Instruction Handbook KL
Chapter 7
BA KL V11 en
10/2014
page 7-3
7.6.2
Mechanical seal, single-acting
The used mechanical seals comply with DIN 24960. These seals are maintenance-free. There may
be minor leaks from time to time as a result of foreign bodies in the medium, which get stuck
between the seal faces. This could happen during the operation and is no fault.
Permanent leaks (meaning that the medium leaks out of the bottom of the bearing seat) are a
symptom of worn seal faces or damaged elastomeric rings.
Make sure the mechanical seal really does come into contact with the medium and thus is lubricated
and cooled.
For mechanical seals in double-acting, back-to-back arrangement
a buffer fluid is necessary. The pressure of the buffer fluid should be checked regularly as a fall in
pressure below the pressure level in the intake chamber can cause the medium to penetrate the
sealing compartment.
For mechanical seals, double acting, tandem arrangement
it will again be necessary to check the necessary buffer fluid regularly. The pressure in the
intermediate sealing compartment must be lower than the pressure in the product chamber of the
pump. If this type of seal is subjected to quench pressure, this will cause the seal on the medium
side to open.
7.6.3
Stuffing box seal
Never tighten a stuffing box seal too much as this will cause overheating in the packing area which
in turn may destroy the seal.
If the stuffing box is too slack, on the other hand, air may be sucked in.
7.6.4
Shaft seal rings
The shaft seal rings, which are used for sealing of the shaft, are also maintenance-free.
Permanent leaks are a symptom of a worn drive shaft (settled down) or worn elastomeric rings.
