Irrigation

• Shows the relationship of delivery rate Q (litres per hour) to delivery head H (in meters). In this regard 10 m delivery head also corresponds to 1 bar. When the performance curve reaches the maximum delivery head, the delivery head goes to 0. When the delivery head goes to 0, the pump reaches the maximum delivery capacity.
• The actual operating point in the system can be determined with the aid of the performance curve.

• A self-priming pump is theoretically capable of sucking in water up to a vertical height difference of 10 m. In this process the pump evacuates the air from the hose line between the water level below and the suction port of the pump above. In practice, due to the conditions and additional fittings, often an intake height of up to 8 m is assumed as the maximum height that can be achieved.
• So-called normal-priming pumps cannot evacuate air from the suction line. In this case the suction line must always be filled with water.

All irrigation pumps with possible applications – overview:

• Irrigation pumps are characterised by the fact that with their high delivery pressures between 4 and 6 bar, and at low to moderate delivery rates, they can be used anywhere in the house and garden where valuable drinking water can be replaced with well water or service water, through their help. Thus, in order to optimally charge valves of washing machines, toilets, etc. with water, the combination of adequate delivery pressure reserved together with full water capacity is always crucial.

• The larger the hose diameter, the better chance you can achieve the greatest possible delivery capacity.
• Also pay particular attention to the cross sections of couplings, connection pieces, valves or fittings. The smallest free cross section in the entire line system has the deciding influence on the undesired reduction of delivery capacity.

• In order for the pump to be capable of evacuating the air from the suction line, this line section between water point and pump must be manufactured vacuum-tight. If there is the smallest leak in this area, air will always flow back into the line thus the pump will not be capable of building up the necessary suction.
• Thus, when commissioning, if the pump does not displace any water, check all components of the suction line with particular thoroughness. Due to the fact that air is suctioned into the line, leaks are hard to find.

• To evacuate the air out of the suction line, prior to initial commissioning, the pump must be filled with water as specified in the operating instructions. The pump can only build up pressure after this has been done.
• On the pressure side, always connect a line section or hose of at least 1 m in length that ends with an opened valve at least 50 cm above the pump. This is necessary so that the air evacuated from the suction hose can be dissipated by the pump via the open end of the pressure line, and so that the fill water is not forced out of the pump while the air is being evacuated.

• Effectively prevent falling of the water column in the line after switching off the pump, to the water level, and thus after successful initial commissioning they ensure that water displacement begins immediately after the pump is switched on again. In this case it is no longer necessary to wait until the pump has evacuated the air out of the suction line.