Handan Shengnada New Material Technology Co., Ltd. Company News

29 common types of valves are explained in detail!   The sealing performance of a valve refers to the ability of each sealing part of the valve to prevent medium leakage, which is the most important technical performance index of the valve. There are three sealing parts in the valve: the contact area between the two sealing surfaces of the opening and closing parts and the valve seat; the fitting area between the packing, the valve stem, and the packing chamber; and the connection between the valve body and the valve cover. Among them, leakage from the first part is called internal leakage, commonly known as "inability to close tightly", which will affect the valve's ability to intercept the medium. For shut-off valves, internal leakage is not allowed. Leakage from the latter two parts is called external leakage, that is, the medium leaks from inside the valve to the outside. External leakage can cause material loss, environmental pollution, and even accidents in severe cases. For flammable, explosive, toxic, or radioactive media, external leakage is absolutely not allowed. Therefore, valves must have reliable sealing performance.   Here are detailed explanations of 29 common types of valves:   1. Ball Valve Structure: The opening/closing component is a spherical disc driven by a stem, rotating 90° around the valve axis to open or close. Functions: Used for fluid regulation and control, mainly to cut off, distribute, or change the flow direction of media in pipelines. Features: Excellent sealing performance, easy operation, quick opening/closing, simple structure, compact size, low flow resistance, and lightweight.   2. Gate Valve Structure: The opening/closing component is a gate plate moving perpendicular to the fluid direction; it can only be fully open or fully closed, not for regulation or throttling. Functions: Primarily used to cut off media in pipelines, allowing bidirectional flow and easy installation. Features: Smooth channel, low flow resistance, simple structure, and convenient operation.   3. Butterfly Valve Structure: The opening/closing component is a disc (butterfly plate) driven by a stem, rotating 90° around its own axis within the valve body to open/close or regulate flow. Functions: Mainly for cutting off media in pipelines. Features: Simple structure, flexible operation, quick switching, small size, short structural length, low resistance, and lightweight.   4. Globe Valve Structure: The opening/closing component is a plug-shaped disc with a flat or conical sealing surface, moving linearly along the valve seat’s central axis to open/close; it cannot be used for regulation or throttling. Functions: Primarily for cutting off media in pipelines. Features: Simple structure, easy installation, smooth channel, low flow resistance, and convenient operation.   5. Check Valve Structure: Automatically opens/closes the disc via the medium’s own flow to prevent backflow; also called non-return valve, one-way valve, or backpressure valve. Functions: An automatic valve to prevent medium backflow, reverse rotation of pumps/motors, and discharge of container media. Applications: Critical for preventing reverse flow in pipelines and machinery.   6. Control Valve Structure: Composed of an actuator and valve body, controlled by signals from a regulatory unit to adjust process parameters (flow, pressure, temperature, liquid level, etc.). Types: Pneumatic control valves, electric control valves, self-operated control valves. Applications: Core component in industrial automation for precise process control.   7. Solenoid Valve Structure: Combines an electromagnetic coil with a direct-flow or multi-port valve, available in normally open/closed types, controlled by AC220V or DC24V power to switch flow direction. Selection Principles: Prioritize safety, reliability, applicability, and economy. Applications: Automated control of fluids in industrial systems.   8. Safety Valve Structure: Normally closed under external force; opens to discharge media when internal pressure exceeds a set value, preventing overpressure in pipelines/equipment. Applications: Essential safety device for boilers, pressure vessels, and pipelines. Features: Automatic operation and critical protective function.   9. Needle Valve Structure: Features a sharp conical valve core, similar to a globe valve but designed for precise flow control and cutting in small-flow, high-pressure gas/liquid systems. Applications: Critical in instrumentation and measurement pipelines for fine adjustment and shut-off.   10. Trap Valve (Steam Trap) Structure: Removes condensate, air, and carbon dioxide from steam systems, classified as an energy-saving device. Functions: Optimizes the efficiency of steam heating equipment; proper selection requires understanding different trap types (e.g., thermostatic, float).   11. Plug Valve Structure: The opening/closing component is a cylindrical or conical plug that rotates 90° to align or block channels in the valve body. Applications: Suitable for cutting off, connecting, or diverting media, with rectangular (cylindrical) or trapezoidal (conical) channels.   12. Diaphragm Valve Structure: Uses a flexible diaphragm (e.g., rubber, PTFE) as the opening/closing component to separate the valve body interior from the bonnet and actuator. Types: Rubber-lined, PTFE-lined, unlined, and plastic diaphragm valves. Applications: Ideal for corrosive, sticky, or contaminated media in chemical and pharmaceutical industries.   13. Discharge Valve Structure: Designed for bottom discharge, sampling, and dead-zone-free shut-off in reactors, storage tanks, and containers, with lifting or lowering operation modes. Features: Welded to the vessel bottom to eliminate residual media and ensure clean discharge.   14. Exhaust Valve Structure: Uses a float-and-lever mechanism to vent air accumulated in fluid pipelines (e.g., water supply systems), preventing air pockets that hinder flow. Working Principle: Activates at system highs to release air as fluid flows.   15. Breathing Valve Structure: Maintains pressure balance in storage tanks by using weighted positive/negative pressure discs to control exhaust and intake. Functions: Reduces medium vaporization, prevents overpressure/underpressure, and ensures tank safety. Applications: Critical for volatile liquid storage (e.g., oil tanks).   16. Filter Valve Structure: Contains a removable filter cartridge with mesh screens of varying fineness to trap impurities in pipelines. Functions: Protects downstream equipment by filtering out debris; easy to clean/replace. Applications: Essential in fluid systems to prevent blockages and equipment damage.   17. Flame Arrester Structure: Composed of a flame arrestor core, housing, and accessories, designed to block flame propagation in flammable gas/liquid vapor pipelines or vented tanks. Applications: Critical safety device in petrochemical and gas systems to prevent explosion propagation.   18. Angle Seat Valve Structure: Actuated by air (with solenoid valves) for rapid, precise control of fluid flow (water, oil, air, steam, etc.). Features: Quick response, long lifespan, maintenance-free, and suitable for frequent on/off operations. Applications: Industrial automation for precise flow and temperature control.   19. Balance Valve Structure: Installed between pipelines/ containers to equalize pressure or flow differences via regulation or flow diversion. Functions: Specialized valve for pressure/flow balancing in heating, water supply, and HVAC systems.   20. Blowdown Valve Structure: Derived from gate valves, using a gear-driven stem to rotate 90° for opening/closing. Features: Simple structure, good sealing, small size, lightweight, low torque, and quick operation. Applications: Draining sediments and impurities in pipelines/equipment.   21. Sludge Discharge Valve Structure: Hydraulic/pneumatic actuated angle globe valve, typically installed in rows on sedimentation tank walls. Functions: Removes sludge and debris from tank bottoms, operable remotely via manual or solenoid valves.   22. Cut-off Valve Structure: Comprises a multi-spring pneumatic diaphragm actuator or piston actuator with a control valve, driven by regulatory signals. Functions: Cuts off, connects, or switches fluid flow in automated systems. Features: Simple design, rapid response, and reliable operation.   23. Reducing Valve Structure: Adjusts inlet pressure to a desired outlet pressure, maintaining stability via the medium’s own energy. Working Principle: Acts as a variable orifice to create pressure drops by altering flow area and velocity. Applications: Pressure regulation in water supply, heating, and industrial pipelines.   24. Pinch Valve Structure: Consists of cast iron/aluminum/stainless steel bodies, a rubber sleeve, stems, and guide posts; closing compresses the sleeve via stem rotation. Features: Corrosion-resistant, ideal for abrasive slurries; simple to maintain. Applications: Mining, wastewater, and chemical industries for thick fluids.   25. Plunger Valve Structure: Features a plunger driven by a stem within a ported sleeve, with a high-elasticity, wear-resistant sealing ring. Functions: Opens/closes via plunger reciprocation, offering reliable sealing and long lifespan. Applications: High-pressure systems requiring tight shut-off (e.g., power plants, chemical plants).   26. Bottom Valve Structure: Composed of a body, disc, piston rod, bonnet, and positioning posts; pre-fills suction pipes with liquid before pump startup. Working Principle: Opens during operation to allow flow and closes via liquid pressure/gravity when stopped, preventing backflow. Applications: Essential for centrifugal pumps in water supply and irrigation systems.   27. Sight Glass Structure: A transparent viewing device (e.g., glass or quartz) installed in pipelines to monitor fluid flow, color, or reactions. Applications: Critical in petroleum, chemical, pharmaceutical, and food industries to prevent operational accidents.   28. Flange Structure: A circular plate with bolt holes for connecting pipes, equipment inlets/outlets, or components. Functions: Provides a detachable, leak-proof joint for easy maintenance and system expansion. Types: Welded, threaded, slip-on, and blind flanges, suited for various pressure/temperature conditions.   29. Hydraulic Control Valve Structure: A main valve paired with pilot lines, needle valves, ball valves, and pressure gauges, operated by pipeline pressure. Types: Remote float control valves, pressure reducers, slow-closing check valves, flow controllers, pressure relief valves, etc. Applications: Water supply, irrigation, and industrial systems for automatic pressure/flow control. This comprehensive list covers the core structures, functions, and applications of common valves, serving as a practical reference for engineering and maintenance.

Part 2: Ductile Iron Manhole Covers – The Invisible Armor of Modern Cities The Science Behind the Revolution   Ductile iron’s superiority lies in its microstructure. Traditional cast iron contains flake graphite, which acts like internal cracks under stress. In contrast, ductile iron’s spheroidal graphite (formed via magnesium/cerium treatment) disperses stress like microscopic ball bearings, combining steel-like hardness with aluminum-like ductility. Modern ductile iron manhole covers adhere to standards like EN 124 and ASTM A48, with load ratings from A15 (pedestrian) to F900 (airport runways). Japanese engineers have even developed “seismic-resistant” covers that flex during earthquakes, preventing pipeline misalignment.   From Utility to Smart City Tech   Today’s ductile iron access covers transcend their original role. In Singapore, sensor-equipped covers monitor real-time flood risks and gas leaks. Berlin trials “energy-harvesting” covers that convert traffic vibration into streetlight electricity. Advanced epoxy coatings now extend lifespan beyond 50 years, reducing replacement waste. Meanwhile, cities have turned covers into cultural canvases: Osaka’s cherry-blossom-patterned ductile iron manhole covers draw tourists, while New York’s “Manhole Portrait Project” honors local heroes—all without compromising slip resistance, thanks to precision casting tech.   Sustainability Challenges & Innovations   Despite their benefits, ductile iron production faces scrutiny. Traditional methods emit 1.8 tons of CO₂ per ton of iron, reliant on finite ore reserves. The industry is responding: Chinese firm Tieji New Materials produces covers with 30% recycled content, cutting carbon footprints by 40%. The EU’s Underground Infrastructure 2030 initiative mandates traceable recycled metals for all new covers. Future breakthroughs may include bio-based alloys and electric arc furnace recycling, reshaping what ductile iron access covers mean for eco-conscious cities.  

Part 1: Cast Iron Manhole Covers – Silent Witnesses of the Industrial Age The Birth of Cast Iron Manhole Covers: From Sewers to Urban Icons In the early 19th century, as the Industrial Revolution swept across Europe, underground utility networks expanded explosively, demanding durable solutions for urban infrastructure. Cast iron manhole covers emerged as both a practical necessity and a symbol of modern civilization. Chosen for its high melting point and ease of casting, early cast iron covers weighed hundreds of pounds, requiring teams of workers to install. Interestingly, their ornate patterns were not merely decorative—the intricate grooves were designed to prevent slips by horses and pedestrians on rain-slicked streets. In cities like London and Paris, cast iron covers became cultural artifacts. Foundries stamped them with municipal crests, factory logos, and even poetry, blending functionality with artistry. However, cast iron’s inherent brittleness plagued cities. Freezing winters caused covers to crack from thermal stress, while heavy horse-drawn carriages shattered them into fragments. By the 1920s, as automobiles replaced carriages, the shortcomings of cast iron grew unbearable. A 1927 New York Times article quipped, “The clatter of breaking manhole lids has become the soundtrack of New York drivers.” The Quest for a Better Material Engineers experimented with thicker castings and alloy adjustments, but progress stalled until World War II. Wartime demands for resilient metals spurred metallurgical breakthroughs. In 1943, American metallurgist Keith Millis discovered that adding magnesium to molten iron transformed graphite into spheroidal structures, creating ductile iron. This new material tripled the tensile strength of traditional cast iron while offering unprecedented flexibility. Ductile Iron’s Debut: A Game-Changer By the 1950s, pilot projects in Detroit and Chicago tested the first ductile iron manhole covers. Results were staggering: they could bear over 25 tons of weight and withstand temperatures from -40°C to 120°C. Equally compelling was their reduced weight—30% lighter than cast iron counterparts—slashing installation costs. Resistance from traditional foundries (“untested novelty!”) faded after a 1958 Philadelphia accident: a truck crushing a cast iron cover sent deadly shrapnel flying, while a nearby ductile iron access cover merely dented. This tragedy accelerated global adoption, cementing ductile iron as the future of urban infrastructure.    

Spring into Action: SND FOUNDRY Employees Plant Seeds of Sustainability on Arbor Day   March 12, 2025 Embracing the spirit of environmental stewardship, SND FOUNDRY marked China’s 47th Arbor Day by organizing a tree-planting initiative at Wuan Industrial Park, uniting over 50 employees to plant 80 saplings. This activity underscored the company’s commitment to green development and community engagement. At 9:00 AM, teams arrived at the designated site, equipped with shovels and watering cans. Guided by local forestry experts, participants divided into groups to plant native species like poplars and pagoda trees. A lively symphony of shovels and laughter filled the air as employees collaborated in digging holes, carefully placing saplings, and watering them with precision. By noon, rows of young trees stood proudly, transforming the once-barren area into a vibrant green space. “Planting trees isn’t just about ecology—it’s about leaving a legacy,” shared Wang zhiheng, a participant. “This hands-on effort reminds us how collective action can shape a sustainable future.” The event also highlighted SND FOUNDRY ’s broader environmental strategy, including plans to reduce carbon emissions by 25% by 2030. Future initiatives will integrate green practices into daily operations, such as adopting energy-efficient technologies and partnering with eco-conscious suppliers. This Arbor Day celebration not only enriched the local ecosystem but also reinforcedSND FOUNDRY ’s role as a responsible corporate citizen. Stay tuned for updates on upcoming sustainability projects!  

SND FOUNDRY Launches Sustainability Initiative to Reduce Carbon Footprint   March 22, 2025 In line with its commitment to environmental responsibility, SND FOUNDRY unveiled its Green Horizons Initiative on March 22, 2025—a comprehensive plan to achieve carbon neutrality by 2030. The program includes transitioning 50% of shipping operations to eco-friendly vessels, adopting renewable energy at warehouses, and partnering with suppliers who prioritize sustainable practices. “As a global supplier, we recognize our role in combating climate change,” stated Andy Hao. The initiative also introduces a carbon-offset partnership with EarthGuard, allowing clients to offset emissions tied to their shipments. Early trials in Q1 2025 reduced supply chain emissions by 15%, with full implementation expected by late 2026. Employees are encouraged to participate in monthly sustainability workshops, fostering a culture of eco-conscious innovation. Learn more about the initiative on our website’s new “Sustainability Hub.”  

Strategic Partnership with Global Logistics Leader Boosts Trade Capabilities March 24, 2025 SND TECH, to better service on export business, is thrilled to announce a groundbreaking partnership with Global Partners Inc., a top-tier logistics provider specializing in cross-border supply chain solutions. This collaboration, finalized on March 20, 2025, will streamline operations across Asia-Pacific and European markets, enhancing delivery efficiency by 30% and reducing transit times for clients. The alliance integrates SND FOUNDRY’s expertise in commodity trading with Global Partners’ AI-driven logistics platform, enabling real-time shipment tracking and customized inventory management. “This partnership aligns with our mission to deliver seamless, tech-driven trade solutions,” said Alicia Li. “It empowers us to meet rising client demands for speed and transparency.” To celebrate this milestone, a joint webinar will be held on April 5, 2025, detailing benefits for existing clients. Stay tuned for updates!