 seconds. Further, in the case where the valve body is a pole, the actual opening operation starts from about 30% of the valve opening, so the effective operation time becomes even shorter. In addition, the rate of change in the opening cross-sectional area over time increases as the valve opening becomes smaller, making water hammer extremely likely to occur.

A common way to alleviate the water hammer phenomenon is to absorb pressure waves using accumulators, surge tanks, etc., but this is difficult to implement when a large number of electrically operated valves are installed in a complex piping system. . In addition, countermeasures such as lengthening the operating time or introducing feedback control may be considered, but in the former case, prolonging the operating time itself goes against the original purpose of the electric on-off valve, which is to quickly open and close the flow path, and the control system It also has a big impact on the whole. In addition, in the latter case, the method of controlling the control valve is required, and the introduction of a complicated and expensive control system is difficult. It had been added.

[Purpose of the invention]

An object of the present invention is to provide a device that alleviates the water hammer phenomenon caused by opening and closing an electric on-off valve and adds a function to the on-off valve to maintain a predetermined opening degree.

[Structure of the invention]

The present invention has an electromagnetic switch in the power source for opening or closing the electric valve, and the electromagnetic switch has an effective opening degree of 0.
Equipped with an adjustment system that intermittently increases or decreases the electric valve only in a range of at least 30% or more, and at least 30% or less,
In addition to greatly alleviating the water hammer phenomenon without impairing rapid opening/closing operations, the structure of the motor-operated valve body allows for TCT-operated opening/closing, which conventionally can only be fully opened or fully closed, by completely adjusting the number of intermittences or the intermittency time. Alternatively, it is possible to add a function of maintaining a predetermined opening degree without changing the electric circuit at all.

[Explanation of Examples]

FIG. 3 shows a conceptual diagram of an embodiment of the present invention, and FIG.

In FIG. 3, reference numeral 18 indicates the basic electrical circuit values of the main body of the electric valve body drive unit. In the figure, reference numerals 19 and 20 indicate open and open power supply circuits. Reference numerals 21 and 22 indicate electromagnetic switches that completely open and close the respective power supply circuits for opening and opening.

Reference numeral 23 is an adjustment system that controls and adjusts the operation of the electromagnetic switches 21 and 22, and can be configured as a timer, counter, relay, changeover switch, etc., but it can also be made independent as a single control device. It is also possible to incorporate it as part of a large-scale control system. Reference numeral 24 denotes an open/close changeover switch, which can of course be incorporated into the A-node system, but is shown separately from the adjustment system here in order to show the basic configuration and adjustment method of the present invention. 2
5 is a power source.

[Operation/principle of the present invention]

Next, the concept of the adjustment method of the present invention having the above-mentioned configuration will be explained based on FIGS. I will explain.

FIG. 4 shows the temporal change in the valve opening at the time of closure according to the present invention and the conventional adjustment method. In the figure, the horizontal axis 26 is the time axis, the origin 27 is the closing end time, and the vertical axis 28 is the valve opening, The solid line 29 shows the change in valve opening when the adjustment method according to the present invention is performed, and the broken line 3
0 represents the change in valve opening when using the conventional adjustment method, and rectangular lines 31 and 32 at the bottom of the graph represent the state of power supply to the opening coil, solid line 31 represents the present invention, and broken line 32 represents the conventional method. There is. Even if an electric valve has a closing characteristic that closes very quickly just before full closure, as shown in 30 in the figure, if the conventional method of closing operation is performed continuously at a constant speed, as shown in 32 in the figure, By introducing the adjustment method according to the present invention in which power is supplied intermittently as shown by the solid line 31, the closing characteristics of the valve can be significantly improved as shown at 29 in the figure.

Next, with reference to FIG. 5, a description will be given of how the water hammer phenomenon is alleviated when the adjustment method of the present invention for improving the valve closing characteristics described above is introduced.

FIG. 5 shows the temporal change in pressure immediately before the valve, where the horizontal axis 33 is the time axis, and the origin 34 indicates the end of valve closing. The vertical axis A indicates the rate of pressure increase, and the origin axis is the static water pressure when the valve is closed. If the solid line 36 is according to the invention, then the dashed line 3
7 shows each water hammer phenomenon in the case of the conventional method.

Further, the lower rectangular lines indicate the method of supplying the open coil power, where the solid line 38 is for the present invention and the broken line 39 is for the conventional method. Further, 40 is the conversion of velocity energy into pressure energy.

Curve 37 in the figure shows that in the case of the conventional method, no pressure rise occurs until the valve opening reaches about 30 degrees after the valve starts to close, and a continuous pressure rise occurs in the range 41 from when the valve opening reaches about 3 degrees or less until closing. This shows a typical water hammer phenomenon in which large pressure waves occur after closure. Next, a control example according to the present invention will be explained.

As shown in FIG. 5 38 and FIG. 4 29, the present invention closes the valve intermittently.
．． At the time when the closing operation is stopped as shown in 6, minute pressure waves are generated. This minute pressure wave has a very small amplitude because the difference in flow velocity caused by one intermittent operation is small.

Moreover, since waves of the same frequency are emitted at regular intervals, the operation
By setting the stop time appropriately, they can cancel each other out, and overall, even when combined with the steady pressure increase caused by the reduction in valve opening, it does not result in a large pressure wave, as shown in the figure. The result is a very small pressure wave with an irregular period. As described above, according to the adjustment method of the present invention, it is possible to significantly alleviate the water hammer phenomenon. The above is an example of the control of the present invention when the valve is closed. When the valve is opened, pressure energy is converted to velocity energy, resulting in a sudden pressure decrease and a similar water hammer phenomenon occurs, but when the valve is closed, Similarly to the above, the water hammer phenomenon can be alleviated by the intermittent opening method of the present invention.

Next, the second aspect of the present invention, which uses the above-mentioned intermittent operation adjustment method, makes it possible to adjust the opening of the electric on-off valve, which was previously impossible.
We will explain the characteristics of

Assume that the intermittent operation is performed over the entire range of the valve opening, and for example, if the number of intermittent operations is 10, the time period for each operation is m, and the opening can be adjusted at 10 intervals. Therefore, the valve opening adjustment range is determined by the minimum settable time of the timer, but if we also consider the minimum operating time of the electromagnetic switch, the minimum intermittent operating time is approximately 0.2
seconds.

Therefore, a valve with an operating time of 2 seconds can be adjusted at 10% intervals, and a valve with an operating time of 10 seconds can be adjusted up to 2 inch intervals, and the present invention does not require any changes to the structure or electric circuit of the electric valve body to the conventional electric on-off valve. It becomes possible to add a function to maintain a predetermined opening degree without the need for the opening.

Next, the electrical side control circuit of the present invention will be explained.

Figure 6 is an example of an electric circuit that performs intermittent operation during opening and closing to alleviate the water hammer phenomenon, and RX in the figure is an open/close switching relay, which is equivalent to Figure 3 24. . The TI is a timer for setting intermittent time, and is switched so that when it is open, the power is turned off after the set time has elapsed, and when it is closed, it is turned on after the set time has elapsed. T2 and T3 are timers for intermittent operation. When open, T-2 is for setting the open time, T-3 is for setting the operation pause time, and when open, T-2 and T-3 are for reverse operation. Become. Further, R in the figure is an excitation coil for an electromagnetic switch installed in the opening and opening power supply circuits shown in FIG. 3 21 or 22.

In addition, Fig. 7 is an example of an electric circuit for adjusting the opening using a counter, and RX in the figure is an open/close switching relay, RX
' is an auxiliary relay, C is a counter, R is an excitation coil for an electromagnetic switch, and T1 and T2 are intermittent operation timers.

〔Effect of the invention〕

As shown above, the present invention introduces a very simple electric circuit into the conventional electric on-off valve control circuit.
It is not an idiot that can greatly alleviate the water hammer phenomenon that occurs when opening and closing while maintaining quick opening and closing operations.
This is an extremely effective invention in that it adds an opening adjustment function to an electric on-off valve, which conventionally could only maintain a closed valve opening.

[Brief explanation of drawings]

Figures 1 (a) to 2) are schematic diagrams showing an example of the basic structure of a valve body used in an electric on-off valve, and Figure 2 is a circuit diagram showing the basic configuration of the electric circuit of the valve body drive unit in a conventional method. , FIG. 3 is a circuit diagram showing the basic configuration of the electrical circuit of the electric valve body drive unit according to the present invention, and FIG. 4 is a diagram showing a graph of changes over time in the valve opening degree when the valve is closed according to the present invention and the conventional adjustment method. , FIG. 5 is a diagram showing a graph of pressure changes over time just before expansion when the valve is closed;
FIG. 6 is a diagram showing an example of an electric circuit for alleviating the water hammer phenomenon during opening and closing according to the present invention, and FIG. 7 is a diagram showing an example of an electric circuit for adjusting the opening using a counter. In the figure, 18 is the electric circuit of the valve body drive unit body, 19 and 20 are power supply circuits for opening and opening, 21 and 22 are electromagnetic switches for opening and opening, 23 is an adjustment system, and 24 is opening/closing. The changeover switch and the ``Go'' indicate the power source. Patent applicant: NEC Corporation Figure 1 Figure 6 Figure 7

Claims (1)

[Claims] (1) In an electric on-off valve that opens and closes a flow path at a constant speed by rotating or parallelly moving the valve body, the electromagnetic switch has an electromagnetic switch in the power supply circuit for opening or closing, and the electromagnetic switch has a switch for opening and closing the flow path. The effective opening degree of the valve is 0 degrees or more, at least 3 degrees.
An electric on-off valve regulating device characterized by being equipped with an adjustment system that intermittently increases or decreases the opening of the electric valve only within a range of 0q6.