Sinopec Pva 088-05,Sundy Pva 088-05,Polyvinyl Alcohol Pva 0588,Changchun Pva Bp-05 Saint Petrochemicals Limited , https://www.saintpec.com
In many homes worldwide, water heating systems like boilers or water heaters are commonly installed. If these devices overheat, internal pressure can increase dramatically, potentially causing the tank to rupture. While rare, such incidents can lead to serious damage, with a water heater even being propelled through a house’s floor and roof. How can we rest easy knowing that such a risk exists in our basements?
The solution lies in a small but vital device known as the Temperature/Pressure Relief Valve (TPRV). This spring-loaded valve is typically located on the side or top of the tank. When pressure or temperature exceeds safe levels, the valve opens, releasing water to reduce internal pressure and prevent catastrophic failure.
This valve rarely needs to open, and its operation should only occur if the thermostat fails. Much like a car’s airbag or a building’s fire sprinkler system, it remains dormant until needed. However, its presence is essential for safety and system integrity.
Pumps are used to move liquids through various systems, creating pressure due to factors like head pressure, friction loss, or resistance from equipment like filters or meters. In an ideal scenario, this pressure is well-managed. But real-world conditions can change—pipes may corrode, filters may clog, or valves might be accidentally closed. These situations can cause dangerous pressure buildup.
For kinetic pumps like centrifugal or turbine pumps, flow rate changes with pressure, and they may not require overpressure protection. However, rotary positive displacement pumps, such as gear or lobe pumps, maintain a consistent flow regardless of pressure. If a blockage occurs, pressure can rise rapidly, risking damage to the pump, drive system, or piping. For these types of pumps, overpressure protection is critical, and relief valves are the most common solution.
Relief valves typically consist of a spring and a poppet. Under normal conditions, the spring keeps the poppet closed. As pressure increases, the spring is overcome, allowing the valve to open and release excess flow. Once pressure returns to normal, the valve closes again. Some models allow for adjustment of the pressure setting.
Important Note: This information applies specifically to Viking Pumps. Other manufacturers may have different designs, such as fixed-setting valves or those requiring the pump to be shut off to close after activation. Always check with the manufacturer when using non-Viking components.
There are three main types of relief valves used with Viking Pumps:
1. **Internal Relief Valves**: These are built into the pump and do not require additional piping. They redirect flow internally from the discharge back to the inlet. While compact and easy to install, they can be hard to detect when in bypass mode and may cause overheating if operated for long periods.
2. **Return-to-Tank Relief Valves**: These divert excess flow back to the supply tank or inlet line via piping. They allow for easier monitoring and help dissipate heat. These are standard on certain Viking Pump models, such as the 4924A Seriesâ„¢ Ammonia Pumps.
3. **Inline Relief Valves**: Installed in the downstream piping, these require additional connections to direct flow back to the tank or inlet. They are useful in systems where frequent bypassing is expected and are often used alongside other valve types.
It's important not to install isolation valves between the pump and a system relief valve, as this could create dangerous overpressure scenarios. In such cases, an additional relief valve on the pump is still necessary.
In an ideal system, a pressure relief valve should never need to activate. It is not a flow control or pressure regulator but a safety mechanism meant to prevent catastrophic failures. Just like the TPR valve on a water heater, multiple layers of protection—such as rupture discs, pressure transmitters, and motor protection—are recommended.
Many Viking pumps have operated for decades without ever needing their relief valves. Yet, their inclusion is crucial for system safety. Often overlooked, the pressure relief valve is the silent guardian your pump system needs.