Year: 1895

page_text: Date of Application, 27th May, 1895
Complete Specification Left, 17th Feb., 1896-Accepted, 21st Mar.. 1896
I, CARL BERGMANN, of 55 Thal Strasse, Meissen on the Elbe, in the German
Empire, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to an improved process of retting or steeping jute and
apparatus therefor.
In order to prepare jute for spinning the gummy or resinous matters which bind
the fibres together are dissolved by retting or steeping. Hitherto it has been the
practice to effect this by piling the raw jute in stacks and then pouring on it the
retting liquid. The fermentation occasioned in this manner proceeds however much
quicker and more actively in the inner than in the outer layers of fibre so that it is
necessary to interrupt the process of fermentation before the outer layers are
affected in order to prevent the inner fibres from being destroyed or damaged.
This irregularity in the process of fermentation is occasioned by the fact that
the outer layers are quickly cooled by the surrounding air and this cooling is also
aided by the evaporation of the retting liquid at the outer surface of the jute heap
whereas the heat produced by the fermentation in the interior of the heap assists
the process.
The evaporation also occasions a considerable loss of the retuing liquid and the
duration of the process depends on the outside temperature so that it is impossible
to calculate beforehand the time required for a particular case.
In order to lessen the effect of the air and of the temperature of the inner and
outer layers of fibres and in order to quicken the process it has been proposed to
treat the jute with the retting liquid at a pressure of from 5 to 6 atmospheres. By
this means the process takes less time but the irregular action of temperature on
the inner and outer layers of the fibre is not materially improved. This process
has further the disadvantage that it is costly and requires constant attention.
Now the object of my invention is to remedy these defects and I effect this by
treating the jute in a closed vessel which is heated on the outside.
For this purpose I advantageously employ a vessel the front and cover of which
are removable or hinged. The other sides and the bottom are either formed double
and steam or highly heated water conducted into the jackets, or steam or hot water
coils are arranged on the outside of the vessel or under the bottom, which coils
supply the necessary heat to the vessel.
After the stacks of jute have been piled up in the vessel and after their treatment
in the usual manner the vessel is closed and heated by the above described means.
The retting liquid then penetrates in the form of vapour regularly throughout
the whole space between the jute fibres which are at the same time regularly
moistened and warmed. The process of fermentation proceeds very rapidly on
account of the supply of heat so that by this process the gummy and resinous
substance is dissolved and the fermentation proceeds at a much quicker rate thau
hitherto. A given quantity of jute requires therefore a less number of vessels
than hitherto so that not only is the cost of working but also the cost of the plant
considerably lower than usual. By my improved process there is moreover
practically no loss from evaporation of the retting liquid thereby effecting economy
in material.

page_text: My process also enables the time taken to dissolve the gummy and resinous
matters to be accurately calculated and the solution is thorough so that the quality
of the fibres for spinning purposes is much improved thereby.
Dated the 27th day of May 1895.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
Improvements in Retting or Steeping Jute.
1. CARL BERGMANN, of 55, Thal Strasse, Meissen on the Elbe, in the German
Empire, Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement:-
This invention relates to au improved process of retting or steeping jute and
apparatus therefor.
In order to prepare jute for spinning the guminy or resinous matters which bind
the fibres together are dissolved by retting or steeping. Hitherto it has been the
practice to effect this by piling the raw jute in stacks and then pouring on it the
retting liquid. The fermentation occasioned in this manner proceeds however much
quicker and more actively in the inner than in the outer layers of fibre so that it is
necessary to interrupt the process of fermentation before the outer layers are
affected in order to prevent the inner fibres from being destroyed or damaged.
This irregularity in the process of fermentation is occasioned by the fact that the
outer layers are quickly cooled by the surrounding air and this cooling is also
nided by the evaporation of the retting liquid at the outer surface of the jute heap
whereas the heat produced by the fermentation in the interior of the heap assists
the process.
The evaporation also occasions a considerable loss of the retting liquid and the
duration of the process depends on the outside temperature so that it is impossible
to calculate beforehand the time required for a particular case.
In order to lessen the effect of the air and of the temperature of the inner and
outer layers of fibres and in order to quicken the process it has been proposed to
treat the jute with the retting liquid at a pressure of from 5 to 6 atmospheres. By
this means the process takes less time but the in regular action of temperature on
the inner and outer layers of the fibre is not materially improved. This process
has further the disadvantage that it is costly and requires constant attention.
Now the object of my invention is to remedy these defects and I effect this by
treating the jute in a closed vessel or chamber which is heated on the outside.
To enable my invention to be fully understood I will describe it by reference to
the accompanying drawing, in which :-
Figure 1 is a longitudinal section of one of a series of retting vessels constructed
in accordance with my invention :
Figure 2 is a plan, and,
Figure 3 is a cross section of the same.
As shewn in the drawing the front a and the cover bare removable or hinged.
The other sides c and the bottom d are either formed double and steam or highly
heated water conducted into the jackets or spaces, or steam or hot water coils are
arranged on the outside of the vessel or under the bottom, which coils f supply
the necessary heat to the vessel.
After the stacks of jute have been piled up in the vessel and after their
treatment in the usual manner the vessel is closed and heated by the above
described means.
The retting liquid then penetrates in the form of vapour regularly throughout

page_text: the whole space between the jute fibres which are at the same time regularly
moistened and warmed. The process of fermentation proceeds very rapidly on
account of the supply of heat so that by this process the gummy and resinous
substance is dissolved and the fermentatiou proceeds at a much quicker rate than
hitherto. A given quantity of jute requires therefore a less number of vessels than
hitherto so that not only is the cost of working but also the cost of the plant
considerably lower than usual. By my improved process there is moreover
practically no loss from evaporation of the retting liquid thereby effecting economy
in material.
My process also enables the time taken to dissolve the gummy and resinous
matters to be accurately calculated and the solution is thorough so that the quality
of the fibres for spinning purposes is much improved thereby.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A process of retting or steeping jute consisting in treating the jute with the
retting or steeping liquid in vessels or chambers, which after being closed are
heated substantially as described.
2. In a process of retting or steeping jute in a closed vessel heating the said
vessel substantially as described.
3. Apparatus for carrying out the process described in Claim 2 consisting of a
retting chamber or vessel adapted to be closed on all sides and the walls c and d of
which are provided with devices for heating the same substantially as described
and illustrated in the drawing.
Dated the 17th day of February 1896.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.