US3653511A

US3653511A - Sedimentation apparatus

Info

Publication number: US3653511A
Application number: US36787A
Authority: US
Inventors: Karl Axel Goran Gustavsson; Knut Melker Evald Tornqvist
Original assignee: Bahco Ventilation AB
Current assignee: Bahco Ventilation AB
Priority date: 1969-06-12
Filing date: 1970-05-13
Publication date: 1972-04-04
Anticipated expiration: 1989-04-04
Also published as: JPS4914498B1; SE337803B; DE2028548B2; DE2028548A1; DE2028548C3

Abstract

An improved sedimentation apparatus is disclosed. The sedimentation apparatus comprises a container with a lower outlet for discharging sediment and a rotating scraper for moving the sediment towards the outlet. The scraper is connected by a shaft to a drive motor resiliently mounted on the container. The drive motor is pivotally mounted relative to the shaft. When resistance to scraper movement increases because of an accumulation of a certain quantity of sediment, the motor swings in relation to the shaft and actuates means to open the outlet. When a certain quantity of the sediment is removed, the motor returns to its normal position and the outlet closes.

Description

Gustavsson et al.

SEDIMENTATION APPARATUS lnventors: Karl Axel Goran Gustavsson; Knut Melker Evald Tornqvist, both of Enkoping, Sweden Assignee: Aktiebolgat Bahco Ventilation, Enkoping,

Sweden Filed: May 13, 1970 Appl. No.: 36,787

Foreign Application Priority Data Field ofSearch ..210/ll2, 113,528

[451 Apr. 4, 1972 {56] References Cited UNITED STATES PATENTS 1,665,081 4/1928 Andrews ..210/ll2 Primary Examiner.lim L. DeCesare AttorneyBirch, Swindler, McKie & Beckett [S 7] ABSTRACT An improved sedimentation apparatus is disclosed. The sedimentation apparatus comprises a container with a lower outlet for discharging sediment and a rotating scraper for moving the sediment towards the outlet. The scraper is connected by a shaft to a drive motor resiliently mounted on the container. The drive motor is pivotally mounted relative to the shaft. When resistance to scraper movement increases because of an accumulation of a certain quantity of sediment, the motor swings in relation to the shaft and actuates means to open the outlet. When a certain quantity of the sediment is removed, the motor returns to its normal position and the outlet closes.

4 Claims, 2 Drawing Figures PATENTEDAPR 4 I972 SHEET 1 []F 2 SEDIMENTATION APPARATUS The present invention relates to a sedimentation apparatus in the form of a container having a central lower outlet for removing sediment (sludge) from the container and a rotating scraper which serves to move the sediment towards the outlet.

An object of the invention is to provide an apparatus for automatically opening the bottom outlet of the container when a certain quantity of the sludge has settled therein, so that the sludge can be removed thereby. This is achieved by means of the present invention, which is mainly characterized in that the motor which drives the scraper is pivotally mounted in relation to the shaft of the scraper and is connected with the container solely by means of a resilient member which, upon increased resistance against movement of the scraper, permits the motor to swing in relation to the shaft, and in that the motor is connected with means which cause a valve mounted in the ,outlet to open when the motor is deflected to a predetermined extent.

When a certain quantity of sludge has settled in the container and, as a resultthereof, theresistance to scraper movement has reached a determined value, the motor as it swings will thus initiate the removal of a determined quantity of the sludge from the container. As soon as the motor swings back, discharging of the sludge ceases.

If the container is filled with a liquid which contains solid material and the scraper is kept inactive for a certain period of time, the firmer material normally settles to the bottom of the container in the form of a relatively solid mass, which when the motor is started is liable to present an unnormally high resistance to scraper movement, even though the quantity of sludge present is less than that which is normally discharged. To prevent in this case a large quantity of liquid from being removed as a result of the outlet being opened immediately the scraper is set into operation, the motor can be connected to a further actuating means which closes the outlet in the event of the motor making a heavy swing. This arrangement is also of value should the scraper meet some other form of obstacle, in spite ofa low sediment level.

The invention will now be described in more detail with reference to the accompanying drawing, in which:

FIG. 1 shows a sedimentation apparatus seen in vertical cross section; and

FIG. 2 is a perspective view, in larger scale, of certain portions of the apparatus.

The sedimentation apparatus includes a container having a cylindrical main portion 1 and a conical bottom portion 2, at the centre of which is arranged an outlet 3. Liquid containing solid material to be separated therefrom is passed to the container by appropriate means (not shown) while liquid freed from solid material is passed from the container by an outlet (not shown), for instance in the form of a spillway.

Mounted in the sludge outlet 3 is a rotatable throttle means 5, which is operated by means of a cylinder 6, the piston rod 7 of which is connected via an arm 8 to the throttle 5. The medium operating the cylinder is passed to and from the cylinder by

lines

9, 10, via a conventional type of reversing valve indicated at 11.

Mounted in the upper portion of the container 1 is a frame structure 12, which supports at the centre thereof a vertical tube 13, through which a shaft 14 extends. The shaft 14 supports a scraper 15, which as the shaft rotates passes over the conical bottom 2 of the container and moves settled solid material towards the centre thereof, at which the outlet 3 is located.

The shaft 14 is journalled in the inner portion of the tube 13 by means of a ball bearing 16 (FIG. 2) and is connected to the output shaft of an electric motor 17. The motor 17 rests on a coil spring 18, which is mounted about the upper portion of the shaft 14. The lower end 19 of the spring is securely connected with the frame 12 while the upper end 20 of said spring is securely connected to the motor by bending the ends of the spring axially and passing said ends into holes in a plate 21 cooperating with the frame 12 and in a plate 22 connected securely to the motor. The motor has no other connection with the container] or the frame 12. Thus, the motor can swing about the centre line of the shaft 14, although the spring 18 endeavours to hold it in a determined angular position so that the motor normally turns the shaft 14 and therewith the scraper 15 when it is in operation.

A ring 23, coaxial with the shaft 14, is connected with the plate 22 by means of stirrup members 24 which engage pins 25 on the plate 22. The ring presents on the outside thereof two raised portions or earns 26, 27. Each of two

brackets

28, 29 mounted on the frame 12 carries a

limit switch

30, 31, which are provided with pivotal actuating

arms

32, 33 having

rollers

34, 35 which run around the outside of the ring 23. The

switches

30, 31 are positioned at an angle of approximately 120 in relation to each other and are also positioned so that, in the normal position of the ring, i.e., the position the ring takes up when the motor is in its normal position determined by the spring 18 as shown in FIG. 2 the two

rollers

34, 35 rest against the peripheral surface of the ring at a distance from the

cam

27 and 26 respectively.

The switch 30 is connected by suitable electrical means, indicated by the dotted line 36 in FIG. 1, with the reversing valve 11 of the operating cylinder 6 in such a way that, as the arm 32 swings in response to the pressure of roller 34, the valve 11 is set so that pressure medium is passed to the cylinder in a manner which causes throttle 5 to open. As is evident from the aforegoing, this takes place when the resistance to the movement of the scraper is so great that the motor, which rotates the shaft 14 in the direction of the arrow and which, at the same time, itself rotates around the shaft against the action of spring 18 in the direction of arrow 38, makes as the resistance increases a deviation or swing of such magnitude that the ring 23 is rotated to an extent whereby the cam 27 presses in the roller 34. Thus, a certain quantity of settled solid material is removed, whereafter the motor, as a result of the reduced resistance, returns to its normal position, and the throttle closes as soon as the roller 34 is no longer actuated by the cam 27.

If the resistance to scraper movement is so great that the ring continues to be turned until the cam 26 meets the roller 35 of the switch 31, the roller 35 causes the switch to close the valve, wherewith the arrangement functions as described in the introduction when the motor is started or when an unnormally large obstacle is present, e.g., a solid body at the bottom of the container.

We claim:

1. A sedimentation apparatus comprising a container having a lower outlet for discharging sediment,

means normally closing said outlet,

a rotatable shaft extending through said container,

a scraper attached to the lower end of said shaft to move sediment toward said outlet upon rotation,

motor means connected to said shaft for rotating said shaft and scraper,

resilient means mounting said motor means on said container,

said resilient means comprising a spring mounted around the upper end of said shaft and connected at one end to said container and at the other to said motor means to permit said motor means to rotate around said shaft when resistance to rotation of said scraper increases to a predetermined amount, and

first switch means mounted on said container for opening said outlet closing means when actuated,

said first switch means being actuated by the initial rotation of said motor means when the resistance to rotation of said scraper reaches said predetermined amount.

2. A sedimentation apparatus according to claim 1 which includes a ring connected to said motor means for rotation therewith and mounted coaxially with said shaft, and a cam surface on the outside of said ring whereby rotation of said motor means and said ring causes said cam surface to actuate said first switch means.

surface on the outside of said ring for actuating said first switch means upon initial rotation of said motor means and said ring, and a second cam surface on the outside of said ring spaced from said first cam surface for actuating said second switch means upon further rotation of said motor means and said ring.

Claims

1. A sedimentation apparatus comprising a container having a lOwer outlet for discharging sediment, means normally closing said outlet, a rotatable shaft extending through said container, a scraper attached to the lower end of said shaft to move sediment toward said outlet upon rotation, motor means connected to said shaft for rotating said shaft and scraper, resilient means mounting said motor means on said container, said resilient means comprising a spring mounted around the upper end of said shaft and connected at one end to said container and at the other to said motor means to permit said motor means to rotate around said shaft when resistance to rotation of said scraper increases to a predetermined amount, and first switch means mounted on said container for opening said outlet closing means when actuated, said first switch means being actuated by the initial rotation of said motor means when the resistance to rotation of said scraper reaches said predetermined amount.

3. A sedimentation apparatus according to claim 1 which includes a second switch means mounted on said container for closing said opening when actuated, said second switch means being actuated by further rotation of said motor means a predetermined degree beyond said initial rotation.

4. A sedimentation apparatus according to claim 3 which includes a ring connected to said motor means for rotation therewith and mounted coaxially with said shaft, a first cam surface on the outside of said ring for actuating said first switch means upon initial rotation of said motor means and said ring, and a second cam surface on the outside of said ring spaced from said first cam surface for actuating said second switch means upon further rotation of said motor means and said ring.