Screen
AssigneeAhlstrom Machinery Inc.
InventorRisto Ljokkoi
Life of this patent
Estimating the term…
Abstract
A pressure screen comprises an outer housing with a pulp inlet, and accepts and rejects outlets and an advantageous mount of a stationary screen drum (screen cylinder) in the housing. The screen drum is secured at an upper end flange with bolts to an intermediate ring and supported via the intermediate ring by the housing. A rotating rotor is disposed inside the screen drum. The bottom end of the screen drum is provided with at least one groove with at least one primarily flexible material ring disposed in the groove. Cooperating substantially conical surfaces are provided in the bottom of the screen drum and a bottom intermediate ring, in which the groove is formed.
Claims22
A pressure screen comprising:
- an outer housing;
- an inlet for material to be screened, and outlets for accepts and rejects, into and from said outer housing;
- a stationary screen drum disposed inside said outer housing;
- a rotatable rotor disposed inside said screen drum for rotation with respect thereto;
- said screen drum having a bottom end with a first flange, and a top end with a second flange;
- bottom and top intermediate rings secured to said outer housing, said bottom intermediate ring having an inner edge with a substantially conical surface opening toward said top ring;
- said second flange connected to said top intermediate ring;
- said first flange having an outer substantially conical downwardly tapering surface having at least one substantially annular groove with at least one primarily flexible material ring therein;
- and
- said first flange outer surface supported by said bottom ring substantially conical surface.
A pressure screen comprising:
- an outer housing;
- an inlet for material to be screened, and outlets for accepts and rejects, into and from said outer housing;
- a stationary screen drum disposed inside said outer housing;
- a rotatable rotor disposed inside said screen drum for rotation with respect thereto;
- said screen drum having a bottom end, and a top end with a flange;
- bottom and top intermediate rings secured to said outer housing;
- said flange connected to said top intermediate ring, and said screen drum bottom end supported by said bottom intermediate ring;
- and
- said bottom intermediate ring comprising a substantially conical inner edge surface having at least one annular groove with at least one primarily flexible material ring therein.
A stationary screen drum for use in a pressure screen, comprising:
- a screen drum body having a screening surface, a top end, and a bottom end;
- a flange provided on said bottom end, said flange having an outer substantially conical surface having a downward taper;
- and
- at least one substantially annular groove provided in said flange outer substantially conical surface.
A method of replacing or maintaining a stationary screen drum within a pressure screen housing including an inlet for material to be screened, outlets for accepts and rejects, and a rotor disposed within and distinct from the screen drum and rotatable about a substantially vertical axis, said method comprising:
- (a) mounting a screen drum devoid of a bottom interior mounting flange within the outer housing so that the screen drum is subjected primarily to tensile stress, and is not subjected to axial compression stress that adversely affects operation thereof;
- and
- (b) when necessary or desired, accessing the screen drum to effect replacement or maintenance thereof without detaching the rotor;
- and
- wherein (a) is practiced utilizing cooperating substantially conical surfaces on the screen drum and on an attachment to the pressure screen housing, at least one of the surfaces having at least one substantially annular groove therein;
- and providing at least one primarily flexible material ring in the substantially annular groove.
Dependencies are inferred from the claim text.