Design Of Hydrodynamic Machines: Pumps And Hydr...
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Pump pressure rating is generally limited by the capability of the pump to withstand pressure without undesirable increase in internal leakage, and without damage to the pump parts. Although many pumps can withstand pressures within the very wide range of 500 to 15,000 psi, ratings for maximum continuous service are often clustered in the 2,000 to 4,000-psi range. Typically, maximum pressure for external gear and vane pumps are from 2,000 to 4,000 psi. Internal-gear units run somewhat lower, with maximums in the range of 1,500 to 2,000 psi. Most piston pumps are designed for a maximum rating of 3,000 psi, although some are suitable for 5,000-psi service. A few permit higher pressures for intermittent peak loads
Most pumps used today were designed for petroleum fluids -- oil -- and nearly all worked well with them. When other fluids are used in these pumps, some suffer. Accordingly, a pump must be specially selected to operate with special fluids. Certain types of pumps do not work well with some hydraulic fluids.
Test data on \"typical\" pumps is readily available from most fluid suppliers, but there are some instances where field and bench experience do not correlate well. Subtle differences in pump design and conditions of use can drastically change wear rates. Size and weight: Straightforward comparison of size and weight characteristics by basic pump type is prevented by the overlap of individual designs. For instance, the axial-piston design that is widely used in industrial, marine, and aircraft applications can have many power/weight ratios, depending on the applications for which it is built. One common type of mobile pump has a ratio around 0.75 hp/lb; others may be 2.5 hp/lb. The additional expense of a highly refined piston pump capable of delivering 4 hp/lb is warranted for aircraft use, where every pound carries a double penalty. When reduced to miniature size for missile use (and when life is sacrificed for power), the same basic mechanism may deliver 8 hp/lb. Environment: Usually, effect of ambient temperature and altitude on performance is independent of the type of pump. Limits for satisfactory operation are established primarily by the effect of the environment on the fluid rather than by the type of pumping action. Humidity only affects requirements for the exterior casing.
In short, machine designers must find ways to fit the required components with the right power into tight spaces to satisfy demands for smaller, more powerful equipment. Here are a few considerations concerning hydraulic pumps that might help engineers strike the right balance.
Liebherr offers axial piston pumps for open and closed circuits. As with all axial piston machines from Liebherr, these feature a swashplate design. The product range covers a broad range of applications in mobile and stationary hydraulics.
Multics is a cross-platform, multi-physics modeling software for positive displacement machines. It enables rapid design assessment and optimization. Multics simulates the operation of hydraulic pumps/motors, combining multiple domains of study, such as:
New feature introduction Maha has worked on innovative design feautes to expand the range of applications in specific pump/motor designs, resulting in a variet of prototype developments Energy efficiency improvement Researching better designs of pump/motor units to decrease losses due to heat and friction is an area in which Maha is doing significant work. Optimal operating range expansion Through study of the limiting factors of unit operation, Maha develops and tests new solutions that can increase the envelope of conditions in which a pump/motor can run. Micro-shaping on running surfaces of lubricating interfaces improves hydrodynamic effects and reduces friction Noise emissions reduction Through increased understanding of unit noise sources from acoustics modeling and study, new solutions are being developed to reduce frequency emissions. See Noise Contol & Acoustics for more. Pump electrification: ePump Maha is creating and validating designs for integrated electric-hydraulic machine prototypes. See Electrification of Fluid Power Systems for more.
The return line in a closed loop circuit is under constant pressure. This must be considered when designing an axial piston pump that is used in a closed loop circuit. It is also very important that a variable displacement volume pump is installed and operates alongside the axial piston pump in the systems. Axial piston pumps can interchange between a pump and a motor in some fixed displacement configurations.
Some gear pumps are quite noisy. However, modern designs incorporating split gears, helical gear teeth and higher precision/quality tooth profiles are much quieter. On top of this, they can mesh and un-mesh more smoothly. Subsequently this reduces pressure ripples and related detrimental problems.
We are a leading supplier of hydraulic pumps, accumulators, valves & Hauhinco systems. Our hydraulic system design & development process is market leading, our lead times are exceptional and our revolutionary COREX cylinder coatings have made headlines around the world.
Flow analysis within machines: The viscous 3-D numerical simulation of steady-state flows in turbines and pumps and the resultant refined knowledge of internal flow physics have led to a significant improvement in the performance characteristics of hydraulic machines. Further improvements in the operating qualities and performance of hydraulic machines can be made using advances in computational modelling. Faster computers, improved computational methods, advances in turbulence modelling, and the inclusion of unsteady multi-phase flow physics in the \"Numerical Laboratory,\" combined and correlated with laser doppler and dynamic pressure measurements of rotating and stationary parts in turbines in the \"physical Model Laboratory\" will provide the basis for these improvements. Analyses accounting for unsteady 3-D viscous flows including the interaction between stationary and rotating components will be a central research theme in the future. The activities of WG 4 will use advanced flow analysis technologies to advance the state of the art in understanding scale effects.
Other activities: Future activities will include research on pumps dealing with two-phase flow and non-linear problems solved by new techniques such as chaos theory. Draft tube flow appears to be one of the subjects suitable to be studied by such methods. As a consequence of the wishes of hydro plant owners for improved reliability and reduced downtime, considerations for the future will also include the development of new materials and manufacturing methods for hydraulic machines, as well as the analytic tools for design and evaluation of machine components. Research to improve the environmental friendliness of hydraulic machines will become a significant theme, including methodologies for increasing fish passage survival and for reducing water borne pollution. Methodologies for sensing and diagnosing impending plant problems and for making recommendations for mitigation are also subjects of growing interest.
Hydraulic fittings and couplings get taken for granted, especially with mobile machinery, where profit margin can overshadow design. The reality is that fittings and couplers are as crucial to the design of a machine as are the pumps, valves and actuators.
Oilgear components operate in the harshest of environments for the toughest applications. Oilgear pumps feature time-tested hard-on-hard technology and a hydrodynamic bearing design that allows the pumps to resist system contamination better than comparable units, as well as operate on environmentally-friendly hydraulic fluids. Today Oilgear supplies fluid power components to the construction, mining, agriculture, and forestry industries, as well as metal forming, stamping, machine tool, and other associated industries.
Centrifugal pumps use hydrodynamic energy to move fluids. They feature a rotating axis, an impeller, and a casing or diffuser. Most often, operators use them for applications such as petroleum pumping, sewage, petrochemical pumping, and water turbine functioning.
Hydraulic ram pumps are a type of hydraulic pump designed to harness hydropower, or the power of water, to elevate it. Featuring only two moving hydraulic parts, hydraulic ram pumps require only the momentum of water to work. Operators use hydraulic ram pumps to move water in industries like manufacturing, waste management and sewage, engineering, plumbing, and agriculture. While hydraulic ram pumps return only about 10% of the water they receive, they are widely used in developing countries because they do not require fuel or electricity.
At Metro Hydraulic, we supply a range of hydraulic parts to different sectors across all industries worldwide. We carry a massive inventory for immediate shipment. Browse our expansive product offerings and services to find components that fit your operational needs. If you are unable to find a product in your desired specification, we also provide customization services. We can help you design and build custom hydraulic pumps, motors, etc., to match your exact specifications.
Keeping a market expectations mindset, Bosch Rexroth is setting a new standard for hydraulic pumps with continuous development at the highest standards and quality. Rexroth pumps are designed for high reliability and efficiency.
A piston pump is a positive displacement pump that uses reciprocating motion to create rotation along an axis. Some piston pumps have variable displacement, while others have a fixed displacement design.
The primary difference between a gear pump and a piston pump is how they are designed. While both pumps need hydraulic fluid to generate mechanical power, a piston pump uses a piston to move liquid throughout the pump valves, while a gear pump uses cogs to move fluid throughout the pump. 59ce067264