Structure and function 1. The equipment is made by two rolled materials, and then form two uniform spiral channels. It can let heat transfer effect better 2. Uses the tangential structure on shell's control, the local resistance is small, because the spiral channel's curvature is even, the liquid does not flow big change in the equipment, the total resistance is small, thus may enhance the design speed of flow to cause it to have the high heat-transfer capability. 3. The total drag is small 4. High leak-proof quality 5. We can do it according to the customers' requirements.