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Understanding Pump Ratios

What is a Pneumatic Pump?

Before jumping into pump ratios, it is vital to have some understanding of pneumatic pumps. Pneumatic pumps are pumps that use the forces of compressed gas to generate mechanical effects on the system. When pneumatic pumps are used in industrial applications, they involve the use of compressed gas to provide the desired force that is used to move fluids through a piping system.

These pumps can be of two types –

  • A Piston Pump
  • A Double Diaphragm Pump

In both pumps, the basic principle of air motor operation is the same. The only difference is that in a double diaphragm pump, the air piston is different from the standard piston configuration used in normal Air Operated Piston Pumps. Generally, the piston in diaphragm pumps is made up of 2 diaphragms connected with a rod and the air is supplied to each of them alternately, causing reciprocation.

Pump Ratios

Pneumatic Pumps have a different motor-to-pump ratio depending on the effective areas of the motor piston and the piston pump. It is the ratio of the effective area of the motor piston to the effective area of the piston pump. The ratio is determined by dividing the motor piston’s effective area by the piston pump’s effective area. For example, if the motor piston’s area is 2 square inches and the piston pump’s area is 2 square inches, the pump ratio is 1:1. If the motor piston’s effective area is 2 inches and the piston pump’s effective area is 1 inch, then the pump ratio is 2:1.

1:1 Pump Ratio

If a pump has a ratio of 1:1, it means that the effective area of the motor piston is equal to the effective area of the piston pump. Therefore, applying a certain amount of pressure to the motor would yield an equal amount of fluid output pressure. For example, if a pressure of 100 psi is applied to the motor, it would yield a fluid output pressure of 100 psi when the fluid outlet is closed.

1:1 Ratio Pumps are ideal for pumping fluids of low viscosity over short distances (approximately 30m).

                                       

RAASM 1:1 Ratio Oil Pump                                                ORION 1:1 Ratio Oil Pump

3:1 Pump Ratio

If a pump has a ratio of 3:1, it means that the effective area of the motor piston is 3 times the effective area of the piston pump. Therefore, applying a certain amount of pressure to the motor would yield a fluid output pressure that is three times higher. For example, if a pressure of 100 psi is applied to the motor, it would yield a fluid output pressure of 300 psi when the fluid output is closed.

3:1 Ratio Pumps are ideal for pumping low to medium-viscosity fluids over fairly long distances than the 1:1 Ratio Pump (approximately 45m).

                                   

RAASM 3:1 Ratio Oil Pump                                             ORION 3:1 Ratio Oil Pump

5:1 Pump Ratio

If a pump has a ratio of 55:1, it means that the effective area of the motor piston is 5 times the effective area of the piston pump. Therefore, applying a certain amount of pressure to the motor would yield a fluid output pressure that is five times higher. For example, if a pressure of 100 psi is applied to the motor, it would yield a fluid output pressure of 500 psi when the fluid output is closed.

5:1 Ratio Pumps are ideal for pumping medium to higher viscosity fluids over distances of 60m or more.

                         

RAASM 5:1 Ratio Oil Pump                                              ORION 5:1 Ratio Oil Pump

Air vs Hydraulic Ratios

Air and Hydraulic ratios work exactly the same way. The only difference is that hydraulic pressures are much higher and the ratio of the motor to pump is much lower. Air compressor systems typically operate with pressures up to 100 psi (7 bar), while hydraulic power systems operate with pressures up to 1500 psi (105 bar). So to achieve similar pump pressures the effective surface area of the hydraulic motor will be much smaller than the effective surface area of the air motor.

Typically, a 10:1 air motor/pump combination is equivalent to a 1:1 hydraulic motor/pump combination because the typical hydraulic pressure is 1000 psi (70 bar) and the typical air pressure is 100 psi (7 bar).

High Flow Oil Pumps at A-FLO Equipment

We at A-FLO Equipment sell a range of different High Flow Oil Pumps ranging from 1:1 ratio Oil Pumps to 18:1 ratio Oil Pumps, giving you a host of different options to choose from. Our Oil Pumps are suitable for all types of lubricants ranging from low-viscosity fluids to high-viscosity fluids and chemicals.

Not sure what is the best Oil Pump or Pump Ratio for your business? Contact our friendly customer support today at 03 9281 6200 for an obligation-free proposal and recommendation on what type of pump is going to best suit your system.

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