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Safety Of Instrument Electrical Construction
Dec 07, 2018


Safety of instrument electrical construction




ⅰ. Preparation before electrical installation of instruments


The installation of electrical instruments is to complete the display, detection or adjustment tasks of each independent component (instrument, pipeline, cable, regulating valve and other ancillary equipment) in accordance with the design requirements to form a circuit or system.That is to say, when the electrical installation of instruments, according to the design requirements to complete a variety of connections between instruments and meters, instrumentation and process pipelines, on-site instrumentation and control room.In this way, when installing electrical instruments, it is necessary to read and analyze the installation design drawing of electrical instruments in detail first, and then make detailed preparations for the construction.Before installation and construction, each item in the instrument installation design drawing shall be analyzed, which mainly includes design description, electrical instrument summary table, electrical instrument list, instrument layout diagram and so on.After detailed analysis and reading of the above drawings, it conforms to the instrument, component model and quality to ensure the installation quality.This is helpful for post-installation testing and commissioning.It also prevents the entire system from failing to run after installation because of a problem with one component. 



ⅱ. Installation process and control of electrical instruments


In order to carry on the electrical instrument construction smoothly, must carry on the reasonable division to the construction step.This can be done by experiencing the instrumentation installation process.Electrical installation is a project with a long period, which will be started in the civil construction stage. It requires civil engineering units to carry out necessary coordination work, and specify the embedded parts, the location, quantity, elevation, coordinate and size of the reserved holes.Then follow the following steps for construction and installation:


1. Installation of instrument panel in instrument control room and on-site installation of primary point

First of all, it is necessary to make the base channel steel of the instrument panel. At present, when the instrument cabinet of the manufacturer comes out, the base channel steel frame with finished products can be installed directly.Then the instrument panel, the operation platform installation.At the same time, the number and position of reserved holes and embedded parts in civil engineering should be checked, and the position and way of pipeline entering and exiting the control room should be checked and installed. 


2. Installation of process pipelines and equipment

After installing the equipment and instruments in the instrument control room, install the process piping, equipment and non-standard parts.In this process, the installation location and quantity should be confirmed, and the construction should be carried out in strict accordance with the pre-design to prevent problems in the installation of non-standard parts. 


3. Check the effectiveness of the instrument before installation

This work is to be carried out before construction begins. The cemetery is to ensure the integrity of the instruments installed and also to check the system instruments. 


4. On-site instrument wiring and protection box installation

After the field instrument is installed, the instrument protection box and other protective facilities shall be installed in time to prevent damage of the already installed instrument in the construction of other construction units.And the instrument box fixed bracket installation.This can be done in a two-step fashion.On the one hand, wiring personnel should install wiring and wind lines of installed instruments.On the other hand, install instrument protection box, etc.This is conducive to wiring work and various pipeline installation portability. 


5. On-site cleaning

After all the field work is completed, the primary meter pipe shall be purged and pressure tested, and the on-site installation project shall be verified once.


6. Check and debug the system

Connect the field system with the control system after the field work is completed.At this time, we can carry out three inspections and four determinations of work, "check design omissions, check project quality and hidden dangers, check unfinished project quantities" for the problems checked out, "set tasks, personnel, time, measures, and a deadline to complete.At the same time, the pilot operation of the construction project is carried out.During the trial run, the system will be improved through verification and debugging. 

In this way, the installation, construction and commissioning will be basically completed.In the later use process, the system is not regularly checked to ensure the stability of the system operation.

Safety of instrument electrical construction


ⅲ.Basic principles of installation of electrical instruments


In order to ensure the installation and construction quality of electrical instruments, and the safe use in the future, the construction and design must be carried out in strict accordance with relevant regulations.The basic principles of its installation design are as follows:

1. The installation location of the instrument shall be constructed in accordance with the provisions of the design document. If the design document is not specified, it shall meet the following requirements: sufficient light, convenient operation and maintenance;The display instrument should be installed in a position where it is convenient to observe the value;Instrument should not be installed in vibration, humidity, vulnerable to mechanical damage, strong electromagnetic interference, high temperature, temperature changes and corrosive gas position;Check the bit number, model number, specification according to the design data before the installation of the instrument. Check the bit number, model number, specification, material and accessories according to the design data before the installation of the instrument.Do not knock or vibrate the instrument during installation.The instrument should be firm and straight after installation.Instrument and equipment, pipes or components of the connection and fixed parts should be uniform hand should not bear abnormal external forces.

2. Instruments directly installed on the pipeline should be installed before pressure test after pipeline purge. When it must be installed at the same time with the pipeline, the instrument should be removed before pipeline purge.The lead inlet of the junction box on the instrument should not face up, and sealing measures should be taken when unavoidable.The junction box cover and inlet shall be closed in time during construction. 

3. The instrument panel, cabinet and box should be installed in dusty, humid and corrosive gas or explosion and fire hazard environment, and the type selection and sealing measures should be taken in accordance with the requirements of the design document.The connection between the operation platform of the instrument panel cabinet and each equipment component in the operation platform of the panel cabinet shall be firm, and the fasteners used for installation shall be of anti-rust materials.Installation and fixation shall not be by welding.The installation of separate instrument panel and cabinet operation platform shall comply with the following provisions: fixed firmly, the allowable deviation of perpendicularity is 1.5mm/m, and the allowable deviation of levelness is 1mm/m.The allowable deviation of the plane on the front of the joints of adjacent two plates, cabinets and tables is 1mm;The clearance of joint between adjacent two plates, cabinets and tables shall not be greater than 2mm.Line installation should be neat and beautiful.Instrument panel, cabinet, table and box should be protected from deformation and damage of surface paint during handling and installation.Gas welding is strictly prohibited during installation and processing. 

4. Measure the installation height of the low-pressure pressure gauge or transmitter, which should be consistent with the height of the pressure point.In the installation direction of the connector, the liquid must flow from the upstream end face of the throttle to the downstream end face of the throttle.The sharp edge of the orifice plate or the curved side of the nozzle should face the flow direction of the fluid on the side.

Safety of instrument electrical construction


ⅳ. Project delivery and acceptance


After the completion of the project, the whole project shall be put into trial operation.Generally speaking, the test run is divided into three stages: single test run, linkage test run and design test run. 

The monomer test is mainly to test the monomer electrical instrument, mainly to test one indicator instrument.The detection instrument is tested by running the detection pipeline and controlling the instrument control room. 

The linkage test is carried out on the basis of the completion of the single test, which is mainly to run the whole system with water instead of materials for operation, and test whether the whole system shows and controls whether the project is running normally. 

After successful linkage test, the whole system can be proved to run.Through the formal production of electrical instrumentation testing.This test must be completed jointly by the construction unit commissioned by the production unit, in the qualified operation, through the completion of the signing of the construction documents.

Conclusion: the construction and debugging of electrical instruments should be carried out in the early stage of the workshop.It needs the production department to put forward the production conditions, the design unit design completed by the construction unit to carry out the construction.Accordingly, before project construction process, contact with design unit, assure construction accurate.In this way, strict construction can build and install a set of suitable for enterprise production, qualified electrical instrument automation system.Ensure the safe and stable production of the device.