Common Mistakes to Avoid When Priming an Air Operated Pump

Air operated double diaphragm pumps are an excellent choice for transfer applications due to their simple design, which makes operation easy and repairs inexpensive. To obtain optimal performance, the pump must be correctly installed and operated. Despite their durability mishandling during the priming phase can result in inefficiencies pump damage or complete malfunction.

To ensure peak performance and longevity of your AODD pump it’s vital to steer clear of priming errors. In this guide, we will discuss about the coming mistakes to avoid when priming an air operated pump.

Priming is the process of preparing a pump to operate by removing air from the pump and its suction line, allowing the pump to create the necessary vacuum to draw liquid. For air-operated pumps, priming is essential because these pumps rely on air pressure to move diaphragms that, in turn, move the fluid. Without proper priming, the pump cannot function correctly, leading to cavitation, reduced flow rates, and potential damage.

1. Ignoring Manufacturer’s Instructions: One of the most prevalent mistakes is neglecting to follow the manufacturer’s instructions. Each air-operated pump model has specific requirements and guidelines provided by the manufacturer. These instructions include detailed steps for priming, recommended pressures, maximum vertical suction lift and maintenance schedules. Ignoring these can lead to improper priming and subsequent pump failure.

Solution: Always read and adhere to the manufacturer’s manual. This will ensure that you are using the pump within its designed parameters and following the correct priming procedure.

2. Incorrect Air Pressure Settings: Air-operated pumps require a specific air pressure to operate efficiently. Too low pressure can prevent the pump from priming correctly, while too high pressure can damage the diaphragms and other components. The AODD pump draws fluid by creating a low-pressure zone within the fluid bowls, which is below the atmospheric pressure of 14.7 psi. If the air pressure supplied to the pump is too high, it causes the pump to switch over too quickly, resulting in insufficient time for the fluid to be effectively drawn into the pump.

Solution: Use a pressure regulator to ensure that the air pressure supplied to the pump is within the recommended range specified by the manufacturer. Start the air supply slowly, then, once primed, increase to the desired operation pressure. Regularly check and adjust the pressure as needed to maintain optimal performance.

3. Improper Suction Line Setup: The setup of the suction line is critical for successful priming. Common mistakes include using a suction line that is too long, too narrow, or having an improper angle, all of which can introduce air pockets and hinder the priming process.

Solution: Ensure that the suction line is as short and straight as possible, with the correct diameter to handle the flow rate. Avoid sharp bends and angles, and ensure all connections are airtight to prevent air leaks.

4. Failure to Remove Air from the System: Air pockets in the pump and suction line can prevent proper priming. These air pockets often occur due to improper installation or failure to bleed the system before starting the pump.

Solution: Before starting the pump, bleed the system to remove any trapped air. This can be done by manually filling the pump and suction line with liquid or using a vacuum pump to evacuate the air.

5. Using Incompatible Fluids: Using fluids that are chemically incompatible with the pump materials can lead to corrosion, swelling of diaphragms, and other issues that impede proper priming.

Solution: Always check the chemical compatibility of the fluid with the pump materials. Refer to the manufacturer’s compatibility chart to ensure that the chosen fluid will not damage the pump components.

6. Neglecting Regular Maintenance: Regular maintenance is crucial for the reliable operation of an air-operated pump. Failing to perform routine checks and maintenance can result in worn-out parts that compromise the priming process.

Solution: Implement a regular maintenance schedule as per the manufacturer’s guidelines. This should include checking and replacing diaphragms, seals, and other wear parts, as well as cleaning the pump and its components.

7. Failing to Monitor Pump Performance: Not monitoring the pump’s performance can result in missing early signs of problems that can affect priming and overall operation.

Solution: Regularly monitor the pump’s performance parameters, such as flow rate, pressure, and any unusual noises or vibrations. Early detection of issues can prevent major problems and ensure consistent priming.

8. Improper Use of Check Valves: Check valves are essential for maintaining the flow direction and preventing backflow, which can hinder priming. Incorrect installation or selection of check valves can disrupt the priming process.

Solution: Ensure that check valves are correctly installed according to the flow direction. Use check valves that are compatible with the pump and the fluid being handled.

9. Improper Fluid Properties: Diaphragm pumps handling low-density fluids may require longer priming times to expel air completely and establish a continuous liquid flow. Operators may need to adjust pump settings or use priming aids to facilitate the process effectively. High-density fluids might require some pump adjustments to material or design for the ball valves properly check synchronously before the next cycle.

Solution: Consult an Iwaki Air pump specialists for a custom solution that take care of your most challenging applications.

To further illustrate how to avoid these common mistakes, here’s a step-by-step guide to correctly priming an air diaphragm pump:

Preparation

• Ensure the pump and its components are clean and free of debris.
• Verify that all connections are secure and there are no leaks in the suction line.
• Check the air supply system, including the compressor, filters, and regulators.

Priming the Suction Line

• If possible, pre-fill the suction line and the pump chamber with the liquid to be pumped. This can help displace air and create an initial prime.
• Use a manual primer or vacuum pump if necessary to remove air from the suction line.

Starting the Pump

• Gradually open the air supply valve to allow air to enter the pump.
• Start the pump at a low air pressure to allow it to build a prime gradually. Avoid sudden increases in pressure.
• Observe the pump’s operation. Look for signs of air being expelled from the discharge line, which indicates that the pump is priming correctly.

Adjusting Air Pressure

• Once the pump is primed and operating smoothly, gradually increase the air pressure to the recommended operating range.
• Continuously monitor the pump for any signs of distress, such as unusual noises or vibrations.

Monitoring and Maintenance

• After the initial priming, regularly check the pump’s performance.
• Conduct routine maintenance as per the manufacturer’s guidelines to ensure long-term reliability.

Despite careful attention to the priming process, issues can still arise. Here are some common problems and their solutions:

1. Pump Fails to Prime

• Possible Causes: Air leaks in the suction line, insufficient air pressure, clogged suction line or filters, high viscosity fluid and excessive suction line length.
• Solutions: Check and tighten all connections, ensure adequate air pressure, and clean or replace clogged components.

2. Intermittent Flow or Pulsation

• Possible Causes: Air pockets in the suction line, improper check valve operation, damaged diaphragms.
• Solutions: Bleed the suction line to remove air pockets, check and replace check valves, inspect and replace damaged diaphragms.

3. Reduced Flow Rate

• Possible Causes: Blockages in the pump or discharge line, worn-out diaphragms, insufficient air supply (air pressure and air volume).
• Solutions: Clear any blockages, replace worn diaphragms, and ensure a consistent air supply at the recommended pressure.

4. Excessive Noise or Vibration

• Possible Causes: Loose mounting, cavitation.
• Solutions: Ensure the pump is securely mounted, check for cavitation and address the underlying causes.

Proper priming is essential for the efficient operation of air-operated pumps. By avoiding common mistakes such as ignoring manufacturer’s instructions, incorrect air pressure settings, improper suction line setup, and neglecting regular maintenance, you can ensure reliable performance and extend the lifespan of your pump. Always follow a systematic approach to priming, monitor the pump’s performance, and address any issues promptly. With careful attention and regular maintenance, your air-operated pump will continue to serve your needs efficiently and effectively.

Remember, a well-primed pump is a key to smooth operation and longevity in any industrial application. By taking the time to prime your pump correctly, you are investing in the reliability and efficiency of your entire pumping system.