Hydraulic pumps play a crucial role in the research and application of hydraulic transmission technology. Among them, hydraulic metering pumps are particularly important for precise fluid control. In general, hydraulic pumps are categorized into four types based on their structure: gear pumps, vane pumps, screw pumps, and piston pumps. However, gear, vane, and screw pumps typically experience higher contact pressures due to their sliding or rotating components, which can lead to increased friction and wear.
For example, in vane pumps, the vanes slide back and forth within the rotor's guide grooves during rotation. The lateral stress is highest at the contact edges, especially under high pressure, where centrifugal force presses the vanes against the stator’s inner surface. Due to the limited contact area, the contact pressure becomes quite significant, contributing to accelerated wear.
In contrast, piston pumps are widely used in hydraulic pressure pump applications, both domestically and internationally. They come in two main structural forms: valve-type axial piston pumps (including radial and swash plate configurations) and swash plate axial piston pumps. The advantage of piston pumps lies not only in their ability to reduce contact friction but also in their use of hydrostatic support for friction pairs, unlike gear or vane pumps that rely on line contact. This significantly lowers the PV value (pressure-velocity product), reducing power loss and wear—especially important in aqueous environments where lubrication is poor and elastic lubrication is difficult to achieve.
As a base pump for variable displacement systems, axial piston pumps are commonly employed. Valve-controlled axial piston pumps offer good resistance to contamination and, in certain applications like bow-bottom drain pumps, provide long service life and high reliability. However, while there are many designs for valve-controlled variable displacement pumps, their complex structures often lead to higher manufacturing costs and limited applicability, making them less economically viable.
Swash plate-type axial piston pumps, on the other hand, come in various operational styles, such as manual, motorized, electric, hydraulic, and electro-hydraulic proportional control. Their basic principle involves adjusting the swash plate angle to vary the pump’s displacement. In terms of structure, these pumps can be divided into those with a rotating swash plate and fixed cylinder or a fixed swash plate and rotating cylinder. The former requires the swash plate to rotate and tilt to change displacement, which complicates the design and limits its application. The latter, however, allows for easier adjustment of the swash plate angle, making it more practical for many industrial uses.
Deadend Accessories
Deadend Hardware
Deadend hardware is a type of pole line hardware that is used to secure the end of a transmission or distribution line to a pole or tower. It is designed to withstand the tension and weight of the line and keep it securely in place.
Deadend hardware typically consists of a variety of components, including Oval Eye Nuts, Thimble Eyelets , Anchor Shackle, Guy clamps, bolts, nuts, washers, and insulators. These components work together to create a strong and durable connection between the line and the pole.
Yokelink supply a full line of deadend hardwares, , provide part number to get a quote on these products, leave your message, or send us an email to get answers for your questions or product you needed.
Thimble Eyenut, Eyelet, Eye nut, Preformed, Clamp, Rope, Clip, Cable, Fitting, Hook, Shackle
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