Compressor is the heart of the refrigeration system, whether it is the important part of air conditioning, cold storage, chemical refrigeration processes, and conditions should have a compressor to do the protection.
Many types and forms of refrigeration compressors screw resolve of central air conditioning equipment compressor works can be divided into two types of volume and speed-type, according to the principle, which displacement is the most common.
Compressor is compressed gases?
Simple and that is by changing the gas volume air conditioning maintenance to complete the process of gas compression and transmission and a driving force behind any power equipment for the successful completion, the compressor is the same, it needs a motor (motor) to drive the.
Positive displacement type compressor is divided into a reciprocating piston and rotary two:
A reciprocating piston through the piston reciprocating in the cylinder to change the gas volume; piston compressor has a long history, the production technology is mature.
2, rotary compressors, including smears (slides) rotary compressors, screw compressors, currently most of the domestic production of air conditioners with rotary compressors; screw compressor is mainly used for large-scale refrigeration equipment, and now some large shopping malls office buildings, there are a lot of screw compressors.
Refrigeration system to several devices:
Compressor – condenser – throttling device – evaporator
Its fundamental principle is, the compressor refrigerant is compressed into a high-pressure saturated gas (ammonia or Freon), this gaseous refrigerant through the condenser condensate.
Through the throttle after throttling device, which leads to the evaporator, the cooling medium for cooling heat exchanger. For example, the evaporator is connected to the various rooms of the building, snake tube evaporator heat exchanger with air by the blast, the air conditioning blowing in the air of the room.
Refrigerant heat exchanger tube evaporator hunting into a low pressure steam back to the compressor to be compressed by the compressor, so recycling is complete refrigeration system.
The heating system is also broadly this principle, just the opposite way.
Screw central air-conditioning maintenance, with the average central air conditioning is not much difference, but the use of the pump, screw pump is relying on one or several root screw mesh with each other to form a volume of space changing transmission fluid. Can be divided according to the number of mutual engagement of the screw, single screw, twin-screw pump, three screw pump. The position of the screw can be divided into vertical or horizontal. Outdoor meshing twin-screw pump screw pump, pump body, the active lever, the composition of the follower rod, gears and bearings. The active lever and the follower rod of a left hand thread, a right hand thread.

Water system in the central air conditioning works, including chilled water systems and cooling water system
Central air-conditioning engineering water system principles: 1) with enough cold (hot) load switching capability to meet the load requirements of the air conditioning system on the cold (hot). 2) has a good stability of the hydraulic conditions. 3) water control and flexible. 4) investment, low energy consumption, running economy, and ease of operation and maintenance management.
Central air-conditioning cooling water circulation system components: pumps, fill water tanks, cooling towers, valves and set of cylinders, filters and other equipment, which is an open system.
One, the installation of the cooling water circulation system
(A) pump
Commonly used pumps are single-stage single-suction clean water centrifugal pump and pipeline pump two.
IS single-stage single-suction Centrifugal water shape the structure and model identification.
IS single stage clear water centrifugal pump, pump, pump cover, impeller, shaft, bushings, seal rings, suspension body and rolling bearings and other components.
(2) the installation of pumps
Most of the pumps are installed on a concrete foundation, a small pipeline pump directly installed in the pipe, without foundation, the method of its installation and the mounting flange valve, as long as the two pump flange and pipe flange connected can.
Pump unit (1) Pre-installation checklist
1) the equipment out of the box should be the following items to check: and make records. The ① box number and box number, and packing of the ② device name, model and specifications ③ equipment whether the lack of damage to the corrosion out of the nozzle protector and cover should be intact.
2) in place before the following review: ① the basis of size, flat location and elevation should be consistent with design requirements and quality requirements ② equipment there should be no missing parts, damage and corrosion, water pump out of the nozzle protector and cover such loss of protective effect, the pump should be the disintegration of the check ③ Turning should be flexible, non-blocking, stuck phenomenon, no abnormal sound.
(2) Installation
1) pump lifting and alignment
2) pump leveling place. Pump level of allowable deviation is generally 0.3 ~ 0.5mm / m.
3) pump vibration isolation
(3) the pump piping layout
1) Installation soft to take over. Connecting a pump suction pipe and pressure pipe, install the software takes over, and help to reduce and weaken the transmission of vibration and noise of the pump.
2) Export loaded check valve. The purpose is to prevent the counterflow of water when the pump suddenly loses power, leaving the water pump impeller is blocked.
3) The pump suction pipe and pressure pipe should be set the inlet valve and outlet valve, the purpose is to facilitate the overhaul without emptying the system kept the water pump does not run.
4) downstream of the check valve installed in the riser should have put the pipes to facilitate pipe cleaning and sewage.
5) of the outlet pipe of the pump should be fitted with pressure gauge and thermometer, in order to facilitate detection. If the pump from the low tank water absorption, water pipe should be equipped with a vacuum gauge.
6) Each pump should be set separately to the suction pipe, the water velocity in the pipe is generally 1.0 ~ 1.2m / s. The outlet flow is generally 1.5 ~ 2.0m / s.
7) When the pump motor capacity greater than 20kw or pump inlet diameter greater than 100mm, the pump unit\\ s layout should be consistent with the outdoor water supply design specifications.
pump based on the height of not less than 0.1m above the ground, the ground should be located drains.
(B) fill pipes
1 fill the water tank constructed
1) The tank shape can be divided into round, square, rectangular.
2) water tank materials can be divided into metal tanks, reinforced concrete water tank, plastic water tank, wave glass tank.
3) water tank accessories. Into the water pipes, outlet and overflow pipes, breather, level gauge, manhole.
(2) fill the water tank installation
Fill the water tank commonly used metal tank. The metal water tank installation shall comply with the design and product specification requirements. The metal water tank installation of reinforced concrete support. Bottom of the tank from the ground should have not less than 700mm of headroom.
(3) water tank full of water test
Tank full water test after assembly. Close the outlet pipe and vent pipes, open pipes, side turn on the water side check until filled, with 2 ~ 3h, impermeable qualified.
(C) cooling tower
Types of cooling towers in use in central air-conditioning engineering, natural ventilation, the spray cooling tower and mechanical draft cooling tower the two categories. Natural ventilated by natural ventilation state, and thus cooling efficiency and cooling effect, and the volume and area of ​​large, therefore, the current application of more mechanical ventilation cooling towers.
A common cooling tower countercurrent cited wind FRP cooling tower and counterflow forced draft cooling tower, cross flow FRP cooling tower three kinds of
Cooling water equipment layout principles
1) cooling tower should be installed in a well ventilated place, the air inlet with the surrounding buildings should maintain a certain distance, to ensure that the new air into the cooling tower.
2) cooling towers should be avoided in the hot air generated locations, should also avoid the dust outlet. Can not be arranged the coals, chemical dumps.
3) Cooling Tabb to set the orientation and the dominant wind direction in summer.
4) The layout of the open cooling tower, the combination of the long side should be less than 30mm.
(3) cooling water equipment installation
The cooling tower high installation and low installed in two forms.
The high-mounted cooling tower is installed on the roofs of buildings in the refrigeration station, cooling tower high-mounted air conditioning and refrigeration systems for cold storage or high housing civil, which can reduce floor space.
Cooling towers low installation, is installed on the refrigeration station nearby on the ground. The disadvantage is that a larger area, commonly used in concrete or mixed structure of large industrial cooling towers.
(1) the overall installation to install the cooling tower.
(2) Installation of water spray device
(3) install a water distribution device
(4) Installation of water distribution device
(5) Install the water collection device
(6) The installation of ventilation equipment
(D) set of cylinders
The purpose of the set of cylinders is promptly eliminated from the air inside the system, in order to ensure the normal operation of the water system in the water system.
(1) set of cylinders and the structure of vertical and horizontal cylinders of the first vertical set under normal circumstances.
(2) set of cylinders installed set of tank should be installed in the system of local commanding heights. Set of cylinders posturing position in the system must be less than the fill water tank, in order to ensure that the emission of air.
(E) filter
Filters can only be installed in a horizontal pipe, the flow direction of the media must be consistent with the shell on the file specified in the direction of the arrow. Filter from the distance measuring instrument or the implementing agency is generally the nominal diameter of 6 to 10 times, and regular cleaning.
(6) Valve
Valve is a device of the fluid flow control pipeline. In the cooling water circulation system, the commonly used valve gate valve `butterfly valve` cut-off valve and check valve. The smaller diameter pipe in the system is often used cut-off valve, large diameter pipes with gate valves and butterfly valves. Check valve for pump outlet to prevent the backflow of the cooling water. Coiled tubing sanctimonious larger bending stresses in the pipe rack, is not conducive to the tightness of the piping and valve connections, and thus can not be installed in the pipe rack.
(G) pipeline installation
The pipes of the cooling water system installation, according to the requirements of the construction plans at the specified location, pipes and pipe fittings, pumps, condensers, cooling towers, fill the tank, the set of cylinders equation logic devices together, and the formation of the circulatory system .
(1) Construction Survey
(2) pipe rack installation
3 pipe laying
Pressure test and pipe cleaning
Second, the installation of hot and cold water circulation system
Central air conditioning, cold (hot) water cycle is often a closed system, this system has a the ① pipeline system isolated from the atmosphere, piping and equipment corrosion opportunity; ② The pump energy consumption; ③ the highest setting expansion tank timely advantage of overtime pay; ④ The system facilities is simple.
An expansion tank due to the central air-conditioning water system rarely used back to the pool open circulatory system, and thus the expansion tank has become one of the main components in the central air conditioning system, water system, its role is the amount of water in the resettlement and compensation system, expansion tank generally set at the highest point in the system, usually connected to the circulating pump suction near the mouth of the return water pipe.
2 points of plumbing and water catchment in the central air conditioning and color warm system, in order conducive to the flow distribution of air-conditioned partition and adjust the flexible convenience, often dry in the cold water system supply and return water pipe set on the water separator ( water supply) and catchment (backwater), and then were connected to water supply and return pipes of the air conditioning partition.
(3) fan coil unit and its installation
The fan coil, also known as fan coil air conditioner, it mainly consists of the fan and heat exchanger plate tubes, as well as condensing water disk, controller, filter, air inlet, return air, insulation materials and box etc..
The fan coil air conditioner including the two parts of the waterway and pneumatic. Waterway by the central cooling (heat) source, the supply of cold (hot) medium water transported to the circulation flow in the coil to the plate pipe, the pump under. The gas line is the outlet inhalation of indoor air by the fan through the return air products, and then cross-passing the coil, and the media of the cold (hot) water heat exchanger coil, cooling in addition to temperature (heating), and then from the outlet into the interior . And so forth, so that the indoor temperature and humidity to control.
(1) to understand the model and the basic parameters of the fan coil
(2) fan coil air conditioner installation principles
1) surface mounted vertical unit is installed, power side slightly higher than through the water side, in order to facilitate the discharge of condensate.
2) when the unit is installed, the unit\\ s condensation pipe to maintain a certain slope (5 degrees), in order to facilitate the discharge of condensate.
3) units access to water should be added to the insulating housing to avoid condensation of water in the summer use.
4) unit condensation water tray drain hose is not crushed, bent, to ensure that the condensation of water discharge flow.
5) during installation, you should protect the heat exchanger fins and elbow, not collapsed or touch leakage.
6) The horizontal unit is installed, should be a reasonable choice of a good boom and expansion bolts.
7) When the horizontal the Ming installation group to install the inlet and outlet pipe, on the ground first out of the water pipes connected to the machine, and then in lifting the pipe connection; in lifting the panel and condensate tray to take , and then connect the water pipe insulation to prevent condensation of water.
When the vertical the Ming installation group to install the inlet and outlet pipe, the outlet panel of the unit removed for installation; and water pipe insulation to prevent is the condensate.
9) unit equipped with a manual release valve return pipe, and run before the release valve to open, to be coil and pipe drain the air and then close the release valve.
10) in the shell of the unit to prepare the ground bolts for installation connected with the protective grounding system.
11) unit power supply rated voltage (220 ± 220×10%) V, 50Hz, connections to connect the electrical connection circuit diagram provided by the manufacturer, required to connect the wire colors and wiring signs.
12) produced by various manufacturers wind plate tube into the outlet of the air conditioner size vary, so make the return air grille and outlet should be careful not to go wrong.
Winter change-over switch on the control panel 13) with a temperature controller unit shall be provided with summer use when placed in the summer and winter when placed in winter.
14) the installation shall not damage the unit of thermal insulation material, shedding should be re-cement should be connected closely with the air supply pipe and outlet connections.
4 pipe connection
Larger diameter trunk water pipes in the cold water system, the user water supply branch pipe of smaller diameter. The connection between the large diameter pipe, tube and pipe is often used welding, the connection between the small-diameter pipe, tube and pipe, often using the screw connection

Correct installation and proper selection of the control valve is equally important. Quality of the installation related to the operating performance of the control system, control quality, safety and cost

, So attention should be paid.

Control valve installed at the scene, fire, explosion, leak-proof, higher demands, control valve noise pollution are also increasingly subject to the relevant departments attach importance to

.

The control valve installation and construction requirements:

The general provisions of the installation and construction

1,. Control valve shall be installed in accordance with design drawings and design documents.

2, the control valve installation should follow the provisions of the relevant national standards, for example, the construction and installation engineering quality inspection and assessment, industrial automation, instrumentation facilities

Work and acceptance of electrical equipment for construction and acceptance.

3, the control valve to install the necessary equipment, auxiliary equipment and materials shall comply with the relevant provisions of the existing national or ministerial standards.

The control valve installation precautions should ease, security and standardization consideration. Details are as follows.

(A), control valve installation position and orientation:

1, in accordance with the provisions of the design drawings and design documents, the installation location should have enough room for maneuver for the installation, operation and maintenance; its location

Should be avoided to install in place of vibration, humidity, and vulnerable to mechanical damage, there is strong electromagnetic interference, high temperature, severe temperature changes and corrosive gases

; Installation should be firm, smooth; mounting positions so that the control valve actuator in the upper part of the meter/">regulatory agencies, and Figure 6-8 shows the straight stroke control valve

Kinds of installation orientation. Among them, the location is the preferred location, the location of the second choice.

Two fluid flow control valves, control valves, fluid flow arrows should be marked on the control valve body. Special circumstances are not subject to this regulation

Given the restrictions.

3, the control valve to connect the control valve connection threaded connections, flange connections and welded connections. Threaded connection for small-bore control valves, install the screw

Lines to connect the control valve, you must also install the removable active connections. Flange connection flange and clamp connecting the two, the connection method

Lan the nominal diameter should be in line to take over the diameter of the control valve. Flange also have different pressure levels, with the control valve of the pressure rating of flange pressure rating

Consistent. The flange diameter should be equal to the pipe diameter. Flange and the pipe axis vertical tolerances l The °. Flange sealing surface should be flush. Law

Lan and the concentricity of the pipe to allow the deviation of t

Met:

t ≤ 0.015D (1 / β) (6-27)

Where D is the pipe diameter; eve of cutting pieces of the inner diameter of the pipe diameter ratio of working conditions. Flange connection should be force

Even appropriate, to avoid local subjected to excessive pressure. Avoid the use of welded connections, welded connections must be installed on removable active connections

Pieces. Control valve connection should not make the connection inside the pipes lead into a new projection. For example, gasket, welded joints should not be protruding in the pipeline

.

4, the control valve and on the upstream and downstream shut-off valve, the connection of the bypass valve control valve downstream of the shut-off valve and bypass valve and control valve installed at the same time. On

Downstream cut off the length of the pipe between the valve and control valve should be considered the resistance of pipeline and the fluid flow state. Straight pipe length, flow

The stability of the body by the cut off valve allows fluid flow is smooth to reduce turbulence effects, reduce noise; short length of straight pipe, the fluid by the cut off after the valve also

Not stable to enter the control valve, so that the noise enhancement, but the short length of pipe is conducive to reduce the pipeline resistance, improve the control valve pressure drop across, so that traffic special

Of distortion decreases, and is conducive to the stable operation of the control system. Should therefore be weighed and taken into account. Typically, the upstream side should be 10D to 20D straight

Pipe, downstream side of the straight pipe in 3D ~ 7D. D is the nominal pipe diameter, where necessary, set the rectifier unit.

(B), the choice of connectivity solutions.

A control valve on the downstream shut-off valve to connect a variety of ways, several common connectivity solutions. The figure, the structure of the program A compact layout, accounting for

Land area is small, easy to maintain and operate, easy to vent or drain system. But often can not meet a sufficient length of straight pipe, causing the noise increase

Strong. The structure covers an area of ??Option B is larger, the location of the control valve can be installed in the lower or upper, easy to adapt to the operational requirements, but the length of straight pipe is not

Easy to guarantee. Option C structure for angular control valve, can reduce the number of elbows, and a smaller footprint. The end of the flow into the side, more

Long upstream straight pipe length. Option B Option D is similar to a larger area. The structure of the program E applies to the angular valve with Scenario C

Than the length of straight pipe upstream side of the shorter, is not conducive to the stability of the fluid. The structure of the program F is the most common connection structure. It covers an area of ??large,

Piping less resistance, but less space to operate and maintain.

(2) relief valve, vent valve, drain valve connection for easy control valve pressure of the bleed valve before and after demolition, should be carried out prior to demolition, relief valve

Should be installed in the control valve on the downstream shut-off valve.

3, the vent valve, drain valve for the discharge fluid entrained non-condensable gases and condensate. Installation, was charged with fluid, gas or steam, in order to

To facilitate the emission of condensate drain valve should be installed in the lowest point of the control valve. Charged fluid is a liquid, for ease of non-condensable gas venting, venting

The valve should be installed in the highest point of the control valve.

4,. Bypass valve. Control valve maintenance of the demolition, the available bypass valve to operate the production process. When charged with the amount of traffic. The control valve can not be positive

Regular adjustment can also be used as an emergency measure, the bypass valve as a control valve connected in parallel program, the process control. To reduce costs, large

Caliber control valve handwheel implementing agencies, can replace the bypass valve to operate. The installation of the bypass valve should be easy to operate, and control valve, downstream

The shut-off valve with the composition of the control valve, the installation should be supporting them, and at the same time to complete construction and installation. The bypass valve nominal diameter pipeline public

The same nominal diameter, pressure rating, consistent with the process pressure rating.

5, the installation of the implementing agencies are usually the executing agency and the control valve body directly connected, but hydraulic actuator of the implementing agencies, long-stroke actuator

Structure and control valve body separate install the implementing agencies should note that the executive body of the connecting rod and the mechanical moving parts should be flexible, loose or card twist

And so on. The connecting rod length should be stable, flexible and reliable action in the full travel range. When the process piping and thermal displacement control valve body is connected,

Should ensure that the relative position between the executing agency and the control valve body remains unchanged. The executive body of the hand wheel side mount and top-mounted, the installation should be left operating

For space. Handwheel operation should be flexible, not stuck or reverse the phenomenon. Label should be hand wheel rotation direction and the valve opening relations. Limit device should be adjusted

Integration of appropriate protective effects. Hydraulic actuators should be lower than the controller is installed, must be higher than the controller, the height difference should not exceed 1.0m

And should be installed in the pipeline gathers gas exhaust valve, close to the controller to install a check valve or automatic shut-off valve.

6, valve positioner, install the valve positioner valve position detection device and the control valve stem or valve shaft directly connected, therefore, should be installed to ensure that anti-

Feed-forward signal to correctly reflect the valve position signal and changes. Typically, the valve positioner and control valve supporting supply, completed by the manufacturer of both

Connection. When the production process control need to add the valve positioner, should ensure that the valve positioner valve position detection device action is correct, reliable and flexible

. The mechanical clearance of the feedback lever fulcrum should be as small as possible. Valve locator signal line should be properly connected to the gas supply lines and output lines, enter the pipeline

Should be marked on the nameplate. The valve positioner valve position signal should be conducive to the operation and maintenance personnel observations.

7, the installation of other accessories other accessories, including valve position sensors, solenoid valves, limit switches, relay, electrical converters, etc., the installation shall comply with

The product specifications with the relevant provisions. The flow control valve should be installed upstream of the filter. Severe turbulence, should be installed at the upstream side rectifier unit.

8, the installation of the connecting pipeline installation and connection pipelines should note the following.

1), signal the trachea and air supply lines generally use brass cable PVC sheathed the diameter sL6Xl or g18Xl

2), gas supply lines should be close to the control valve.

3), signal pipelines and hydraulic lines should be as short as possible, used to shorten the signal time delay and system time constant.

I 4), the pipeline should be enough stretching, and should not impede the implementation of agency action.

5), pipeline welding should not be welding slag falling tube. Connecting lines should be cleaned before installation, to remove oil, water and rust and dirt. Even

Take over the line piping should be neat and beautiful.

6), The hydraulic oil pipelines should be kept away from high-temperature equipment and piping, with the hot surface of the distance should be greater than 150mm.

7), prior to installation to cope with the drain valve connected to the pipeline, the vent valve for cleaning, remove the oil, and inspection and testing.

8), hydraulic and pneumatic piping system should be pressure test, and compliance.

9), Connect the signal wires, cables should wear pipe laying, metal hose connection on the device side. Required explosion-proof equipment should take appropriate explosion-proof measures

Measures should be taken to seal all protected system.

10), the laying of the pipeline should not impede the operation of the operator and maintenance personnel to maintain.

11), connected to the pipeline shall be marked with nameplate. Available when necessary, support frame fixed connection pipeline, to prevent the connecting lines can not be fixed after the control valve disassembly

.

12), the cable should be avoided soaked in water and liquid and the corrosion or the intrusion of harmful gases.

9, additional fittings to install additional tube of reduced diameter pipe and expanding tube. The installation of additional pipe to pipe pressure loss increases, and affect the control valve flow coefficient

Number. Install additional pipe connections to leave the room for maneuver, easy maintenance, remove the connecting bolts. When installing the pipe installation support frame or

Bearing, if necessary, to add anti-vibration pads, anti-vibration spring.

10, control valve and other accessories off the month of purpose, insulation and heating in need of the degreasing treatment, control valves and other accessories must be carried off by design requirements

Grease treatment. Drying the degreasing control valves, piping and other required natural ventilation with dry air or nitrogen, save closed after inspection

The installation should be kept clean without oil. Need for insulation and with heat-treated control valves and other accessories for insulation and with heat treatment. Heating use

Steam pipeline or heating cable laying should be consistent with the provisions of the installation and construction. Insulation material and thickness of thermal insulation should meet the design requirements. Installation

Control valves and accessories for a variety of supporting frames, bearings, and connecting lines need to paint handling. Should be removed before painting was painted surface rust \\\\ welding slag, burrs and

Dirt. The color and thickness of paint, the painting operation conditions should be consistent with the relevant provisions.

11, self-control valve to take the source components installed self-operated pressure, differential pressure control valve pressure components with reference to the installation requirements of the pressure to take the source components carried Shi

Workers. Self-operated temperature control valve to take the source components can refer to the temperature of the package installation provisions of the construction.

Control valve installed in the production process should be carried out before driving the on-site commissioning of the control valve. Site commissioning sub-circuit debugging and system debugging.

(A), line debugging

Line debugging used to check the signal lines connecting the control valve, the gas supply lines or hydraulic lines connected correctly.

A control valve connection of the input signal. Typically, together with the valve positioner checks. Control valve input signal from the controller, therefore, from the controller

The output signal of a starting point, check the control valve is in the starting position; outputs an end signal, check the control valve is in the end position. To this end

, Should check the supply air source pressure is normal; filter pressure reducer is working properly; the oil pressure of the hydraulic system supply is normal; power supply whether it is

Often; the output signal is correct, etc., and the measurement range of at least take to meet the required relationship between the 5:00 check the input signal and valve position. Shall be submitted

Check the open air, gas-related mode of action is correct, whether or not to meet the safety requirements of the process of the production process.

(2) control valve connection of the output signal. The control valve output signal is the valve position signal may be analog signals or digital signals. Should check the control

The valve input signal at the same time, check the valve position signal is correct. HART or intelligent electric valve locator, you should check the valve position status information

Whether the correct transmission. Control valve stroke during operation should be listening on the control valve spool and the valve seat, mechanical vibration and abnormal noise.

(3) the handwheel organizations debugging. Hand wheel mechanism to check whether the correct rotation and actions, limiting and locking device is easy to use.

(4) When the deviation exceeds the allowable deviation limit corresponding debugging. For example, to change the position of the valve position switch, check wiring or pipe is

There is leakage.

(B), the system debugging

The control valve is the final component of the control system, therefore, before the control valve operation for system debugging. System debugging with the work

Arts and operation together.

A negative feedback debugging. The control system should meet the negative feedback, therefore, should the controller to detect the transmission and control valves (including the valve positioner)

Considered together and controlled objects, and set the controller\\ s positive reaction. Criteria of negative feedback control system open-loop gain is positive. Set up control

Positive reaction after the manner of, can be measured in the controller-ended analog input signal to increase or decrease the observation controller output changes in line with

The requirements of the mode of action, and check the control valve action direction is correct, whether we can make the controlled variable to reduce the direction of change.

(2) the control valve pressure drop checks. Control valve pressure drop checks during the water simulation debugging. In the control valve stroke during operation, check the control

Across the valve pressure drop, whether free or flash caused by the noise occurred, how the flow changes, compliance with the design of the flow characteristics

.

Response time check. Some control system control valve response time requirements, should check the control valve response time. The controller output

Start timing signal is changed to 63 percent the time required to reach the final steady-state position control valve position is the response time, its time to meet work

Art production process operating requirements.

Agent: not otherwise commissioned
    Owners: Qinghai Yuntianhua, International Fertilizer Co., Ltd.
    In their respective districts: Qinghai
     Qinghai sky International Fertilizer Co., Ltd. phosphate and compound fertilizer project, Qinghai Province Development and Reform Commission approved the construction of (symbol: Green Development and Reform work

Industry prepared [2008] 49). It is decided that the project the necessary import control valve through open tender to the selected contractor.
    1, the tender project is summarized as follows:
    1.1 The import control valve tenders schedules:
    The tenders valve type devices into the name of the number of (Taiwan) Remarks
    A butterfly valve synthetic ammonia Europe and the United States imported products
    
    B overloaded ball valves, eccentric rotary valve synthetic ammonia 4 Europe and the United States on imported products
    
    C high temperature, high pressure and large diameter valves ammonia 12 Europe and the United States on imported products
    
    D low-noise cage valves, single-seat valve of synthetic ammonia 17 Europe and the United States on imported products
    
    E urea angle valve, butterfly valve urea of ??urea 7 Europe and the United States on imported products
    
    F cut off valve synthetic ammonia 20 Europe and the United States on imported products
    Total 67
    1.2 Project Construction Location: Xining, Qinghai (national) economic and technological development zones Gan River Industrial Park;
    1.3 Equipment in line with national quality requirements and industry standards.
    2, where the agents have to bear the tender for the project equipment to provide the ability to pre-qualification available for the above tender equipment to the tenderer

Interlocutory applications, only the pre-qualified bidding applicants in order to participate in the bidding.
    
    4, pre-qualification application form should be clearly marked \"the Qinghai Yuntianhua International Fertilizer Co., Ltd. two imports of phosphate and compound fertilizer project control valve tender

Purchasing \"words.
    5, applied to the pre-qualification requirements:
    5.1 products have the required proxy authorization certificate;
    5.2 has independently signed a contract authorized;
    5.3 has a good corporate credit and business reputation, current financial condition;
    6, pre-qualification information submitted in the pre-qualification:
    6.1 effective legal power of attorney;
    6.2 is authorized copies of identity cards;
    6.3 agent authorization certificate; (with the original for future reference)
    6.4 enterprise copy of business license, and nearly a year must pass the annual review of the higher administrative department; (with the original reference)
    6.5 by the photocopy of the audited financial statements;

By fluorine close valve Co., Ltd. developed the efficient and intelligent fluorine control valves manufactured by Fujian production base in Zhejiang, and recently by the Fujian Province

Identification of new product technology. Experts believe that the technical indicators have reached the leading domestic level, to fill the gaps in the field, and received the National Invention

Patents.
   
    The new product first solve the problem of the formation of the lining of the complex geometry of the structure, to solve the resistance to strong oxidants and strong acid and alkali corrosion

And the problem of high temperature, while addressing the vacuum resistance, resistance to negative pressure and fluorine plastic and metal parts into one of the difficult problems, in addition to solve the overall powder

Molding and pieces of metal stuck together at the end process problems. The product exceeded the limitations of the existing lining pipe in the use of, and widened the similar products

Use the scope and use of media types.

SAMSON is a brand of Germany, is Europe\\ s largest control valve brand has a strong influence in Europe, like many other European companies.

Is a family business, development cautious, conservative, but the emphasis on product quality. Since entering the Chinese market since 1996, the relatively rapid development in Beijing,

Shanghai and Chengdu offices, a strong competitive advantage in the chemical industry and light industry.

FISHER is the world\\ s largest control valve brand, accounting for about 25 percent of the global market, the main application industries such as petrochemical, power, metallurgy, light industry.

As the world\\ s largest control valve brand FISHER hundred years of glorious history. 1888, to create it as a starting point to produce the regulator pump regulator

Process control career. Since the sixties of last century, the FISHER in the plant control system to establish its international leadership position in 1992

Emerson acquired. FISHER since 1984, began its valve business in China, and plant in Tianjin in 1992 with its first

Advanced technology, has become a leading supplier of Chinese control valve.

KOSO is a Japanese brand valves have a stronger influence in Asia, but in other parts of the world, a weak effect. Its wide range of products can be widely

Used in various industries. In metallurgy, petroleum, chemical industry and FISHER competition is fierce.

MASONEILAN American brand, is the world\\ s second largest control valve brand, second only to the FISHER. The early 1990s was the DRESSER Group after the acquisition,

Institutional restructuring and other reasons, the development is not satisfactory. Market share decline. 12% market share in 1997, and in recent years

The market share of around 7%.

As a leading provider of Process Automation Instrumentation, Shenzhen 10000 News Controls Co., Ltd. Shi Fu Yue the Mysore Nick control valve of this year

The sales situation is very optimistic. First eight months of sales growth over the same period last year more than 300%, and the number of users has improved significantly, and its products

The performance of a high degree of recognition from the national key industries conglomerates in the metallurgical, chemical, petrochemical, nonferrous metals, building materials, electricity, to extend the Group, Po

Steel, Wuhan Iron and Steel, Yanshan Petrochemical, Fujian Refinery and other domestic key enterprises have selected Shi Fu Yue Mysore Nick control valves used in key projects.
   
    It is understood that, \"Shi Fu Yue, Mysore Nick,\" 10000 News Controls Company of a new brand, its main product control valve for the introduction of foreign technology, hardware

Sealed valves, butterfly valves, and a special control valve production base in Germany, Italy, Wuxi, and European advanced control valve technology

, The introduction of the world\\ s most advanced production equipment, and build the automated production line. The product is a mature design concepts, advanced production management, strict

Grid in accordance with today\\ s world the main criteria for manufacturing and inspection of control valve manufacturing excellence, quality and performance, with a large flow capacity, pressure loss is small, dense

Sealed, low noise, adjust the excellent performance, adjustable, reliable operation and long life, compact structure and other characteristics, by the petroleum, chemical, power line

Favor of industry, and after a long time a variety of performance tests in these industries and enterprises, by virtue of its high product quality, performance, cost-effective to

International standards, is fully capable to meet the needs of China\\ s national conditions, suitable for industrial process automation and control.

 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 requirements of the valve

The door supplier provided between the valves and flanges, gaskets, should be marked in the Technical Annex of the contract requirements and the flange material, pressure rating and flange connected

Tubes 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

Require valve 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, proof 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, the specific models

By the valve supplier in accordance with the final calculation or factory test selection type, but should indicate whether to allow the supplier in the solenoid valve control gas

As a pilot valve. When implementing agencies require air volume control valve, in order to shorten the travel time of the control valve, solenoid valve as a pilot valve and flow

Capacity pneumatic following actuator combination, can reduce costs, but also increased the number of attachments, because of the increase of gas road link means failure

Point increase, so the discussion of technical attachment should be to determine whether to allow the gas control program.
 
        Suggest that either the diaphragm actuator or piston actuator should be equipped with air filter pressure reducer, the executing agency to Driven

The pressure of the angry source.

       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 the supply side should be based on the applications of the valve, determine the connecting pipe is steel pipe, PVC jacket tube or stainless steel tube, according to the valve travel

Time calling for a decision on 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 control

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

        Diameter size of the control valve should be consistent with the design documents, if you need to change, should the process piping, equipment and related professional

Engineers, communications (such as not allowed to change 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 control valves there are cavitation, flashing, cavitation, erosion and other problems, you should note that

Whether it has taken the appropriate means of disposing of and ability to avoid these problems or to minimize the possibility of occurrence of these phenomena. Housing, spool

The valve cage ring material should be rigid steel or alloy steel, nitriding treatment or surface coating (such as plating Sri Lanka too Levin). Should be absolutely

Avoid control 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

Control valve installation space, if there are conflicts on the installation location of the free space between the attachment mounting positions and drawings. If there is a conflict, should first ensure

Recognized ability to 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, should pass

Report process, piping, equipment, electrical and other related professionals as soon as possible to modify the corresponding layout to the design.

       Contracting parties should be required to provide material analysis of the key components of the control valve, control valve leakage test reports, pressure test, test reports,

The formation of the 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, review.

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

), The application performance. Technology contract, the contract parties should be required to provide routine maintenance manual valve body and its annex, Annex agents and sellers

Address, fax number, telephone number.

       Protection level should not be less than the control valve attachment IP54/NEMA4 (level of protection of the digital valve positioner is generally IP65/NEMA4X)

Inlet and outlet ports of the junction box should be sealed. Control valve applications bit in the valve plate reflected or shown separately in

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