For tasks where precision and accuracy are critical, a torque wrench becomes an indispensable tool. Using hydraulic pumps alongside hydraulic torque wrenches helps you to exert controlled force, ensuring secure fastening or loosening of nuts and bolts without the risk of over-torquing.
Whether you’re a technician, construction professional, engineer, or mechanic dealing with hydraulic pumps and associated systems, it’s important to grasp fundamental information to guarantee proper usage and optimal performance.
To begin with, hydraulic pumps can be categorized into various types, including vane pumps, gear pumps, and piston pumps. Each category has numerous variants, and understanding these, along with other components, is essential for the effective planning, implementation, and maintenance of hydraulic systems.
What Does a Hydraulic Pump Do?
In the operation of a hydraulic system, a hydraulic pump carries out two fundamental functions. Firstly, it converts mechanical energy into fluid power by drawing oil from the reservoir into the pump inlet. The second function involves pumping the fluid through the pump outlet, forcing it into the hydraulic system. Both of these actions are considered mechanical processes.
Is the Creation of Pressure an Attribute of Hydraulic Pumps?
Contrary to a common misconception, hydraulic pumps do not generate pressure to propel hydraulic fluid through the system. Instead, pumps generate fluid flow, and it is the resistance encountered by the fluid as it moves through the system that creates the necessary pressure to overcome resistance and facilitate correct fluid flow.
Understanding Pump Classifications
Hydraulic pumps are categorized into one of two classes—non-positive-displacement pumps or positive-displacement pumps.
- Non-Positive Displacement Pumps: These pumps deliver a consistent fluid flow and are suitable for low-pressure systems. However, the flow rate output fluctuates with changes in system pressure.
- Positive-Displacement Pumps: Widely used in high-pressure hydraulic systems, positive-displacement pumps exhibit no slippage. Additionally, the pump speed can be controlled and adjusted as required.
What Are Some Common Types of Pumps?
Various types of pumps serve distinct functions and applications. Some common ones include:
- Fixed-Displacement Pumps: A positive-displacement pump where the flow rate remains constant and cannot be altered.
- Variable-Displacement Pumps: Another positive-displacement pump allowing adjustment of the flow rate to change outlet pressure.
- Rotary Impeller Pumps: A positive-displacement pump using a rotating component to accelerate fluid away from the center of rotation. The same amount of fluid is moved out for each rotation, regardless of pressure.
- Axial and Radial Piston Pumps: Positive-displacement pumps using a cylinder-inside-a-cylinder design for fluid movement through up-and-down motions and rotations. Both fixed and variable-displacement piston pumps exist.
- Plunger Pumps: Positive-displacement pumps where pistons reciprocate within fixed cylinders, creating a positive seal between the inlet and outlet for higher pressures.
- Reciprocating Pumps: Positive-displacement pumps where a partial vacuum is created as the piston extends, drawing fluid through the inlet. Fluid is forced out when the piston retracts.
- External Gear Pumps: Positive-displacement pumps where identical gears rotate against each other inside a housing, causing fluid flow around the gears.
- Internal Gear Pumps: Positive-displacement pumps where two internal gears of different sizes rotate inside one another, providing smoother oil flow and quieter performance compared to most external gear pumps.
- Screw Pumps: Positive-displacement pumps using helical screw shafts to guide fluid linearly. Typically larger, suitable for large-volume and lower-pressure applications.
- Lobe Pumps: A positive-displacement rotary, external gear pump using lobes to direct fluid through the pump housing while maintaining a tight seal.
- Vane Pumps: Another positive-displacement rotary pump utilizing vanes to direct fluid through the pump housing while maintaining a tight seal.
- Centrifugal Pumps: A non-positive-displacement pump using impellers to move fluid through the pump, creating centrifugal force.
- Trochoidal Pump: A type of internal gear pump combining features of a rotary lobe and an internal gear pump, used in low-pressure applications like providing charge flows to closed-loop piston pumps.
Common Hydraulic Pump Components
The composition of hydraulic pump components can vary based on the specific pump employed in the hydraulic system. Nevertheless, there are shared elements among all hydraulic pumps, including:
- Pump Housing: The external casing present in all pumps to safeguard internal components.
- Pump Shaft: At least one rotating shaft responsible for turning the impeller inside the pump.
- Seals: Elements strategically placed within the pump to prevent fluid leaks.
Additional components may be found in hydraulic pumps, contingent on the pump type, and encompass:
Check Valve, Gears, Load Sense Controls, Pistons, Rotors, Torque Limiter Controls, Compensators, Electronic Displacement Controls, Springs, Pressure Valves, Pressure Compensators
What Type of Pump Is Best?
Selecting the optimal pump for your applications involves considering various factors, such as:
- System Design: Taking into account the overall design of the hydraulic system.
- Fluid Flow Rate: Determining the desired rate at which the hydraulic fluid should flow.
- Pressure Requirements: Assessing whether the application involves high-pressure or low-pressure conditions.
- Hydraulic Fluid Type: Considering the type of hydraulic fluid used in the system.
- Maximum Operating Pressure: Identifying the maximum pressure the system will encounter during operation.
- Maintenance Needs: Evaluating the level of maintenance the pump requires.
- Replacement Costs: Considering the financial aspects related to pump replacement.
- Variable Displacement: Deciding whether a variable displacement pump is necessary.
Choosing the most suitable pump demands a comprehensive understanding of your hydraulic system and the diverse pump types available. Therefore, before engaging with or using a hydraulic system, it is crucial to verify the pump in use and acquaint yourself with the controls, parts, and components.
Whether you possess the knowledge to identify the required pump or seek guidance in making the right choice, the hydraulic system experts at TorcStark stand ready to assist you.
