Determination of moisture ratio in parts of the hop cone during the drying process in belt dryer
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Kuupäev
2018
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Ajakirja pealkiri
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Abstrakt
The
paper deals with monitoring the moisture content of hop cones and their parts
(strigs and bracts) in PCHB 750 hop belt dryer. When drying hop cones, the critical point is the
sufficient drying of the strig. These are therefore dried to a moisture content o
f 6 to 8%. This
exact moisture provides a sufficient guarantee ensuring that the strig is dried up. On the other
hand, bracts are dried up to such a level which makes pressing the hops impossible. Therefore,
after drying, the bracts are remoistened. This i
s called hops conditioning. After conditioning the
moisture content of hops is optimal, ranging between 8 and 11%. There is no doubt that drying
or any further moistening
does not benefit the hop cone.
During the experiment, the moisture content was determ
ined regarding the whole hop cones as
well as the bracts and strigs separately, the samples of which had been taken from the hops prior
to entering the dryer, from different parts of belts in the dryer and subsequently before and after
the conditioning. Th
e moisture content was determined by means of Mettler HE53 moisture
analyzer. After the bracts and strigs had been dried, we calculated their weight ratio which was
approx. 90% of bracts and 10% of strigs. Based on this ratio the weighted average was calcu
lated
which corresponds to the moisture
content of the whole hop cone.
The measured values indicate that the average moisture content of hops below 10% was already
at the beginning of the third belt of the dryer. The hops had been unnecessarily overdried a
long
the whole third belt. Another output refers to the moisture ratio of hop cones, bracts and strigs in
different parts of the dryer. The obtained values will serve as a basis for the follow
-
up design of
a device for monitoring the dryer parameters and i
ts visualisation.
Kirjeldus
Article
Märksõnad
hop, hop cone, bract, strig, drying, belt dryer, moisture, articles