JPS5828627A - Instrumental error controlling method for flow meter - Google Patents

Abstract

PURPOSE:To realize the automatic and simultaneous control of instrumental errors to many flow rate meters, by actuating at one time all flow meters for both standard and inspection and then actuating an instrumental error controlling mechanism when the number of output pulses of each flow meter reaches a prescribed level. CONSTITUTION:A reference flow meter M0 containing the flow rate pulse transmitters P0-P3 is connected in series to flow meters M1-M3 to be inspected. The counter circuits C0-C3 are connected to the transmitters P0-P3, respectively. Then measurement is carried out simultaneously by each flow meter after resetting all counter circuits C to zero. When the count value of the circuit C0 reaches a certain level, the difference or the ratio is obtained between the count value and the count values of the circuits C1-C3. According to this difference or ratio, the instrumental control mechanisms K1-K3 are actuated. Thus the instrumental errors are controlled for the meters M1-M3.

Description

[Detailed Description of the Invention] This application deals with instrumental difference in flow rate needles (metering difference in individual flow rate needles)
It concerns how to adjust the

Conventionally, instrumental adjustment of the flow rate needle has been performed as follows. In other words, connect multiple flow rate needles to be tested in series, allow fluid to pass through them, measure the amount of fluid that has passed in a reference tank, and calculate the difference between this measured value and the indicated value of each flow rate needle to be tested. The metering adjustment mechanism for each flow rate needle to be tested was manually operated.

However, this had the disadvantage that adjustment was a trial-and-talk process, which took time and effort.

The present invention provides a method in which the above-mentioned instrumental difference adjustment can be automatically and simultaneously performed for a large number of flow rate needles.

To explain in detail the illustrated example of the dormitory, 11, the liquid storage tank, 2
．． Reference numeral 2' denotes a circulation liquid feeding path, 3 a three-way solenoid valve inserted in the liquid feeding path 2, and the other boat 3/ can be opened to the atmosphere. Reference numeral numeral 5 indicates a driving motor for the lump 4, and 5 is a motor for driving the lump 4, which is controlled as described later to circulate the liquid in the tank 1 through the liquid feeding path 2.2/.

A0 is a reference flow rate needle, and M2S MI, MI are flow rate needles to be inspected, which are inserted into the liquid feeding path 2 so that they can be taken up.

1 is the number 1, flowmeters M and 7 connectors for connecting the flowmeters #M5 to the liquid sending path 2, 2 and MUS are the adjustment of the metering adjustment mechanisms provided in the flowmeters M1 to Mg, respectively. At the axis,
This adjustment shaft is used to perform metering adjustment, for example, by controlling the stroke of the piston of a piston-cylinder flow rate needle.

'@s Pl, Pl, Pg are flow rate bar A/X transmitters, which transmit the number of flow rate pulses (for example, l/100 liter pulse) corresponding to the measured value by each flow meter M@~ town. do. O@SO1 and 02110S are counting circuits that count the flow rate pulses from the flow rate pulse transmitters P and ~Pl, respectively. The liquid feeding path N7 connected and arranged in parallel with / is the liquid feeding path 2.
The reference tank inserted in / is the reference tank inserted in V, the valve inserted in the liquid feeding path 2', v2 and v is the valve inserted in the inflow side and the outflow side of the reference tank in the liquid feeding path 6, respectively. be.

Reference numeral 8 designates a circuit for setting operating standards of the adjustment device, 9 a setting key, and 10 an operation start key. The operating standards include, for example, the time from when the start key is pressed until the reset signal is output, and the measured value in one inspection of the reference flowmeter MO (for example,
10 liters), the tolerance or ratio between the measured values of the flowmeter to be tested and the reference flowmeter, the time required to complete the adjustment of the flowmeter to be tested, the number of repetitions of reset, comparison, and adjustment, etc. The setting time 16B is set in advance by operating the setting key 9, and the control circuit 11 is set in advance as necessary.
be taken in. The control circuit 11 performs the following control operations based on the parent/subordinate information and other necessary information stored in advance.

Close valves v2, v, open valve v1 and press start key 10.
When is pressed, the signal a from the control circuit 11 switches the three-way valve 3 to close &-)3/, and the signal causes the motor drive circuit 13 to rotate the pump number 5 at the normal speed. let Due to the operation of the pump number, the liquid in the storage tank 1 flows through the ζ flow meter → M1 → M2 → Ml → valve v
1→tank 1 and is circulated at a normal flow rate. After a sufficient time has elapsed for the air in each flow rate needle to be completely discharged, a reset signal a output from the control circuit 11 causes the needle number circuit O0 to
~The OS is reset to zero at the same time. The reset signal O also resets the arithmetic circuit 14.

Since the pump number continues to operate at normal speed, counting circuits a and ~'0& count the measured values (flow rate pulses) by flowmeters ~M5 after the simultaneous return of counting circuit Oo#O3 to zero ( (Testing at normal flow rate). Count output is from arithmetic circuit 1
4 is input.

Note that the arithmetic circuit 14 switches the count values of the count circuits 0 to 05 to the display unit 1 via the display drive circuit 16.
7, the switching circuit 15 is currently set to the counting circuit 0.7. The needle value (measured value of the reference flow rate needle) is set to be displayed.

The count value of the counting circuit Go is a constant value (for example, lOrissil)
When the machine is warmed up, the control circuit 11 determines this and outputs a hold signal (l- pulse) e to stop the stitch count operation of the counting circuit 0@-01 and hold the count value at that time.

As mentioned above, at this time, the counting circuit 0. The count value of is 1, O
If there is no instrumental error in the other flowmeters, the count value of the needle number circuits 01-Os should also be 10 liters.

Therefore, by inputting the hold signal e, the arithmetic circuit 14 calculates the count value of the counting circuit O (represented by 00) of each of the other counting circuits 01 to O5 (represented by 01 to Ol). ) to perform a comparison operation (find a difference or ratio) °. - Now, the calculation result is, for example, Jloll -
1-031% 0210 (1”0.992.0110s
= 0.000. In accordance with the result of this calculation, the drive circuits D1-D1 drive the instrumental error adjustment mechanisms X, S, which are connected in advance to the metering adjustment shafts M1-MU of the flowmeters M1-M, respectively. In other words, 1. For example, if the flow meters M1 to Ml are of the piston-cylinder type as described above, the Sam adjustment mechanism * As well as decrease! 2 are respectively driven so as to increase the above-mentioned discharge amount of M2. However, since the instrumental difference between MA and the blade is -jFw or within the permissible range, !S is not driven.

In addition, the instrumental difference adjustment mechanism! 1~! As S, a reversible rotating stepping motor or the like is used, and its rotation angle and direction within one rotation are instructed according to the above calculation results.

When sufficient time has elapsed for one adjustment operation by the above-mentioned instrumental difference adjustment mechanisms h to Km to be completed, the control circuit 11 outputs the reset signal O again, and the above-mentioned operation is repeated.
If there is any residual instrumental error after the previous instrumental error adjustment, this is adjusted.

After the above operation is repeated a predetermined number of times (for example, three times) (or when sufficient time has elapsed for the predetermined number of repetitions), the arithmetic circuit 14 operates each counting circuit 01.
The control circuit 11 sequentially uses the final calculated values of ~O5 as a signal d.
send to The control circuit 11 controls the instrumental error of any of the flow rate needles to be tested within a predetermined tolerance range H (for example, 0.999≦01.2
．． 510o≦1001'), the notification 411B notifies the user of this fact, and the signal disappears to stop the motor 5.

Then, operate the changeover key 19 to operate the count value of the stitch count circuit o0 (
Counting circuit 01 to OS instead of the measured value of the reference flowmeter Mo
Each count value or the above calculated value (0@106% 021
0., 03/center 6) are sequentially displayed on the display, the flow rate needle whose instrumental error exceeds the allowable range is removed from the flow path, and necessary measures such as replacing necessary parts are taken.

If the above notification is not made, that is, if the instrumental error of all flowmeters to be tested falls within the above tolerance range, the control circuit 1
1 outputs the signal b'. This signal b/ causes the motor drive open circuit 13 to shift the motor 5 and therefore the pump 4 to low speed rotation @ At the same time, the 1 control circuit 11 sends the signal ft to the drive circuits D1 to D1 of the instrumental difference adjustment mechanism to control these operations. prevent.

Then, under the low-speed rotation of motor 5 (low-speed operation of pump 4), reset the counting circuits 00 to 04 in the same way as in the case of the inspection with normal rotation (however, only once in this case). , the counted value is held and calculated, and the calculation circuit 14 sends the calculation result to the control circuit 11 as a signal d/, and the instrumental error of any of the flow rate needles to be tested is within the allowable range m<for example, 0.998≦01 at low flow speeds. .2.510.≦LOO2), a notification is made in the same manner as described above, and the signal b/ is also erased to stop the motor 5. In addition,
In this case, when testing at a normal flow rate, the adjustment mechanism will be hlI& based on the calculation result! From 1 onwards, notification is made without performing instrumental error adjustment due to snow.

When the motor 5 stops, operate the switching key 19 in the same way as in the previous case to change the measured value of each flow rate needle or O@10@,
Display the values of 0210@ and O@10@ sequentially on the display lf, check which flow needle's instrumental error exceeds the permissible range at low flow speed, and take necessary action for that flow needle. °
Do the following. The other flow needles are accurate flow needles with acceptable instrumental errors at normal and low flow rates.

Once the instrumental error of all flow rate needles to be tested falls within the permissible range in the test at the low flow rate described above, the control circuit outputs the signal a/ to switch the three-way valve 3 to open the boat 3/ to the atmosphere. The pump motor 5 is rotated at a normal speed by outputting a signal S, and air is sent to the flow needle M@-Ml to feed the liquid into the liquid feeding path 2.
．． 2' and the liquid in the flowmeters MO to Ml are returned to tank 1. When sufficient time has elapsed for all the liquid to be returned to tank 1, control circuit 11 disables the signal and motor 3
to stop. Then, remove all flow rate needles to be tested.

By performing tests at low flow rates in addition to tests at normal flow rates, the performance of the flow needle can be increased accordingly.

In addition, it is preferable to send air as described above to remove the liquid before removing the flow rate needle to be tested from the flow path when the above-mentioned normal flow rate or low flow rate test is notified. This can be done by pressing a switch (not shown) provided on the manual operation keyboard 20 to generate signals a' and b. For the remaining flow rate needles after removing the flow rate needle that exceeded the range, insert a short tube in the place of the removed flow rate needle, and then press the test continuation switch (not shown) provided on the keyboard 20. This allows the air to be expelled before testing at a low flow rate.

To calibrate the reference flow rotor blade, close valve v1 and open valve V! Open the calibration start key (II) on the keyboard 20.
Press (not shown) to switch the three-way valve 3 &-) 3/ and close it.
The operation of the dumper 4 completely replaces the air in the flow path 2 and flowmeters ◎~Ms with liquid, then closes the valve v1. After confirming that the liquid in the reference tank has been completely drained, close the valve. Close the vB and press the zero key (not shown) on the keymate 20 to allow liquid to flow into the meter 7. While checking the reference tank 70 scale, close the valve Vg at an appropriate value (for example, 10 liters) and calibrate by comparing the scale indicated by the liquid in the reference tank and the indicated value of the needle count circuit Go at display $917. Do the following.

゛As described above, according to the present invention, it is possible to efficiently (adjust) the instrumental error of a large number of flow rate needles◎

[Brief explanation of the drawing]

The figure is a boot diagram showing an example of an apparatus for carrying out the method of the present invention. 1 bottle - storage tank, 4...Lump, 5...I
I motor, 11... Control circuit, 14. Calculation circuit, l)... Display, 1B... Alarm, M
a”MS...Flow rate needle, Qt+NQs, count circuit,

Claims (2)

[Claims] (1) After connecting the reference flow rate needle and the tested flow rate needle, each having a flow rate pulse transmitter, in series, connecting a needle number circuit to each of the flow rate pulse transmitters, and returning all the counting circuits to zero. , When the flow rate needles are simultaneously operated for measurement and the count value of the counting circuit of the reference flow rate needle reaches a certain value, the difference or ratio between this count value and the count value of the counting circuit of the flow rate needle to be inspected is determined. 1. A method for adjusting an instrumental difference in a flow rate needle, the method comprising the step of operating an instrumental difference adjustment mechanism in accordance with the difference or ratio to adjust the flow meter to be inspected. (2) After connecting a reference flowmeter and a flow rate needle to be tested, each having a flow rate pulse transmitter in series, and connecting a counting circuit to each of the flow rate pulse transmitters, and returning all the counting circuits to zero. , when the flow rate needles are simultaneously operated for measurement and the count value of the counting circuit of the reference flow rate needle reaches a certain value,
A series of steps for determining the difference or ratio between this counted value and the counted value of the needle number circuit of the flow meter to be inspected, and operating an instrumental error adjustment mechanism according to this difference or ratio to adjust the instrumental error of the flowmeter to be inspected. A method for adjusting an instrumental difference in a flow rate needle, characterized in that the above operation is repeated a predetermined number of times, and after that, if the instrumental difference of the flow meter does not fall within a predetermined tolerance range, this is notified.