In order to concreting various concrete walls including shear walls, reservoir walls, pools, water transfer channels, tunnels, dams and so on, it is necessary to have suitable framing operations based upon thickness and diameter of wall and type of application. About %95 of wall framing systems are applied for controlling the hydrostatic pressures of concrete at the time of concreting. Then it is necessary to have required facilities for controlling of frames and prevention from opening and disintegration of frames. One of the most important equipment in controlling of side pressures of concrete is to apply belt, nut and washer accompanied with mold restraints. The concept of water stopping structures is so much important in water structures, the created hole by belt in concrete after the end of concreting and frame/belts removing is considered as a constructional weak point which should be filled and sealed accordingly. In order to fill the mentioned hole, it is so much difficult to fill with cement mortars especially in any walls with high & dense thickness and compressing it for prevention from water exit. The best method of water sealing at belt location in concrete is any action prior to concreting and at the time of placing the belt inside the structure. Plastic Water Stop Mid-belt is the cheapest and most economic item for water stop at belt location. It has been designed and manufactured from 5 parts. The consumption costs for plastic water stop mid-belt is at least %70 lower than other current belts such as cast iron belt and spring belt. It has lots of advantages for employer as well. One of the most important advantages for applying of plastic water stop mid-belt is a 1-piece and usual belt in comparison with other metallic and/or cast iron belts which applicable in other projects as well.
But it is necessary to apply any belts with smaller length and/or external belts among other items (One side a small gear, the other side a large gear) which makes a limitations to apply the belt in other projects. Therefore, benefiting from plastic water stop mid-belt has considerable economic advantages for employer. Plastic water stop mid-belt is able to increase the length simply by increasing the length of the plastic ribbed tube meanwhile it is limited in cast iron and/or metallic belts and/or it is applied with higher costs. The major parts of plastic water stop mid-belt are made from polyvinylchloride and free from any negative effects on concrete. Also those parts of mid-belt which may remain inside the concrete (pipe & interface) have some tread and teeth for better involvement with concrete.
The final part in water stop process is from inside of concrete any by plastic water stop mid-belt named as plastic mid-belt cone which may exit from both heads of mid-belt upon the end of concreting and opening of frames by pliers.
Pulley or mid-belt interface:
Plastic mid-belt interface is the middle part of mid-belt cone and tread pipe which may remain inside the concrete after the operation and then simple & edged plastic stoppers would be embedded / fixed inside the plastic mid-belt interface and PVC tread pipe.
PVC tread pipe is applied in plastic water stop mid-belt structure as an intermediate part. It is responsible for decrease/ increase of the length of plastic water stop mid-belt in production & assembly process. The real reason of treating of pipe surface si for better involvement of pipe with concrete.
As a middle water stopper in water stopping process, this part is located at passing place of belt which may be lead towards middle part of the pipe upon the end of concreting and exiting of the mid-belt cone from the end of mid-belt by pressing on middle part of the pipe.
This part is the same water stopper at both ends of mid-belt in water stopping process and passing place of mid-belt from among plastic belt which may be embedded at both ends of mid-belt upon the end of concreting and opening of frames and exiting the mid-belt cone by pressing on both ends.