JPH0159193B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a fixed-quantity shipping device for fluid that divides the period from the start of shipping to a set amount into a plurality of sections, and each section is indicated by a voltage proportional to the flow velocity. This invention relates to time chart generation means for valve control signals.

[Prior Art] In a quantitative liquid supply device that ships or receives a fixed amount of fluid using a quantitative meter, a flow meter and a control valve are arranged in the liquid supply flow path, and the flow rate to be shipped is set in advance in the quantitative meter. When the shipping start command switch of the quantitative meter is pressed, the control valve is opened by the signal sent and shipping is started. The shipped flow rate is detected by integrating the flow rate pulse signal transmitted from the flow meter in a quantitative meter, and when the integrated value reaches the set flow rate, the control valve closes to complete liquid supply. First, when the above-mentioned fixed-quantity liquid supply device opens and closes the control valve, a shock is applied to the control valve due to the water hammer phenomenon based on the inertia of the fluid to be supplied.
There is a problem in that the control valve deteriorates early, leading to damage. Second, when the control valve is closed, there is a problem in that the amount of liquid supplied becomes excessive due to a time delay in the valve closing operation, resulting in a decrease in the accuracy of quantitative determination. Thirdly, there is a problem in that there is a risk of electrostatic explosion due to static electricity generated by fluid friction when transporting hazardous materials such as petroleum or other non-conductive current. Because of these problems, it is common practice to prevent water hammer from occurring in the valve by giving a time gradient to the valve opening and closing operations, and to reduce the flow rate to a small flow rate during the initial stage of quantitative shipment and for a predetermined period before the completion of quantitative shipment. By doing so, we aim to improve quantitative accuracy, prevent the generation of static electricity, and increase the flow rate in the intermediate region to streamline shipping operations.

In other words, the set flow rate to be shipped is divided into a plurality of sections for each predetermined flow rate, and the flow speed corresponding to each section is calculated by taking into account the flow speed conditions described above, and a time chart is created with the voltage proportional to the flow speed on the vertical axis and the cumulative flow rate on the horizontal axis. The flow velocity corresponding to the current cumulative flow rate in the time chart is compared with the flow velocity obtained from the pulse velocity of the flow pulse, and the control valve is quantified so that the flow velocity becomes the reference flow velocity shown in the time chart. The flow rate is controlled by the control means built into the meter before shipment. The voltage value of the time chart is determined based on 1 to 5 V (volts), and the current value is shown as an analog value of 4 to 20 mA.
For example, if the time chart is shown as a voltage value, and the shipping setting flow rate is 2000Kl, and the control valve is opened according to a shipping command and shipping is started, the first 1Kl is
150Kl/hour, the flow rate when shipping from 1999Kl to 1999Kl is 600Kl/hour, and the flow rate from 1999Kl until reaching a constant flow rate of 2000Kl is 150Kl/hour again.The time chart when closing the valve corresponds to the above flow rate. It is shown in a pattern of 0 → 2V → 5V → 5V → 2V → 0. This time chart employs an addition method in which a voltage increase of 3 V in the shipping flow rate range from 1 Kl to 1999 Kl is added to the voltage of the time chart corresponding to 0 to 2000 Kl from 0 to 2 V to 2 V to 0.

[Problems to be Solved by the Invention] When creating the conventional time chart described above using the voltage addition method, if the voltage of the time chart is changed to create a new pattern, for example, the initial flow rate of 1 Kl is changed to a large flow rate. When shipping at 450Kl/hour, the voltage will be 4V, and from the last 1999Kl
Similarly, when the flow rate up to 2000Kl is 450Kl/hour, it is selected to be equal to the initial flow rate at shipping, and since the flow rate is large, it becomes complicated to create a time chart when considering the valve closing point, and a voltage addition circuit is also required. Therefore, there is a problem in that circuit conditions such as impedance matching of each voltage generating circuit must be taken into consideration, which is inconvenient and inefficient.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and the voltage of the time chart is created in advance so that it can be arbitrarily set for each flow rate section, and this voltage is set as desired. By outputting via a switch that can be switched sequentially for each flow rate category over the shipping flow rate range of the time chart, there is no need to consider circuit conditions when changing the flow rate in a flow rate category, making it simple and easy to use without special skill. The purpose of this is to make it possible to create a time chart without having to use the first signal. In the second signal up to the shipping section, the third signal from the end of the second signal until reaching the set amount, and the predetermined section before reaching the set amount of the third signal, the flow velocity is set to a small flow velocity equal to the second signal section. a signal conversion circuit that sequentially transmits a fourth signal as a digital signal; and a first reference voltage generating means that is closed by the first signal of the signal conversion circuit and generates a reference voltage corresponding to the small flow velocity that can be set arbitrarily. , a second reference voltage generation means that can arbitrarily generate a reference voltage corresponding to a large flow velocity, a first subtraction circuit that subtracts the first reference voltage from the second reference voltage, and a first and a second reference voltage. a second subtraction circuit which has one input by switching the reference voltage of the first subtraction circuit and the other input which receives the output of the first subtraction circuit; Time chart generation for valve control signals in quantitative meters, consisting of an integrating circuit that gives a predetermined slope to the rising edge of the output reference voltage, and a time chart generating circuit that shows the shipping flow rate from the start of shipping to the set amount in voltage. It is a means.

[Function] The flow rate from the start of fluid shipment until reaching the set amount can be set in two stages, large and small, and a reference voltage proportional to the flow rate can be individually set in the time chart generation circuit, and the flow rate is determined by the shipping flow rate at which the flow rate is changed in the time chart. The reference voltage is output through a switch that is sequentially opened and closed in the second, third, and fourth flow rate sections, and in the fourth flow rate section, a subtracted value obtained by subtracting the reference voltage of the second flow rate section from the third flow rate section is output. By subtracting the reference voltage of the third flow rate segment, an arbitrarily adjustable time slope is provided for the transient change in the flowchart voltage of each flow rate segment.

[Embodiment] FIG. 1 is a block diagram showing the configuration of a time chart generating means in a quantitative meter of the present invention. In the figure, 100 is a command signal transmitting section and 200 is a time chart generating circuit. The command signal transmitting section 100 is composed of a quantitative batch sequence circuit 1 and a signal conversion circuit 2. The quantitative batch sequence circuit 1 has quantitative meter functions such as flow rate setting and flow rate integration.
Here, a digital signal indicating a shipping flow rate range which is a first signal from the start of fluid shipping until reaching a set amount and a flow rate range M in which the flow rate is shipped at a large flow rate within the first signal section is output. The signal conversion circuit 2 inputs the digital signal of the quantitative batch sequence circuit 1 and the signal M, and outputs a digital signal corresponding to the shipping flow rate on the time chart and a section where the flow velocity changes, and the digital signal will be described later. This is the switch voltage that opens and closes the corresponding circuit element of the time chart voltage generation circuit. Figure 2 A is the first
A time chart is shown for creating a second signal, a third signal, and a fourth signal, which will be described later, as digital signals in a section where the flow velocity changes from the signal and the signal M. On the horizontal axis, A is the start of shipping, B is the flow rate switching point that switches from the start of shipping to a large flow rate, C is a flow rate switching point that switches the large flow rate switched at point B to a small flow rate again, and D
is the set amount for fixed quantity shipment, the first signal is the AD interval, the second signal is the M signal subtracted from the first signal,
Small flow section with CD section deleted, 3rd signal is 1st
High flow area is the area where the second signal is subtracted from the signal.
Includes BC and small flow section CD. The fourth signal is a small flow area obtained by subtracting the M signal and the second signal from the first signal.
This is provided to prevent over-shipment of CDs at the set point D. 200 is a time chart generation circuit, and 3 is a switch that is closed by a first signal, which is a digital signal, and supplies a reference voltage to the time chart generation circuit 200 from a reference voltage (not shown). 8 and 11 are switches that are opened and closed by the second signal, 9 and 12 are switches that are opened and closed by the third signal, 13 and 20 are switches that are opened and closed by the fourth signal, and VR ₁ is connected between the reference voltage and ground. The volume VR 2 is the volume VR ₁ that determines the voltage V ₁ in the small flow velocity section of AB and CD, which are the first and _second signals.
Similarly, a volume is connected between the reference voltage and ground and determines the voltage V ₂ of the high flow velocity of BC which is the M signal section. 7 is an amplifier that converts the output voltage of the volume VR ₂ into impedance as voltage V ₂ and outputs it. Similarly, the voltage input via switch 8 or 9
The V ₁ or V ₂ amplifier can clamp the input or output ratio to an arbitrarily set value. 14 is a first subtracter that inputs the voltages V ₁ and V ₂ and outputs the subtracted value; 15 uses the amplifier 10 that inputs the voltage V ₁ or V ₂ as one input; and the output of the first subtracter 14 is a second subtractor with the other input;
18 is a terminal that outputs the voltage of the time chart, 1
6 is a voltage frequency conversion circuit (V/
F conversion circuit), 17 is the voltage frequency conversion circuit 16
A frequency dividing circuit divides the flow rate pulse and converts it into a unit pulse which is a digital unit flow rate, and 19 is a terminal for outputting the unit pulse. a and b are constant current circuits that introduce a constant current into the capacitor C ₁ using the reference voltage supplied by the closed circuit of the switch 3, and give a constant voltage slope to the rise of the voltages V ₁ and V ₂ ;
Each can set a current value that defines an arbitrary voltage slope. Similarly to constant current sources a and b, c is also a constant current circuit that outputs a constant current and gives a voltage slope determined by the constant current value and capacitor _C2 to the output voltage of the subtracter 14 by closing the switch 13. .

Next, the operation of the time chart generating circuit described above will be explained in comparison with FIGS. 2 and 3.

The switch 3 is closed by the first signal sent from the signal conversion circuit 2, and the voltages V ₁ and V _{2 preset by the volume VR 1 and VR 2 are applied} to the volume VR 1 and VR ₂ .
Each is output from VR ₂ . In response to the command to start shipping, a second signal is output, which closes the switch 8 and the switch 11, and the voltage _V1 is increased to the third signal by the amplifier 10, the current of the constant current source a, and the capacitor _C1 .
The voltage in the AA′B section shown in FIG. ₃ is input to one input terminal of the second subtracter 15. Then the second
When the signal ends, switches 8 and 11 are opened, a third signal is transmitted and switches 9 and 12 are closed, and the current of constant current source b and the voltage with the slope of BB' determined by capacitor C ₁ become V ₂ and input to one input terminal of the second subtracter 15. Since the switch 20 is open at this point, there is no input to the other input terminal of the second subtractor 15, and the voltage _V3 in FIG. 3 is output to the terminal 18. The third signal continues until the point D when the shipping flow rate reaches the set amount, but in the section CD immediately before reaching the set amount D.
A fourth signal is transmitted. The fourth signal closes switches 13 and 20. Since the voltage V ₁ corresponding to a small flow velocity is input to one input of the first subtractor 14 and the voltage V ₂ corresponding to a large flow velocity is input to the other input, the second subtractor 14 is closed by closing the switches 13 and 20. The voltage _V4 in FIG. 3 is input to the other input terminal 15. The voltage V ₄ is the voltage slope obtained by the current of the constant current source c and the capacitor C ₂ as CC′ and V ₄ = V ₂ − V ₁
It consists of a CD section with a voltage of . Since the output from the second subtractor 15 in the section CD is calculated as V ₃ - V ₄ , the time chart shown in FIG. 3 V ₅ which is V ₁ pressure in the section CD
A voltage of AA'BB'CC'D is output from terminal 18.
Since the time chart voltage V ₅ shown above becomes the reference voltage of the flow velocity, the voltage-frequency conversion circuit 16
and the frequency divider 17 constitute a master oscillator, and since a reference unit pulse is transmitted from the terminal 19, the shipping flow rate is digitally controlled by comparing the reference pulse with the flow rate pulse transmitted from the flow meter. It is also possible.

[Effects of the Invention] According to the time chart generating means in the quantitative meter of the present invention described above, the voltage value of the time chart is switched by the digital signal of the signal conversion circuit that is sequentially transmitted according to the flow rate division of the time chart. It is continuously output from the time chart generating means, and the typical voltage value of the time chart can be set in advance with a volume control, and it is designed to prevent shocks such as water hammer phenomenon from acting on the flow rate control means such as control valves. The means for giving a predetermined slope to the voltage of the time chart also has an integral circuit that can change the integral value, and can be set independently. By using the first and second subtractors for tilting, it is possible to use the same means used to prevent water hammer at the time of the start of shipment, so there is no need for special skill, and the circuit requirements can be reduced. This has the effect of being easy to set without having to consider other factors.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the time chart generating means in the quantitative meter of the present invention, and FIG. 2 shows the digital signals output from the command signal generating section 100.
FIG. 3 shows the voltage value of the time chart in the main circuit elements output from the time chart generating circuit 200 which has been changed by the digital signal shown in FIG. 1...Quantitative batch sequence circuit, 2...Signal conversion circuit, 3, 8, 9, 11, 12, 13, 20
...Switch, 7, 8...Amplifier, 14...1st
subtractor, 15...second subtractor, 16...V/
F conversion circuit, 17... Frequency divider, a, b, c... Constant current source, 100... Command signal transmitter, 200...
Time chart generation circuit.

Claims (1)

[Claims] 1. In a fluid quantitative shipping device that uses a quantitative meter that receives and integrates the flow rate signals transmitted from the flow meter and transmits a drive signal for the control valve according to a predetermined cumulative volume, the settings are set from the start of shipment of the shipped fluid. A first signal indicating the section until the amount is reached, a second signal from the start of shipping to the section where shipping is carried out at a specified small flow rate, a third signal from the end of the second signal until the section when the set amount is reached, and a third signal. a signal conversion circuit that sequentially transmits a fourth signal as a digital signal in which the flow velocity is set to a small flow velocity equal to the second signal interval in a predetermined section before reaching a set amount of the signal; a first reference voltage generation means that arbitrarily generates a reference voltage corresponding to a small flow velocity; a second reference voltage generation means that arbitrarily generates a reference voltage corresponding to a large flow velocity; and a second reference voltage. a first subtraction circuit that subtracts a first reference voltage from the voltage; and a first subtraction circuit that switches between the first and second reference voltages and uses one as an input and the output of the first subtraction circuit as the other for a fourth signal period only. It consists of a second subtraction circuit as an input, and an integration circuit that is switched by the second, third, and fourth signals and gives a predetermined slope to the rise of the output reference voltage, and reaches the set amount from the start of shipment. 1. A time chart generating means for a valve control signal in a quantitative meter, comprising a time chart generating circuit for a valve control signal indicating a shipping flow rate in terms of voltage.