The strainer is an element of water installations, used for removing impurities in industrial water and non-corrosive liquid supply installations. It has a first end and a second end connected by a slantwise positioned flow chamber with strainer. This flow chamber has a side opening (6) with cover (7) , whereas the interior of the chamber has projections (16) from the opposite walls (12) and (15) . There are flat surfaces with ring gaskets (11) and cylindrical strainer between these projections. On the contrary, the flat surfaces of the chamber diverge from the rear wall (17) towards the edge (18) of the side opening (6) , with respect to the transversal symmetry axis (19) of the chamber, at angles taking values between 1 and 3 degrees. According to the invention, the shape of flow chamber and of the gaskets result in a very compact shape of the whole sediment trap. Its length was minimized and so it needs less place as a part of any pipeline. Furthermore, because of specific positioning of the first and second ends the active surface of the strainer increased and the whirling of flowing liquids decreased. Also some inconveniences of assembly and exchange procedures were eliminated.