1.product description
Shanghai Huhang Valve Co., Ltd. has successfully developed a versatile piston-type control valve after extensive on-site inspections, market research, and user feedback. With nearly a decade of production experience, this valve is suitable for various media such as clean water, raw water (including sediment), sewage, seawater, etc. It operates across a wide temperature range (-50°C to 135°C) and finds applications in water plants, power plants, water diversion projects, water supply and drainage, metallurgy, chemical industry, and other industries. It regulates the flow and pressure of pipeline media, especially excelling in large diameters, high pressures, and large pressure differentials. It serves as the ideal control equipment for various hydraulic engineering and hydroelectric power stations.
Especially suited for high, medium-head, long-distance, and large-diameter pressurized water pipeline flow and pressure regulation control, ensuring safety, reliability, precision, and long lifespan.
Outstanding cavitation elimination functionality significantly extends the lifespan of the valve.
2.Working principle and design features
(1) Working Principle:
The regulating function is achieved by a piston-like cylinder moving axially within the valve chamber, with its stroke aligned with the direction of the pipeline flow. This piston movement alters the flow area of the outlet component (cage), thereby regulating flow and pressure. The piston, guided by rails inside the inner cylinder, moves axially along the pipeline, changing the flow area to achieve control regulation. The flow channel is axially symmetrical and streamlined to prevent debris blockage, ensuring minimal head loss and linear operation characteristics. The flow passage design prevents cavitation and damage to valve components. The crank-slider mechanism operates steadily and reliably, with constant output torque and gradual closing to prevent water hammer. By adjusting the electric actuator through a regulator based on outlet pressure, the valve's opening can be modified to achieve automatic pressure reduction and flow regulation functions.
(2) Design Characteristics:
1. Linear valve body, straight-through structure
The valve body is designed in a linear shape with a straight-through structure, providing high flow capacity and minimal pressure loss. Its smooth inlet and outlet structure avoids turbulence, vibration, noise, and cavitation caused by structural changes. Regardless of the piston's position, the water flow cross-section inside the valve chamber remains annular, enabling linear adjustment within a wide operating range.
2. Regulating component design.
The design of regulating valves is typically determined based on system pressure conditions and maximum/minimum flow rate requirements. Various operating conditions and technical specifications vary significantly. Traditional regulating valves face challenges in achieving precise control over output during flow rate adjustment and pressure control due to inherent limitations in the structure and operation of traditional regulating components. However, piston-type multifunctional control valves can adapt to different operating conditions with excellent performance and adaptability. We have designed the valve body to be modular, with the closing and regulating parts designed as a modular split-body structure. When the system has different requirements, only minor adjustments or replacements to the closing and regulating parts are needed to meet these requirements. Based on the analysis of the operating characteristics of regulating valves, we have developed two standard types of piston-type multifunctional control valves: cage-type and fan-blade-ring type. These designs can be slightly modified to meet specific requirements in systems with special demands, addressing various technical challenges, especially in high-precision, high-pressure, and high-flow rate regulation scenarios. The pressure rating of the piston-type multifunctional control valves can exceed PN10, and the pressure difference between the upstream and downstream of the valve can reach 4 MPa.
3. The piston motion method
The piston sliding is guided by rails to prevent tilting or uneven operation. The flow channel inside the valve is axially symmetrical, resulting in symmetrical distribution of pressure on the piston. This pressure balance ensures smooth operation with minimal torque and prevents turbulence when fluid flows through. The rails are made of bronze material, providing self-lubrication and wear resistance, further reducing operating torque and extending the valve's lifespan.
4. Dual Soft and Hard Seal Design:
Utilizing both rubber and metal seals, the valve achieves bidirectional zero leakage, significantly enhancing its reliability and lifespan. The sealing pair of the valve consists of a hard seal, where the annular sealing surface of the valve seat fully matches the sealing surface of the piston (valve core) when completely closed, ensuring excellent sealing with no leakage or pressure rise. The valve seals are only pressed against each other to form a seal when the valve is closed, and they do not press against each other or generate friction during the valve adjustment process. This ensures that the valve can operate effectively even when the medium passing through contains impurities such as sediment, preventing leakage or control failure due to incomplete closure.
rat cage:
The squirrel cage is a section of cylinder with holes extending from the front of the piston. The holes are symmetrically distributed. When the medium flow passes through the cylindrical squirrel cage throttling hole, it is divided into multiple streams of high-speed fluid, which are sprayed and collided radially toward the center of the squirrel cage. The cavitation is limited to the center of the squirrel cage and will not cause cavitation damage to valves and pipelines.
See below:
Fan-blade ring:
The fan-blade ring consists of evenly distributed guide blades, which divide the upstream flow into multiple smaller streams and guide them to flow smoothly under the influence of the fan-blade ring. The change in flow direction of the medium results in cavitation bubbles being confined to the center of the pipeline, and the rupture of unstable bubbles occurs away from the walls of the pipeline and the valve, preventing cavitation damage.
3. Main technical performance
1. The regulating mechanism of the piston-type multifunctional control valve (hereinafter referred to as the piston valve) is a crank-slider mechanism. The closing component slider is a cylindrical piston guided by rails within the valve body to move axially along the center of the pipeline, thereby changing the flow area to achieve control regulation. The sealing pair is non-metallic, and the connection with the pipeline is made through flange connection, with flange dimensions following national standards.
2. The piston valve consists mainly of the valve body, outlet valve body, piston, crank, connecting rod, cage (fan blade), guide rail, valve stem, shaft sleeve, valve seat, sealing ring, and other components. Valve opening and closing are achieved by rotating the valve stem to cut off or allow the flow of the medium.
3. The driving method of the piston valve is electric actuation, which provides convenient, flexible, safe, and reliable operation. The manual operation torque should not exceed national standards. The electric actuator of the piston valve includes a motor, reduction gear, foot limit switch adjuster, torque control adjuster, stroke control adjuster, and opening indicator adjuster, all of which are made by well-known brands. The motor can adapt to the working environment of power plants (ambient temperature -20~60°C, relative humidity ≤90%, working power supply AC380±15% and control power supply AC220±15%, 50Hz ±2%), and has overheating protection function, with a protection level not lower than IP55.
4. The electric actuator of the piston valve adopts a fully integrated design, with the control cabinet and components integrated within the enclosed actuator housing. It is required to meet remote control requirements and provide signal output (able to receive external contact control signals, execute control commands, and provide feedback on action signals). Additionally, it can be manually operated on-site for valve switching.
5. The piston valve exhibits strong cavitation resistance.
6. During the opening or closing process of the piston valve, there is no friction between the valve seat and sealing ring, prolonging the valve's lifespan.
7. The sealing of the piston valve adopts a dual soft and hard seal design, providing excellent sealing effectiveness and achieving bidirectional zero leakage completely.
8. The piston valve features a reasonable and high-strength structure. During opening, it ensures unobstructed flow passage, resulting in minimal water loss during operation. The loss coefficient when fully open ranges from 0.25 to 0.28. At high flow rates, it should exhibit no vibration, and shell tests are conducted according to national standards. The pressure loss coefficient (K value) curves for DN200 and DN300 fan-blade ring and cage-type structures with valve stem opening are shown in Figure 4.
9. The piston valve requires minimal opening and closing torque.
10. The piston valve adopts a streamlined and axially symmetrical flow channel design, enabling linear adjustment of pressure (flow). The deviation of outlet pressure (flow) should not exceed 5% of the set value.
11. Castings are produced using advanced casting processes.
12.The main internal components of the valve are made of high-quality stainless steel or are determined based on specific conditions and customer requirements.
Quality and inspection:
Regular check on production line at each working procedure, and one special inspector inspecting the goods in random during the period time of production.regular performance check on finished goods.
Production step:
1.The raw materials are cast or forged and processed into semi-finished products.
2.Processing the semi-products in works shop
3.Assembling the goods
4.Testing the sealing in pressure and checking quality of the goods
5.Package
6.Delivery the goods on time
Package:
1.The pakage standard:inside PVC bag and small box and standard export carton
2.If you have any special requirements pakage,we can pakage as per your artworks.
Primary Competitive Advantages:
1) We have several years of experience in manufacturing various types of valves professionally.
2) Products are of good quality, with reasonable prices.
3) Our style:Promise must be kept and action must be prompt and fruitful.
Certifications
Our business idea:All for customers and everything from innovation.The size standards can be customized according to your specific requirements. Please feel free to contact us for more details.
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