What Is a Threaded Pipe?

Threaded pipe, also known as low-rib pipe, is mainly used to expand the heat transfer area by external ribbing (ribbed coefficient of 2-3). It is generally used in cases where the heat supply coefficient inside the pipe is more than 1 times larger than the heat supply coefficient outside the pipe. Condensation and boiling outside the tube also have a better strengthening effect due to surface tension.

The heat exchange tube is used as the core heat exchange element of the heat exchanger to improve its heat transfer performance and control

Aiming at the characteristics of small-diameter thin-wall stainless steel pipes with poor rigidity and small volume, if traditional processing methods are used for processing, not only will it be difficult to manufacture small-sized processing tools, the accuracy of processing will not be easily guaranteed, and the product specifications will be single. Considering that the small-diameter thin-walled stainless steel pipe is better shaped, the spinning method can be used for reference. That is, one end of the stainless steel pipe is fixed to the chuck by a clamping cylinder. The chuck is driven by the spindle motor to rotate. The shaft is provided with a threaded cylinder and a hard alloy turning wheel. The turning wheel frame is connected with a threaded motor through a screw rod. The rotation of the threaded motor drives the turning frame to move axially. The stainless steel tube achieves continuous point-by-point plastic deformation under the combined action of the radial extrusion of the rotary wheel and the spindle motor. Its schematic diagram is shown in Figure 1.

The specific production process includes five stages: automatic feeding, feeding, clamping, thread processing, and returning. The entire system can realize unattended automatic processing, as long as the number of processing roots, product parameters, and system parameters are entered on the touch screen interface. Product parameters include the working speed of the main motor, the pitch, the number of thread sections of each stainless steel pipe, and the length and starting distance of each thread. The system parameters include the sensor delay time, lead screw lead, servo motor acceleration and deceleration time, and reverse motion of the thread motor. speed. By setting product parameters and system parameters, and adjusting the screw wheel depth by adjusting the screw cylinder at the same time, the specifications of the processed product can be flexibly adjusted ^[2]

The United States Phillips Petroleum Company uses a combination of threaded tubes and baffles, which not only eliminates the problem of heat exchange tube vibration, but also increases the coefficient of cross flow heat exchanger by about 30%, and reduces the pressure drop of the tube bundle by 50%.

The threaded pipe is divided into an externally threaded pipe and an internally threaded pipe. The internally threaded pipe is also called a dry steam pipe, an internal rib pipe, or an internal finned pipe. It is mainly used on dry evaporators in central air conditioners.

Internally threaded tubes are also called dry steam tubes, internal ribbed tubes or internal finned tubes. In the central air conditioner, it is mainly used in dry-type internally threaded tube evaporators. During heat exchange, who is outside the tube is cooled by the refrigerant that evaporates inside the tube. It is also used in domestic and commercial air-conditioning heat exchangers or high-temperature heat exchangers. Heat pipe. The internal surface area per unit length of the internally threaded pipe is 1.5-2 times that of ordinary smooth copper pipes, and its heat transfer coefficient is 1.5-2.4 times that of smooth copper pipes of the same specification. The carrier flow resistance is only increased by 3-5%, which can save energy by 20-35%, and reduce the total weight of the refrigeration air conditioner by 10-25%. ^[3]