JPS626168B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flow rate measuring device that measures a large flow rate that cannot be measured with a single flow meter by arranging a plurality of flow meters in parallel. .

Among this type of flow rate measurement devices, one has already been proposed that automatically changes the number of flowmeters that are allowed to pass liquid in accordance with the flow rate. However, these are for example for small flow rate (A), medium flow rate (B), and high flow rate.
The flowmeter (C) is fixed, and when the flow rate is small, only (A) is used.
At medium flow rates, (A) and (B) are passed through, and at high flow rates, (A), (B), and (C) are passed through, so (B) is more concentrated than (C). Flowmeters in (A) are more commonly used than those in (A), and as flowmeters in (A) constantly pass liquid regardless of the flow rate, they have the disadvantage of significant mechanical wear on their component parts. It was hot.

The present invention is proposed in order to solve the above-mentioned drawbacks, and uses a plurality of flowmeters with the same capacity, and allows the flowmeter to pass liquid regardless of the flow rate to be connected to the energization or deenergization of the pump device. Make sure to change them sequentially,
This prevents only certain flowmeters from becoming extremely worn out.

To explain the illustrated embodiment below, P is a pump inserted in a pipe line C, which is rotationally driven by a motor M to pump out liquid stored in a liquid storage tank (not shown), etc., and forcefully send it to a flow meter to be described later. do.

F ₁ , F ₂ , and F ₃ are flowmeters with the same capacity,
The measured values by the flowmeters F ₁ , F ₂ , F ₃ are arranged in parallel in the conduit C, and the measured values from the respective pulse transmitters G ₁ , G ₂ , G ₃ are transmitted by pulses g ₁ , g ₂ , g corresponding to the measured values. It is converted to the number ₃ and output. V ₁ , V ₂ , and V ₃ each indicate a valve such as a solenoid valve, which is opened or closed in response to signals v ₁ , v ₂ , and v ₃ described later, and only when open, each of the flow rates connected in series is Allows fluid to flow through the meter.

N is a nozzle provided at the tip of the conduit C, and by operating its operating lever N', the speed (flow rate) of liquid supplied to the liquid tank (not shown) is adjusted.

1 is a counting circuit, and each pulse oscillator G ₁ , G ₂ , G ₃
The number of pulses g ₁ , g ₂ , g ₃ outputted from the flowmeters F ₁ , F ₂ , Display the numerical value as the sum of the weight values measured by _F3 .

4 is a determination circuit that determines the flow rate per unit time by counting the sum of each pulse g ₁ , g ₂ , g ₃ every fixed time (for example, 1 second), and outputs the determination result as a determination signal. d, d', d'' to the valve control circuit 5. The determination contents of the determination circuit 4 and the determination signals d, d', d'' will be described later.

The valve control circuit 5 receives the determination signals d, d', d'' and applies valve control signals v ₁ , v ₂ , v ₃ to each valve V ₁ , V ₂ , V ₃ to open the valve.

6 is a switch for starting the motor, which is manually operated, and when it is ON, the output signal e is High (H) and OFF.
When the signal e is low (L), the motor control circuit 7 energizes the motor M to rotate the pump P, and when the signal e is low, the motor M is deenergized.

In addition, in response to the change of the signal e from H to L, the switching signal generation circuit 8 outputs the switching signal f to instruct the valve control circuit 5 to switch the normally open valves V ₁ , V ₂ or V ₃ , and the switching signal e changes from L to H. As a result, the count value of the counting circuit 1 returns to zero.

The above is an outline of the configuration, and now, based on FIG. 2, the advantages and disadvantages of using a plurality of flowmeters connected in parallel will be described.

Figure 2 shows the maximum usable flow rate of the flowmeter at 100%.
It shows the change in the instrumental error curve h at each flow rate when the maximum flow rate of one flowmeter is 100
/min, the lowest flow rate that can actually be used is 20/min, and a flow rate lower than that will cause a large deviation in the measured value.

However, one flowmeter can only measure up to 100/min, so if you connect three flowmeters in parallel, you can increase the maximum usable flow rate to 300/min, but the minimum usable flow rate is 20×3=60/min, which causes inconvenience when measuring small flow rates.

Also, since it is practically undesirable to use each flowmeter at the maximum flow rate, for example, when the flow rate is 0 to 60/
min (small flow rate), use one flowmeter, 61~
At 120/min (medium flow rate), two flowmeters, 121
The configuration is such that all three flowmeters are used for measurement when the flow rate exceeds /min (large flow rate).

Next, returning to FIG. 1 and explaining in detail based on the example explained in FIG. 2, the determination circuit 4 counts the number of pulses g ₁ , g ₂ , g ₃ per unit time as described above. When it is determined that the flow rate corresponds to a small flow rate, the signal d is added to the signal d, and when it is determined that the flow rate is a medium flow rate, a signal d' is added to the signal d.When it is determined that the flow rate is a large flow rate, a signal d'' is also output to control the valve. The valve control circuit 5 outputs the signal v 1 to open the valve V ₁ in response to the input of the signal d, and outputs the signal v ₂ to open the valve _{V 2} in response to the input of the signal d'. The valve V ₃ is opened by outputting the signal v ₃ in response to the input of the signal d″.

Therefore, according to the judgment of the judgment circuit 4, the flowmeter F ₁ is set at a small flow rate, and the flowmeters F ₁ and F ₂ are set at a medium flow rate.
When the flow rate is large, the flowmeters F ₁ , F ₂ and F ₃ will each be supplied with liquid. Note that when the flow rate decreases from a large flow rate to a medium flow rate, the signal d'' disappears, and when the flow rate further decreases from a medium flow rate to a small flow rate, the signal d' disappears, and in response to this, the output of the valve control circuit 5 also becomes v ₃ In addition, v ₂ disappears and valve V ₃ and V ₂ are closed, reducing the number of flowmeters that are flowed.

On the other hand, the switching signal generation circuit 8 outputs the signal f once (one pulse) every time the signal e changes from H to L, and supplies it to the valve control circuit 5. This changes the output signal when the flow is small, medium, or large. That is, as described above, the valve control circuit 5 currently outputs the signal v ₁ when the flow rate is small (when the signal d is input), and the signals v 1 and v ₂ when the flow rate is medium (when the signals d and _d ' are input). , at large flow rate (signals d, d′,
The signals v ₁ , v ₂ , v ₃ are output when the current is input (d''), but when the signal f is input once, the signal v ₂ is output when the flow is small, and the signals v 2 , v ₂ when the flow is midstream. When v ₃ is a large flow, signals v ₂ , v ₃ , v ₁ are output, and further signal f is output.
When input twice, signal V ₃ is generated when the flow is small, and signal V 3 when the flow is medium.
When v ₃ , v ₁ is large, signals v ₃ , v ₁ , v ₂ are output,
When the next signal f is input, the state returns to the original state.

In this embodiment, the switching signal generating circuit 8 outputs the signal f when the signal e changes from H to L, but it can also output the signal f when the signal e changes from L to H. The number of is also not limited to three.

With the configuration described in detail above, each flowmeter passes liquid evenly, effectively preventing problems such as only a specific flowmeter being overworked and significantly shortening its life. Since it is used, there is no variation in measured values and maintenance is easy.

[Brief explanation of the drawing]

Figure 1 shows a block diagram of the pipe line and each control circuit according to the present invention, and Figure 2 shows the change in instrumental error at each flow rate when the maximum usable flow rate of the flowmeter is 100%. FIG. 1... Counting circuit, 3... Display, 4... Judgment circuit, 5... Valve control circuit, 6... Switch, 8...
Switching signal generation circuit, V ₁ , V ₂ , V ₃ ... valve, F ₁ ,
F ₂ , F ₃ ...flow meter, P ... pump, N ... nozzle.

Claims (1)

[Claims] 1 A plurality of flowmeters are arranged in parallel in the flow path, and valves are provided to restrict or allow the flow of liquid to each flowmeter, and the valves are driven according to the magnitude of the flow rate of the liquid to pass the liquid. controls the number of flow meters that should be allowed, and in the flow measurement device equipped with a pump device for sending liquid to each flow meter, all of the plurality of flow meters are of the same capacity, The output order of the valve drive signals output to each valve according to the magnitude of the flow rate is sequentially changed by the input of the switching signal output in connection with the output of the motor control signal that controls energization or deenergization of the pump device. 1. A flow rate measuring device comprising a valve control circuit.