The main types of cold bed in spiral pipe production line are single chain cold bed, double chain cold bed, new chain cold bed, step rack cold bed and screw cold bed.
1. Single Chain Cold Bed
Single-chain cold bed mostly adopts climbing structure. The cold bed consists of a forward transport chain and a fixed guide rail with a transmission system. The steel pipe is placed between the two pulling grasps of the forward transportation chain, and the fixed guide rail bears the weight of the steel pipe body. The single-chain cold bed makes use of the thrust of the forward chain pawl and the friction force of the fixed guide rail to make the steel pipe rotate. At the same time, it relies on the self-weight of the steel pipe and the angle of lifting, so that the steel pipe is always close to the forward chain pawl, so as to realize the smooth rotation of the steel pipe.
2. Double Chain Cold Bed
The double-chain cold bed consists of forward and reverse transport chains, each of which has a transmission system. The steel pipe is placed between two pulls of the forward transport chain, and the reverse chain bears the weight of the steel pipe body. The double-chain cold bed makes use of the pulling force of the forward transport chain to make the steel pipe move forward, and the friction force of the reverse chain to make the steel pipe rotate continuously. The movement of the reverse chain makes the steel pipe always lean on the pawl of the forward transport chain to achieve smooth rotation and even cooling.
3. New Chain Cooling Bed
Combining the characteristics of single-chain cold bed and double-chain cold bed, the cold bed is divided into uphill section and downhill section. Uphill section is a double-chain structure consisting of forward and reverse transport chains. The positive and negative interaction makes the steel pipe continue to rotate forward and make climbing movement. The downhill section is a single chain structure arranged parallel to the forward transport chain and the steel tube guide rail. It rotates by self-weight and makes landslide movement.
4. Stepping rack type cold bed
The stepping rack type cold bed bed surface is composed of two groups of racks. One is mounted on the fixed beam, which is called static rack. The other is mounted on the moving beam, which is called moving rack.
When the lifting mechanism moves, the moving rack lifts the steel pipe. Because of the inclined angle, the steel pipe rolls along the tooth shape once when it is lifted. After the moving gear rises to the highest position, the action of the stepping mechanism makes the moving rack advance a step towards the output direction of the cold bed. The lifting mechanism continues to move, driving the rack down and putting the steel pipe into the fixed rack slot. The steel pipe rolls again along the fixed rack's tooth shape, and then the rack returns to its original position to complete a work cycle.
5. Screw type cold bed
Screw cooling is composed of main transmission device, screw and fixed cooling bench. The screw includes screw core and screw helix. The working surface of the fixed cooling bench is higher than that of the spiral rod core and lower than that of the spiral line. The weight of the steel tube body is borne by the fixed cooling bench. The main transmission device drives the screw to rotate synchronously, and the spiral line on the screw drives the steel pipe to roll forward on the fixed cooling bench for cooling.