A rubber compound for use in a stator in a positive displacement motor. The rubber compound includes a fiber reinforcement, wherein fibers in the fiber reinforcement create a grain direction in which “with the grain” is generally orthogonal to “across the grain”. In some embodiments, the rubber compound has a first value for 25% tensile Modulus across the grain and a second value for 25% tensile Modulus with the grain, wherein the first value is at least 10% lower than the second value. In such embodiments, the fiber reinforcement may further include a fiber loading of greater than 5.0 phr of fibers. In such embodiments, the rubber compound may further have a 25% tensile Modulus of greater than 400 psi across the grain and a 50% tensile Modulus of greater than 700 psi across the grain.

A device providing a dosed supply of a liquid includes: a pump configured to deliver the liquid and having a pump housing with an inlet and an outlet; an eccentric on the pump housing; and a deformable diaphragm between the pump housing and the eccentric, the deformable diaphragm and the pump housing delimiting a delivery path from the inlet to the outlet and forming a seal of the delivery path. The seal is displaceable along the delivery path, by a movement of the eccentric, in a delivery direction from the inlet to the outlet to deliver the liquid. The pump is configured such that within the pump a friction torque that must be overcome for the eccentric to move is greater than a maximum pressure torque that can be generated by pressurized liquid in the delivery path, so as to prevent movement of the eccentric counter to the delivery direction.

An impeller pump having a housing, which has an inlet and an outlet, and having an impeller wheel with a plurality of elastic impeller blades is described. The cross section of the inlet and/or of the outlet is substantially in the shape of a polygon on the side facing the housing interior.

A rubber compound for use in a stator in a positive displacement motor. The rubber compound includes a fiber reinforcement, wherein fibers in the fiber reinforcement create a grain direction in which “with the grain” is generally orthogonal to “across the grain”. In some embodiments, the rubber compound has a first value for 25% tensile Modulus across the grain and a second value for 25% tensile Modulus with the grain, wherein the first value is at least 10% lower than the second value. In such embodiments, the fiber reinforcement may further include a fiber loading of greater flan 1.0 phr of fibers. In such embodiments, the rubber compound may further have a 25% tensile Modulus of greater than 400 psi across the grain and a 50% tensile Modulus of greater than 700 psi across the grain.

A water pump for a marine engine includes a cap covering an internal cavity of the pump's housing when the pump is operating. The cap functions as a tool to remove a damaged or worn impeller from inside the internal cavity. A threaded hub of the cap engages internal threads of the impeller to assist a user in removing the impeller for replacement. A cap lock ring threaded onto the pump housing retains the cap over the internal cavity. A rotatable drive shaft has splines which mate with a splined portion of the impeller to rotate the impeller. The cap lock ring is disengaged from the housing and the cap removed to enable a person to use the threaded hub of the cap to remove the impeller.

A mud motor stator or a pump comprising of a tubular outer portion; a number of lobes extending radially inwardly from the tubular outer portion, at least one of which comprises a skeletal structure and method for producing a mud motor stator or a pump comprising of placing material and bonding the material together in a pattern dictated by the design shape of the stator or pump.

A rubber compound for use in a stator. The stator may be deployed in a positive displacement motor. The rubber compound includes a fiber reinforcement, wherein fibers in the fiber reinforcement create a grain direction in which with the grain is generally orthogonal to across the grain. In some embodiments, the rubber compound has a first value for 25% tensile Modulus across the grain and a second value for 25% tensile Modulus with the grain, wherein the first value is at least 10% lower than the second value. In such embodiments, the fiber reinforcement may further include a fiber loading of greater than 1.0 phr of fibers. In such embodiments, the rubber compound may further have a 25% tensile Modulus of greater than 400 psi across the grain and a 50% tensile Modulus of greater than 700 psi across the grain.

A uniaxial eccentric screw pump includes: a casing; a stator having one end portion thereof connected to the casing and having an inner peripheral surface which is formed into a female threaded shaped; a rotor configured to be insertable into the stator and formed of a shaft body having a male threaded shape; and an end stud connected to the other end portion of the stator. The stator is configured to be expandable and shrinkable in a radial direction.

A pump for delivering a fluid includes: a pump housing having an inlet and an outlet, and having an inner circumferential face; a drive shaft; an eccentric inside the pump housing, the eccentric being eccentrically movable relative to the pump housing; a deformable element arranged in a pump gap between the inner circumferential face and an outer surface of the eccentric, the deformable element and the inner circumferential face defining a delivery channel. The deformable element is forced against the pump housing by the outer surface of the eccentric along at least a portion of the delivery channel such to form a sliding sealing of the delivery channel that can be slid along the delivery channel from the inlet to the outlet to deliver fluid by movement of the eccentric. A reinforcing ring has a coefficient of thermal expansion smaller than a coefficient of thermal expansion of the pump housing.

A stator for use in a positive displacement motor. The stator comprises a rubber compound including fiber reinforcement. The fiber reinforcement includes a plurality of elongated fibers. The elongated fibers in the fiber reinforcement create a grain direction generally with the grain in the longitudinal direction of the stator tube and across the grain in the transverse direction. The rubber compound has a 25% tensile Modulus that is at least 10% lower across the grain than with the grain. The fiber reinforcement includes a fiber loading of greater than about 2.5 phr of elongate fibers, the elongate fibers have a Modulus of greater than about 60 GPa, and the rubber compound has a 25% tensile Modulus of greater than about 400 psi against the grain and a 50% tensile Modulus of greater than about 700 psi against the grain. In some embodiments, the rubber reinforcement also comprises a blend of fibrillated fibers and short cut fibers.