Priming is a fundamental consideration in hydraulic systems, especially with certain pump types. Like many other hydraulic pumps, vane pumps may or may not require priming, depending on their design and specific application.
A. Understand the priming effect
Priming in a hydraulic system is the process of removing air or gas from the pump and suction lines and filling them with hydraulic fluid (usually oil). Proper starting ensures that the pump works efficiently and that problems such as cavitation do not occur.
Cavitation is a common problem in hydraulic systems and occurs when air or bubbles are present on the suction side of the pump. When a pump attempts to suck in fluid, it creates an area of low pressure that causes these bubbles to form and collapse. This implosion can cause noise, reduced efficiency, and damage to pump components.
B. Priming in Vane Pump
Vane pumps have fewer starting problems than other pump types such as centrifugal pumps. However, this is not entirely irrelevant. The necessity of starting the vane pump is affected by the following factors:
1. Design: Vane pumps are available in different designs, including fixed displacement and variable displacement models. Variable displacement vane pumps may require more attention to start-up due to their ability to regulate flow.
2. Suction lift: The height that the pump needs to lift the fluid plays a vital role. Vane pumps are generally better able to handle certain suction lifts without cavitation than other pump types, but there are limitations.
3. Fluid characteristics: Hydraulic oil characteristics (such as viscosity, temperature, and cleanliness) affect the need for priming. Thicker liquids may require more effort to prime.
4. Operating conditions: The operating conditions of the vane pump (including flow and pressure) will affect the starting requirements.
C. How to start the vane pump
If start-up is required, there are several methods that can be used to remove air from the system and ensure that the vane pump is functioning properly:
Fill the tank: One of the easiest ways to do this is to fill the hydraulic tank or system with hydraulic fluid before starting the pump. This reduces the chance of air being drawn into the pump.
Using a vacuum pump: A vacuum pump can be used to remove air from the system, creating a vacuum that draws in the hydraulic fluid. This is particularly useful when working with larger systems.
Bleed Valve: Some vane pump systems include a bleed valve or vent that allows trapped air to escape. Proper use of these valves aids in starting.
Air intake duct: Making sure the intake duct is clear and well-sealed is critical to preventing air from entering.
Proper Maintenance: Regular maintenance, including checking for air leaks and ensuring seals are intact, can help avoid frequent fillings.
While vane pumps are less susceptible to starting problems than other pump types, they are not immune to the challenges posed by cavitation. Whether priming is required depends on factors such as design, suction lift, fluid characteristics and operating conditions. Understanding these factors and employing proper startup methods when necessary is critical to maintaining the efficiency and longevity of your vane pump system.
