What Is a Watertight Plug?
A watertight plug is a device used to stop the flow of water. Depending on the application, there are two types of plugs: ball plugs, which use air pressure to adhere to the pipe, and mechanical plugs, which do not use air pressure but are made to adhere to the pipe by expanding the diameter by hand-tightening the thumbscrews.
The ball plug can be easily used by simply filling it with air. For this reason, they are often used when temporary water sealing is required, such as for cleaning inside sewage drainage pipes during post-disaster restoration work or for sewage drainage pipeline maintenance work.
Uses of Watertight Plugs
The main use of watertight plugs is to stop the flow of water. There are two types, the ball type and the mechanical type, depending on the application.
Characteristics of Watertight Plugs
Advantages
Watertight plugs are characterized by their ability to stop the flow of water easily. Various types are available, from those suitable for temporary water shutoff during cleaning and repair work to those capable of long-term water shutoff. Because of their simplicity of use and structure, many plugs can be easily used by beginners and are useful in a variety of situations.
Since there are many products available in various sizes and types of water shutoff methods, it is possible to choose the type that best suits the purpose and location of use.
Disadvantages
Watertight plugs cannot be used for chemicals, gases, or pressure pipes because they stop the flow of water. They must never be used for these applications because of the risk of plug failure or rupture.
Types of Watertight Plugs
There are two main types of watertight plugs:
- Ball Type: This plug stops the water by expanding using a compressor or similar device and adhering to the inside of the pipe. This type of plug can only be used for temporary water sealing. The type with a bypass is a high-flow drainage type, and water can be drained by removing the bypass cap.
- Mechanical Type: The thumbscrew is tightened by hand to adhere tightly to the pipe. It can stop water for a long period. There are three types: KS type for narrow pipe, G type for a pipe mouth, and IG type used for insertion in a pipe.
There are also air plugs, which use air pressure to inflate the plug to stop the watertight plug. These are available with or without a device called a bypass, which is used to discharge water and air in pipes with large water volumes, or as a special type for permanent installation in large pipes.
There is a wide range of sizes available, and each product has a different diameter of pipe to accommodate each. A wide variety of products are available, from palm-sized plugs to those used in public sewage systems.
How to Select a Watertight Plug
When selecting a watertight plug, it is necessary to consider the type to be used depending on how long the plug will be used. When using temporary watertight plugs, use the ball-type or air plugs without bypass. If the watertight plug is intended to be used for a long period, a mechanical type, an air plug with a bypass, or a special type of air plug should be selected.
The next consideration is the diameter of the watertight plug. If the nominal diameter does not match the pipe, the watertight plug will not be effective.
It is also important to check the pressure resistance and material of the plug, since it is expected to be subjected to strong water pressure.
How to Use Watertight Plugs
Wear a helmet and safety glasses when working and always check that the pipe diameter and the size of the watertight plug match before inserting the watertight plug into the pipe. Since water pressure is applied, it is necessary to work with full consideration of the possibility of accidents occurring.
Most watertight plugs are simple in construction and easy to use. Ball-type and air plugs are effective when inserted into a pipe and inflated, but there is a caveat that they must be inserted about as far away from the pipe mouth as the diameter of the pipe at the time of installation.
Mechanical plugs have slightly different specifications depending on the product, but they are characterized by a lower diameter expansion rate and do not expand as much as the air-injected watertight plugs mentioned above. Be sure to use a plug that matches the pipe diameter and carefully tighten the thumbscrews.
Since detailed specifications vary by manufacturer and product, it is important to read the instruction manual and use with safety in mind.