Product Overview
The Internal Bladder/Diaphragm Type Pressure Tank is a precision-engineered water treatment component from Hangzhou Shuidun Technology Co., Ltd. (Shuidun Technology), designed to maintain stable water pressure, absorb hydraulic shock, and extend the service life of pumps and downstream equipment in residential, commercial, and industrial water supply systems. As a critical component in modern water treatment and pressurization systems, this pressure tank ensures consistent water flow, reduces pump cycling frequency, and protects the entire plumbing network from pressure fluctuations.
Hangzhou Shuidun Technology Co., Ltd. is a professional manufacturer specializing in the design, manufacture, and distribution of water treatment spare parts, industrial water purification plants, and sewage water treatment systems. The company's product portfolio includes SS membrane housings, cartridge filter housings, bag filter vessels, mechanical filter housings, ion exchange systems, water tanks, and softening vessels. With a manufacturing base located along the beautiful Fuchun River in Fuyang, Hangzhou, and in the Xindeng Economic Development Zone, Shuidun Technology benefits from superior geographical position and convenient transportation infrastructure.
The company operates over 500,000 square meters of intelligent manufacturing facilities, has earned more than 4,000 patents with a compound annual growth rate exceeding 35% over the past three years, and has won over 100 international design awards including the prestigious Red Dot Design Award and iF Design Award. Shuidun Technology maintains ISO9001:2008 Quality Management System certification and holds the National Product of Drinking Water Hygiene and Safety Health Permit Document, ensuring that all products meet the highest standards for potable water applications.
Understanding Pressure Tank Technology
The Role of Pressure Tanks in Water Systems
Pressure tanks serve three essential functions in water supply and treatment systems:
Pressure Stabilization: By providing a reservoir of pressurized water, the tank absorbs fluctuations in demand, maintaining consistent outlet pressure even when multiple fixtures are used simultaneously.
Pump Protection: The tank reduces the frequency of pump start/stop cycles (known as "short cycling"), which is a leading cause of premature pump failure. Each pump activation draws significant inrush current; minimizing cycles extends motor life and reduces energy consumption.
Water Hammer Absorption: When valves close suddenly or pumps shut off, the momentum of moving water creates pressure spikes (water hammer) that can damage pipes, fittings, and fixtures. The pressure tank's compressible gas cushion absorbs these shock waves, protecting the entire system.
Internal Bladder/Diaphragm Design: The Superior Solution
Shuidun Technology's Internal Bladder/Diaphragm Type Pressure Tank represents the most advanced approach to pressure tank design. Unlike traditional galvanized tanks where water and air share a common chamber (leading to air dissolution and waterlogging), this design employs a flexible bladder or diaphragm that physically separates the water chamber from the air charge chamber .
How It Works: The tank is pre-charged with compressed air (typically 1-2 bar below pump cut-in pressure) on one side of the bladder/diaphragm. As water enters the tank, it compresses the air charge, storing energy. When a faucet opens, this stored energy pushes water out, maintaining pressure without immediate pump activation. The bladder expands and contracts with each cycle, never allowing water and air to mix.
Key Advantages Over Conventional Tanks:
No Waterlogging: The physical barrier prevents air from dissolving into the water, maintaining proper air charge indefinitely
No Air Recharge Required: Unlike galvanized tanks that require periodic air addition, bladder/diaphragm tanks maintain their charge throughout their service life
Better Water Quality: Water contacts only the bladder material (FDA-approved butyl rubber), not the tank's metal interior, preventing rust and contamination
Higher Drawdown Efficiency: More usable water volume per tank size compared to conventional designs
Longer Lifespan: The bladder protects the tank shell from corrosion and stress
Construction and Materials
Tank Shell Construction
The pressure tank shell is constructed from high-quality materials selected for durability and corrosion resistance:
Carbon Steel with Anti-Corrosion Coating: The standard tank shell is fabricated from deep-drawn carbon steel, providing excellent structural strength for pressure containment. The exterior receives a durable epoxy or polyester coating for environmental corrosion protection. The interior, where not in contact with the bladder, is coated with a food-grade epoxy lining that meets drinking water safety requirements.
Stainless Steel Option: For applications requiring superior corrosion resistance-such as marine environments, chemical processing, or high-chloride water supplies-Shuidun Technology offers tanks constructed from SS304 or SS316L stainless steel. These tanks provide exceptional longevity in aggressive conditions.
Connection Fittings: All water connections are precision-machined from brass, stainless steel, or high-quality composite materials. Standard configurations include a threaded water inlet/outlet, a pre-charge valve (Schrader-type), and a drain port for maintenance.
Bladder/Diaphragm Material
The heart of the pressure tank is its bladder or diaphragm, which must be flexible, durable, and safe for potable water contact:
Butyl Rubber (FDA-Approved): The standard bladder material is high-quality butyl rubber formulated for drinking water applications. Butyl rubber offers excellent flexibility over a wide temperature range, outstanding resistance to aging and fatigue, and negligible permeability to air-critical for maintaining the pre-charge over time. The material is FDA-approved and meets NSF/ANSI 61 standards for potable water system components.
EPDM Option: For applications involving slightly higher temperatures or specific chemical resistance requirements, EPDM (ethylene propylene diene monomer) rubber bladders are available. EPDM offers excellent resistance to hot water and steam, making it suitable for certain industrial applications.
Diaphragm vs. Bladder Configuration: Shuidun Technology offers both diaphragm-type (a flat or molded rubber sheet fixed at the tank's midpoint) and bladder-type (a balloon-like rubber bag attached at the water connection) configurations. Diaphragm tanks are generally more economical and suitable for smaller sizes, while bladder tanks offer higher drawdown efficiency and are preferred for larger capacities.
Performance Characteristics
Pre-Charge and Operating Pressure
Each pressure tank is factory pre-charged with dry nitrogen or filtered air to a specified pressure, typically 1-2 bar below the pump's cut-in pressure. For example, if a pump is set to start at 2.5 bar and stop at 4.0 bar, the tank would be pre-charged to approximately 2.0-2.3 bar. This pre-charge ensures maximum drawdown (usable water volume) and optimal pump cycle reduction.
The maximum working pressure varies by model, with standard tanks rated for 10 bar (145 psi) and high-pressure models available up to 16 bar (232 psi) or higher for specialized applications.
Drawdown Volume and Efficiency
The drawdown volume-the amount of water that can be drawn from the tank between pump cut-in and cut-out pressures-is a critical performance metric. Bladder/diaphragm tanks typically achieve 70-80% drawdown efficiency, meaning that 70-80% of the tank's nominal volume is usable water. This is significantly higher than conventional galvanized tanks, which may achieve only 30-50% efficiency due to waterlogging.
Temperature Range
Standard pressure tanks with butyl bladders are suitable for water temperatures from 0°C to 60°C (32°F to 140°F). EPDM bladders extend the upper limit to approximately 80°C (176°F) for certain models. For higher temperature applications, consultation with Shuidun Technology's technical team is recommended.
Applications
The Internal Bladder/Diaphragm Type Pressure Tank serves a diverse range of water supply and treatment applications:
Residential Water Systems: Boosting water pressure from wells, cisterns, or municipal supplies; maintaining consistent pressure in multi-story homes; and protecting pumps from short cycling.
Commercial Buildings: Hotels, office buildings, schools, and hospitals requiring stable water pressure across multiple fixtures and floors.
Industrial Water Treatment: RO (reverse osmosis) systems, where pressure tanks maintain consistent feed pressure and absorb pump pulsations; and as buffer tanks in filtration and softening systems.
Agricultural Irrigation: Maintaining pressure in drip irrigation and sprinkler systems; and providing surge protection for irrigation pumps.
Fire Protection Systems: As a component in fire suppression systems, providing immediate water pressure for initial response while the main pump starts.
Why Choose Shuidun Technology's Pressure Tank?
Manufacturing Excellence: Over 500,000 square meters of intelligent manufacturing facilities with advanced automation and quality control systems ensure consistent product quality and reliability.
Certified Quality: ISO9001:2008 Quality Management System certification and National Product of Drinking Water Hygiene and Safety Health Permit Document guarantee that products meet the highest standards for potable water applications.
Innovation Leadership: With over 4,000 patents and more than 100 international design awards including Red Dot and iF Design Awards, Shuidun Technology is at the forefront of product innovation in the water treatment industry.
Comprehensive Product Range: From membrane housings and filter vessels to pressure tanks and softening vessels, Shuidun Technology offers a complete portfolio of water treatment components, enabling one-stop sourcing.
Customization Capability: The company provides custom product design, rich material selection, and customized performance parameters to meet specific customer requirements.
Global Support: With a passionate, experienced team committed to customer satisfaction, Shuidun Technology provides comprehensive pre-sales consultation, technical support, and after-sales service to customers worldwide.
For residential, commercial, and industrial water system designers and operators seeking a reliable, efficient, and hygienic pressure tank solution, the Internal Bladder/Diaphragm Type Pressure Tank from Hangzhou Shuidun Technology Co., Ltd. represents the optimal choice. Combining advanced design, premium materials, and rigorous quality assurance, this product delivers stable pressure, protects system components, and ensures a consistent, reliable water supply.
