Masterfilter Ltd is the company that owns this patent.
The patent no is PN 829158 GB I believe payments were suspended.
Has the application been abandoned, or is it still pending.
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Espacent shows this patent was filed in 1957 (the priority date) so it has in fact expired. Granted patent are only valid for 20 years from the original filing date. (in this case that was in the USA 12/02/1957)
After publication the disclosed product/prodcution method can be used as a basis for a new patent by adding a new inventive step that improves some deficiency in the original patent.The added inventive step has to be novel and must not be obvious. At filing stage the patent is given an "A" suffix and when granted a "B" suffix
In this case there is only an spec "A" (i.e.: GB829158A) patent shown. This normally indicates that it was never granted in the first place but fell during the search examination procedure.
You may find this link helpfull
[how to read a patent specification]