Gas Control Valve

Correct choice of end connections (connection of the annular surface / convex connection / right clip-on) in the form of control valves and process piping. With the flange, such as to require valve

Supplier between the valves and flanges, gaskets, and should indicate in the Technical Annex of the contract requirements and the flange material, pressure rating and flange to take over

The tube label. Clip-on control valve itself if a single flange, flange connection hole carrier silk thread should be metric, if the thread contained Bi inch should be

Requirements of the valve the supply side with the connecting bolts.

If the control valve with solenoid valve, it is recommended that the contract in the Technical Annex part of the technical parameters of solenoid valve to indicate the manufacturer, brand, voltage level, anti

Burst form, material requirements and the control valve on and off the travel time requirements, but do not need to specify the specific model of the solenoid valve model by valve

Supplier selection type, but according to the final calculation or factory test should indicate whether to allow the supplier to control gas solenoid valve as a pilot

Valve. When the control valve actuator requirements of the air volume in order to shorten the travel time of the control valve, the solenoid valve as a pilot valve and the flow capacity

Pneumatic Following the actuators used in combination, can reduce costs, but also increased the number of attachments, because the increase of the gas path links the increase means that the point of failure

Discuss technical attachment should be to determine whether to allow the gas control program.

Recommended regardless of the diaphragm actuator or piston actuator should be equipped with air filter pressure reducer, the executing agency driven gas source of

Pressure.

Prior to shipment, the control valve is equipped with accessories should be connected in the production plant complete and tested, in line with the requirements of the contract the Technical Annex. Control valve

Supply-side valve applications, the decision connecting pipe is steel pipe, PVC jacket tube or stainless steel pipe, valve travel time requirements

Decides that the gas line connection pipe diameter. General control valve of the gas line connection pipe diameter of not less than 8 × 1mm too small will cause the response of the control valve

Too slow, of course, if the control valve switch trip time permits, can also be used for 6 × 1mm diameter gas line connecting pipe.

Control valve diameter size should be consistent with the design documents, if you must change the engineer through the process piping, equipment and related professional should be

Reported (for example, does not allow changes to the relevant professionals should discuss with the decision to change the program) to make the appropriate design changes.

 Should pay attention to the problem of corrosion of the valve. If the procurement of the control valve cavitation, flashing, cavitation, erosion and other problems, you should pay attention to whether to take

Corresponding processing means, can avoid these problems or to minimize the possibility of occurrence of these phenomena. Valve body, valve, valve cage,

Ring material should be rigid steel or alloy steel, nitriding treatment or surface coating (such as plating Sri Lanka too Levin). Should absolutely avoid control

System valve cavitation in a variety of conditions.

 Must have the installation location of the attachment of the valve Dimensions and locators in the Technical Annex of the contract confirmation requirements to determine the control valve

The installation space, attachment mounting positions of the drawings if there are conflicts between the installation location of the available space. Such a conflict exists, we should first confirm whether the

Change the installation location and orientation of the mounting positions of the control valve actuator or valve attachments. If the position of the valve can not be changed, you should notice the process

, Pipes, equipment, electrical and other relevant professionals as soon as possible to modify the layout and the trend of design.

Contracting parties should be required material analysis reports provide key components of the control valve, control valve leakage test reports, pressure test, the test report, and form a test

Report or compliance certification, the gas line connection diagram, the control valve pressure test procedures, methods and test control valve leakage test procedures, methods,

For inspection and review.

 The RFP should require bidders to provide the selection of samples of the control valve (model-specific code in the sample, abbreviations should be explained in detail) should be

With performance. Technology contracts should require the contract to provide routine maintenance manual valve body and its annex, the annex to the dealer and vendor contact to

Address, fax, and telephone number.

 Control valve attachment level of protection should not be lower than IP54/NEMA4 (the level of protection of the digital valve positioner generally IP65/NEMA4X), wiring

Inlet and outlet ports of the box should be sealed.
Control valve applications bit in the valve plate reflected, or a separate note

In a sign and attached to the valve. In addition to double out on the body to visibly mark the valve to allow the media by the direction.

; Handwheel is set according to the control valve applications, and key considerations.

Shall require the supplier to provide the basic error parameters of the valve dead zone parameter and distribution of electricity / gas valve positioner control valve control valve. General, the valve

The dead zone parameter should not exceed 2%, the basic error of the distribution / gas valve positioner control valve should be less than ± 10%, if equipped with a digital positioner

The basic error of the control valve should be less than ± 1%.

Should be noted that the control valve on the pressure of the gas source. According to the actual situation of the device, check the control valve actuator instrument air pressure. As

Instrument air pressure in the fruit unit can not meet the requirements of the implementing agencies, the valve supplier should replace the executing agency should provide high-quality

Instrument air should be at least meet the following requirements: clean, dry, and does not contain corrosive impurities, the gas containing solid particles of less than

0.1g/m3, the particle diameter of not more than 3μm, an oil content not greater than 1 x 10 (-6 power) caused by the locator According to statistics, due to the gas source is not clean can not be

Normal work conditions accounted for more than 60% of the entire locator failure rate.

; The general designer of the design units have been selected core body parts (spool, valve seats, valve stem, valve cage, ring, packing, gasket) material.

Final valve selection should be consistent with the design requirements, and if not, must confirm that the material change is appropriate, if in doubt, you must be a technical

Technical clarification.

Control valve arrival, you should promptly notify the supplier out of the box time to require the supplier to send personnel to participate in commodity inspection, if the supplier by fax or to

Letter of confirmation, and endorsed the results of the user out of the box. Inspection should record the results of all the commodity inspection, you should not miss any details, but should the provider

Review the results and contract technical annex to the control, a note of the deviation, together with inspection reports and timely feedback to the supplier, and requirements in a timely manner for processing. Feel

We can not delay the time of inspection out of the box, otherwise it may affect the claims and progress of the project. Another to note is that the bit number control valve, the valve body, the Executive

Line agencies and accessories, model, serial number and other parameters should be recorded, to make the record work order with goods accessories for later use. If you do not

Timely note of these parameters, the control valve after prolonged use, on the nameplate will be vague and difficult to recognize, there may be lost nameplate

Loss, and some parameters required for purchase of spare parts.

The latest version you can order digital locator software required, just state the name of the software and annotated to provide delivery, software version number

Can not write.

Spare parts and control valve with the order, the cost savings, the number of procurement of spare parts to meet the needs of the normal production of the principle of 1 to 2 years. If

Usage of the control valve components is not clear, may require the supplier recommended, taking into account financial factors.

Avoid bundling tender. Purchasing two or more different goods and control valves, both in a package of cheap goods and performance

Poor or extremely expensive goods, are not allowed to unpacking, it is difficult to achieve co-existence of choice.

Proposed payment and delivery schedule, product quality, services, linked to set aside a certain amount of retention money for the supplier to provide the product quality and service

Quality assessment.

If unidirectional flow through the media of the control valve, control valves must not reverse the installation, otherwise it will affect the flow capacity of the valve flow characteristics, density

Sealing performance and operation stability.

Signing of the contract, the contract in the Technical Annex, a supplier suppliers supply products can not be the normal use or failure

Should be promptly provided for debugging to deal with the problem of the existence of, or replacement, and provide temporary substitutes for any reason

Delay in processing affect the user\\ s normal production, or will be poor quality of service to pursue the responsibility of the supplier; once the problem is, the occurrence of

Costs, should identify the reason for the two sides discuss their problems.
 Port into the line of control valve accessories should be bottom-up access, should not the reverse, to prevent water damage to parts. If the cable must be a top-down access

Should be appropriate to lengthen the cables, to ensure that a U-shaped bend before entering the terminal port. So that rain water will not enter the secondary instrument. If you use threading

Tube should be left in the U-shaped bend of the lower part of the outfall. Threading pipe in the direction of the interface on the bridge should be noted that when the cable leads from the instrument cable tray

The nozzle must not be up; and respond to the nozzle to be sealed to eliminate the possibility of water. Control valve type, material, and pipe connections

Access way, the choice of attachment, the preparation of tender documents, evaluation, technical contracts signed, installation, maintenance is a complicated process, any

A part of a loophole that may affect the use of control valves. Although there are a variety of books, standards and software for designers and users

Technical personnel for reference, generally do not have too much difficulty, but from the process design of process parameters in preparation for the control valve of tender documents

Issued tenders, tender evaluation, technical clarifications, formation evaluation report, the approval of the bid evaluation reports, technical negotiations, signed a technology contract, to unpacking inspection, installation

, Debug, and put into use, generally have to go through quite a long time, during a little to the effect would be negligence or missed one or several, may work

Plant losses and affect the progress of the project. This several times purchasing some of the control valve and use in Anhui Huainan Chemical Group Co., Ltd.

And understanding of a summary, the proposed procurement of control valves should be sufficient time, as long as the technical conditions are met, to advance the preparation of tender documents

, Evaluation, technical clarifications, signed a technical contract work, really careful and meticulous work to do deep, less technical flaws. As for the progress of the business contract,

Will have to decide according to the progress of the project and funding.