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McElroy > FAQ


  1. What is the butt fusion process?
  2. What pipe sizes will McElroy machines fuse?
  3. What is an “IPS” pipe size?
  4. What is a “DIPS” pipe size?
  5. What is a “JIS” pipe size?
  6. What is “ISO” metric pipe size?
  7. What is “CTS” pipe size?
  8. What does the “DR” or “SDR” number on the pipe mean?
  9. How many people are required to operate McElroy machines?
  10. What accessories may be needed to fuse pipe?
  11. How long should it take to make a fusion joint?
  12. What heater surface temperature should be used to butt fuse PE pipe?
  13. What is the best way to measure and monitor heater temperature?
  14. Why doesn't the temperature on the thermometer correspond to the temperature of the heater surface?
  15. How long should the heater be left between the pipe ends to achieve the proper melt pattern?
  16. What is the correct cooling time?
  17. How are the pipe ends properly aligned?
  18. Why should I always face to the stops?
  19. How much material should be faced from the pipe ends?
  20. Should the pipe ends be wiped after facing?
  21. How much force should be applied to make a fusion joint?
  22. How is the gauge pressure calculated to make a fusion joint?
  23. What is “drag”, and how is it used to calculate fusion pressure?
  24. How long should fusion force be maintained to ensure a high quality joint?
  25. What is the minimum power requirement for my McElroy machine?
  26. What size generator will my machine require?
  27. How often should the facer blades be replaced?
  28. How often should the non-stick butt fusion adapters be replaced?
  29. What should a proper fusion joint look like?
  30. If a fusion joint does not pass visual inspection, what should be done?
 
1. What is the butt fusion process?
“The most commonly used method for joining two pieces of pipe. To learn more, view this animation.

2. What pipe sizes will McElroy machines fuse?
Most McElroy fusion machines have a model number that will give you the pipe range of the equipment. Example: Model No.412 Machine will fuse 4” to 12” pipe sizes, Model No.1236 machine will fuse 12” to 36” pipe sizes, etc.. With a variety of McElroy machines, you can fuse from ½” CTS to 65” O.D. pipe sizes. Refer to our catalog or web site for the exact pipe sizes each machine can accommodate.

3. What is an “IPS” pipe size?
IPS stands for “Iron Pipe Size” which is a steel pipe sizing standard that has been in existence for years. For a comparison of pipe sizes consult our online reference.

4. What is a “DIPS” pipe size?
DIPS stands for “Ductile Iron Pipe Size” which is a Ductile pipe sizing standard that has been in existence for years. For a comparison of pipe sizes consult our online reference.

5. What is a “JIS” pipe size?
JIS stands for “Japanese Industrial Standard” which is the piping standard for Japan. For a comparison of pipe sizes consult our online reference.

6. What is “ISO” metric pipe size?
ISO metric stands for “International Standards Organization” which is the piping standard used in many parts of the world. For a comparison of pipe sizes consult our online reference.

7. What is “CTS” pipe size?
ANSWER: CTS stands for “Copper Tube Size” which is the copper tubing sizing standard in the United States. For a comparison of pipe sizes consult our online reference.

8. What does the “DR” or “SDR” number on the pipe mean?
It is the ratio of pipe diameter to wall thickness. It is calculated by dividing the specified outside diameter of the pipe by the minimum specified wall thickness. Any size pipe with a common DR is qualified to operate at the same pressure regardless of pipe OD (e.g. 2” IPS DR 11 pipe can have the same operating pressure as 12” DR 11).

9. How many people are required to operate McElroy machines?
McElroy fusion machines are designed to be operated by one person. Support equipment and personnel may be required to move the pipe and equipment to the job site.

10. What accessories may be needed to fuse pipe?
There are a variety of accessory items available depending on the machine size and application. A list of these can be found in our catalog. Some examples are:
Inserts
Required to fuse different pipe sizes that a machine can accommodate.
Pipe Support Stands
Used to support the pipe about 20' from each end of the fusion machine. These are used to give the pipe proper alignment in the machine.
Pyrometer
Used to measure the heater surface temperature before making the butt fusion joint.
Hydraulic Extension Hoses
Used to operate an No.28, No.412 or No.618 Fusion machine off the chassis in a remote application.
Stub End Holder
Used to hold a stub end fitting for a butt fusion connection

11. How long should it take to make a fusion joint?
The amount of time to make a fusion joint depends on a number of variables such as pipe size, job set-up, and fusion parameters and procedures. With an experienced crew and a McElroy machine, a rule of thumb is 1 ½ to 2 minutes per inch of pipe diameter, depending on the DR. Always consult the pipe manufacturer's recommended parameters and procedures in their installation manual. For pipe outside the United States, use the temperatures prescribed by applicable company, local, state, or federal standards.

12. What heater surface temperature should be used to butt fuse PE pipe?
Always consult the pipe manufacturer's recommended parameters and procedures. A pyrometer or Datalogger should be used periodically to insure proper temperature of the heater. For pipe outside the United States, use the temperatures prescribed by applicable company, local, state, or federal standards.

13. What is the best way to measure and monitor heater temperature?
Use a surface pyrometer to check the surface temperature of the heater or heater adapter. The dial thermometer on the heater reads internal temperature. Use this as a reference to monitor the heater temperature during the fusion process.

14. Why doesn't the temperature on the thermometer correspond to the temperature of the heater surface?
The dial thermometer on the heater indicates internal temperature. Some heat is lost on the transfer of heat to the outside of the heater adapters. Strong wind currents can also drop the surface temperature below the desired setting. Keep the heater in the insulated heater stand, when not being used to heat pipe ends. Loose heater plates or foreign material between the heater and the heater plates will also cause a drop in the surface temperature and the internal reading of the heater plate. Surface readings should be taken with a pyrometer

15. How long should the heater be left between the pipe ends to achieve the proper melt pattern?
Most pipe manufacturer's recommend a certain heating time or bead size against the heater. Always consult the pipe manufacturer's recommended parameters and procedures. For pipe outside the United States, use the temperatures prescribed by applicable company, local, state, or federal standards.

16. What is the correct cooling time?
The molten joint must be held immobile under force until cooled adequately to develop strength. The proper cooling times for the joint are material, pipe-diameter and wall thickness dependent and are established by the pipe manufacturer or by applicable company, local, state, or federal standards. Allowing proper times under force for cooling prior to removal from the clamps of the machine is important in achieving joint integrity.

17. How are the pipe ends properly aligned?
The pipe ends must be rounded and aligned with each other to minimize mismatch (high-low) of the pipe walls. This can be accomplished by adjusting the clamping jaws until the outside diameters of the pipe ends match. Always make sure the pipe is coming into the machine level and straight, then tighten down the high side until the pipe ends are even. The use of pipe support stands will allow you to bring the pipe into the fusion machine on a level plane, which greatly helps in alignment and also reduces drag on the moveable jaws. When working with coiled pipe, if you place the them into the machine in an S configuration, the pipe ends are easier to align properly.

18. Why should I always face to the stops?
McElroy facers are equipped with machined facer stops. These stops provide a square face-off by ensuring the facer is held perpendicular to the pipe ends. This also establishes a controlled stand-off of pipe to the jaw surface to provide optimum rounding and pipe alignment.

19. How much material should be faced from the pipe ends?
A minimum of (1) complete revolution on each pipe end must be removed in order to expose clean material suitable for butt fusion. Always face to the stops to insure a square face -off perpendicular to the pipe.

20. Should the pipe ends be wiped after facing?
Always wipe the pipe ends before the facing operation to make sure they are free of dirt and contamination. After facing the pipe, care should be taken to remove all shavings from the fusion area. Brush away loose particles with a clean, non-synthetic cloth. It is not necessary to wipe the pipe ends unless there is contamination present. Always consult the pipe manufacturer's recommended parameters and procedures. For pipe outside the United States, use the temperatures prescribed by applicable company, local, state, or federal standards.

21. How much force should be applied to make a fusion joint?
After the pipe ends have been properly heated, the heater tool is removed and the molten pipe ends are brought together with sufficient force to properly mix the pipe materials and form a homogeneous joint. The pipe manufacturer's instructions may specify either interface pressure or bead size of molten material as a guide for a proper joint. Always consult the pipe manufacturer's recommended parameters and procedures. For pipe outside the United States, use the temperatures prescribed by applicable company, local, state, or federal standards.

22. How is the gauge pressure calculated to make a fusion joint?
With your information of pipe diameter, wall thickness (or DR), and the recommended interfacial pressure you may use the McElroy Slide Rule Pressure Calculator, the McElroy nomogram pressure calculator, or our online pressure calculator. To determine the gauge pressure in each case, follow the instructions on the calculator to determine the theoretical fusion pressure for use in the fusion mode of the selected McElroy Hydraulic Fusion Machine. Drag pressure should always be added to the theoretical fusion pressure. Always consult the pipe manufacturer's recommended parameters and procedures. For pipe outside the United States, use the temperatures prescribed by the applicable company, local, state, or federal standards.

23. What is “drag”, and how is it used to calculate fusion pressure?
Drag is the frictional resistance occurring during carriage movement. The amount of drag pressure on a machine should be added to the theoretical fusion pressure from the slide rule or McCalc number to get the fusion pressure.

24. How long should fusion force be maintained to ensure a high quality joint?
The molten joint must be held immobile under force until cooled adequately to develop strength. The proper cooling times for the joint are material, pipe-diameter and wall thickness dependent and are established by the pipe manufacturer. Allowing proper times under force for cooling prior to removal from the clamps of the machine is important in achieving joint integrity.

25. What is the minimum power requirement for my McElroy machine?
The minimum power requirement for a McElroy fusion machine represents the minimum power required at the machine to do the work. The Generator size will be larger depending on the altitude, temperature, operational distance from the unit, and other variables. View the online power requirements chart.

26. What size generator will my machine require?
Consult the online Generator Sizing Form.

27. How often should the facer blades be replaced?
If the blades become dull or chipped, replace the blades. The life of the blades will vary depending on several variables including cleanliness, hours of operation, material being faced, etc. .

28. How often should the non-stick butt fusion adapters be replaced?
If the coating on the heater adapters are worn or damaged, remove the adapters and replace them with a new coated set. See the McElroy catalog or the product manual for the proper part number.

29. What should a proper fusion joint look like?
Most U.S. pipe manufacturer's have pictures and a good description of a proper butt fusion joint. Always consult the pipe manufacturer's recommended parameters and procedures. For pipe outside the United States, use the temperatures prescribed by the applicable company, local, state, or federal standards.

30. If a fusion joint does not pass visual inspection, what should be done?
Cut the joint out and make another butt fusion joint using the proper fusion parameters and procedures . Always consult the pipe manufacturer's recommended parameters and procedures. For pipe outside the United States, use the temperatures prescribed by the applicable company, local, state, or federal standards.
 
 
               
 
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