One. Glass fiber pipe connection method
Glass fiber pipe connection methods include: butt joint connection, keyed and glued connection, flange connection, and keyed and sealed ring connection. 1. Butt joint connection and keyed and glued connection are commonly used for fixing connections between pipes and pipes.
2、Flange connections are used for frequently disassembled areas.
3、Sealing rings are commonly used to connect underground pipelines, particularly for connecting and repairing large-diameter pipe bends. Sealing ring connections include single O-ring connections and double O-ring connections.
4、The socket-welding method is suitable for connecting pipes of fixed lengths, but cannot be used with pipes that have a corrosion-resistant layer. When connecting pipes to pumps, flexible joints should be used to minimize deformation of the pipe and pipe fitting due to vibrations.
Two. How to connect glass fiber pipes
For glass fiber pipes, use "O" type sealing ring connections. Pay attention to the smoothness of the groove and the working surface, as well as the presence of cracks, bubbles, or other defects.
The O-ring is installed in the groove, and a preliminary compression allowance should be reserved to ensure its sealing performance. The required preliminary compression allowance also varies depending on the application and relative to the cross-sectional diameter (W). Typically, for static sealing, it is approximately 15%~30%, while for dynamic sealing, it is approximately 9%~25%.
When installing the O-ring in the groove, it will be subjected to tension or compression. If the tension and compression values are excessive, it can cause the cross-section of the O-ring to become either too large or too small, as a 1% extension will reduce the cross-section diameter W by approximately 0.5%.
ForSeal for borehole, the O-ring should be in a stretched state, with a maximum allowable stretching of 6%. ForShaft sealing, the O-ring should be compressed along its circumference, with a maximum allowable circumference compression of 3%.
Three. Glass Fiber Bonding Process
1. Curing treatment.Newly produced fiberglass parts, once removed from the mold, cannot be immediately used for bonding and sealing. They must undergo a curing process to remove residual monomers and other volatile substances that may not have fully reacted during the fabrication of the fiberglass parts. The curing process also helps to release and eliminate internal stresses within the fiberglass parts. This curing process refers to the condition where fiberglass parts are stored at a temperature of 23 degrees Celsius and a relative humidity of 50% for at least two weeks. Prior to the curing process, the fiberglass parts should also be heated to a temperature of 60-80 degrees Celsius for 4-6 hours.
2. Sanding.Glass fiber components that have undergone aging treatment must be abraded with a coarse abrasive, typically 80#～120#, to remove any chemical substances that have been released during the aging process.
3. Cleaning.Cleaning agents and adhesives should be used in conjunction. The cleaning agents typically have two purposes:① Cleaning: Use industrial cleaning wipes to hold the bottle mouth, gently shake to ensure only a small amount of cleaning agent is on the wipe. When wiping, only wipe in one direction, and do not wipe back and forth. After wiping, immediately wipe the cleaning agent dry with a dry wipe (the wipe should not have any stains). After cleaning, allow the cleaning agent to dry completely according to the temperature conditions.② Activation: Cleaning agents that are used with adhesives typically have an activation effect on the substrate, which improves the bonding between the adhesive and the substrate.
4、Primer.Bus-grade glass fiber components are typically semi-transparent, and some are even transparent. This allows ultraviolet (UV) radiation to directly penetrate the glass fiber components and act on the adhesive, thereby accelerating the aging of the adhesive, reducing its bonding strength, and even causing bonding failure. Therefore, a primer should be applied to the glass fiber components before bonding to block UV radiation. If the UV or visible light transmission rate through the glass fiber components is less than 0.5%, or the transmission rate of visible light is not more than 20%, applying a primer to the bonding area of the glass fiber components can effectively prevent UV radiation from damaging the adhesive. If the UV or visible light transmission rate exceeds these limits, in addition to applying a primer, it is also necessary to cover the bonding layer with masking tape or opaque materials to completely prevent UV radiation from damaging the adhesive. As the bonding surface for the car body frame, it should be designed and arranged according to the bonding process characteristics to facilitate bonding. Before bonding the glass fiber, the surface to be bonded (typically carbon steel, galvanized steel profiles, or aluminum profiles) should be treated in the same way as the glass fiber components, i.e., grinding, cleaning, and applying a primer.
5、Apply adhesive.Apply polyurethane or silicone adhesive to the car body frame. The resulting adhesive should form a triangular shape. The dimensions of the triangle should be determined based on the desired adhesive thickness and width. When bonding the fiberglass component to the frame, the triangular shape also helps to completely expel air from the adhesive, preventing air from remaining within the adhesive and causing bonding defects.
6. important considerations during the bonding process.①Applying adhesive to the surface before bonding will significantly weaken the adhesive's bonding strength, therefore, during bonding, it is essential to control the application time to be no more than half of the adhesive's drying time.②Elastomeric adhesives have a certain bonding thickness requirement. To achieve the ideal thickness, use rubber or plastic pads with a Shore A hardness that is equivalent or close to the hardness of the adhesive layer. This is very important for bonding.