The right piston pump is necessary for your hydraulic system to function properly, use less power and last a long time. Both fixed displacement piston pump and variable displacement piston pumps are made for different types of use. This guide explains how piston pumps differ so you know which one to choose.
Pumps are available in two types: fixed displacement and variable displacement:
Now, we will examine what sets these approaches apart.
Fixed Displacement Pump
- Ensures a reliable rate of flow.
- The same quantity of fluid is generated by each cycle of the fixed displacement hydraulic pump.
- It is appropriate when the energy used does not change.
Variable Displacement Pump
- The system’s needs decide the required flow speed.
- The pump can automatically change the amount of fluid it pumps.
- Excellent for developing systems that help save energy.
Key Differences Between Piston Pump Types
| Feature          | Fixed Displacement Pump                   | Variable Displacement Pump      |
| Flow Rate | Constant | Adjustable |
| Energy Efficiency | Less efficient (wastes energy at low load) | More efficient (adjusts to load) |
| System Complexity | Simple | More complex |
| Cost | Lower initial cost | Higher initial cost |
| Maintenance | Easier, fewer parts | Requires more expertise |
| Best For | Constant-speed operations | Variable-speed and load systems |
The pros and cons of using displacement pumps
Pros and Cons of Fixed Displacement Pumps
Pros:
- You don’t have to pay much upfront
- It is not hard to set up and run the system
- These systems are relied upon by steady-state systems for dependable operation.
Cons:
- Not recommended when the load keeps changing
- Makes more heat than required
- The system does not offer much control flexibility.
Advantages and Disadvantages of Variable Displacement Pumps
Pros:
- Very energy efficient
- More precise control over how much air is used
- Slows the breakdown of machinery
Cons:
- This approach is both costly and difficult to use.
- Needs to be maintained by skilled technicians
- Getting used to the system takes time at first
Selecting the Right Piston Pump
Let’s look at some important things to consider when choosing a piston pump.
1. Check the amount of work a system is handling.
For constant loads, a fixed displacement hydraulic pump is generally adequate. A load that changes in size should be handled with a variable piston pump.
2. Check how much energy the house uses.
Want to reduce your energy costs? A variable displacement pump works most efficiently when the load is not at its maximum.
3. Check the type of application you are using.
Fixed pumps are suitable for: conveyor belts, small lifts or basic tools.
Variable displacement piston pumps are used in: CNC machines, injection molding and mobile equipment.
4. Maintenance Capability
Do you employ staff or support who are skilled in what they do? Variable pumps need more attention and knowledge from the user.
5. Budget Constraints
Tight budget? Go fixed.
Want to make sure your investment pays off and operates efficiently over time? Go variable.
Variable Piston Pump Comparison Use Cases
| Industry/Application     | Recommended Pump Type             |
| Plastic injection molding | Variable Displacement Piston Pumps |
| Agricultural machinery | Fixed Displacement Pumps |
| Construction equipment | Variable for efficiency |
| Small hydraulic presses | Fixed for simplicity |
Expert Tips for Optimal Use
- Make sure to check your filters and fluids often so you don’t experience cavitation or early wear.
- Hydraulic sensors are put in place to measure the flow and pressure in systems that vary.
- Buy your pumps from well-known brands to ensure you get high-quality service.
- Teach your maintenance workers how to care for variable systems.
Conclusion – Finding the Best Piston Pump for Your Purposes
You need to understand the difference between fixed and variable displacement pumps when designing or updating your hydraulic system. This guide and comparison will help you determine the best type of pump for your needs.
For energy efficiency, flexibility of the system and a high return on investment, variable displacement piston pumps are the best option. With simple and economical systems, fixed pumps are the right choice.
Get in touch with THM Huade experts today—we offer a free consultation for your hydraulic needs.
