1.2 Self-Breaking Side Member (Insert) - GB2533426B
Key Excerpts:
"heat exchangers are subjected to transient thermal stresses during operation. These stresses can eventually lead to fatigue failure in the product. As hot fluid flows through the tubes, the tubes heat up and are prone to expand. Expansion of the tubes is restricted by the side members, however. As the side members are not in direct contact with the hot fluid, they will be at lower temperature than the tubes, at least initially, and hence there will be a tension between the hot, expanding tubes and the still cool side members. This leads to fatigue from heating and cooling cycles and can lead to failure of the heat exchanger. A typical failure point is at the corner of the heat exchanger, where the tubes and side member meet the header plate. If the heat exchanger fails, a hole will open up to the interior of the tubes leading to a loss of pressure and loss of efficiency or indeed the heat exchanger may become ineffective. As one function of the side members is to hold the tubes and fins and header plates together during assembly and brazing, and that function is complete after the heat exchanger has been manufactured, one solution to the failure problem has been to cut through the side member across its width, from one side to the other, after manufacture is complete."....."In this way, the tubes have more freedom to expand, because they will no longer be so restricted by the side member, as the cuts can simply widen and close up. The step of cutting through the side member after brazing is an additional manufacturing step however and it is desirable to avoid that."
"According to one aspect of the invention,"...."the side member including a line of weakening"..."the thinned sections being arranged to break during normal use of the heat exchanger".