Sealing cap for use in internal cleaning of can fillers

A sealing cap for use in sealing the can filling head of can filling apparatus to allow cleaning fluid to be pumped through the head. The sealing cap closes off the head in substitution for a can and comprises a sealing member rotatably mounted within a threaded retaining ring adapted to be screwed onto a threaded outer surface of the can filling head. This configuration allows easy fitment of the sealing cap during head cleaning operations.

This invention relates to a sealing cap for use in the internal cleaning of 
can filling apparatus. 
Can filling apparatus comprise a number of can filling heads mounted on a 
common framework. These can filling heads have to be cleaned regularly and 
when cleaning is to be carried out it has previously been the practice to 
fit a plastics material cap over the filling heads to seal the head and 
allow a cleaning fluid to be pumped through the apparatus. These known 
caps have been a clip fit on the filling heads with inwardly facing 
protrusions on the cap engaging a groove formed on the outer surface of 
the filling head assembly. This type of fitting is necessary as the cap 
has to be able to withstand the high pressure of the cleaning fluid being 
forced through the machine. These known caps have the disadvantage that 
the clip fittings often tend to break when the cap is removed after 
cleaning. 
It is an object of the present invention to obviate or mitigate the above 
disadvantages and provide a sealing cap which is easy to manufacture and 
use. 
According to the present invention there is provided a sealing cap for use 
in the internal cleaning of can filling apparatus and adapted to be fitted 
to the can filling head of the apparatus, the sealing cap comprising a 
sealing member rotatably mounted within a threaded retaining ring adapted 
to be screwed onto a threaded outer surface of the can filling head. 
Preferably, the sealing member of the cap sealably engages a seal already 
provided within the can filler head for sealing a can being filled.

Referring to FIGS. 1 to 3 of the drawings, a sealing cap for use in the 
internal cleaning of can filling apparatus comprises a plastics material 
sealing member 1 and a plastics material retaining ring 2. The sealing 
member 1 is rotatably mounted within the retaining ring 2 by way of a 
cylindrical lower portion 1a of the member 1 extending through a central 
bore 2a of the retaining ring 2. A downwardly facing surface 20 on the 
sealing member 1 bears against an upwardly facing surface 21 on the 
retaining ring 2 and a groove 3 in the cylindrical lower portion 1a of the 
member 1 serves as a seating for an `O` ring 4. The `O` ring 4 bears 
against a lower surface 5 of an annular ledge 6 in the central bore 2a of 
the retaining ring 2 and thus rotatably locates the sealing member 1 
within the retaining ring 2. A cylindrical upper portion 2b of the 
retaining ring 2 is provided with an internal thread 2c formed on its 
inwardly facing surface and the lower portion 1a of the cap 1 has a 
circular recess 8 formed in an upper surface 9. 
Examples of suitable plastics materials for the sealing cap are Nylatron 
G.S.M. for the sealing member and rotating ring or Ertalon G.S.A. for the 
sealing member and Ertacetal `C` for the rotating ring. 
Referring now to FIG. 4, a can filler head 10 of can filling apparatus has 
an outer cover 11, liquid injectors 12 and a gas valve 13. An annular can 
seal 14 is fitted to the inside of the cover 11 and the cover 11 has a 
thread 15 cut on its outer surface. 
In use, the sealing cap assembly is first fitted to the can filler head 10 
with the upper portion 2b of the retaining ring 2 threaded onto the cover 
11 of the can filler head 10, the internal thread 2c on the ring 2 
engaging the external thread 15 on the cover 11. As the retaining ring 2 
is screwed onto the cover 11, face 21 on the ring 2 bears against the face 
20 on the sealing member 1. The sealing member 1 is thus forced upwards so 
that an annular bevelled sealing surface 7, of the member 1 comes into 
contact with and seals against the rubber seal 14 in the cover 11. The 
recess 8 in the cap 1 provides clearance for the gas valve 13. The cap is 
now held firmly in position on the operating head 10 and the seal 14 
provides a liquid tight seal against the sealing surface 7. Cleaning fluid 
can then be pumped through the gas valve 13 into the liquid injectors 12. 
After use, the sealing member 1 and retaining ring 2 assembly can be 
easily removed without damage and be stored ready for their next use. 
In most cases, can filling apparatus have a large number of can filling 
heads 10. In these cases a corresponding number of cap and retaining ring 
assemblies are provided and these can be quickly and easily fitted one to 
each can filling head 10. 
The sealing cap of the invention can be used a large number of times and 
requires little maintenance the seal being provided by the existing can 
seal 14 in the can filling head itself. 
Modifications and improvements may be incorporated without departing from 
the scope of the invention. I claim: