The invention relates to a positive displacement pump (10) comprising a pump body (11, 101, 201) comprising an inlet end (16, 116, 216) and an outlet end (18, 118, 218), a pumping chamber (30, 130, 230) arranged between said inlet end (16, 116, 216) and said outlet end (18, 118, 218), at least one membrane (20, 120, 220) active in the pumping chamber (30, 130, 230) and mobile between an expanded configuration in which the volume of the pumping chamber (30, 130, 230) is maximum and a retracted configuration in which the volume of the pumping chamber (30, 130, 230) is minimum, a delivery valve (46, 146, 246) arranged close to the outlet end (18, 118, 218) of the pump body (11, 101, 201), an intake valve (26, 126, 226) comprising an intake mouth (27, 127, 227), an outlet mouth (28, 128, 228) and a valve wall (29, 129, 229) that joins the intake mouth (27, 127, 227) to the outlet mouth (28, 128, 228), the intake mouth (27, 127, 227) being coupled to the inlet end (16, 116, 216) of the pump body (11, 101, 201) and the outlet mouth (28, 128, 228) being inserted in the pumping chamber (30, 130, 230). Said at least one membrane (20, 120, 220), when in the retracted configuration, adheres to the valve wall (29, 129, 229) of the intake valve (26, 126, 226) and the intake valve has the outlet mouth closed.

A piston fuel pump for an internal combustion engine includes a pump housing, a piston, and a non-return discharge valve. The non-return discharge valve has a valve element and a guide element configured to guide the movement of the valve element. The guide element is at least indirectly pressed in a radial manner into an opening in the pump housing.

The invention relates to a positive displacement pump (10) comprising a pump body (11, 101, 201) comprising an inlet end (16, 116, 216) and an outlet end (18, 118, 218), a pumping chamber (30, 130, 230) arranged between said inlet end (16, 116, 216) and said outlet end (18, 118, 218), at least one membrane (20, 120, 220) active in the pumping chamber (30, 130, 230) and mobile between an expanded configuration in which the volume of the pumping chamber (30, 130, 230) is maximum and a retracted configuration in which the volume of the pumping chamber (30, 130, 230) is minimum, a delivery valve (46, 146, 246) arranged close to the outlet end (18, 118, 218) of the pump body (11, 101, 201), an intake valve (26, 126, 226) comprising an intake mouth (27, 127, 227), an outlet mouth (28, 128, 228) and a valve wall (29, 129, 229) that joins the intake mouth (27, 127, 227) to the outlet mouth (28, 128, 228), the intake mouth (27, 127, 227) being coupled to the inlet end (16, 116, 216) of the pump body (11, 101, 201) and the outlet mouth (28, 128, 228) being inserted in the pumping chamber (30, 130, 230). Said at least one membrane (20, 120, 220), when in the retracted configuration, adheres to the valve wall (29, 129, 229) of the intake valve (26, 126, 226) and the intake valve has the outlet mouth closed.

A piston-type fuel pump for an internal combustion engine includes a pump housing, a piston, an annular counterplate, and a non-return outlet valve. The pump housing includes a stepped opening and a piston opening. The piston is guided in the piston opening. The counterplate is pressed into the stepped opening and includes a valve seat. The non-return valve includes a valve element and a guide element. The guide element guides the valve element, is arranged radially outside the valve element and in the stepped opening, and includes a guide section, a retention section, and a support section. The guide section guides the valve element, the retention section is connected to the guide section via a radially extending connecting section, and the support section supports a valve spring. The sections are arranged axially at different points such that the guide section is between the counterplate and the support section.

A piston-type fuel pump for an internal combustion engine includes a pump housing, a piston, an annular counterplate, and a non-return outlet valve. The pump housing includes a stepped opening and a piston opening. The piston is guided in the piston opening. The counterplate is pressed into the stepped opening and includes a valve seat. The non-return valve includes a valve element and a guide element. The guide element guides the valve element, is arranged radially outside the valve element and in the stepped opening, and includes a guide section, a retention section, and a support section. The guide section guides the valve element, the retention section is connected to the guide section via a radially extending connecting section, and the support section supports a valve spring. The sections are arranged axially at different points such that the guide section is between the counterplate and the support section.