In the past, when aluminum evaporators were connected with copper tubes or Bundy tubes, the copper-aluminum joints were welded by argon arc welding or resistance welding, and then the copper-aluminum joints were welded to the copper tubes or Bundy tubes with open flame. The disadvantages of this process are: there are two solder joints and the risk of leakage is high; The welding quality is controlled by the operator's level.
If welding is carried out in the freezer, the operation is more difficult and the welding quality is difficult to guarantee. However, the use of Locke ring pressure welding is simple, clean and beautiful, which ensures the reliability of changing two solder joints into one solder joint and reduces the cost, that is, the original cost of two solder joints and copper-aluminum head is completed by one ring, which is calculated by domestic refrigerator factories.
The comprehensive cost of a refrigerator can reduce the 20 yuan after adopting Locke's ring technology. Authors: Ren Zhaofeng, Sun Qingqing. Once the pipeline material and size of the raw material 1 pipeline designed according to the system requirements are determined, the specifications and corresponding technical parameters of the corresponding Locke ring joint are also determined. The size of the pipeline needs to be controlled, including the external diameter and wall thickness of the pipeline.
The tolerance range of the pipeline is determined according to the specific situation. The connecting part of the pipeline should not be bent or greasy. 2 Rockring Rockring (see figure 1) is a patented product of German Fu Erkang Locklin Company. Rockring technology uses the principle of cold extrusion plastic deformation to realize aluminum to aluminum, aluminum to copper, copper to copper and copper to steel.
The tight connection between copper and titanium is specially used to connect small diameter non-ferrous metal pipes. The maximum nominal pressure pn is 7 MPa, and the maximum detection pressure PP is 4 pn = 28 MPa, which is suitable for -50 ~+ 150℃. For Locke's ring single-ring pipe joint, the pipe made of soft material should be flared, such as aluminum and copper.
Aluminum tubes should be flared. In Figure 2, D 1= the original outer diameter of the outer sleeve, D2= the original outer diameter of the inner sleeve and D3= the inner diameter of the outer sleeve after flaring, where D3=D2+0.2△= the wall thickness of the outer sleeve and L= the axial length of the straight line at the flaring position of the outer sleeve, where l >: = the axial length of the corresponding locking ring +3.
Locke's ring process is an alternative process to welding process in the production of refrigeration household appliances. In mass production, the lock ring can be pressed with hydraulic tongs, and a hydraulic station is needed. For small batch production or product trial production, manual pliers can be used for crimping. The composite locking ring for maintenance is especially suitable for connecting different materials with different diameters.
Manual pressure welding is adopted. The special pneumatic sealing pliers for R600a liquid can also be used for sealing other refrigerants, and can be used together with the Locke ring plug, which can completely replace the ultrasonic welding machine in small batch production.