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Safety instrument system and method for permitting PST

A technology of safety instrumented system and start command, which is applied in the field of safety instrumented system, can solve the problem of high cost and achieve the effect of suppressing bad influence

Inactive Publication Date: 2014-07-02
YAMATAKE HONEYWELL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The fully closed test must be carried out when the process equipment is stopped for regular maintenance, and the cost is high

Method used

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  • Safety instrument system and method for permitting PST
  • Safety instrument system and method for permitting PST
  • Safety instrument system and method for permitting PST

Examples

Experimental program
Comparison scheme
Effect test

no. 1 approach ］

[0041] Hereinafter, embodiments of the present invention will be described with reference to the drawings. figure 1 It is a block diagram showing the configuration of the safety instrumented system according to the first embodiment of the present invention.

[0042] The emergency shut-off valve 1 set in the pipeline of the process equipment to prevent accidents of the process equipment in the future is driven by air pressure. The positioner 2 that controls the opening of the emergency shut-off valve 1 receives a positioner control signal from the host system 3 that manages the maintenance of each field device of the process equipment, and uses the air supply from the air supply according to the opening indication value shown by the positioner control signal. The air in the pipe 4 supplies the required operator air pressure to the emergency shut-off valve 1. Operator air pressure from positioner 2 is supplied to emergency shut-off valve 1 through air duct 5 . In addition, the...

no. 2 approach ］

[0054] Next, a second embodiment of the present invention will be described. Figure 4 It is a block diagram showing the structure of the positioner 2 and the host system 3 in this embodiment. In this embodiment, since the overall structure of the safety instrumented system is also the same as that of the first embodiment, using figure 1 symbols are explained. In the first embodiment, the locator 2 manages the PST activation period, and individually judges whether the PST can be activated. On the other hand, in the present embodiment, the host system 3 manages the PST activation cycle of the plurality of emergency shut-off valves 1, and judges whether or not the PST activation is possible.

[0055] The host system 3 has a storage unit 30, a PST start instruction unit 31, a PST start prohibition determination unit 32 for judging the prohibition / permission of PST start-up of each emergency shut-off valve 1, and a timer 33 for measuring The time elapsed after the PST is comple...

no. 3 approach ］

[0064] Next, a third embodiment of the present invention will be described. Figure 6 It is a block diagram showing the structure of the positioner 2 and the host system 3 in this embodiment. In this embodiment, since the overall structure of the safety instrumented system is the same as that of the first embodiment, using figure 1 symbols are explained. In the second embodiment, the PST performed by the command from the higher-level system 3 is periodically executed regardless of the PST performed by the command from the operation panel on site. On the other hand, this embodiment combines the PST performed by the command from the host system 3 and the PST performed by the command from the operation panel on site.

[0065] When the originally scheduled PST is activated by the PST activation command signal of the host system 3 without a sufficient time interval after completion of the PST performed by the on-site operation, the PST becomes an unnecessary PST that may not be a...

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PUM

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Abstract

A safety instrument system comprises a positioner for controlling the degree of opening of an emergency cutoff valve that is provided in a pipe in a plant, and a higher-level system for controlling the PSTs (partial stroke tests) of the emergency cutoff valve. The positioner has: a portion for executing a PST on the emergency cutoff valve in response to an initiating instruction from the higher-level system or to an initiating instruction from an operating panel on the plant floor wherein the positioner is provided; a timer for measuring elapsed time from the completion of a PST on the emergency cutoff valve; and a portion for evaluating whether or not a PST is permitted, by comparing elapsed time from the previous PST, to a PST minimum interval that is set in advance.

Description

technical field [0001] The invention relates to a safety instrument system for protecting the safety of process equipment and a PST starting method. Background technique [0002] There are high demands on a safety instrumented system (Safety Instrument System, hereinafter referred to as SIS) that protects the safety of process equipment. The SIS is equipped with an emergency shut-off valve, which will be closed when the process equipment is abnormal, so as to ensure safety. Normally, the emergency shut-off valve remains fully open. If the emergency shut-off valve is stuck, it is difficult to detect the sticking of the emergency shut-off valve even if it does not operate in an emergency. [0003] In order to detect this kind of failure, the full closure test of the emergency shut-off valve under off-line is carried out periodically. The fully closed test must be carried out when the process equipment is stopped for regular maintenance, and the cost is high. Partial Stroke ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G05B23/02
CPCG05B19/0428G05B23/0205G05B2219/14112F16K37/0075
Inventor 大塚贤司
Owner YAMATAKE HONEYWELL CO LTD
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