5.1.? Student Book © 2005 Propane Education & Research Council Page 1

Selecting the pump for a propane dispenser should include a complete understanding of how the dispenser will be operated, and the functions that the dispenser must fulfill.

In this module you will learn to:

5.1.4Applying Propane Pump

Operating Characteristics & Selecting the Dispenser Pump

1. Identify the operating characteristics of propane pumps

2. Select the dispenser pump

5.1.4 Student Book © 2005 Propane Education & Research Council Page 1

Identifying the operating characteristics of propane pumps

Regenerative turbine pumps

Courtesy of Corken Pump Div. of IDEX

Figure 1. Regenerative Turbine Pump

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Positive displacement pumps

Courtesy of Blackmer Div. of Dove r

Figure 2a. Sliding Vane Pump

5.1.4 Student Book © 2005 Propane Education & Research Council Page 2

Courtesy of Smith Precision Products

Figure 2b. Gear Pump(Coupling Shield Removed for Illustration)

Positive displacement pumps

5.1.4 Student Book © 2005 Propane Education & Research Council Page 2

Selecting the dispenser pump

Dispenser application and operating requirements

What containers will be filled?

If the dispenser will be primarily used to fill smaller cylinders, with larger containers filled only occasionally, a pump with minimal gallon per minute rating should be selected. The primary consideration in this case is minimizing the risk of over filling small cylinders.

If the installation is primarily used to fill larger, vehicle-mounted mobile or motor fuel tanks, a higher volume pump should be considered to reduce filling time and minimize operator waiting that could contribute to lack of attention during the filling operation.

5.1.4 Student Book © 2005 Propane Education & Research Council Pages 2 & 3

Selecting the dispenser pump

Dispenser application and operating requirements

What is the expected volume of daily usage?

Does the installation location present particular limitations?

If the power supply at the site will only support low-voltage, single-phase electric motors, the pump size and volume must be matched to the limitations of the power supply.

If site requirements or jurisdictional authority approval mandates the use of a buried or mounted underground supply tank, the pump selection should be made after consulting the pump manufacturer or distributor.

5.1.4 Student Book © 2005 Propane Education & Research Council Page 3

Pump rating

Manufacturers’ propane pump ratings are generally shown in relation to differential pressure. Differential pressure is the difference between the pressure at the outlet side of the pump and the pressure at the inlet side of the pump.

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Motor Selection

Three factors must be known to verify that the explosion-proof motor is appropriate for the dispenser installation and pump:

1. The pump’s horsepower and revolutions per minute (rpm) requirements

2. The installation’s available electrical power supply voltage and phase

3. The motor frame style required; the frame style refers to how the motor is mounted and how the pump is driven by the motor

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Pump protection devices

1. Proper bypass valve and system

Courtesy of Corken Pump Div. of IDEX

Figure 3a. For Pumps Up to 40 GPM

Figure 3b. For Pumps Up to 80 GPM

5.1.4 Student Book © 2005 Propane Education & Research Council Page 5

NOTE: For LP-gas installations, Underwriters Laboratories, Inc. listing and NFPA 58 allow a maximum differential of 125 psig.

Courtesy of Dover Corp., Blackmer Pump Div.

Figure 4. Automatic Bypass Valve & Adjustment Mechanism

If the pump is equipped with an internal bypass (sometimes called a pump “relief valve”), check its pressure setting on the rating plate attached to the pump or in the manufacturer’s IOM instructions. The internal bypass valve pressure must be set according to manufacturer instructions, typically at least 10-25 psig higher than the external bypass valve setting.

5.1.4 Student Book © 2005 Propane Education & Research Council Pages 6 & 7

Pump protection devices

2. Verify that a flexible connector for piping stress relief is provided in the pump inlet piping, and if needed, in the pump outlet piping.

Figure 5. Stainless Steel Flexible Connector

• Flexible sections of the proper length must be selected, and should be installed so that they are as close as practical to a straight line.

• They should never be used in place of pipe fittings to make turns or bends. Improper installation may result in damage to the reinforcement braids and complete failure of the connector.

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Figure 6a. Improperly InstalledFlex Connector

Figure 6b. Reverse SideDamage to Stainless Steel Reinforcement Webbing

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Figure 7. Inline Strainer Body(Note Flow Direction Arrow, L to R)

3. The pump should be protected by the installation of an inline strainer upstream of the pump inlet. Pump manufacturer IOM instructions give strainer screen size specifications for protecting the pump from debris that could damage internal components.

5.1.4 Student Book © 2005 Propane Education & Research Council Pages 8 - 10

Time to See If You Got the Key Points of This Module…

• Complete the Review on pages 8 & 9.

• See if you are ready for the Certification Exam by checking off the performance criteria on page 10.