Cooling housing (cooling jacket, jacket cooling). A hollow-type seal housing with internal flow of coolant (mostly water) for cooling the stuffing box. Preferred for pumps with single mechanical seals in dead-end arrangement to lower the temperature and hence the vapour pressure of the medium to be sealed. More effective still is a combination of cooling housing and cooling flange, as it also reduces the flow of heat through the shaft. In the case of agitator seals for top drives, the use of cooling housings no longer complies with the state of the art. Here a cooling housing has several disadvantages compared with a cooling flange: 

• Heat is not dissipated until after passing through the shaft and the buffer/quench medium.
• The secondary seals of the mechanical seal are loaded with the boiler temperature.
• The cooling housing obstructs the thermosyphon circuit of the buffer/quench medium.
• The double-walled housing requires a greater design (financial) effort.

Mechanical seal for agitators with cooling flange (1), cooling housing (2) and leakage outlet (3) with leakage trap (4)