Globe Valves Manufacturers
globe valve also stop valve. The closing principle is to make the disc sealing surface and valve seat sealing surface closely fit with the valve stem pressure.
Press-Fit Globe Valve Stainless steel Press End Connections
ANSI Class 300 Globe Valve/stop valve Flanged Stainless & carbon steel
ANSI Class 150 Flanged Globe Valve/Stop valve
JIS 20K Flanged Globe valve /Stop Valve
JIS 10K Globe Valve SCS13/SCS14/SCPH2 Flanged Stop valve
JIS 10K Flanged Globe Valve 15A-50A-Stop valve SCS13
ASIAV Globe Valves Series
Globe valve is also Stop valve ，Globe Stop Valves is one of the most widely used valves. It is popular because the friction between the sealing surfaces during opening and closing is small, it is relatively durable, the opening height is not high, it is easy to manufacture and easy to maintain. It is not only suitable for medium and low pressure, but also suitable for high pressure. The closing principle of the stop valve is to make the sealing surface of the valve disc and the sealing surface of the valve seat closely fit with the pressure of the valve stem to prevent the medium from flowing. Therefore, this type of shut-off valve is very suitable for cutting off or regulating and throttling. Because the valve stem opening or closing stroke of this type of valve is relatively short, and has a very reliable cut-off function, and because the change of the valve seat opening is in direct proportion to the stroke of the valve disc, it is very suitable for regulating the flow.
Working principle and characteristics of stop valve
The valve plays an important role in cutting off and throttling the medium in the pipeline where it is located. As an extremely important cut-off valve, the sealing of the stop valve is to apply torque to the valve stem, and the valve stem exerts pressure on the valve disc in the axial direction, so that the sealing surface of the valve disc and the sealing surface of the valve seat closely fit, and prevent the medium from leaking along the gap between the sealing surfaces.
The sealing pair of the stop valve is composed of the sealing surface of the valve disc and the sealing surface of the valve seat. The valve stem drives the valve disc to move vertically along the center line of the valve seat. The stop valve has a small opening height in the process of opening and closing, which is easy to adjust the flow, convenient for manufacturing and maintenance, and has a wide range of pressure applications.
Compared with the gate valve, another commonly used block valve in industrial production, the stop valve is simpler in structure and easier to manufacture and maintain. In terms of service life, the sealing surface of the stop valve is not easy to wear and scratch, and the valve disc and_ There is no relative sliding between the sealing surfaces of the seat, so the wear and scratch on the sealing surface are small, so the service life of the sealing pair is improved. The valve disc stroke is small during the full closing process of the stop valve, and its height is smaller than that of the gate valve. The disadvantage of the stop valve is that the opening and closing torque is large and it is difficult to realize rapid opening and closing. Because the flow channel in the valve body is tortuous and the fluid flow resistance is large, the fluid power is lost in the pipeline.
(1) The structure of the stop valve is simpler than that of the gate valve, and the manufacturing and maintenance are more convenient.
(2) The sealing surface is not easy to wear and scratch, with good sealing performance. There is no relative sliding between the valve disc and the sealing surface of the valve body during opening and closing, so the wear and scratch are not serious, with good sealing performance and long service life.
(3) During opening and closing, the valve disc stroke is small, so the height of the stop valve is smaller than that of the gate valve, but the structure length is longer than that of the gate valve.
(4) The opening and closing torque is large, the opening and closing is laborious, and the opening and closing time is long.
(5) The fluid resistance is large. Because the medium channel in the valve body is tortuous, the fluid resistance is large and the power consumption is large.
(6) When the nominal pressure in the medium flow direction is PN ≤ 16MPa, the downstream flow is generally adopted, and the medium flows upward from the lower direction of the valve disc; When the nominal pressure is PN ≥ 20MPa, the reverse flow is generally adopted, and the medium flows down from the valve disc to increase the sealing element energy. In use, the medium of the stop valve can only flow in one direction, and the flow direction cannot be changed.
(7) The valve disc is often eroded when it is fully opened.
The stem axis of the stop valve is perpendicular to the sealing surface of the valve seat. The opening or closing stroke of the valve rod is relatively short, and it has a very reliable cutting action, which makes this valve suitable for cutting off or regulating the medium and throttling.
1. The fluid resistance of the stop valve is large, and the force required for opening and closing is large.
2. The stop valve is not suitable for medium with particles, high viscosity and easy coking.
3. The regulating performance of the stop valve is poor.
1. The stop valve is simple in structure and convenient in manufacture and maintenance.
2. The stop valve has small working stroke and short opening and closing time.
3. The stop valve has good sealing performance, small friction force between sealing surfaces and long service life.
The types of stop valves are divided into external thread type stop valves and internal thread type stop valves according to the position of valve stem threads. According to the flow direction of the medium, there are straight cut-off valves, direct cut-off valves and angle cut-off valves. Stop valves are divided into packing sealed stop valves and bellows sealed stop valves according to the sealing forms.
According to the channel direction
1) Straight cut-off valve
2) Direct flow stop valve: in the direct flow or Y-shaped stop valve, the flow channel of the valve body and the main flow channel form an oblique line, so the damage degree of the flow state is smaller than that of the conventional stop valve, so the pressure loss through the valve is correspondingly small.
3) Angle stop valve: in the angle stop valve, the fluid only needs to change direction once, so that the pressure drop through the valve is smaller than that of the conventional stop valve.
4) Plunger type stop valve: this type of stop valve is a variation of the conventional stop valve. In this valve, the disc and seat are usually designed based on the plunger principle. The valve disc is polished into a cylindrical plug and connected with the valve stem. The sealing is realized by two elastic sealing rings sleeved on the plunger. The two elastic sealing rings are separated by a collar, and the sealing ring around the plunger is firmly pressed by the load applied on the bonnet by the bonnet nut. The elastic sealing ring can be replaced and can be made of various materials. The valve is mainly used for “opening” or “closing”, but it is equipped with a special plunger or special collar, which can also be used to regulate the flow.
Position of threads on valve stem
1) Upper thread stem stop valve: the thread of the stem of the stop valve is outside the valve body. Its advantage is that the valve stem is not eroded by the medium and is easy to lubricate. This structure is widely used.
2) Lower threaded stem stop valve: the thread of the stem of the stop valve is in the valve body. The thread of the valve stem with this structure is in direct contact with the medium, which is easy to be eroded and cannot be lubricated. This structure is used in places with small caliber and low temperature.
There are many domestic manufacturers of stop valves, and most of the connection sizes are not uniform. It is mainly divided into the following categories: general category based on structural length of globe valves (JB / t2203-1999). At present, most domestic stop valve manufacturers are designed and produced according to this standard. However, this standard is not perfect and the specifications are not complete. The maximum nominal diameter of single gate stop valve is DN1200, and the maximum nominal diameter of double gate stop valve is DN1500. According to the specifications of the stop valve produced by the manufacturer and the information available, the minimum nominal diameter of the angle stop valve is DN15, and the nominal diameter of the Z-type straight stop valve is DN2000. According to the research, the connection size of each manufacturer is not uniform. In order to have a unified standard and the same specification can be interchanged when users select and install, it is suggested that China General Machinery Research Institute revise the structural length of stop valve (JB / t2203-1999). It is recommended that the design institute and the user select according to the standard, and the stop valve manufacturer shall design and manufacture according to the standard.
According to use
The fluorine lined stop valve is applicable to aqua regia, sulfuric acid, hydrochloric acid, hydrofluoric acid and various organic acids, strong acids and strong oxidizing agents of various concentrations at – 50 ~ 150 ℃, and is also applicable to strong alkali organic solvents of various concentrations and other corrosive gases and liquid medium pipelines
National standard globe valve is the most commonly used product in globe valve series. API American Standard globe valve American Standard globe valve implements ANSI and API standards. The sealing surface of valve disc and valve seat is made of Stellite cobalt based hard alloy with different hardness. It has reliable sealing, high hardness, wear resistance, high temperature resistance, corrosion resistance, good scratch resistance and long service life.
Needle valve is a small-diameter instrument valve, which plays the role of opening and closing and accurate flow control in the instrument measurement pipeline system, mainly including power station instrument series, oilfield special series, American standard series, etc.
Low temperature stop valve usually refers to the valve with working temperature lower than – 110 ℃, which is widely used in liquefied natural gas, liquefied petroleum gas and other low-temperature industries. Since 2008, stop valves with applicable temperature up to – 196 ℃ can be manufactured. All parts are pretreated with liquid nitrogen at low temperature to completely avoid sealing deformation and leakage during use.
Plunger valve is also known as plunger stop valve. Its sealing surface adopts radial sealing structure. Two elastic sealing rings sleeved on the polished plunger compress the elastic sealing rings around the plunger through the load applied on the bonnet by the connecting bolts of the valve body and the bonnet to achieve sealing.
The insulation jacket stop valve adopts the insulation jacket design, and the external heat source is used to heat the outside of the valve, which can effectively prevent the temperature loss of the medium when passing through the valve and ensure the temperature of the medium.
Forged steel globe valves are designed and manufactured in accordance with API 602 standard. Three bonnet design forms are provided: Bolted bonnet, Welded Bonnet and pressure self tightening sealing bonnet. Users can choose different forms according to their needs, and provide RF flange, NPT thread and SW Welded Bonnet.
The oxygen special stop valve is made of silicon brass or stainless steel with excellent material, which has the advantages of high mechanical strength, wear resistance and good safety. When used in oxygen pipeline, it has the best explosion-proof and flame-retardant performance and eliminates the unsafe factors on the oxygen pipeline. It is widely used in the pipe network of steel, metallurgy, petrochemical, chemical and other oxygen consuming projects. In addition to the functions of ordinary valves, it also has its own characteristics. Strict oil prohibition measures shall be taken during manufacturing, and all parts shall be degreased before installation.
The bellows stop valve is designed with shaped stainless steel bellows. The bellows has no fault after 10000 reciprocating tests, and the sealing performance is reliable. It is suitable for industrial and mining with inflammable, explosive, toxic and harmful media, and can effectively prevent the leakage of the valve.
Comparison between bellows stop valve and common stop valve
1. Double sealing design (bellows + packing) if the bellows fails, the stem packing will also avoid leakage and meet the international sealing standards.
2. No fluid loss, reduce energy loss and improve plant equipment safety.
3. Long service life, reduce maintenance times and reduce operating costs.
4. The rugged and durable bellows sealing design ensures zero leakage of the valve stem and provides maintenance free conditions.
5. PTFE soft sealing material is adopted for the gas medium valve seat to improve the sealing performance of the valve.
6. The valve seat with high temperature resistance ≤ 425 ℃ adopts conical hard seal. Achieve air tightness and zero leakage.
With the continuous rise of labor cost, more and more enterprises hope to reduce labor force. With such bellows stop valve, workers can switch more easily. Products with longer service life and better sealing performance have reason to believe that its prospects will be more and more broad.
According to the channel position, it can be divided into straight type and right angle type.
The working principle of the stop valve is to make the valve unblocked or blocked by rotating the valve. The gate valve is light and small in size, can be made into a large diameter, reliable in sealing, simple in structure, convenient in maintenance, and the sealing surface and spherical surface are always closed, which is not easily eroded by the medium. It is widely used in various industries.
A. Opening process
1 in the closed position, the valve body is pressed against the valve seat by the mechanical pressure of the valve stem.
2 when the handwheel is rotated counterclockwise, the valve rod will move in reverse direction, and the angular plane at the bottom will make the ball disengage from the valve seat.
3 the valve rod continues to lift and interacts with the guide pin in the spiral groove of the valve rod to make the ball rotate frictionlessly.
4 until it reaches the fully open position, the valve rod is lifted to the limit position, and the ball rotates to the fully open position.
B. Closing process
1 when the valve is closed, rotate the hand wheel clockwise, the valve stem starts to drop and the ball starts to rotate away from the valve seat.
2. Continue to rotate the handwheel, and the valve stem is subject to the action of the guide pin embedded in the spiral groove on the handwheel, so that the valve stem and the ram rotate 90 ° at the same time.
3 when the valve body is about to close, it has rotated 90 ° without contacting the valve seat.
4 during the last few turns of handwheel rotation, the angular plane at the bottom of the valve stem mechanically wedges the ball to make it tightly press against the valve seat to achieve complete sealing.
Structural features of stop valve:
1. There is no friction during opening and closing. This function completely solves the problem that the sealing of traditional valves is affected by the friction between the sealing surfaces.
2. Top mounted structure. The valve installed on the pipeline can be directly inspected and maintained online, which can effectively reduce the shutdown of the device and reduce the cost.
3. Single seat design. The problem that the medium in the chamber of the valve affects the use safety due to abnormal pressure rise is eliminated.
4. Low torque design. The valve stem with special structure design can be easily opened and closed with only a small handle.
5. Wedge seal structure. The valve is sealed by pressing the ball wedge onto the valve seat by the mechanical force provided by the valve stem, so that the sealing performance of the valve is not affected by the change of pipeline pressure difference, and the sealing performance is reliably guaranteed under various working conditions.
6. Self cleaning structure of sealing surface. When the ball tilts away from the valve seat, the fluid in the pipeline passes through the sealing surface of the ball at 360 ° evenly, which not only eliminates the local scouring of the valve seat by the high-speed fluid, but also washes away the accumulation on the sealing surface to achieve the purpose of self-cleaning.
7. The valve body and bonnet with the valve diameter below DN50 are die forgings, and the valve body and bonnet with the valve diameter above DN65 are steel castings.
8. The connection forms of valve body and bonnet are different, clamp pin shaft connection, flange gasket connection and self sealing thread connection.
9. The sealing surfaces of the valve seat and valve disc are made of plasma spray welding or surfacing cobalt chromium tungsten hard alloy, with high hardness, wear resistance, abrasion resistance and long service life.
10. The valve rod is made of nitrided steel. The nitrided valve rod has high surface hardness, wear resistance, abrasion resistance, corrosion resistance and long service life.