Does Cherne offer chemical resistant mechanical test plugs?
Yes. Cherne offers two chemical resistant mechanical plugs: The Cherne Well Monitor Plug and the Cherne Petro Econ-O–Grip.
Why is it important to know pounds of force calculation?
This calculation is important to the end user and helps them understand the forces behind the plug so that they can decide the proper way block the plug.
What is the formula to calculate backpressure?
Backpressure is defined in PSI (pound per square inch) or feet of head.
Simply read the gauge pressure for PSI.
For feet of head, calculate height of water over the centerline of the plug.
Example; 100’ line at 1% slope with a 10’ manhole (100 x .01) + 10 = 11 feet of head.
How long can a Cherne pneumatic plug be expected to stay in good condition?
This answer depends on how the plug is maintained. If the instructions are followed in the Cherne Safety Instruction Manual, it is not unusual for the plug to last for many years. If the instructions are not followed, a plug can be destroyed during the first use. Cherne pneumatic plugs come with a 2 year warranty from date of manufacture.
What is the definition for feet of head?
Feet of head is the height of water over the center line of the plug.
Which inflatable plugs are repairable?
There are patch kits available for Urethane plugs. Other plugs that can be patched or have the bag replaced, are as follows; 15”-30” / 24”-42” / 20”-40” / 24”-48” / 24”-60” / 48”-72” and 54”-96”.
How is the Muni-Ball (bypass plug) converted for air testing?
The bypass cap or plug is removed and replaced with an Air Loc Conversion Kit.
How often should a pneumatic plug pressure be checked?
Inflation pressure should be checked a minimum of once every 4 hours while a pneumatic plug is in use.
What size plugs is repairable and which plugs are not repairable?
Generally speaking pneumatic plugs that do not have sealing rings may be eligible for patching. The damage to the plug cannot be any longer than 4 inches, or deep enough to penetrate the cording. Plugs cannot be patched more than 4 times. Other repairs can be made as well, like replacing inflatable bladders, bypass hoses, castings and fittings. When in doubt, ask the customer to take a few digital pictures of the damaged area and email it to you. Forward the pictures by email to the Cherne QA Department along with a brief description of the damage for final determination.
Can Cherne plugs be used on elliptical pipe?
Yes. Cherne publishes a chart that pairs up our pneumatic pipe plugs with some of the most popular sizes of elliptical pipes.