4-dimensional braid – trapeze cross-section
- low frictional heat
- ideal spread of force
- little wear on packing and shaft
2-dimensional braid (plait)
- big surface
- good elasticity
- good cross-section stability
- dense braid structure
- very dense braid structure
- smooth surface
- high cross-section stability
Concentric, one or multiple braided around core
- dense surface
pressed rings from pure graphite foil
- high cross-section density
- very high pressure, temperature and chemical resistance
Assembly and disassembly information
Only use packings to fit the relevant gland! Packings which are too thin or thick may not be brought down to size by hitting or pressing them.
Pump packings should have a low minus allowance (depending on dimension between 0,1 and 0,4 mm), never a positive allowance.
Remove old packing residue, clean gland thoroughly. Grooves, dirt and potential rust on shaft, spindle and housing have to be cleaned – polish if necessary.
Gap between shaft and housing.
0,2 mm should not be exceeded to prevent the packing from extruding into the gap under pressure. If necessary backing rings or exactly fitting base bushing have to be provided.
Trimming the packings when using piece good
packing lengths have to be made using the packing cutter or the packing has to be wound around a spike (same diameter as the shaft to be sealed) and has then to be cut with a knife alongside the thorn centre line.
Another method is to calculate the required length of the packing sections and then cut the lengths individually with a diagonal cut. Only regression functions can be used since packings are textile structures with differing upsetting and expansion properties.
We recommend the calculation formula:
L = (Di + s) · π · 1.07 for asbestos-free packings
L = length of packing section [mm]
Di=Ring-inner diameter [mm]
s = packing width [mm]
Deviations are possible depending on packing material and dimensions.
Insert the packing rings or lengths
Insert only individual packing rings or lengths corresponding to ring dimensions. Don’t wind the packing around the shaft or spindle that requires sealing. Put the cut rings carefully around the shaft or spindle (radial and axial) and insert with the cut surface first into the bushing. Then press the rings individually using suitable packing tools (e.g. one or two part shells – never a screwdriver etc.) rectangular to the shaft or spindle axis. The cut surfaces of the packing rings have to be shifted at 90° each when inserted.
Tightening the gland
Tighten the gland screws or nuts securely for valves (spindle wheel, however, still needs to be able to be turned by hand).
Only tighten the gland screws or nuts lightly by hand for pumps, then carry out intake process as described below.
Intake of packings (pumps)
One must not expect absolute tightness of a pump packing of normal design. A so-called drop leakage is necessary in order to prevent overheating or burning of the packing due to frictional heat. The correct setting or adjustment of a packing determines the service life of a packing. It requires experience and know-how. The inlet and outlet pipes have to be opened first if coolant or sealing liquid is required. Then start the pump. Allow plenty of leakage initially, then carefully adjust the gland by step-by-step tightening of the gland nuts (each 1/6 or 1/12 turns) until the leakage is reduced to the required minimum.
The shaft and packing gland have to be checked for an increase in temperature during this process. If there are signs of overheating stop tightening the gland and loosen it slightly if necessary to achieve normal temperature again by increasing the leakage. Then start adjusting the gland again (in gaps of 10 – 15 minutes), until the leakage is under control again.
If the temperature and leakage have adjusted to an even level, then maintenance and checks are only required in longerr time intervals.
We recommend especially for our pump packings type 2229 and 2722 to seal the complete packing when idle prior to start up by tightening the nuts, then release the nuts again, finally tighten them again and only then start the pump up.
All information in this technical document reflects today's state of the art and is designed to inform about our products and their scope. They are not designed to guarantee certain product properties and their suitability for certain uses and do not constitute any liability from our part.