JPH03295419A - Flow rate measuring instrument - Google Patents

Abstract

PURPOSE:To output an abnormality signal when abnormality is judged by contrasting a standard differential pressure value corresponding to the instantaneous flow rate of fluid to be measured with the differential pressure between the intake side and outlet side of the flowmeter. CONSTITUTION:A flow rate comparing means 28 compares the instantaneous flow rate Q from a flow rate arithmetic means 24 with a maximum and a minimum measurable flow rate signal from a temporary storage means 27, and outputs a normalcy signal to an abnormality signal counting means 29 when the flow rate Q is in the measurable flow rate range or the abnormality signal when the measurable flow rate is exceeded. The means 29 counts the frequency of the input of the abnormality signal and when a specific value is exceeded, a 1st alarm lamp 14 and an alarm 32 indicate that the flow rate exceeds the measurable range. Thus, it can be decided whether the flowmeter wears or not and whether the viscosity of the fluid to be measured exceeds the range of a specified instrumental error or not.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a flow rate measuring device, and more particularly to a flow rate measuring device that notifies the user of a state other than a designated meter set point.

(Prior art) There are two types of flowmeters: certified flowmeters that undergo certification over a certain period of time, and non-certified flowmeters that do not require certification, but in both types of flowmeters, friction can occur in the measuring section due to use. may occur, reducing the performance of the device, or measuring a flow rate that exceeds the specified flow rate, or measuring the flow rate of a fluid that exceeds the specified viscosity range, resulting in improper metering. The problem is that even if it disappears, it is not easy to detect its condition.

(Problems to be Solved by the Invention) The present invention was made in view of these problems, and its purpose is to solve the problem when a situation exceeding the specified instrumental error range occurs. MIF is a flow measurement device that detects situations quickly and always performs appropriate measurements.
There are three servings.

(Means for Solving the Problems) That is, the present invention provides a flow rate measuring device for achieving the above-mentioned problems, including an instantaneous flow rate calculating means for calculating an instantaneous flow rate in response to a flow rate pulse signal from a flow meter; Differential pressure calculating means disposed on the inflow and outflow sides of the meter to calculate the differential pressure in response to pressure signals from each tL pressure sensor, and a memory that stores the standard differential pressure value corresponding to the instantaneous flow rate of the fluid to be measured. means and
The differential pressure comparison means compares the differential pressure signal from the differential pressure calculating means with the standard differential pressure value signal from the storage means and outputs an abnormal signal when an abnormality is determined. It is.

(Function) In the process of flow measurement operation, the instantaneous flow rate of the fluid to be measured and the differential pressure between the inflow side and the outflow side of the flowmeter are detected, and this detected differential pressure corresponds to the instantaneous flow rate of the fluid to be measured. By comparing the measured pressure difference with the standard differential pressure value, it is possible to check whether there is an abnormality in the flowmeter or whether the viscosity of the fluid to be measured exceeds the specified instrument difference range, thereby improving measurement accuracy.

(Example) Therefore, the illustrated embodiment will be described below.

FIG. 1 shows a flow rate measuring device which is one embodiment of the present invention.

In the figure, reference numeral 1 is a positive displacement flowmeter using two rotors.The inflow side of this flowmeter 1 is connected to a liquid storage tank (not shown) via a liquid supply pump 2, and the outflow side is controlled. It is connected to a liquid supply nozzle (not shown) through a valve 4.

10 indicates the flow rate J based on various signals from the flowmeter 1.
While calculating and displaying l, if there is an abnormality in the flowmeter 1 or if the flow rate or viscosity of the fluid to be measured exceeds the designated instrument differential, the system will detect the condition 18 and take necessary warning actions. The measuring unit 1o is equipped with a control circuit 20, which will be described later, and receives a flow rate pulse signal from a flow rate pulse transmitter 6 coupled to the rotor shaft 5 of the flowmeter 1. , installed on the inflow side and outflow side of the flow meter 1, and is configured to receive pressure signals from the pressure sensors 7 and 8, and a setting signal from the key switch 12, and output from the control circuit 20. Depending on the signal, indicator 13
The liquid supply amount is displayed in the first and second warning lamps 14.
15, the lighting operation alarm 32 is activated, the pump motor 3 is caused to stop, and the control valve 4 is caused to be closed.

FIG. 2 shows the circuit configuration of this control circuit 20. In this figure, reference numeral 21 denotes a counting means, which counts the flow rate pulse signal from the flow rate pulse transmitter 6 to calculate the supplied liquid. Display. Reference numeral 24 denotes instantaneous flow rate calculation means, which detects the instantaneous flow rate 1 of the fluid to be measured based on the pulse signal from the flow rate pulse generator 6, and outputs the signal to flow rate comparison means 28 and temporary storage means 27, which will be described later.

Reference numeral 25 denotes a storage means for storing the setting value. For example, in the case of a flow rate measuring device used at a gas station, this storage means 25 stores the first setting value.
Data as shown in the table, that is, the viscosity Cp of the fluid to be measured such as gasoline, the standard differential pressure value of these fluids in increments of 10I2/1Tlin (inflow side pressure P1 - outflow side pressure Po), and the maximum measurement of flowmeter 1 Each data of the possible flow rate 1tQmax and the minimum measurable flow rate Qmin are input and stored.

Reference numeral 26 denotes a differential pressure calculation means for calculating a standard differential pressure value in detail, for example, in a flow rate unit of 1β/min, based on the above data inputted to the storage means 25, and the data from this is stored in -hour memory. The time storage means 27 selects a standard differential pressure value corresponding to the instantaneous meteor at that time based on the instantaneous flow rate Q from the instantaneous flow rate calculation means 24 input here. This is output to the differential pressure comparison means 34.

Reference numeral 28 is a flow rate comparing means, which compares the instantaneous flow rate signal from the flow rate calculation means 24 and the maximum and minimum measurable flow rate signals from the -time storage means 27, and determines whether the instantaneous flow rate Q is within the measurable flow rate. If the flow rate exceeds the measurable flow rate, an abnormal signal is output to the abnormal signal counting means 29.

The abnormal signal counting means 29 counts the input frequency of the abnormal signal, and outputs a signal to the warning lamp driving means 3o and the alarm driving means 31 when the abnormal signal is counted five times in a row, and the first warning lamp 14 The alarm 32 notifies that the flow rate has exceeded the measurable flow rate.

Reference numeral 33 denotes differential pressure calculating means, which calculates the pressure difference between the inflow side and the outflow side of the flowmeter 1, that is, the differential pressure ΔP, based on the signals from the inlet side pressure sensor 7 and the outlet side pressure sensor 8. 34 is
The differential pressure ΔP calculated by the differential pressure calculating means 33 is compared with the standard differential pressure value corresponding to the instantaneous flow rate at that point from the temporary storage means 27, and if both differential pressures are approximately equal, it is normal. If the signals are different, an abnormal signal is output to the counting means 35. The abnormal signal counting means 35 counts the input frequency of the abnormal signal, and when the abnormal signal is counted five times in a row, outputs the signal to the alarm driving means 31 and the warning lamp driving means 36,
The alarm 32 and the second warning lamp 15 notify that the viscosity C1 of the measured fluid is outside the specified instrument difference range or that there is an abnormality in the equipment, and at the same time a signal is sent to the valve closing means 37 and the pump motor stopping means 38. The control valve 4 is outputted and the control valve 4 is closed via the valve closing means 27 and the pump motor stopping means 38, and the pump motor 3 is stopped.

Next, the operation of the apparatus configured as described above will be explained based on the flowcharts shown in FIGS. 2 and 3.

First, when the viscosity of the liquid to be measured is set using the key switch 12, the data stored in the storage means 25 (first
Table), the set viscosity data is the differential pressure calculation means 2.
6, the standard differential pressure value is calculated every 1j2/min and is stored in the - hour storage means 27.

Next, when a metering start signal is input using the key switch] 2, the pump motor 3 rotates to operate the pump 2, and the control valve 4 opens.

Due to the flow of the liquid, a pulse signal corresponding to the flow rate is output from the flow rate pulse transmitter 6 connected to the rotor shaft 5 of the flow meter 1, which is input to the counting means 21 and the amount of liquid to be supplied is displayed on the display 3. Ru.

This flow rate pulse signal is input to the instantaneous flow rate calculation means 24,
After being converted as an instantaneous flow rate Q, the signal is input to the temporary storage means 27 and the flow rate comparison means 28.

On the other hand, the differential pressure calculating means 33 calculates the differential pressure ΔPI at that time based on the output signals from the inlet side pressure sensor 7 and the outlet side pressure sensor 8, and compares the signal corresponding to this differential pressure ΔP with the differential pressure. Output to means 34. Further, when a signal indicating the instantaneous flow rate QV is input from the instantaneous flow rate calculation means 24 to the - hour storage means 27, a standard differential pressure value corresponding to the instantaneous flow rate Q at that time is outputted to the differential pressure comparison means 34. Thereby, the differential pressure comparison means 34 compares the differential pressure ΔP input from the differential pressure calculation means 33 at that point with the standard differential pressure value corresponding to the instantaneous flow rate Q input from the temporary storage means 27 at that moment. do. and,
As a result of comparison, if the differential pressure ΔP exceeds the standard differential pressure value, it means that the measuring part is worn out, and if the differential pressure ΔP is lower than the standard differential pressure value, the gear, etc. has come off. It also means that there is no abnormality in the flowmeter 1 and the differential pressure ΔP
If ΔP exceeds the standard differential pressure value, it means that the viscosity of the fluid to be measured has exceeded the specified range, and if differential pressure ΔP is below the standard differential pressure value, it means that the viscosity of the fluid to be measured has exceeded the specified range. It means that: Therefore, in such a case, the differential pressure comparison means 34 outputs an abnormal signal to the abnormal signal counting means 35, and when normal, a normal signal for returning the count to zero is output. The abnormal signal counting means 35 counts this abnormal signal, and if it is input five times in a row, it indicates that there is an abnormality in the equipment or that the viscosity of the fluid to be measured exceeds the range of instrumental error. It outputs a signal to the warning lamp driving means 36 and the alarm driving means 31, and notifies the second warning lamp 15 and the alarm 32 (from this) of the abnormality, and also outputs a signal to the valve closing means 37 and the pump motor stopping means 38. A signal is output, the control valve 4 is closed ( ), the pump motor 3 is stopped, and the measurement operation is stopped.

In addition, the - time storage means 27 outputs the maximum flow rate Qmax and minimum flow jlQminl that can be set to 1 and the viscosity to the flow rate comparison means 28, and this means 28 compares the instantaneous flow jiQ with the instantaneous flow jIQ. If it exceeds the measurable range, it outputs an abnormal signal to the abnormal signal counting means 29, and if it does not exceed it, it outputs a normal signal for returning the count to zero.

The abnormal signal counting means 29 counts the input frequency of the abnormal signal input here, and if the abnormal signal is input 5 times in a row, the instantaneous flow IQ actually exceeds the measurable range. A signal is output to the warning lamp driving means 30 and the alarm driving means 31 without determining the abnormality, and the abnormality is notified by the first warning lamp 14 and the alarm 32 via these.

(Effects) As described above, according to the present invention, the difference between the inlet side pressure and the drifting side pressure of the flowmeter is calculated, and the difference pressure and the v of the measured fluid are calculated.
The flow rate measurement operation is equipped with a means to compare the standard differential pressure value corresponding to the flow rate between A and output an abnormal signal when an abnormality is determined. By detecting the instantaneous flow rate and the differential pressure, it is possible to determine whether the viscosity of the flow rate exceeds one range of the specified device difference, thereby making it possible to easily check the metering accuracy during the flow rate measurement operation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a device showing an embodiment of the present invention, FIG. 2 is a diagram showing its circuit structure, and FIG. 3 is a diagram showing a flowchart. 1...Flowmeter 2...Pump 3.
...Pump motor 4...Control valve 6...
・Flow rate pulse transmitter 7.8...Pressure sensor 10...Measuring unit 13...Display device 1
4.15... Warning lamp 20... Control circuit

Claims (1)

[Claims] Instantaneous flow rate calculation means that calculates an instantaneous flow rate in response to a flow rate pulse signal from a flowmeter; and A differential pressure calculation means for calculating a differential pressure, a storage means for storing a standard differential pressure value corresponding to the instantaneous flow rate of the fluid to be measured, and a differential pressure signal from the differential pressure calculation means and a standard differential pressure from the storage means. A flow rate measuring device comprising: a differential pressure comparison means that outputs an abnormality signal when an abnormality is determined by comparing the value with a value signal;