CA1261199A

CA1261199A - Dewatering press

Info

Publication number: CA1261199A
Application number: CA000488027A
Authority: CA
Inventors: Timo T. Saalasti
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-08-15
Filing date: 1985-08-02
Publication date: 1989-09-26
Also published as: FI84397C; SE8405234L; SE457863B; FI843218A; SE8405234D0; FI843218A0; FI84397B

Abstract

Abstract of the Disclosure The invention is concerned with a dewatering press in which the material to be dewatered is fed in between a perforated drum (1) and a press roll (4) revolving inside the said drum and in which the perfo-rated drum (1) is supported by means of a support roll (2) placed outside the drum. When the material is being dewatered, besides water, some of the material to be dewatered is also extruded out of the holes in the drum. In order to remove the material from the faces of the drum and of the support roll, a mechanical knife has been used, scraping the face of the drum. The sandy bark remaining between the knife blade and the drum, however, abrades the knife and the drum.
According to the invention, the faces of the drum and of the roll are cleaned by means of water jets. A
perforated pipe in the "throat" between the drum and the support roll sprays the faces clean, so that abrasion is excluded.

Description

Dewatering Press The present invention is concerned with a machine by means of which wet, mainly fibrous materials, such as wet bark, paper waste, peat containing long fibres, etc. can be dewatered, e.g., to fuel.
The present invention is concerned in par-ticular with such dewatering presses in which the de-watering takes place so that the material to be dewatered is fed in between a perforated drum and a press roll xevolving inside the said drum, and the perforated drum is supported by means of a support roll placed outside the drum. Thus, the material to be dewatered is placed between the revolving perforated drum and the press roll revolving inside the drum. When the press roll presses the material to be dewatered, besides water, some of the material to be dewatered i5 also extruded. The extruded paper or bark is denoted with numeral . When the perorated drum revolves in the direction of the arrow , and the support roll also revolves correspondingly in the direction of the arrow the bark extruded out of the holes in the drum, on rotation of the drum, ends up between the drum and the roll , and causes undue abrasion therein.
This is why in prior-art constructions, near the contact point between the revolving drum and the support roll , so to say in the "throat", there is a mechanical knife, not shown in the drawing, which cuts off the bark extruded out of the holes in order that the faces of the perforated drum and of the support roll should remain as clean as possible.
This knife, however, involves the drawback that sand carried along with the bark first wears small grooves into the knife, thereinafter more bark and more sand adhere to the knife, and the abrasion becomes more intensive. In practice, grooves of a depth of 1 to 2 ~m are already worn into the drum during one year ~e

2 ~

of operation. This is a considerable drawback, which results in replacement of the drum after 3 to 4 years of operation. The object of the present invention is to eliminate this very drawback.
A dewatering press in accordance with the present invention, in which the material to be dewatered is fed in between a perforated drum and a press roll revolving inside the drum and in which the perforated drum is supported by a support roll placed outside the drum, is characterized in the features stated in the characterizing portion of claim 1.
The invention will be described in more detail with the aid of the attached drawing.
The figure illustrates mainly just the press zone between the drum 1~ the press roll 4, and the support roll 2, in the dewatering press. The in-vention will be illustrated here only schematically.
According to the invention, in place of the knife, e.g., the quadrangle pipe 9 shown in the drawing is installed, which pipe is provided with holes. Out of these holes, high-pressure water jets 10 are dis-charged and cut off any bark 6 extruded out of the holes, and keep the drum clean.
The water jet 10 is preferably directed at the drum face slightly obliquely to the plane perpen-dicular to the axis of the drum, whereat the jet meets all the holes better when the drum revolves.
The solution illustrated in the drawing has two directions of jets. The jet 10 is directed at the face of the drum 1, and the jet 11 is directed at the face of the support roll to make it clean. Of course, it is possible to provide a pipe of its own for each jet if this is found necessary in view of, e.g., the use of water, jet pressures, or out of some other reason.
In order to produce a jet of water against the faces of the drum and of the support roll, it is possible to use devices of any sort whatsoever. The pipe of rectangular section shown here is a simple solution for the positioning of the jet devices in the "throat" between the drum and the support roll.
Besides on the construction of the dewatering press, the pressure and the constructions required for the water jet depend on what is to be dewatered. The essential matter is that the jet shall keep the faces clean.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a dewatering press in which the material to be dewatered is fed in between a perforated drum and a press roll revolving inside the said drum and in which the perforated drum is supported by means of a support roll placed outside the drum, the improvement characterized that in advance of the press point between the drum and the support roll, in the direction of its rotation, spray means are provided adapted to spray water or an equivalent thereof approximately in the direction of the face of the circumference of the drum whereby the face of the drum may be cleaned, said dewatering press also including means for spraying said support roll, said spraying means for spraying of said drum and said support roll being operate spray means or spray means adapted to spray both the support roll and said drum.

2. A dewatering press as claimed in claim 1, wherein said spray means comprises nozzles mounted relative to said press whereby said the nozzles are adapted to spray a jet of water directed obliquely to a plane perpendicular to the axis of the drum.

3. A dewatering press as claimed in claim 1 or 2, wherein said spray means includes a pipe in advance of the press point between said drum and said support roll, said pipe having nozzle holes therein directed obliquely to the transverse plane of the pipe.