Cavitation is the leading cause of pump failure, and is especially prevalent in high-pressure pumps where flow rate and rotational speed can cause increased pump cavitation. To remedy this issue, our PWH series (hot water high-pressure washers) are designed with a positive feed water tank.
What is a Positive Feed Water Tank?
A positive feed water tank supplies water to a pump under a positive head pressure by elevating the water level above the pump inlet, utilising gravity to push the water into the pump.
In simpler terms: Imagine a water tank on a raised platform, with a hose or tap connected to the bottom. If you open the tap the water will flow out – no pump, no motor, just gravity pushing the water out. The higher the tank, the stronger the water pressure will be at the tap. This is the basic principle behind the positive feed water tank.
How Positive Feed Water Tanks Protect Our Hot Water High-Pressure Washers from Damage
Our PWH range is designed with an L-shaped tank that raises the water level above the pump’s inlet. Inside this tank, gravity pushes the above water down on the water below, generating a positive head pressure at the base of the tank. This pressure helps to push water into the pump without the pump having to “suck” water in, as this can cause pump cavitation and starvation.
What Is Pump Cavitation in High-Pressure Washers, and Why is it Dangerous?
Cavitation takes place when a pump does not get enough water and starts pulling in air instead. This either happens when the pump runs out of water, or when it does not have sufficient water available due to a lack of water inlet pressure. When this happens, air bubbles are created inside the pump.
This is particularly dangerous in a high-pressure system where water gets pressurised, because water cannot be compressed – but air can. And when the air bubbles are compressed inside the pump, it creates shockwaves inside the machine. These shockwaves can hit small and precise components inside the pump (like the valves), throwing the pump out of sync and causing damage to your machine.
Cavitation remains one of the most common causes of pump failure in high-pressure machines. That is why it might be time to make the switch to one of our CEMSA Hot Water High-Pressure Washers. Reach out to one of our distributors or contact us to learn more.
