Pumps are destined for pumping fresh and service water, dung water, sludge, liquid manure and thick homogenous liquids with solid particles up to size 5 mm. Possible application e.g. during drainage of flooded spaces, pumping-off underground and waste water, spray irrigation and watering gardens, pumping out of waste water and sludge sump pits. This pump features a simple design and long service life and it is provided with a safety valve.