Mechanical Seal Coolers： A Basic Accessory Gets a Facelift
Mechanical seal coolers often are considered a basic accessory, with little effort placed on selecting the optimal one. A seal cooler directly affects performance of a mechanical seal and extends its mean time between failures (MTBF). The heat removal and thermosiphoning capabilities of the cooler, its hydraulic characteristicstics, as well as its ability to remove trapped air (ventability) influence mechanical seal performance. Industry has long considered the single coiled tube heat exchanger, known as “coil in a can”, the standard for mechanical seal cooling. Recent comparative testing concluded that helically coiled heat exchangers are superior in terms of heat rejection, pressure drop, thermosiphoning capability and venting of trapped air. This article introduces helically coiled mechanical seal coolers and acquaints the reader with the construction features and material options for this type of device. An analysis of the comparative testing is also presented.
Helically Coiled Seal Cooler
Helically coiled heat exchangers offer certain advantages: compact size, higher film coefficient (the rate at which heat is transferred through a wall from one fluid to another) and more effective use of available pressure drop. These combined
features result in more efficient and less expensive designs.
True counter-current flow fully uses the available LMTD (Logarithmic Mean Temperature Difference). Helical geometry enables the handling of high temperatures and extreme temperature differences without high-induced stresses, High operating pressure capability and an ability to fully clean the service fluid flow area add to the exchanger’s advantages. Gas bubbles are a frequent cause of seal cooler performance problems....