WELL PUMPING UNIT WITH SLUDGE TRAP Russian patent published in 1999 - IPC

FIELD: well pumping units. SUBSTANCE: unit includes sections of electric motor and multi-stage centrifugal pump connected in series by means of delivery pipe line and located in well. Drain valve unit is arranged between sections. Sludge trap mounted between pump discharge and delivery pipe lines includes fishing head, body and base. Delivery branch pipe provided with radial displacement compensator and check valve is secured on base. Check valve has seat with holes for flow of formation fluid which are closed by shut-off member fitted with axial displacement limiter in case of stoppage of pump. Shut-off member is made in form of cone changing into cylinder with rod. Angle between cone generatrices of shut-off member is equal to 120 deg; ratio of diameters of cylinder and rod exceeds 5:1. provision is made for avoidance of clogging of working members of pump in case of its stoppage. EFFECT: facilitated start of pump; avoidance of clogging of upper stages of pump in case of stoppage of pump. 3 cl, 2 dwg