Gear pump

About: Gear pump is a research topic. Over the lifetime, 7490 publications have been published within this topic receiving 38837 citations. The topic is also known as: Gear pump.

Injection of additives into liquid streams

Abstract: A gear pump is modified by the incorporation of a hollow rod means to permit a liquid additive to be injected into the gear pump at the point at which the gear wheels separate. At this point the pressure is at or below atmospheric pressure and, as a result, the additive can be added uniformly and independently of the pumped liquid flow and pressure.

Continuously variable transmission-based planetary gear

Abstract: A continuous variable transmission is provided that is based on gearwheels. The novel gear acts as an efficient transmission that can replace conventional manually or automatics gears. The CVT comprises sun gear connected to input shaft and ring gear fixedly connected to output shaft. Planet gear is arranged between and engaged with the sun gear and the ring gear wherein a planet carrier that is vertically enclosing the ring gear and the sun gear is provided with a canal in which an oil pump is provided. A control valve is capable of controlling the flow of lubricant within the canal.

Test stand for testing hydraulic devices

Abstract: A test stand for testing hydraulic devices such as hydraulic pumps and motors, either separately or jointly. The test stand is comprised of a primary power source which acts in combination with a hydraulic motor to drive a drive train, which is in turn, operated by a hydraulic pump. The hydraulic pump and the hydraulic motor are fluidly connected together by passage means so that hydraulic fluid can be pumped therebetween. A pressure control means is present in the passage means for sensing and preventing the pressure from going above a predetermined value. Connected between this pressure control means and the hydraulic motor is a control means for adjusting the fluid displacement of the hydraulic motor to correspond to the fluid output of the hydraulic pump. This control means enables the hydraulic motor to operate in synch with the hydraulic pump at all times. The test stand also has power regenerative features wherein the hydraulic motor is capable of converting the fluid pressure to mechanical power. This power is then used to drive the drive train.

Cooling system for a motor

Abstract: Cooling system for an electric motor with a gear case, a liquid-, internally cooled or at least hollow rotary shaft and an externally cooled stator, particularly for a traction motor. In order to provide a cooling system, incorporating shaft cooling, which permits high utilisation of the machine and can also be employed for encapsulated and therefore low-noise motors, a system of passages 16, 17, 19 which connects the rotor shaft 6 and the gear case is provided to allow the introduction of gear oil from the oil space 18 of the gear case 15 into the rotor shaft 6 as a coolant and to allow the said gear oil to be returned from the rotor shaft 6 to the gear case 15.

Evaluation of the Hydro—Mechanical Efficiency of External Gear Pumps

Abstract: This paper proposes and describes a model for evaluating the hydro-mechanical efficiency of external gear machines. The model is built considering and evaluating the main friction losses in the machines, including the viscous friction losses at the tooth tip gap, at the bearing blocks-gears gaps, at the journal bearings, and the meshing loss. To calculate the shear stress at each gap interface, the geometry of the gap has to be known. For this reason, the actual position of the gears inside the pump casing and consequent radial pressure distribution are numerically calculated to evaluate the gap height at the tooth tips. Moreover, the variation of the tilt and reference height of the lateral gaps between the gears and the pump bushings are considered. The shear stresses within the lateral gaps are estimated, for different lateral heights and tilt values. At the journal bearings gaps, the half Sommerfeld solution has been applied. The meshing loss has been calculated according to the suggestion of the International Standards. The hydro-mechanical efficiency results are then discussed with reference to commercial pumps experimentally characterized by the authors in a previous work. The average percentage deviation from experimental data was around 2%, without considering the most critical operating conditions (high delivery pressure, low rotational speed). The limits of this approach are also explained. Finally, the role of each source of loss is discussed, considering different operating conditions and two values of fluid viscosity. Lateral gap losses and meshing loss are much more relevant in determining the hydro-mechanical efficiency variation in the pump’s operating range, especially at a low delivery pressure. Moreover, while lateral gap losses increase with the rotational speed, the meshing loss shows the opposite behavior. The tooth tip gap losses are never as relevant, but they increase at high pressure. The journal bearings losses become comparable with the lateral and meshing ones at high delivery pressure values. Considering the pumps analyzed and the operating range of delivery pressure values and rotational speed values, the meshing loss made the mechanical efficiency vary in a percentage range of ±7%, with lateral losses in the range of about the ±15%, when also considering the extreme operating points (low speed, high pressure; high speed, low pressure). The weight of the lateral losses slightly reduced when we analyzed the higher temperature results, while the meshing losses slightly increased.