Car Lift For Sale | A History of Hydraulic Pumps

Before delving into the various types of hydraulic pumps, it’s important to review how hydraulic systems operate and the role of the hydraulic pump within these systems.

Car Lift For Sale Hydraulic systems use pressurized liquids to transmit power in a controlled manner. While the use of hydraulic systems dates back to Ancient Greece, modern hydraulics are attributed to Blaise Pascal, a French mathematician. In 1653, Pascal demonstrated that an increase in pressure at any point within a confined fluid results in an equal increase in pressure throughout the container.

This principle enabled the design of systems that use hydraulics to amplify small forces into much larger ones. All hydraulic systems are based on this fundamental concept.

Pressure in a Car Lift For Sale hydraulic system is generated through the careful design of applied forces and pipe gauges. Smaller hoses or pipes increase resistance and pressure, as illustrated in the image from LunchBox Sessions’ training platform.

 How Do Hydraulic Pumps Work?

The primary function of a hydraulic pump is to create flow with enough power to overcome the pressure imposed by the load at the pump outlet. 

A Car Lift For Sale hydraulic pump performs two main functions:

1. Its mechanical action creates a vacuum at the pump inlet, allowing atmospheric pressure to push liquid from the reservoir into the pump.

2. It then delivers this liquid to the pump outlet and into the hydraulic system.

Contrary to common belief, the pump does not influence the pressure in the hydraulic system. Instead, its role is to ensure continuous fluid flow.

For more information on pressure and flow, check out LunchBox Sessions’ online learning platform. Subscribers can access free, bite-sized lessons on hydraulics and other industrial technologies.

 Common Types of Hydraulic Pumps

The three most prevalent hydraulic pump designs are vane pumps, gear pumps, and radial piston pumps. While all are suitable for common hydraulic applications, piston pumps are recommended for higher pressures.

Most hydraulic pumps are positive-displacement types, meaning they deliver a constant amount of liquid per pumping cycle, regardless of pressure changes.

Positive-displacement pumps can be fixed or variable displacement. Fixed displacement pumps maintain a constant output per cycle and speed, whereas variable displacement pumps allow for changes in output by adjusting the displacement chamber’s geometry.

Car Lift For Sale Fixed displacement pumps, such as screw pumps, are quiet and ideal for applications in environments like theaters. Variable displacement pumps are well-suited for circuits with hydraulic motors where variable speeds or reversibility are needed.

 Gear Pumps

How Do Gear Pumps Work?

Invented by Johannes Kepler around 1600, gear pumps are one of the most common types of hydraulic pumps. Also known as positive displacement pumps, gear pumps displace a consistent volume of fluid per revolution and do not allow for volume adjustment.

Fluid is carried between meshing gear teeth, producing flow. The Car Lift For Sale pump housing and pressure plates enclose the chambers formed between adjacent gear teeth. A partial vacuum created by the pump suction draws fluid in, which is then moved through the pump and forced out as the gears mesh.

Modern gear pumps, with designs featuring split gears and helical teeth, are much quieter and smoother in operation compared to older models. Gear wear tends to reduce efficiency gradually, preventing sudden catastrophic failures.

Reversibility of Gear Pumps

Many gear pumps can be reversed by disassembling and flipping the center section, making them symmetrical in design.

Types of Gear Pumps

– Internal Gear Pump: Utilizes an external and an internal spur gear, with inward-facing teeth.

Gear pumps are widely used in industries such as petrochemical, chemical, and food processing.

 Piston Pumps

Piston pumps use pistons moving back and forth in cylinders. They are often variable displacement pumps, allowing control of fluid displacement even at constant RPMs. This makes them suitable for applications requiring variable speeds or reversibility.

Piston pumps excel in high-flow, high-pressure environments, such as in marine, mobile, and construction equipment. They are known for their low oil leakage and high volumetric efficiency.

Axial Piston Pumps

Car Lift For Sale Axial piston pumps are among the most widely used variable displacement pumps, with applications ranging from heavy industry to mobile systems. They can be configured for both open and closed circuits, with displacement adjusted based on load requirements and pressure settings.

Bent Axis Pumps

Bent axis pumps are highly efficient, with displacement volume determined by the swivel angle. They come in two designs: the Thoma-principle and the Wahlmark-principle, differing in their angle and piston configurations.

Radial Piston Pumps

Radial piston pumps handle high pressure and smaller flows, with pressures up to 650 bar. They are unique in their ability to operate continuously under high pressure and are used in applications such as presses and machine tools.

 Vane Pumps

Vane pumps can be either variable or fixed displacement. They use rectangular vanes sliding back and forth within slots to move fluids. Vane pumps are most efficient with low-viscosity fluids and are commonly used in fuel loading terminals and transport vehicles.

 Gerotor Pumps

A gerotor pump, named for its “generated rotor” design, consists of an inner rotor with N teeth and an outer rotor with N+1 teeth. This design enables precise fluid displacement and is used in various hydraulic applications.

A Car Lift For Sale hydraulic pump functions on the principle of positive displacement, where a confined fluid is subjected to pressure through either reciprocating or rotary action. The driving force for the pump can come from various sources, including an electric motor, internal combustion engine, human effort, or compressed air. This force powers components like an impeller, gear, or vane to generate fluid flow within the pump’s housing.

This incoming fluid creates a vacuum in the inlet chamber, which is then pressurized and forced towards the outlet.

Different types of hydraulic pumps use distinct mechanisms to produce fluid flow and pressure:

– Gear Pump: Two meshing gears rotate in opposite directions, forming expanding and contracting chambers that generate fluid flow and pressure.

– Vane Pump: Vanes are pushed outward by centrifugal force and then retracted into the rotor as they pass the pump’s inlet and outlet, creating fluid flow and pressure.