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.

Method and apparatus for producing cement or plaster

Abstract: A method and apparatus for forming a cement or plaster slurry, for example, for use in mines, in which bags of cement or plaster are fed into a substantially closed chamber, are ruptured, and water is fed into the chamber at a controlled rate. The resulting mixture is fed into a macerator which serves to comminute the bag material and to mix the cement or plaster which is then fed into a pump, preferably a positive displacement pump, such as a helical gear pump and is thus pumped on to the point of use.

Infinitely variable hydrostatic torque-routing transmission

Abstract: An infinitely variable hydrostatic torque-routing transmission with at least two operating ranges shiftable via switching elements includes a first, mechanical part, including a planetary differential gear, and a second, hydrostatic part, including two adjustable hydrounits. The hydrounits are coupled to each other energetically, are operable in both directions as pump or motor, and are coupled to the mechanical part. The ring gear is coupled, in the various operating ranges, for control of the direction of rotation and speed of rotation of the transmission output shaft, to a first hydrounit, and with the second hydrounit being in the first operating range in drive connection with the transmission output shaft via an alternating switching element, while the first hydrounit, connected to the ring gear, operates as a pump and the second hydrounit as a motor. The ring gear, by means of a second alternating switching element, can be selectively coupled by way of a first gear drive or a second gear drive to the input or output shaft of the first hydrounit. The first gear drive is structured such that the ring gear and the input or output shaft of the first hydrounit rotate in different directions when the ring gear is coupled to the first hydrounit via the first gear drive. The second gear drive is structured such that the ring gear and the input or output shaft of the hydrounit rotate equidirectionally when the ring gear is coupled to the first hydrounit via the second gear drive.

Oil temperature influence on friction torque characteristics in hydraulic pumps

Abstract: This article presents a practical approach to the investigation of the influence of oil temperature on the friction torque in various types of hydraulic pumps using a mathematical model Currently, an external gear, an internal gear or a vane pump is commonly used for an automatic transmission These pumps have their own friction torque characteristics, which depend not only on pump-operating conditions such as operating pressures, pump speeds and oil temperature but also on structures and dimensions of the pumps For various pumps, however, the friction torque characteristics can be represented by an identical mathematical model In the pump-operating conditions, the oil temperature significantly and complicatedly affects them The pump should be operated under conditions to obtain a higher mechanical efficiency, and the mathematical model is helpful to analyse how the oil temperature influences the friction torque It is found that with an increase in oil temperature, the friction torque at a high pump

Cyclic hydraulic actuation for soft robotic devices

Abstract: Undulating structures are one of the most diverse and successful forms of locomotion in nature, both on ground and in water. This paper presents a comparative study for actuation by undulation in water. We focus on actuating a 1DOF systems with several mechanisms. A hydraulic pump attached to a soft body allows for water movement between two inner cavities, ultimately leading to a flexing actuation in a side-to-side manner. The effectiveness of six different, self-contained designs based on centrifugal pump, flexible impeller pump, external gear pump and rotating valves are compared. These hydraulic actuation systems combined with soft test bodies were then measured at a lower and higher oscillation frequency. The deflection characteristics of the soft body, the acoustic noise of the pump and the overall efficiency of the system are recorded. A brushless, centrifugal pump combined with a novel rotating valve performed at both test frequencies as the most efficient pump, producing sufficiently large cyclic body deflections along with the least acoustic noise among all pumps tested. An external gear pump design produced the largest body deflection, but consumes an order of magnitude more power and produced high noise levels. Further refinement remains on determining the suitable oscillation frequencies and inner cavity designs for optimal efficiency and movement.