JPH0259310B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a fluid flow rate control method in a system in which fluid is transferred by turbine drive. The present invention relates to a fluid flow rate control method that can reduce the amount of steam that is a driving source by minimizing loss and controlling the rotation speed of a turbine pump.

[Problems to be solved by conventional technology and invention]

Conventionally, flow rate control when transferring fluid using a turbine as a driving source has been performed, for example, in the case of a turbine pump.
This was accomplished by operating the turbine pump at a constant rotational speed and reducing the flow rate to a desired flow rate using a pump discharge valve.

However, the opening degree of this pump discharge valve had to be kept at about 80% or less of the maximum opening degree in order to cope with disturbances to the flow rate control system during operation. Similarly, when a flow meter is installed at the discharge port of a pump and the flow rate control valve is opened and closed according to its output to adjust the flow rate of the fluid, the flow rate control valve tends to close at normal flow rates, resulting in waste. A lot of energy was being consumed.

Generally speaking, the pressure loss ∆P for the control valve of a fluid flow control system is said to be 1/3 or more of the ∆P of the entire system. ΔP of the control valve should be kept to the minimum necessary. In other words, it is desirable to reduce the rotational speed of the turbine pump by opening the pump discharge valve as much as possible so that ΔP is the minimum. A certain amount of steam can be reduced.

An object of the present invention is to provide a control method that eliminates the above-mentioned drawbacks by regulating the flow rate or pressure of fluid by controlling the rotational speed of a turbine-driven machine.

[Means to solve the problem]

That is, the present invention sets the opening degree of the flow rate or pressure control valve to a state close to fully open, then detects the amount of fluid transferred and/or the transfer pressure, and adjusts the amount of fluid transferred and/or the transferred pressure to the detected amount. Based on this, the arithmetic processing is performed so that the opening degree of the flow rate or pressure control valve is constant, and then the command based on the electrical signal determined here is converted into an air signal, and the rotation speed of the turbine is adjusted using this signal. The present invention provides a fluid flow rate control method by controlling the rotational speed of a turbine, which is characterized by the following.

The method of the present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 is a block diagram showing the case of a turbine pump.

The pump 1 transfers fluid by rotating a turbine 2 driven by steam.

Normally, if the flow rate of pump 1 is sufficient,
The flow rate or pressure control valve 4 is in a slightly closed state.

Therefore, first, the arithmetic processing unit 6 sets the opening degree of the flow rate or pressure control valve 4 to a state close to fully open, for example.
Set to 90±5%.

Naturally, this will result in a flow rate greater than necessary.

Therefore, the amount of fluid transferred and/or the transfer pressure is detected by a detection means 3 such as a flow meter or a pressure gauge, and the detected flow rate or pressure is sent to a processor 6 through a controller 5. In this way, the flow rate or pressure is detected before the flow rate or pressure of the fluid is adjusted by the flow rate or pressure regulating valve 4, which is a discharge valve.

Next, the processor 6 receives the detected fluid transfer amount and/or transfer pressure through the controller 5, and based on this, the flow rate or the opening degree of the pressure regulating valve 4 is kept constant. , performs calculations for the various operations described above, and issues commands as signals to suit the fluid transfer system.

The arithmetic processor 6 that performs arithmetic processing for various operations is equipped with a computer function and performs proportional operation, differential operation, integral operation, etc., so that the opening degree of the flow rate or pressure control valve 4 is constant. To,
The minimum required rotational speed of the turbine is calculated, and a time delay operation or gap operation is added to suit the fluid transfer system, and as an electrical signal,
It is sent to the next converter (I/P) 7.

The electrical signal command determined here is converted into an air signal by the converter 7, and upon receiving this signal, the governor or control valve 8 adjusts the rotation speed of the turbine 2 to make the flow rate of the pump appropriate. .

More specifically, the signal converted into an air signal by the converter 7 is transmitted to the governor or control valve 8, and the conditions set in the governor or the opening degree of the steam amount control valve are corrected. According to the revised command, the rotational speed of the turbine 2 is lowered, and as a result, the opening degree of the flow rate or pressure regulating valve 4 is opened to the opening degree set in the processor 6, and in this state, fluid transfer is performed. It is done.

Thereafter, the rotation of the turbine 2 controls the flow rate or the opening degree of the pressure regulating valve 4 to be constant.

Note that the processor 6 that performs arithmetic processing is equipped with a timer, etc. to enable time delay operation or gap operation, and the output of the processor is increased to ensure the safety of the turbine. - Consideration can be given to switching to low stage 2 or limiting output.

Since the flow rate or pressure of the fluid is controlled as described above, the flow rate or pressure regulating valve 4 can always be kept fully open or close to fully open to obtain the required flow rate or pressure.

Therefore, it is possible to reduce the wasteful loss of energy conventionally spent in absorbing fluid pressure with the control valve, and it is also possible to reduce steam from the turbine drive source.

The embodiment shown in FIG. 2 is a block diagram showing the case of suction pressure control of a reciprocating compressor.

Conventionally, the suction pressure in this embodiment is controlled by providing a pressure transmitter on the suction side.
When the suction pressure increases, the spillback control valve is closed to increase the discharge flow rate of fluid, and on the other hand, when the suction pressure decreases, the spillback control valve is opened to reduce the discharge flow rate of the fluid. but,
Such a control method wastes a lot of power and is not favorable in terms of energy economy.

Therefore, by the control method of the present invention as shown in FIG. 2, the spillback control valve is closed.
By changing the rotational speed of the turbine, it is possible to significantly reduce the amount of power steam. In the figure, reference numeral 9 is a reciprocating compressor.

Further, the embodiment shown in FIG. 3 is a block diagram when the control method of the present invention is applied to draft control of a heating furnace.

In the draft control of a heating furnace with a suction blower, conventionally, when controlling the draft to a constant level, the draft of the heating furnace was controlled by opening and closing a damper using a parasitic valve in response to a signal from a pressure transmitter. However, such an adjustment method wastes a large amount of power as described above.

According to the control method of the present invention, in the case of draft control of such a heating furnace, the damper is used in a state close to fully open, and the rotation speed of the turbine is changed according to changes in the draft, so that the power steam can be reduced. can be achieved. In the figure, numeral 10 is a heating furnace, 11 is a control valve, and 12 is a suction blower.

[Effects of the Invention] According to the present invention, the flow rate or pressure regulating valve can obtain the required flow rate or pressure while always being fully open or close to being fully open.

Therefore, it is possible to reduce the wasteful loss of energy conventionally spent in absorbing fluid pressure with the control valve, and it is also possible to reduce steam from the turbine drive source.

Moreover, since the pressure loss of the flow rate or pressure regulating valve is reduced, erosion of the inner valve is reduced and noise generation can also be prevented.

[Brief explanation of drawings]

1-3 are block diagrams of embodiments of the invention. 2...Turbine, 3...Fluid transfer amount detection means,
4...Flow control valve, 5...Controller, 6...Computational processor, 7...Converter, 8...Governor or control valve, 9...Reciprocating compressor.

Claims (1)

[Claims] 1 Set the opening degree of the flow rate or pressure control valve to a state close to fully open, then detect the amount of fluid transferred and/or the transfer pressure, and adjust the amount of fluid transferred based on the detected amount and/or transfer pressure of the fluid. After performing arithmetic processing so that the opening degree of the flow rate or pressure control valve is constant, the electrical signal command determined here is converted into an air signal, and this signal is used to adjust the rotation speed of the turbine. A fluid flow rate control method by controlling the rotation speed of a turbine.