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Research and analysis of the flow control valve

In modern automatic control, the control valve plays a very important role. The proper distribution and control of flowing liquid, gas, or solid powder requires a control valve to complete. The low-pressure pneumatic conveying device uses a blower as a power source, and the fan is at the front end of the feeding device, and the powder in the silo continuously goes high through the feeding device. In modern automatic control, the control valve plays a very important role. The proper distribution and control of flowing liquid, gas or solid powder requires a control valve to complete. The low-pressure pneumatic conveying device uses a blower as a power source, and the fan is at the front end of the feeding device, and the powder in the silo is continuously and uniformly fed to the high-speed airflow through the feeding device, so that the powder is transported in a suspended state. In the ...

8 ways to solve the vibration problem of the control valve

1. INCREASE THE STIFFNESS METHOD For oscillation and slight vibration, the stiffness can be increased to eliminate or weaken. For example, it is feasible to use a spring with a large stiffness and a piston actuator. 2.  INCREASE THE DAMPING METHOD Increasing the damping increases friction against vibration. For example, the valve plug of the sleeve valve can be sealed with an "O" ring, and a graphite filler with a large frictional force is used, which has a certain effect on eliminating or attenuating a slight vibration. 3. INCREASE THE GUIDE SIZE, REDUCE THE FIT GAP METHOD Shaft plug valves generally have small guide sizes, and all valve fit clearances are generally large, 0.4 to 1 mm, which is helpful for generating mechanical vibration. Therefore, when a slight mechanical vibration occurs, the vibration can be weakened by increasing the guide size and reducing the fit clearance. 4. CHANGE THE SHAPE ...

4 Major Elements to Selecting a Suitable Regulator Valve Actuator Type and Specification

DRIVING ENERGY The most commonly used driving energy source is the power source or fluid source. If the power source is selected as the driving energy source, the three-phase power source is generally selected for the large-size valve, and the single-phase power source is selected for the small-sized valve. General electric actuators are available in a variety of power types. Sometimes DC power can be selected. At this time, the battery can be safely operated by installing a battery. There are many types of fluid sources, which can be different media such as compressed air, nitrogen, natural gas, hydraulic fluid, etc. Secondly, they can have various pressures, and the third actuator has various sizes to provide output torque. CONTROL VALVE TYPE When selecting the actuator for the control valve, it is necessary to know the type of control valve so that the correct actuator type can be selected. Some valves require a ...

The reason for and treatment of the pneumatic control valve is not tight

Pneumatic control valves often present some troublesome problems during use. For example, if the pneumatic control valve is not tight and the door is not tight, what should I do? Under normal circumstances, if it is not critical, first check to see if the valve is closed. If it is closed, it is still leaky and can not be sealed. Then look at the sealing surface condition, some valve sealing pair It is detachable, so take it out for grinding and experiment again. Of course, if it is still not tight, then it is necessary to return to the factory for repair or replace the valve, so as not to affect the normal use of the valve and the occurrence of working conditions and other problems. If the valve is not tight, you should first find out where the problem is, and then deal with it according to the corresponding method. There are ...

How to correctly choose the positive and negative ways of the pneumatic control valve

The working model of the pneumatic control valve is air opening and gas closing. The opening of the air opening valve increases with the increase of the signal pressure. When there is no pressure signal, the valve is in the fully open state, and the gas closing is the opposite. Reasonable selection of the mode of action of the control valve is essential to ensure production safety, improve product quality and reduce economic losses. It is also possible to achieve the function of fault retention by correct selection of the air opening and air closing modes. ADJUSTING VALVE AIR OPENING AND AIR CLOSING SELECTION The choice of the mode of operation of the control valve should be determined according to the requirements of the production process. Consider the position where the control valve is opened or closed when the signal pressure is interrupted (such as the failure of the control valve, the interruption of ...

Common faults of gate valves and their solutions

1. Leakage at the gate of the gate valve The packing gland is too loose to evenly tighten the nut for the compression packing gland.If the number of packing rings is not enough, the packing should be added.Fillers should be replaced with new fillers due to excessive use or improper storage. When replacing, be careful that the joints between the rings should be staggered 1200. 2. BETWEEN THE GATE VALVE AND THE SEAT SEALING SURFACE There is dirt between the sealing surfaces, which can be washed away.If the sealing surface is damaged, it should be re-ground. If necessary, it can be re-welded and processed. The grinding sealing surface must be flat and its roughness should not be less than 0.4. 3. THE LEAKAGE NUT OF THE GATE VALVE BODY AND THE BONNET JOINT IS NOT TIGHTLY TIGHTENED OR THE TENSION IS UNEVEN, AND CAN BE RE-ADJUSTED. Damage to the flange seal ...

Forged steel gate valve use characteristics and installation

FORGED STEEL GATE VALVE FEATURES The forged steel gate valve has low flow resistance. The inner medium passage of the valve body is straight through, the medium flows in a straight line, and the flow resistance is small.It is more labor-saving when opening and closing. Compared with the shut-off valve, the direction of movement of the shutter is perpendicular to the direction of flow of the medium, whether it is open or closed.High height and long opening and closing time. The opening and closing stroke of the shutter is large, and the drop is performed by the screw.The water hammer phenomenon is not easy to produce. The reason is that the shutdown time is long.The media can flow in any direction on both sides for easy installation. The gate valve channels are symmetrical on both sides.The length of the structure (the distance between the two connecting end faces of the casing) is ...

Model code of gate valve

The description of the gate valve type is based on the Chinese valve model. It does not include some of the latest gate valve products developed and produced by our company. In the case that there is no uniform standard for new products, we will adopt the enterprise preparation method of the gate valve model. However, for your convenience, versatility and standards, we will try our best to use the Chinese gate valve model. Special requirements code:body, cover bolting structure (default) Hs one, cover welding structure PS a pressure sealing structure D a low temperature valve B a bellows valve E a valve body extension end valveValve type code:Z one gate valveDrive mode code:4 a spur gear transmission 5 a bevel gear transmission 6 a pneumatic 6s a pneumatic belt manual 7 a hydraulic 9 electric (handwheel drive slightly) 9B an explosion-proof electricConnection form code:1 an internal thread 2 an external thread ...

Why natural gas pipelines must use forged steel ball valves

The natural gas pipeline forged steel ball valve is a forged steel structure, which is especially suitable for working conditions of gas, purified natural gas, acid natural gas, water, coal slurry and oil. It is suitable for oils with Class150~Class1500 and working temperature of -28~300°C. In the pipelines of various working conditions, such as chemical and thermal power stations, it acts to cut off or turn on the medium. Because the material of the forged steel ball valve is also carefully selected, the wall thickness of the valve body and the bolt strength of the valve body are in accordance with the requirements of the American standard ASME B16.34, and are strictly calculated to ensure the corresponding valve body pressure level and joint. Reliable strength. The ball adopts a fixed structure, a floating valve seat, which can achieve a small torque under operating pressure. A metal bushing with self-lubricating PTFE is used ...

Comparisons of Pneumatic Ball Valves and Electric Ball Valves

The pneumatic ball valve consists of the ball valve and the pneumatic actuator. It generally needs to be used in conjunction with accessories including the magnetic valve, air treatment FRL, limit switch, and positioner so as to be controlled remotely and locally as well as to be opened and closed in the control room. It improves safety, largely saves the cost of human resources and time, and makes manual control on site, above the ground and in dangerous palces not needed any more. CLASSIFICATIONS OF PNEUMATIC BALL VALVES According to the material, pneumatic ball valves can be divided into stainless steel pneumatic ball valves, plastic pneumatic ball valves, sanitary pneumatic ball valves, carbon steel pneumatic ball valves, cast iron pneumatic ball valves, etc.According to the connection mode, pneumatic ball valves can be divided into pneumatic flanged ball valves, screw thread pneumatic ball valves, welded pneumatic valves, etc.According to pressure, pneumatic ball ...

Float Ball Valve design feature

BOW-OUT PROOF STEM For the purpose of preventing the stem from flying off resulting in abnormal rising of the inner pressure of valve,shoulder is fixed at the lower part of the stem.In addition,in order to prevent leakage resulting from burnout of packing set of the stem in a fire,thrust bearing is set at the contact position of the shoulder at lower part of the stem and ball valve body.Thus an inverse seal seat is formed which will prevent leakage and avoid accident. KEY LOCK Locks can be used to lock the manual valve when it is fully open or closed so as to prevent non-working personnel from pulling the handle which may result in misoperation of valve.It can also avoid opening or closing of valve resulting from the shock from pipelines or unpredictable factors that may cause an accident.For working pipelines such as combustible and explosive oil,gas and chemical medium,or for field ...

Mr.Naoki Sawamur visits Datian Valve factory

On November 14, 2019, the famous Japanese valve manufacturer sawamura Valve Co., Ltd. and its president, Mr. Naoki sawamura, came to our company for inspection. Mr. Yu Chengshan, chairman of the company, warmly welcomed the arrival of Naoki sawamura, accompanied Naoki sawamura to conduct a comprehensive inspection and understanding of the company's production base, and then conducted in-depth exchanges on technology and business. Since its establishment in 1925, SAWAMURA Co., Ltd. has been providing products for ships, power plants, petrochemical plants, etc. The main customers of the company include Mitsubishi Heavy Industries, Tokyo Electric Power, Toshiba Corporation, Kawasaki Heavy Industries, Nisshin Steel, Nippon steel corporation, Miho shipyard, Nakatani shipbuilding and other fields. Adhering to the business philosophy of "Just try it", Sawamura valve has developed and improved a variety of valves in a variety of applications to meet customers' needs for safety, durability, performance and cost effectiveness. Through centuries of accumulated experience, ...

An Analysis Of Flow Characteristics Control Valves and Flow Optimization Computation of a Perforated Sleeve Valve

As an important element in the flow control system, the control valve adjusts the medium flow rate of the system by changing its own resistance characteristics. Its regulating quality affects the efficiency and stability of the entire system. Design the control valve according to the regulation needs of the system. The key is to design the control valve structure and the flow area distribution of the valve core. The existing researches on the flow characteristics of the control valve are mainly concentrated on the following aspects. First, the research on the flow regulation theory, including the establishment and improvement of mathematical models and the discussion of evaluation standards. The second is to analyze the flow characteristics and improvement methods based on specific valve types using tests or engineering experience; the third is to analyze the flow characteristics using CED technology for specific valve types. For the discussion of the relationship ...
Valve products have been widely applied in petroleum, chemical engineering, nuclear power, metallurgy, electric power, hydraulic power, large coal chemical industry and other industries. Total quantity of valve products is constantly growing. Valve technology is developing and application of valve is also expanding continuously. Valve standards relative to valve products are showing their importance in at present.

Usage of Valve Standards in China

Valve products have been widely applied in petroleum, chemical engineering, nuclear power, metallurgy, electric power, hydraulic power, large coal chemical industry and other industries. Total quantity of valve products is constantly growing. Valve technology is developing and application of valve is also expanding continuously. Valve standards relative to valve products are showing their importance in at present. Valve products have been widely applied in petroleum, chemical engineering, nuclear power, metallurgy, electric power, hydraulic power, large coal chemical industry and other industries. Total quantity of valve products is constantly growing. Valve technology is developing and application of valve is also expanding continuously. Valve standards relative to valve products are showing their importance in at present. USAGE OF VALVE STANDARDS IN CHINA Using international standards and foreign advanced standards is an important standardization policy in China. Valve standards are also implementing the policy actively. For basic standards, method standards and product standards, ...
About Control Valve

About Control Valve

A control valve is a valve used to control fluid flow by varying the size of the flow passage as directed by a signal from a controller.[1] This enables the direct control of flow rate and the consequential control of process quantities such as pressure, temperature, and liquid level. In automatic control terminology a control valve is termed a "final control element". Contents    OperationControl action Valve positionersTypes of control valve bodiesList of common types of control valve  Operation Air-actuated control valves each with a 4-20 mA "I to P" converter integral to a valve positioner. In this example each positioner is comparing the valve stem travel against control signal, and applying any correction.The opening or closing of automatic control valves is usually done by electrical, hydraulic or pneumatic actuators. Normally with a modulating valve, which can be set to any position between fully open and fully closed, valve positioners are used to ensure the ...
What Is A Centrifugal Pump Minimum Flow Bypass Line?

What Is A Centrifugal Pump Minimum Flow Bypass Line?

Centrifugal pumps rely on fluid to keep cool and lubricated while operating. They also rely on the fact that discharged fluid has somewhere to go. But what if the process dictates it needs only a fraction of the pump’s minimum flow requirement? What if there's a closed valve downstream? What happens when a pump’s basic hydraulic needs are no longer met? This is where a minimum flow bypass line is best applied. A bypass line is most commonly used when there’s an issue meeting the minimum flow requirements, and/or for protection against deadheading the pump. A minimum flow bypass, or recirculation, line can be configured many ways. It could be as simple as a continuous bypass, where the requirements are only piping and an orifice. A more complex line could be set up to use a series of valves. Below is an illustration of a simple minimum flow bypass line. ...

Cavitation in Control valve

From Wikipedia, the free encyclopedia Cavitation is the formation of vapour cavities in a liquid, small liquid-free zones ("bubbles" or "voids"), that are the consequence of forces acting upon the liquid. It usually occurs when a liquid is subjected to rapid changes of pressure that cause the formation of cavities in the liquid where the pressure is relatively low. When subjected to higher pressure, the voids implode and can generate an intense shock wave. Cavitation is a significant cause of wear in some engineering contexts. Collapsing voids that implode near to a metal surface cause cyclic stress through repeated implosion. This results in surface fatigue of the metal causing a type of wear also called "cavitation". The most common examples of this kind of wear are to pump impellers, and bends where a sudden change in the direction of liquid occurs. Cavitation is usually divided into two classes of behavior: ...
Pump Run Out Protection

Pump Run Out Protection

Normally pump protection valves are limited to minimum flow protection; however, severe damage can occur to the pump and driver by exceeding the intended operating range of the pump. Damage due to excessive flow can be eliminated by designing a "Maxi-Flow" as an addition to the standard minimum flow valve. Excessive flow protection is achieved by installing an insert with a row of orifice holes into the main valve body. During normal main flow operation, the fluid passes through the holes with a minimal pressure head loss. In addition, a special disc is provided which has a sleeve around the diameter with a row of orifice holes. The disc is at full lift when the forward flow reaches the maximum desired flow rate. At the full lift, the orifice holes in the body insert and disc line up stopping the additional flow. Maximum flow protection prevents exceeding the steam drum desired ...

Automatic Recirculation Valves Start-Up

Automatic recirculation valves Before start-up all lines must be flushed and the medium must be free from solids. Our valves are not designed to handle these. The lifetime of the valves will be strongly reduced due to increased wear when the fluid handled contains solids. If the lines are not clean they can be flushed with the valves installed. This should, however, be done with the valve internals removed and at reduced pressures. Note that with the removal of the internals the non-return- and pressure letdown function are no longer present. After flushing, the internals shall be reinstalled again. If the medium contains solids in the normal process we advise you to install a strainer with a mesh aperture of 0,25 to 0,5 mm in front of the pump inlet because solids could block the movement of the valve internals. Once the system is clean and filled with liquid the ...

Automatic Recirculation Valves Installation

The DATIAN automatic recirculation valves are best installed directly on the outlet of the pumps for which they are meant. The valve layout is mainly based on the pump curve. Ensure that the valves are installed on the right pumps. The flow direction is indicated on the valve nameplate. This nameplate is riveted to the valve body. On this nameplate, you will also find the valve’s commissioning- or fabrication number. This number is unique and therefore different for each valve. This ensures that the valves can always be related to the right pump. In case of spare parts requirements always refer to this number. As a standard, the valves are supplied as a complete unit and can be installed directly after receipt. Normally the connections are flanged but upon request, we can also supply the valves with butt weld ends. The packing is required between the valves and the piping is ...
PRECAUTIONS WHEN USING BACK PRESSURE VALVE

Precautions when using back pressure valve

Avoid resonance with the system.When used with a pulsation damper, the pulsation damper should be placed between the pump and the backpressure valve to absorb the peak flow between the pump and the backpressure valve. Slow down the wear rate of the backpressure valve.For outdoor use, a protective shed or a protective cover should be added.Before performing any maintenance on the backpressure valve, stop the equipment, relieve pressure, close the valve that the backpressure valve is connected to the system, and verify that there is no pressure in the pulsation damper. Take care to prevent the liquid from being transported from harming the human body during maintenance.If the inlet and outlet of the backpressure valve are reversed, the back pressure will be multiplied, which will bring harm to the system and may be dangerous. Valve imported pump industrial washing machineIf the backpressure valve fails during operation, the power should be ...
Use of automatic recirculation valve

Use of automatic recirculation valve

The automatic recirculation valve is mainly installed at the outlet of the centrifugal pump. When the centrifugal pump outlet flow is lower than the minimum flow, the pump protection valve is bypassed, and the minimum flow of the pump design is bypassed to the pump suction device to avoid centrifugation. The pump is damaged due to overheating. PERFORMANCE ADVANTAGES OF AUTOMATIC RECIRCULATION VALVES The automatic recirculation valve (ARC valve) is a fully mechanical structure that controls the valve by the flow and pressure of the medium and does not require additional energy.The automatic recirculation valve (ARC valve) only recirculates when the flow rate is low so that the pump is cooled, and there is no recirculation when the pump is in normal operation, thereby saving the electric energy and water energy consumed by continuous recirculation.The automatic recirculation valve (ARC valve) does not require electrical wiring or two series of regulating ...
3 Way Auto-reflux Valve

3 Way Auto-reflux Valve Application and Features

There are many types of auto-reflux valves. The 3-way auto-reflux valve we have today has three ports, one in and two out, (left in, right and bottom). Unlike ordinary valves, there is an outlet at the bottom, when the internal spool is in different positions. When the outlet is different, for example, when the spool is at the lower part, the left and right sides communicate. If the spool is at the upper part, the right outlet is blocked, and the left and lower ports are open. Because the left and right mouths are not on a horizontal line. When the emergency is disengaged, the valve is closed and the water is bypassed. The 3-way auto-reflux valve, A valve that protects the system from damage due to excessive pressure. Once the pressure of the medium in the system piping or device exceeds the set value, the pressure is automatically released to achieve safety ...
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