Gas tightness monitoring of ductile iron pipe fittings is a process in the production and use of ductile iron pipes, as well as product quality. Gas leakage detection in important production processes includes leakage detection of toxic gases, leakage detection of combustible gases, and gas tightness detection. Most of the first two can be detected using chemical sensors, usually during the use of components or systems. If there is a suitable sensor, the method is relatively simple.
Ductile iron pipes are protected with 180 degree plain concrete walls. Air tightness testing requires covering the cast iron pipe with soil. If there is leakage, it is necessary to clean the soil and break the plain concrete, which inevitably affects the project progress.
Usage of cold welding materials for ductile iron pipe fittings: First, the surface to be repaired must be treated well, and rust and oil must not be present. Otherwise, the adhesive layer may fall off. Coarsening treatment is good, which can increase the adhesion between molecules and enhance the service life of the repaired product. Also remember to choose the cold welding materials corresponding to the material of the ductile iron pipe casting itself. For example, for ductile iron pipe castings, it is necessary to choose (Jinsucheng) JS902 iron cold welding materials, and for steel, aluminum, copper, etc., it is also necessary to choose their cold welding materials to achieve good repair results.
Before hot and semi hot welding of ductile iron pipes, preheat the weldment to a temperature (above 400 ℃), use homogeneous electrodes, select high current continuous repair welding, and slowly cool after welding. Its characteristics are good welding quality, low productivity, high cost, and poor labor conditions. Manual arc welding repair welding can also use polymer materials for cold welding. This repair only needs to clean the surface to be repaired, and can be directly operated manually. Non cast iron type welding rods are used for cold welding, without preheating before welding. During welding, small current and dispersed welding are used to reduce the stress of the weldment. The strength and color of the weld are different from the base metal, and the processing performance is poor. However, the deformation after welding is small, the labor conditions are good, and the cost is low.
Installation of rubber ring for ductile iron pipe fittings:
1. During the installation of ductile iron pipe fittings, the installation surface should be aligned using an observer and a level gauge according to the design. The trench bottom should be regular and tidy, and it is necessary to avoid placing the pipe on the convex surface of the underlying stone. The direction of water flow in ductile iron pipe fittings is closely related to the direction of the socket. Generally, the direction of water flow in ductile iron pipe fittings should flow from the socket to the socket. However, when the slope is large, the socket of ductile iron pipe fittings should be upward, and the installation of ductile iron pipe fittings should be carried out from the bottom up. When lowering ductile iron pipe fittings into the trench, it is necessary to avoid strong collisions between the bottom and the wall.
2. Socket cleaning. Clean the inside of the socket of ductile iron pipe fittings with a brush and a clean cloth, especially at the location where the sealing rubber ring of the ductile iron pipe is placed. No residues such as paint, soil, sand, etc.
3. Lubricate the rubber ring and socket. Clean the edges of the socket of ductile iron pipe fittings, and lubricate the rubber ring and socket of ductile iron pipe fittings with lubricant.
4. Installation of rubber ring for ductile iron pipe fittings. Use force to bend the rubber ring of ductile iron pipe fittings into a gourd shape. Place the rubber sealing ring into the socket, check for fit, and then lubricate with lubricant.
5. Links. When connecting ductile iron pipe fittings, different tools should be used for ductile iron pipe fittings with different pipe diameters.
Precautions for handling ductile iron pipe fittings:
1. Cast pipes and pipe fittings should be lifted using slings or tools. During loading and unloading, they should be handled with care. During transportation, they should be cushioned firmly and not collide with each other.
2. During hoisting, for cast pipes packaged in bundles, the lifting belt should be wrapped around the bottom and never be hung in the middle of the pipe layer to avoid breakage of the packaging belt and loose binding during hoisting.
3. For bulk cast pipes, use a hook or lifting belt for one-time lifting.
4. If a forklift is used for lifting, all places that may come into contact with the cast pipe during the operation shall be protected.
5. The lifting of the cast pipe should be stable and slow. It is strictly prohibited to wrap the lifting belt around the cast pipe, causing the cast pipe to rotate in the air. Be careful not to collide with other hard objects.