US2982482A - Double-disk refiner - Google Patents

Description

May 2, 1961 D. w. CURTIS DOUBLE-DISK REFINER Filed June 1, 1960 INVENTOR. )arzald W flarl United sta e Paten "10 DOUBLE-DISK REFINER Donald w. Curtis Pittsfield, Mass., assignor to E. D. Jones Corporation, Pittsfield, Mass, a corporation of Delaware Filed June 1, 1960, Ser. No. 33,238

4 Claims. (Cl. 241-33) This invention relates to machines for refining paper pulp and other materials but more particularly to machines of the so-called double-disk type comprising a rotary disk having a set of blades on each side and a set of stationary blades facing each of said sets with a passageway extending radially between the blades of each pair of opposed rotary and stationary blades and a circumferential space interconnecting the outer ends of said passageways, with an inlet to the inner end of one of the passageways and an outlet from the inner end of the other passageway. Such a machine is disclosed in Patent No. 2,690,098, granted September 24, 1954, to Dwight E. Jones et a1.

One difficulty with machines of this kind is that variations in the rate of fiow of materials through a machine produce unequal pressures on opposite sides of the rotating disk thereby crowding the rotating disk closer to one or the other stationary disks. This makes one passageway narrower than the other so that the refining actions in the two passageways are not the same and so that excessive wear occurs on the blades in the passageway which is narrower.

Objects of the present invention are to provide apparatus which is simple and economical in construction and which automatically equalizes the pressure on opposite sides of the rotating disks and equalizes wear on the two sets of blades.

According to the present invention the apparatus is characterized by a by-pass leading from said circumferential space to said inlet, with ,a throttle valve in the by-pass, whereby the pressure drop between the inlet and the outlet may be controlled by varying the opening in the throttle valve. By maintaining this pressure drop constant the widths of the aforesaid passageways will remain equal after being adjusted to thatparticular pressure drop. Preferably the throttle valve is controlled automatically by a diflerential pressure device connected between the inlet and the outlet. Such devices are made and sold by the Foxboro Company, of Foxboro, Massachusetts, and are described in their Patents 2,539,892; 2,761,471; 2,770,- 258; and 2,806,480.

For the purpose of illustration a typical embodiment of the invention is shown in the accompanying drawing in which the parts are constructed and arranged as in the aforesaid patent of Dwight E. Jones et al.

The apparatus comprises a rotating'disk 1, having blades 2 and 3 on opposite side and two sets of stationary blades 4 and 5 opposed to the rotary blades with passageways 6 and 7 between the pairs of opposed rotary and stationary blades respectively. Extending around the disk is a circumferential space 8 interconnecting the two passageways. Material is fed to the inner end of passageway 6 through an inlet 9 and the material is delivered from the inner end of the passageway 7 through an outlet 10.

According to this invention a by-pass 11 extends from the space 8 to the inlet 9 and in the by-pass is a throttle valve 12 for regulating the amount of material lay-passed from the space to the'inlet 9. The aforesaid difieren valve through a'connection 16 which may be pneumatic,

' hydraulic or electrical as is well known.

In use the disks are adjusted as described in the aforesaid patent of Dwight E. Jones, et al., so that the passageways 6 and 7 are equal in width for the rate of fiow to be maintained in a particular run of material. Then the pressure differential device is adjusted to maintain a predetermined pressure drop between the inlet and outlet, this being established by controlling the amount of recirculation thru the by-pass. If the difierential pressure between the inlet and outlet tends to rise above the predetermined value the throttle valve tends to close and if the difierential pressure tends to drop below the predetermined value the throttle valve tends to open. In this way the pressure drop between inlet and outlet is kept constant and the pressures on opposite sides of the rotating disk 1 remain equal.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. Refining apparatus comprising a rotary' disk having a set of blades on each side, a set of stationary blades facing each of said sets with a radial passageway extending between the blades of each pair of opposed rotary and stationary blades and a circumferential space interconnecting the outer ends of said passageways, an inlet to the inner end of one of said passageways and an outlet from the inner end of the other passageway, characterized by a by-pass leading from said space to said inlet, and a throttle valve in said by-pass, whereby the pressure drop between the inlet and outlet may. be controlled by varying the opening in the throttle valve.

2. Refining apparatus comprising a rotary disk having a set of blades on each side, a set of stationary blades facing each of said sets with a radial passageway extending between the blades of each pair of opposed rotary and stationary blades and a circumferential space interconnecting the outer ends of said passageways, an inlet to the inner end of one of said passageways and an outlet from the inner end of the other passageway, characterized by a by-pass leading from said space to said inlet, an automatic throttle valve in said by-pass, and a differential pressure device hydraulically connected between said inlet and outlet for controlling said throttle valve.

3. Refining apparatus comprising a rotary disk having a set of blades on each side, a set of stationary blades facing each of said sets with a passageway extending radially between the blades of each pair of opposed rotary between said inlet and outlet, a by-pass from said space to said inlet, and a controller in said by-pass responsive to said device for controlling the amount of recirculation through the by-pass.

4. Refining apparatus comprising a rotary diskhaving a set of blades on each side, a set of stationary blades facing each of said sets with a passageway extending radially between the blades of each pair of opposed rotary and stationary blades throughout the circumference of the ar 961f 3 disk, a housing having a space around said disk and an inlet leading to theinner end of one of said passageways and an outlet leading from the inner end of the other of said passageways so that material may flow outwardly through one passageway to said space and thence inwardly through the other passageway to said outlet, a differential-pressure device hydraulically interconnected between said inlet and outlet, a by-pass from said space to said inlet, and an automatic throttle yalve in said bypass responsive to said device for controlling the amount UNITED STATES PATENTS Fraser Mar. 16, 1954 Jones et al. Sept. 26, 1954 Jones et al. Dec. 20, 1955 Bowditch Sept. 17, 1957

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