SERVICE TIP

An improperly adjusted bell down unit on a packerhead pipe machine can result in poor quality of the finished bells and unnecessary wear and tear on the equipment can also affect production efficiency.

The proper setting of the bell down unit determines if or how high the pallet is lifted off the mold support lugs when the bell is being made. Lifting to the proper height has two advantages:

1. It reduces wear on the pallets and mold support lugs, giving them a longer service life.

2. It permits better transfer of vibration from the bell down unit vibrator to the bell, making for a better bell and/or shorter vibration times.

Care should be taken that the curing pallet is not lifted too high, since the pallet and/or pipe may not drop completely down until the pipe is stripped. If the curing pallet and pipe are not resting on the pallet support blocks when the mold is opened, the pipe will settle, causing concrete to separate from the cage. Loss of the bell and/or pipe is also possible.

Two of the more commonly-used methods of adjusting the height of the bell down unit are detailed below.

Setting the height of the bell down unit.

Step 1: Place a curing pallet on the turning and vibrating standard.

Step 2: Adjust the bell down unit height until the curing pallet is lifted 1/16" (1.5 mm) to 1/8" (3 mm) above the pallet support blocks on the mold.

Distance=Height of Pallet Support Block + Clearance.

This height is set by adjusting the stop rods on the bell down unit in the machine pit.

NEVER INSERT ANY PARTS OF YOUR BODY INTO EQUIPMENT SUCH AS A BELL DOWN UNIT THAT CAN BE STARTED FROM A REMOTE LOCATION.

The following is another method of setting the bell down unit height, possibly more accurate in that it compensates for any deflection in the bottom centering ring and turntable. This method applies mainly to machines with self-cleaning bell down units.

Step 1: Lower the bell down unit.

Step 2: Place a mold and curing pallet on the turntable and rotate them under the packershaft.

Step 3: Lower the top table until it holds the mold down.

Step 4: Raise the bell down unit.

Step 5: Adjust the bell down unit height until the curing pallet flange is 1/16" (1.5 mm) to 1/8" (3 mm) above the mold pallet supports. This height is set by adjusting the stop rods on the bell down unit in the machine pit. This measurement should be made by visual observation in the pit. NEVER INSERT ANY PARTS OF YOUR BODY INTO EQUIPMENT SUCH AS A BELL DOWN UNIT THAT CAN BE STARTED FROM A REMOTE LOCATION.

Step 6: After the height of the bell down unit is set, the bell down unit should be lowered.

Step 7: Rotate the mold and curing pallet out of the way.

After using either of the above methods, set the vibration timer to the proper vibration setting for the diameter of pipe to be made (refer to your machine operator’s manual). Machine setup can now resume.

McCracken realizes that there are many practical ways to solve problems and to make equipment adjustments in the pipe plant. We are presenting methods that work for us, but our lists are by no means all- inclusive. If you have other solutions, ideas, or questions, or if you feel require service assistance, please e-mail sales@besser.com.

Posted 7 May 2001