JPS63241426A - Correcting method for valve closure timing of estimation meter - Google Patents

Abstract

PURPOSE:To make measurement accurate by detecting an integral flow rate from the start of valve closing operation to the end of the valve closing opera tion and correcting the start point of the valve closing operation by an estima tion meter which integrates flow rate pulses and feed a preset amount of liquid. CONSTITUTION:An estimation control means is provided with counters 3 and 4 as 1st and 2nd stages for counting flow rate pulses inputted to an input termi nal 1. Then the feed amount of liquid is set in a target setting register 7 and shift quantities are preset in 1st and 2nd stage shift quantity setting registers 5 and 6 respectively. Then the liquid begins to be fed, the counters 3 and 4 count flow rate pulses from the preset initial values and when their counted values reach the set value in the register 7, a comparator 8 sends out a main valve closing signal to reduce the flow rate and a comparator 9 sends out a subordinate value closing signal to stop feeding the liquid. Then flow rate pulses after the subordinate valve is closed are inputted to an integrating mem ory 11 through an AND gate 10 and the counted value in the memory 11 is set in the 2nd stage shift quantity setting register to update the shift quantity of the 2nd stage every time a measurement is taken.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention integrates flow rate pulses transmitted from a flow meter, and outputs a valve closing signal when the integrated value reaches the valve closing operation start point. The present invention relates to a valve closing timing correction method in a quantitative meter that supplies a preset amount of fluid by controlling a valve mechanism to close.

[Prior Art] Generally, a quantitative meter is well known which integrates flow rate pulses weighted by flow rate and supplies a preset fluid.

Normally, fixed-quantity liquid supply is performed using a constant flow needle valve that distributes a constant flow, a flow meter that transmits a meteor pulse, and a mechanism j' that stops liquid flow to a liquid supply line that is supplied from a fluid transfer means such as a pump. 5
and a fixed rate control means for controlling the valve mechanism so as to stop the flow of fluid when the amount of fluid reaches a fixed amount, and these operations are carried out.

In the above-mentioned fixed-rate liquid supply system, the constant flow valve uses elastic force to hold the valve in such a way that the opening area formed by the valve that moves in response to the dynamic pressure of the fluid and the fixed valve seat is determined in relation to the dynamic pressure. A structure with a structure that

Further, flowmeters are usually of a positive displacement type and emit flow rate pulses even in a low flow rate range. After inputting the flow rate pulse into the quantitative meter and shaping it, it becomes a pulse! M is calculated, and when the integrated value reaches a preset valve closing operation start point, a valve closing signal is transmitted. This valve closing operation start point is determined in anticipation of the amount of fluid that will be passed during the valve closing operation so that the amount of fluid supplied will match the set value when the valve mechanism finishes closing the valve.

Various functions are added to quantitative meters having the above functions depending on the state of the liquid supplied. For example, when the valve opens, when the fluid is flammable oil, etc., the end of the oil supply pipe is placed inside the tank where it rises due to refueling, in order to prevent the risk of ignition due to electrostatic discharge that occurs during the liquid supply. The so-called two-stage flow rate function restricts the flow rate in the oil supply pipe so that it does not exceed a specified speed until it comes into contact with the oil surface of There is. In addition, as a function when closing the valve, with one purpose of improving liquid supply accuracy, when closing the valve, the valve is closed in the first stage to throttle the flow rate, and then the valve is closed in the final stage. There is.

[Problems to be Solved by the Invention] Quantitative meters are often used for fluid transactions, and attempts are made to make the difference between the set amount and the supplied amount as small as possible. In other words, even if there is a fluid supply load fluctuation in the constant flow valve described above, the influence of that fluctuation is eliminated, and during fixed fluid supply, the flow rate is limited by the two-stage closing function as described above. .

FIG. 2 shows a flow pattern in the conventional quantitative meter. In the figure, the vertical axis shows flow rate and the horizontal axis shows time.

Now, according to the flow pattern shown in FIG. 2, the conventional quantitative meter described in item 1 operates as follows. At time 〇, the valve is opened by the valve open signal, and fluid flows in at a constant flow rate Q by opening the first stage, and when the predetermined amount is reached, the valve is fully opened by the valve full open signal at time t2, and the valve is fully opened at time t. After the full opening is completed at , liquid is supplied at a constant flow rate Q2. At time t4, when the predetermined first stage valve closing start point for the set amount is reached,
Closing of the first stage valve is started, the flow rate is throttled, and liquid is supplied at a constant tJtMQ from time t5. Then, at time t6 when the flow rate integrated value reaches the value of the second stage valve closing start point, a valve closing signal is transmitted, and the valve is completely closed at time t7.

Set the cumulative amount of compassion to S. When closing, ideally the above S is performed at 1 time t7. In reality, due to a delay in the transmission of the valve closing signal, a delay in the valve closing operation, etc., the valve closing end may be 70, which is different from the set full closing time t7. There is.

In this case, the flow rate integrated value S. becomes larger by ΔS indicated by diagonal lines in FIG. 2, resulting in an error corresponding to this amount. Therefore,
For quantitative meters, it is desired to reduce this error ΔS as much as possible.

In this case, the magnitude of this type of error varies depending on the pump load, liquid type, temperature, pressure, etc., and normally, once the liquid type is determined, system variables such as the pump can be set. Therefore, it is sufficient to correct the magnitude of the error once.

However, if the liquid type changes frequently, the pump load, temperature, etc.
If the pressure or the like is not constant, system variables such as the pump will constantly fluctuate, and the magnitude of the error will also fluctuate accordingly. Therefore, in order to reduce the error ΔS as much as possible, the operator must frequently reset the valve closing starting point, which is inconvenient.

Suekan IJI was created to solve the above drawbacks,
Even if an error occurs in the liquid supply amount due to fluctuations in temperature, pressure, liquid type, etc., or due to an inappropriate set shift amount, the error is automatically reflected in the shift amount. , the next measurement can be performed easily and accurately without requiring manual resetting. The purpose of the present invention is to provide a method for correcting the valve closing timing of a quantitative meter.

[Means for Solving the Problems] The present invention has been made to solve the above problems.

The liquid supply line is equipped with a Fltl meter valve mechanism that transmits a flow rate pulse, and has a function of presetting the start point of the valve closing operation so that the amount of liquid supplied matches the set amount at the end of the valve closing operation, and the above-mentioned The flow rate pulses sent from the flowmeter are integrated, and when the integrated value reaches the valve closing operation start point, a valve closing signal is output to control the valve mechanism to close, supplying a preset amount of fluid. A valve-closing timing correction method for a quantitative meter is characterized in that the m-calculated flow rate from the start of the valve-closing operation to the end of the valve-closing operation is detected, and the above-mentioned valve-closing operation start point is corrected based on the detected flow rate. .

To set the valve closing start point in the quantitative meter described above, fix the liquid supply target value, and add a preset flow rate to the cumulative flow rate to shift the cumulative flow rate. By subtracting a predetermined flow rate set in advance from the liquid supply target value, the target value is shifted and the target value is reached before the actual target value is reached. A possible method would be to generate a valve closing signal as if the value had been reached. In the former case,
Preset the QM) to be added as a shift signal,
This can be realized by calculating the flow rate by jlI. On the other hand, the latter case can be realized by presetting the shifted target value itself.

The correction of the present invention can be applied not only to the case where the liquid supply is stopped by one valve closing operation but also to the case where the liquid supply is stopped by sequentially reducing the flow rate through multiple stages. In this case, the correction method of the present invention may be applied to the final stage valve closing operation. When performing accurate quantitative determination at large flow rates, generally 2
There are many stages.

[Operation] The present invention is characterized in that the starting point of the next valve closing operation is reset based on the excess/deficiency data from the previous measurement. That is, in the present invention, if a flow rate greater than the set value is supplied after the start of the valve-closing operation and until the end of the valve-closing operation, the start point of the next valve-closing operation is shifted to a point earlier than the current start point by that amount. Correct by setting to Furthermore, when the amount of liquid supplied is less than the set value, correction is made by setting the start point of the next valve closing operation to be shifted to a later point in time than the current start point by the amount of the small amount.

The excess/deficiency data at the time of the immediately preceding measurement can be easily determined from the difference between the actual Ii amount from the start of the valve-closing operation to the end of the valve-closing operation and the set value for the same period. On the other hand, the correction value for shifting the valve closing start point can be set by the sum of the excess/deficiency data and the set value. Therefore, the actual integrated flow rate from the start of the valve closing operation to the end of the valve closing operation can be used as the correction value.

Therefore, in the present invention, first, the integration from the start of the valve-closing operation to the end of the valve-closing operation is calculated. If and ffl are detected, and the preset valve closing operation start point is corrected based on the detected values. By correcting the preset values mentioned above, the point at which the valve closes at the end of the valve close and the supply liquid reaches the set amount changes from the previously set value, so the valve can be closed more appropriately to the actual situation. Control will be implemented. In addition, 8! The detected value of the calculated flow rate is stored and held until the preset value is corrected, or cleared after that to enable detection of the next integrated flow rate.

As a result, even if the initial settings are not appropriate, or if the temperature, pressure, liquid type, etc. are changed, the error is automatically determined, and the preset value is corrected based on the error, so the next time Accurate liquid supply can be performed.

[Example] Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of a circuit configuration for implementing the valve closing timing correction method of the present invention. This example shows an example in which the present invention is applied to a quantitative meter having a two-stage closing function.

The quantitative meter to which this embodiment is applied is constructed of N13, which is equipped with a flowmeter and a valve mechanism in the liquid supply line (none of which are shown), as well as a constant flow rate control means and a correction means. Ru.

The quantitative control means includes a waveform shaping circuit 2 that shapes the waveform of a flow rate pulse input from a flowmeter (not shown) to an input terminal l, and first and second stage counters 3 that count the flow rate pulse.
4, first-stage and second-stage shift amount setting registers 5.6 for presetting shift amounts in each of the counters 3.4, and a target value setting register 7 for setting a target value of the fluid to be supplied. , the setting value of the target value setting register 7 and the first
A comparator 8 that compares the count value of the stage counter 3 and outputs a main valve closing signal when the latter matches the former, the set value of the target value setting register 7, and the second stage counter 4. Compare with the count value 1. The comparator 9 outputs an auxiliary valve closing signal when the latter matches the former.

In this embodiment, the correction means is composed of an AND gate 10 and an integration memory 11. Ant Gate 10 is
Controlled by the auxiliary valve closing signal output from the comparator 9,
It acts to send the flow rate pulse inputted after the output of the auxiliary valve closing signal to the integration memory IT. The m calculation memory 11 is composed of a counter and counts the flow rate pulses inputted through the ant gate 1O.

Next, the valve closing timing correction method of this embodiment for the quantitative meter configured as described above will be explained.

First, the amount of fluid to be supplied is set in the target value setting register 7 as a target value. Settings are made, for example, using digital values from input means such as a keyboard on a console (not shown).

In addition, the first stage shift amount setting register 5 is set to indicate the liquid supply adjustment flow rate or when the first stage close timing for closing the main valve is reached.
The count value of the first stage counter 3 is J of the target value setting register 7.
A shift amount by which the count value is shifted is set so that the count value becomes a fixed value. That is, the difference between the cumulative flow rate pulse number corresponding to the settlement fIi,m at time t4 shown in FIG. 2 and the flow rate pulse number corresponding to the target liquid supply amount is set as the shift amount.

Similarly, the count value of the second stage counter 4 is stored in the second stage shift amount setting register 6 when the liquid supply adjustment flow rate reaches the second stage closing timing for closing the sub valve. A shift amount by which the count value is shifted is set so that the count value becomes the set value. The shift amounts set in the first and second stage shift amount setting registers 5.6 are
2nd stage counter 3.4. That is, the difference between the cumulative flow rate pulse number corresponding to the cumulative flow rate at time t6 shown in FIG. 2 and the flow rate pulse number corresponding to the target liquid supply amount is set as the shift amount.

In this state, fluid supply begins. Along with the liquid supply,
A flow rate pulse is sent from a flow meter (not shown). When this flow rate pulse is input to the input terminal l, it is shaped into a rectangular wave by the waveform shaping circuit 2.

The shaped flow rate pulses are input to the first stage counter 3, the second stage counter 4, and the AND gate 10, respectively. The first stage counter 3 and the second stage counter 4 count flow rate pulses that are sequentially input.

At this time, the preset value is used as the initial value and is added to this value for counting. On the other hand, in the ant gate IO, since the sub-valve closing signal is not output from the comparator 9, the gate does not open and the flow rate pulse is not input to the integration memory 11.

Next, comparators 8 and 9 each have a corresponding first stage,
Count value of second stage counter 3.4 and target value setting register 7
Compare with the setting value. Then, when the counted value of the first stage counter 3 and the set value of the target value setting register 7 match,
Comparator 8 outputs a main valve closing signal. As a result, the flow rate is restricted, and the liquid is supplied at a flow rate of approximately Q□ shown in FIG. 2, for example.

Furthermore, when the counted value of the second stage counter 4 and the set value of the target value setting register 7 match, the comparison module 9
Outputs sub-valve close signal. As a result, the valve mechanism stops the liquid supply after a certain period of time.

The auxiliary valve closing signal is also sent to the AND gate 10, which opens the gate IO. As a result, if a flow rate pulse is input from the input terminal 1 after the output of the auxiliary valve closing signal, the flow rate pulse is input to the integration memory 11 via the ant gate 10, and is sequentially counted by a. With this count,
The actual flow rate of liquid supplied can be determined after the sub-valve closing signal is output.

The counting result in the integration memory 11 is stored in the second stage shift amount setting register 6 as the second stage shift amount based on the current measurement.
is set to When this measured value is greater than the set value,
The shift amount increases by that amount, and on the other hand, when the measured value is less than the set value, the shift amount decreases by that amount.

In this way, by repeating the measurement in the same manner as described in L and updating the second stage shift amount each time, it is possible to always perform accurate measurement in accordance with the latest state.

Other Embodiments> In the first embodiment, an example was shown in which the valve closing operation is performed in two stages, but the present invention is applicable to the case where the valve closing operation is performed in one stage, and also in the case where the valve closing action is performed in multiple stages of three or more stages. This can also be applied when conducting For example, when closing is performed in one stage, the first stage counter 3, the first stage shift amount setting register 5, and the comparator 8 may be removed from the circuit shown in FIG.

In the above embodiment, the valve closing start point is set by fixing the liquid supply target value and shifting the integrated flow rate.
It is also possible to adopt a configuration in which the liquid supply target value is shifted.

[Effects of the Invention] As explained above, the present invention can prevent errors in the amount of liquid supplied due to fluctuations in temperature, pressure, liquid type, etc., or due to an inappropriate shift amount being set. By automatically reflecting the error in the shift amount, it is possible to easily and accurately perform the first measurement without requiring manual resetting.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a circuit configuration for implementing the valve closing timing correction method of the present invention, and FIG. 2 is a flow pattern diagram showing an underflow control operation in a quantitative meter. l...Input terminal 2...Waveform shaping circuit 3.
...1st stage counter 4...2nd stage counter 5...
・First stage shift amount setting register 6...Second stage shift amount setting register 7...Target value setting register 8...Comparator 9...Comparator lO...
ANDGATE 11...Applicant for integrated memory Oval Equipment Industry Co., Ltd. Agent Patent attorney Iwao Mishina Figure 1

Claims (2)

[Claims] (1) The liquid supply line is equipped with a flow meter that transmits flow rate pulses and a valve mechanism, and a function that presets the valve closing operation start point so that the liquid supply amount matches the set amount at the end of the valve closing operation. It integrates the flow rate pulses sent from the flow meter, and when the integrated value reaches the valve closing operation start point, it outputs a valve closing signal to close the valve mechanism, and the preset amount is reached. In a valve closing timing correction method for a quantitative meter that supplies fluid, the cumulative flow rate from the start of the valve closing operation to the end of the valve closing operation is detected, and the above-mentioned valve closing operation start point is corrected based on the detected flow rate. A valve closing timing correction method for a quantitative meter, characterized by: (2) The above valve closing operation is performed in two stages, and the second
A valve closing timing correction method for a quantitative meter according to claim 1, wherein the method is configured to correct a valve closing start point of a stage.