What Does a Pressure Vessel do on a Booster Set?

The Basics: What is a Pressure Vessel?

At its core, a pressure vessel holds an amount of pressurised water within a rubber bladder contained inside the vessel. It’s specifically engineered to withstand the constant pressure fluctuations inherent in a pumping system and ‘cushions’ your system against shockwaves which occur when the demand for water either stops or is closed off suddenly. It is situated on the discharge pipework and prevents the booster set from stopping or starting too regularly.

A pressure vessel doesn’t create any pressure but the bladder is effectively filled as a result of the pressure created by the booster pumps, before discharging it as and when required.

The Key Roles of a Pressure Vessel in a Booster Set:

Here’s where the magic happens. The pressure vessel performs several vital functions to keep your booster set operating efficiently and reliably:

1. Pressure Stabilisation: The Smooth Operator:
   Imagine a booster set constantly cycling on and off to maintain pressure. This would lead to significant wear and tear on the pump, cause annoying pressure fluctuations and wasted energy. The pressure vessel acts as a reservoir, absorbing pressure spikes and smoothing out the pressure curve. It’s like a shock absorber for your water system, preventing sudden surges and dips.
2. Reducing Pump Cycling: Extending Pump Lifespan:
   By providing a buffer of pressurised water, the pressure vessel allows the pump to run for longer periods and less frequently. This significantly reduces the number of starts and stops, which are the most stressful events for a pump motor. Fewer starts mean less wear and tear, leading to a longer lifespan for your valuable pump.
3. Water Storage: Instant Availability:
   Think of the pressure vessel as a reserve tank ready to provide water when needed. When demand is low, the pump refills the vessel, keeping it pressurised. Then, when someone turns on a tap or flushes a toilet, the pressurised water in the vessel is readily available, minimising the time it takes for the pump to kick in.
4. Preventing Water Hammer: The Silent Protector:
   Water hammer, also known as hydraulic shock, is a sudden pressure surge that can occur when a valve is rapidly closed. This can cause loud banging noises in the pipes and, in severe cases, damage the system. The pressure vessel acts as a cushion, absorbing the energy of the surge and preventing it from spreading through the pipes.
5. Improved System Efficiency: Saving Energy and Money:
   By reducing pump cycling and maintaining stable pressure, the pressure vessel helps to optimise the energy consumption of the booster set. The pump doesn’t have to work as hard, resulting in lower electricity bills and a smaller carbon footprint.

The set pressure of a vessel will vary depending on the system pressure. The set pressure of the vessel, however, is typically around 0.5 bars below the set pressure to turn the booster pump on. When a tap is opened, the vessel is first emptied of water, which maintains pressure on the system. Once it’s emptied, the pressure of the system drops. This in-turn activates the pressure transducer, which signals for the pumps to start and ensures that the required flow is continued. Once demand is cut off, the booster will continue to run until the vessel is filled and the maximum set pressure on the system is reached.

Different Types of Pressure Vessels:

While the basic principle remains the same, pressure vessels come in different types, primarily:

• Bladder Tanks:  These have a flexible bladder that separates the water from the pressurised air. This prevents the air from dissolving into the water and improves performance.
• Diaphragm Tanks:  Similar to bladder tanks but use a diaphragm instead of a bladder.
• Air-Over-Water Tanks:  The oldest design, where the air is in direct contact with the water. These require more frequent maintenance to replenish the air charge.

Why Choosing the Right Pressure Vessel Matters:

Selecting the correct size and type of pressure vessel is critical for optimal booster set performance. Factors to consider include:

• System Flow Rate:  The amount of water used in the system.
• Pump Capacity:  The maximum flow rate of the pump.
• Pressure Requirements:  The desired water pressure in the system.
• Application Type:  Commercial or industrial.

Consult with a qualified pump system professional like Dura Pump to ensure you choose the right pressure vessel for your specific needs.