| This is completely fabricated in the sack factory with an
opening or valve in one corner through which the sack is filled. The valve
is made with an inner flap which functions as a self-closing check valve
after filling. It is available with a plain valve or with an extended
inner sleeve of paper or film. If an extended "tuck-in
sleeve" is used, the sleeve is manually folded down and back into the
pocket under the sleeve for positive closure against sifting. Sleeves that
are thermoplastic-coated may be heat-sealed. |
