Pumping protection equipment - I

Pumping protection equipment is essential to prolong the life of the network. Pumping systems are vital parts of the maintenance of irrigated fields and sports fields, and in critical periods we need to have the system ready.

The greatest dangers to which an irrigation system is subjected are the pressure changes not contemplated in the project. This refers, for example, to the set of pressures and suction that occur during shutdown and start-up, loss of energy supply, or singular points that were not contemplated. This results in phenomena such as water hammer.

Water hammer is a phenomenon that can occur for a variety of reasons, although all are related to the sudden discontinuity in the water supply.

In order to avoid these problems, there is a variety of protective equipment for pumping systems.

• Suction cup.

Suction cups are one of the most versatile protection elements in hydraulics. They are essentially divided into three types of suction cups.

Purging machine - The air vents are used to eliminate air that can enter the hydraulic network due to a problem in the suction or simply the air dissolved in the water. Air tends to accumulate in water installations at high points and if it is not vented, it can affect the correct water supply.

Bifunctional suction cup - This type of device performs two functions. On the one hand it is able to bleed air from the pipes, and on the other hand it allows air to be introduced at times when the pipes suffer from low pressures. The sudden drop in pressure can cause pipes to collapse.

Tri-functional suction cup -  An additional function is added to those described above. The trifunctional suction cups have the capacity to expel water in moments of overpressure in the irrigation system. In this way, the pressure would be normalised more quickly, reducing the impact of water hammer.

• Cauldron.

A boiler is a tank with an air bag inside it at a certain pressure. The air inside the bag works like the suspension of a car, reducing the impact of bumps in the road. The air bag is capable of absorbing over- and under-pressure in the system. For high pressures and flow rates it is necessary to use large capacity boilers, but it is a very useful tool to maintain the stability of the network pressures.

The boiler is a non-hazardous item if used in accordance with the manufacturer's instructions.

• Quick relief valve.

This device is a water outlet. When, for example, the demand for water in the system is drastically reduced, a point overpressure occurs. The quick relief valves are set to the maximum pressure at which the system must work and when this pressure is exceeded, they open automatically and release water until the pressure returns to normal.

These valves must be correctly sized for the pressure and flow rate that the system will be working at. And they are a very effective way of reducing the pressure in the network to safe levels.

There are other methods of protecting the irrigation network which will be explained in future entries in the Greenkeepedia.