JPH0512912U - Blend direct shipment control device - Google Patents

Abstract

(57) [Summary] [Purpose] A control installed at the tip of the shipping port.
It should be possible to prevent a sudden rise in pressure due to the valve being throttled. [Structure] A master controller that controls the flow rate of each semi-finished product sent from multiple semi-finished product tanks to a specified mixing ratio, and the cumulative amount of the mixed fluid sent from the shipping port reaches the set batch amount. And a shipping port controller that controls the control valve that shuts down the delivery of the mixed fluid, and the flow rate set value given to the master controller is the flow rate given to the shipping port controller when the control valve is narrowed down. A set value changing means for lowering the set value earlier than the set value is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a blending direct shipment control device for off-site and ocean shipping. More specifically, a blending direct shipment control device capable of preventing a rapid increase in pressure due to narrowing down of a control valve installed at the tip of a shipping port. Regarding the control device.

[0002]

[Prior Art]

 FIG. 5 is a conceptual diagram of the configuration of the blend direct shipment control device. In the figure, 1a, 1b, 1c are semi-finished product tanks, 2a, 2b, 2c are pumps for sending semi-finished products (components) from the respective tanks, 3a, 3b, 3c are flow rates of the semi-finished products sent out. Displacement type flowmeters (component flowmeters) 4a, 4b, 4c are flow rate controllers (component controllers) that operate the control valves 5a, 5b, 5c to flow the semi-finished products from each tank (flow rate). ) Control. Reference numeral 60 denotes a pipeline through which the semi-finished products sent from the semi-finished product tanks 1a, 1b, 1c are mixed and sent out, and this pipeline is connected to the shipping port 7. 30 is a flow meter provided in a pipe line 61 connected to the shipping port 7, 40 is a shipping port controller that controls the flow rate of the mixed product shipped from the shipping port 7 by a control valve 50, and 8 is a mixing master control. It is a total.

The mixing master controller 8 adds signals from respective positive displacement type flow meters and calculates the total delivery amount by integrating the signals, and also sets the shipment amount of the shipped product and the mixing (mixing) ratio. The flow rate setting value of each flow rate controller is given so that it becomes a fixed ratio, and the start and stop controls at the time of shipment and the control when the control valve 50 installed at the tip is narrowed down. To do.

FIG. 6 is a time chart showing an example of shipping port control performed by the mixing master controller 8. When there is an operation start command from the operator, first, the control valve 50 is opened by a certain width (). Next, the own set value SV (current flow rate set value) is changed at a specified gradient so as to match the target flow rate set value, and PI control is performed on the set value SV (such an operation). Is called SET UP).

At this time, if the initial flow velocity control is designated, first, SET UP is performed on the initial flow velocity set value, and then SET UP is performed on the final flow velocity set value. If not specified, SET UP is performed for the final flow velocity set value.

The cancellation () of the initial flow velocity control is performed when the integrated amount reaches the initial flow velocity control cancellation amount or when there is an instruction from the operator. After the completion of SET UP, shift to normal PI flow rate control. In this PI flow rate control, the total of the set value SV from the flow rate controller 40 installed at the shipping port is used as its own set value, and it is multiplied by the ratio instructed by the host computer, and the flow rate controller 4a, 4b of each component is multiplied. , 4c ... are set to the set value SV, and the mixing control is performed. Then, when the cumulative amount of fluid from the shipping port reaches (set batch amount-prebatch amount), the set value SV of itself is decreased at a specified gradient until it matches the prebatch flow rate set value (this is an early process. (...) When the pre-batch flow velocity set value matches, the set value SV is held at the pre-batch flow velocity set value (pre-batch processing). Finally, when the integrated amount matches the set batch amount, the control valve 50 is tightly shut and the batch ends ().

If an emergency stop command is issued while the batch is in progress, or if a deviation abnormality is detected, the control valve 50 is closed and the batch is temporarily stopped. ).

[0008]

[Problems to be solved by the device]

 In such a conventional device, the control valve 50 is throttled at the time of early processing or at the time of an emergency stop command. However, if the timing of this throttle is not appropriate, the pressure at the header rises rapidly. was there.

An object of the present invention is to provide a blending direct shipping control device that prevents a sudden pressure increase in the header during early processing or when an emergency stop command is issued, and has high safety.

[0010]

[Means for Solving the Problems]

 The present invention, which solves such problems, provides a mixing master controller that controls the flow rate of each semi-finished product sent from a plurality of semi-finished product tanks to a mixing ratio given by a host computer, and a delivery master. It is a direct-blending controller that has a control valve that shuts down the delivery of the mixed fluid when the integrated amount of the mixed fluid reaches a set batch amount, and a shipping port controller that controls this control valve. And a setting value changing means for lowering the flow rate setting value given to the master controller earlier than the flow rate setting value given to the shipping port controller when the control valve is narrowed down. ..

[0011]

[Action]

 In the direct shipping operation of the blend, the set value changing means lowers the flow rate set value SV applied to the blend master controller at an earlier timing than the set value of the shipping port controller during the early or shut down.

As a result, the flow rate of each component decreases at an early timing, and it becomes possible to prevent the pressure increase due to the narrowing down at the shipping port.

[0013]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration block diagram showing an embodiment of the present invention. In the figure, the same parts as those in FIG. 5 are designated by the same reference numerals. In the mixing master controller 8, 81 is an adding means for adding the flow rate signals from the respective component flow meters 1a, 82 is an integrating calculating means for integrating these added flow signals, and 83 is an integrating calculating means 82. It is a control means for inputting an integrated value of PV as PV (process amount). Reference numeral 84 denotes a zone control means, which determines the flow velocity set value to be given to the flow rate controllers 4a ... At each stage (step) as described in FIG. 6 based on the control result of the control means 84. Reference numeral 85 is a set value changing means for changing its own set value, which is a feature of the present invention. This set value changing means is configured to lower its flow set value earlier than the flow set value given to the shipping port controller 40 when the control valve 50 is narrowed down.

FIG. 2 is a functional conceptual diagram of the inside of the mixing master controller 8. The set value changing means 85 refers to the blend SV output means 85 for inputting the shipping port set value SV given to the shipping port flow meter 30 and the zone (control step) by referring to the signal from the shipping port flow meter 30. The zone determining means 87 determines which zone the zone is in.

The operation of the apparatus thus configured will be described below. FIG. 3 is a time chart showing main operations. In the direct-blending operation for blending, the zone determining means 87 in the setting value changing means 85 inputs the signals from the shipping port flow meter 30 and reaches the early point from those values, that is, the control step is "3." From “4” to “4” or at the time of shutdown (EM-ST), the flow rate set value SV given to the control means 83 is set at an earlier timing than the set value of the shipping port controller 40 is lowered. Lower it. In FIG. 3, when the Early point is reached, the set value given to the control means 83 is rapidly lowered by α.

FIG. 4 is a time chart of the blending direct shipping work corresponding to FIG. 6 when the present invention is applied. (A) shows the set value of the shipping port controller, (b) shows the set value of the mixed master controller, and (c) shows the transition of the set value of the component controller.

In the conventional device, when the shipping port reaches the early point or when it becomes shut down (EM-ST), the flow rate set values of the mixing master controller and the component controller are respectively set to the shipping port. In synchronism with the flow velocity set value (SV), the flow velocity set value of itself was lowered as indicated by. In the present invention, when the early point is reached or the shutdown (EM-ST) timing is detected by the zone determination means, at these points, the flow velocity set value of itself is drastically reduced as shown by. Then, the aperture is narrowed down by one step.

As a result, the flow velocity of the components delivered from the semi-finished product tank can be reduced rapidly to prevent pressure increase due to narrowing down at the shipping port.

[0020]

[Effect of the device]

 As described in detail above, according to the present invention, it is possible to prevent a rapid increase in pressure due to the narrowing down of the control valve arranged at the tip of the shipping port in the direct blending shipping work in the off-site and sea shipping. Therefore, it is possible to provide a highly safe blending direct shipment control device.

[Brief description of drawings]

FIG. 1 is a configuration block diagram showing an embodiment of the present invention.

FIG. 2 is a functional conceptual diagram of the inside of a mixed master controller.

FIG. 3 is a time chart showing main operations.

FIG. 4 is a time chart of a blending direct shipping operation when the present invention is applied.

FIG. 5 is a conceptual diagram of the configuration of a blend direct shipment control device.

FIG. 6 is a time chart showing an example of shipping port control performed by the mixing master controller of the apparatus of FIG.

[Explanation of symbols]

1a, 1b, 1c Semi-finished product tanks 2a, 2b, 2c Pumps 3a, 3b, 3c Volumetric flowmeters (component flowmeters) 4a, 4b, 4c Flow controllers (component controllers) 5a, 5b, 5c Control valves 40 shipping port controller 50 control valve 7 shipping port 8 mixed master controller 85 set value changing means

Claims (1)

[Scope of utility model registration request] 1. A mixing master controller for controlling the flow rate of each semi-finished product sent out from a plurality of semi-finished product tanks so as to have a mixing ratio given by a host computer, and an integrated amount of a mixed fluid sent out from a shipping port. Is a blend direct-shipping control device having a control valve for shutting down the delivery of the mixed fluid when the set batch amount has been reached, and a shipping port controller for controlling the control valve. A blending direct shipping control device comprising a set value changing means for lowering a given flow rate set value earlier than the flow rate set value given to the shipping port controller when the control valve is narrowed down.