Valve characteristics

　　Supply of pressure seal high and low pressure gate valves

　　The design, manufacturing procedure and quality inspection of pressure seal gate valve are in accordance with ASME, MSS, API and other international standards.

　　The pressure seal connects the valve body and the bonnet flange, reducing the weight and playing a simple role of peripheral insulation. In contrast to bolted bonnet valves, the chamber pressure acts on the pressure seal ring to make the seal tighter.

　　Main advantages

　　Generally used in environments with temperatures up to 1200 ° F

　　Sealed by fluid pressure itself, not by mechanical action, to eliminate thermal binding

　　Very suitable for applications where the process involves large temperature changes

　　Both ends of the valve can be perfectly closed

　　The valve plate can be aligned automatically

　　Elastic compensation for distortion of valve seat surface

　　Self cleaning function
 

　　Gate Valve

　　Gate type: Balance gate, wedge gate
 

　　The flange adopts ASME B16.10 international standard
 

　　ASME B16.25 international standard is adopted for butt welding
 

　　Manufactured in accordance with ASME B16.34
 

　　Pressure class (ASME): 150-4500
 

　　Size: 4 "- 36"
 

　　Material:　WCB/A105, WC9/F22, C12A/F91, 316, CF8M/347
 

　　Gate valve - high-pressure gate valve

　　1、At the pressure self-sealing position of the bonnet of GRAND valve, the linear seal between the bonnet and the sealing ring is formed through the angle combination structure. In addition, the sealing ring is made of silvered low-carbon steel, which is cavitation-resisting and prolongs sealing life, thus reducing the risk of leakage under high-pressure differential. Other manufacturers generally use face seal or only provide low-carbon steel materials.

　　2、When a GRAND valve is under Class 2500 or above pressure, the interface of the inner cavity of valve body and the sealing ring overlaid by stainless steel lining is able to avoid leakage caused by pitting from steam erosion in sealing area of valve body under high pressure difference, thus assuring the safe and long-term operation of the valve.

　　3、The GRAND valve is designedwith Full Port or Reduced PortVenturi End in strict accordance with the user's requirements for the valve diameter. When the user does not clearly define the internal and external diameter, the proper valve diameter should be calculated and selected in strict accordance with the size and flow parameters of the pipeline, the flow rate and pressure loss of the valve.

　　4、To assure the sealing performance of the GRAND valve, not onlythe sealing surface of the valve seat and valve core is hardened to extend the service life of the valve, but also the sealing surface of the rear valve seat is overlaid with Stellite alloy. Even if the packing leaks, as long as the valve is turned to the full open position, and the rear seat seal can play the role of sealing the stem and avoid leakage. The packing can be replaced with a new one when the power plant is shut down or overhauled.

　　5、The bracket of the GRAND valve adopts the combined patent structure, which can not only facilitate the removal and assemble of actuator but also act as a special tool for removing the sealing ring around the bonnet to prevent the pressurized and sealing position of the valve from maintenance-related damage structurally, which will bring great convenient to the user's on-site maintenance. But some manufacturers still adopt the whole casting structure.

　　6、The design, manufacture and quality inspection of the GRAND valve are in full accordance with US ASME ANSIB16.34 and API598/601 standards. The whole production and after-sales service are controlled by ISO9001 and other series ofinternational quality standard systems; In addition, we also have the license of NPT production nuclear valve issued by ASME.

　　7、To strictly control the quality of the GRAND valve, the valve, actuator and all accessories would be manufactured, installed and inspected in the UK.

　　8、All GRAND valves are provided with ex-factory test in 100% accordance with ASME standards.
 

　　Structural style

　　GRAND can provide two options, i.e., parallel plate gate valve and wedge gate valve, according to different process features and use requirements.

Features of parallel plate gate valve

　　The parallel plate gate valve consists of two interchangeable spring-loaded discs, one fully guided discbracket, and one retaining ring pin. The spring-loaded disc is conducive to producing tighter seals in applications with low pressure differential. The discs are interchangeable, so online maintenance is easier and eliminates the requirement for customizing special seats for disc. The wear between the valve plate and the valve seat is also uniform. The built-in integral molded stop device provides travel protection for the power actuator and serves as a reference for positioning theopening and closingposition of the valve.

　　(1) Yoke sleeve - aluminum bronze yoke sleeve is equipped with needle thrust bearing to minimize operating torque.

　　(2) Stem--the thread can length up to bracket. Retaining pin and spot welding ensure stable connection between stem and valve plate and the transmission of thrust.

　　(3) Pressure self-sealing bonnet

　　(4) Seat ring—a welded seat ring is perpendicular to the flow path for easy maintenance.

　　(5) Drive mechanism—these valves can be equipped with manual, pneumatic and electric actuator. Those below 12” are equipped with standard manual hand-wheels and those above 12” are equipped with gearbox operating mechanism.

　　(6) Yoke—the fully assembled yoke has passed shock test and is convenient for maintaining and installing the actuators.

　　(7) Gland—the two-layer self-aligned packing gland can eliminate jamming.

　　(8) Integral rear seat—hardened on the surface to assure durable utilization.

　　(9) Valve disc—the spring-loaded disc can realize self-regulating and assure better sealing through spring compensation force in the environment with a low pressure differential. When the disc/stem/seat deforms with the change of temperature, the self-regulating ability reduces the torque demand for the actuator, and avoids the possibility of the valve plate being stuck in the seat due to thermal deformation.

　　(10) Integral stop device--integral cast bracket stop device, which provides travel protection for power actuator and ensures more stable and reliable travel action of the valve.

Features of wedge gate valve

　　(1) Yoke sleeve—aluminum bronze yoke sleeve is equipped with needle-like thrust bearing to minimize operating torque.

　　(2) Stem—all GRAND Wedge Gate Valves are provided with a Type-T-head stem. This structure enables the wedge to adjust itself, eliminates the possibility that the bending deformation of the valve stem affects the ram.

　　(3) Pressure seal bonnet

　　(4) Seat ring—The surface hardened valve seat ring is welded into the valve body. The conical structure is matched with the wedge valve plate to form a tight sealing surface.

　　(5) Body—streamlined flow path minimizes pressure drop. The end-to-end dimension meets the requirements of ANSIB16.10. Most calibers can provide products whose meeting API 600 standard wall thickness.

　　(6) Drive mechanism—these valves canbe equipped with manual, electric, hydraulicor pneumatic actuators. Those below 12” are provided with standard hand-wheels and those above 12” are provided with gearbox operating mechanism.

　　(7) Yoke—the fully assembled yoke has passedshock test and is convenient for maintaining and installing the actuator.

　　(8) Gland—the two-layer self-aligned stuffing gland can eliminate jamming.

　　(9) Integral rear seat—hardened surface can assure durable utilization.

　　(10) Wedge—the single-piece flexible wedge is designed with the whole-guide central axis, which allows the sealing surface of the valve plate to move radially, and can compensate for the seat deformation caused by thermal expansion or pipeline stress. The angle between the valve seat surface and the valve plate surface and the vertical line is 4degrees, so that the sliding friction between the valve plate and the valve seat is minimized during the opening and closing process of the valve.

　　List of gate valve materials