US2551395A

US2551395A - Sewage disposal system

Info

Publication number: US2551395A
Application number: US701004A
Authority: US
Inventors: Rimann Walter
Original assignee: Sulzer AG
Current assignee: Sulzer AG
Priority date: 1946-06-05
Filing date: 1946-10-03
Publication date: 1951-05-01
Anticipated expiration: 1968-05-01

Description

y 1, 1951 w. RIMANN 2,551,395

SEWAGE DISPOSAL SYSTEM Filed Oct. 3, 1946 4 Sheets-Sheet l INVENTOR %L7'E/ ZMA/V/V. BY Ki ATTORNE y 1, 1951 w. RIMANN 2,551,395

SEWAGE DISPOSAL SYSTEM Filed Oct. 5, 1946 4 Sheets-Sheet 2 INVENTOR WA 75 P/M/i/v/v.

Q BY w ATTORN Y y 1, 1951 w. RlMANN 2,551,395

SEWAGE DISPOSAL SYSTEM Filed Oct. 3, 1946 4 Sheets-Sheet 5 INVENTOR I WA 75,? F/MA/v/v.

ATTORNE.

y 1, 1951 w. RIMANN 2,551,395

SEWAGE DISPOSAL SYSTEM Filed Oct. 5, 1946 4 Sheets-Sheet 4 Q3 INVENTOR I #414 7-5 P/MA/v/v.

ATTORN Y Patented May 1, 1951 SEWAGE DISPOSAL SYSTEM Walter Ri'mann, Winterthur, Switzerland, assignor'to Sulzer'Freres, Societe Anonyme, Winterthur, Switzerland Application October 3, 1946, Serial No. 701,004 In Switzerland June 5, 1946 4 Claims. 1

The invention relates to sewage disposal systems having a disintegrator with cutting device for reducing the size of the particles of the solid matter' carried in the sewage and includes means for temporarily reversing. the operation of the disintegrator to loosen periodically the substance adhering to the cutting device and thus prevent the disintegrator from becoming choked. An object of the invention consists in the provision of controlling means for the operation of the cutting device, through which atemporary backward motion of the cutting device is effected.

The system according to the invention comprises an open container communicating with the intake of the disintegrator and receiving lumpy, solid matter and liquid separated from the main stream of sewage. The disintegrator discharges into the sewage stream after the point where the solid matter and a portion of the liquid has been separated. If the disintegrator becomes clogged the liquid level in the container rises. The control means for temporarily reversing the operation of the disintegrator are either automatically operated in dependence on the liquid level in the container or, if manual operation is preferred, are placed in a position where the oper ator can see the liquid level in the container. Other modifications of the invention include automatic clockwork controlled means for reversing the rotation of the motor operating the disintegrator atregular, predetermined time intervals and for regular, predetermined periods, for operating the motor reversing means in dependence on the strength of the current flowing through the motor, and for semi-automatic operation of the reversing means whereby reversing of the motor is actuated by manual operation of a push button and is automatically continued for a predetermined period, whereafter the motor is automatically stopped and restarted to normal operation.

An object of the invention resides in the provision of a cam operated main switch of the motor for the disintegrator, whereby the cam is operated by an auxiliary electric motor and comprises a portion holding the main switch in position for normal operation, another portion for positioning the main switch for reversed operation of the motor, and intermediary portions for positioning the main switch for stopping the motor between normal and reversed operation.

On the drawing examples of arrangements according to the invention are illustrated diagrammati'cally.

Figs. 1 and 2 show a plant for reducing the size of solid matter contained in town sewage in part sectional elevation and plan view, respectively,

Fig. 3 shows a disintegrator in section, an electric motor therefore, and a wiring diagram for push button control of the plant,

Fig. 4- illustrates a hand operated switch gear with automatic reversing,

Fig .5 illustrates an actuating mechanism for the switch gear in response to a certain liquid level,

Fig. 6 shows a switch gear actuated by a time switch, and

Fig. '7 a switch gear actuated, according to the output.

Referring more particularly to Figs. 1 and 2, a channel serves for conducting the sewage from a municipal system of sewers to one or more settling tanks 2, from which the settled mud is withdrawn under water and led .to closed fermentation chambers, not shown in the drawing. The sewage flows along the channel l in the direction of the arrow 3, the larger particles of solid matter carried in the water being heldback by the grid 4, so that they can be removed later by the prongs of the cleaning rake 5, and brought through the chute 6 into the channel I. From the channel '5 the solid particles are washed by means of a stream of rinsing water into the shaft or container 8, whose water level 9 is kept below the water level In of the channel I. The flow from the channel 1 and, if necessary, an additional flow through the pipe 12, controlled by means of the throttle valve H, are maintained in such a way that it corresponds to the quantity withdrawn from the shaft 8 through the suction pipe I3, with undisturbed working of the disintegrator.

In the case of simply designed sewage plants which have no fermenting chambers, or even allow the sewage to pass direct into the sea, the solid matter cut up by the size-reducing device is worked up into manure or allowed to pass away into the sea.

The disintegrator l4, driven by an electric motor I5, delivers the reduced solid substances together with the water through the delivery pipe IE to the basin 2. For the pipes l3 and [6, stop valves I! and [8 are provided. The motor I5 is switched on and ofl by means of the main switch in the switch box 19 by operating the switch handle 20. In the same way the push button remote control 21 at the shaft 8, which is connected to the switch box l9, serves for operating the main switch.

Instead of the channel I, a tipping truck service may be provided, the tipping truck being loaded under the chute 6 with the solid substances, drawn to the shaft 3 and there emptied. Then water is introduced solely through the pipe 52 and regulated by means of the throttle valve H.

Ihe disintegrator l4, Fig. 3, with the cutting device, the rotating knife 23, the grid 2d and the stationary counter-knife 25, is connected through its intake 26 to the shaft 8, Figs. 1 and 2. The solid substances carried over in the rinsing water are reduced in size by the

cutting device

23, 25, Fig. 3, and pass through the grid 24 into the delivery branch 21 and in the delivery pipe i 6. The motor it drives the rotating knife 23.

With the diiferent character of the substances carried in the water, there occurs not only great wear in the cutting device 2325, but also a gradual choking which can be only partly prevented by the counter-knife 25,. which keeps the upper side of the knife 23 clean. The choking may take place more or less quickly, and even quite suddenly. The choking occurs by substances sticking between the knives 23 and the grid 24 and being carried round with the knives 23, so that disintegration of further substances is more or less prevented.

As soon as choking of the disintegrator device l4 begins, this makes itself perceptible by a rise in the water level 8 in shaft 8, Figs. 1 and 2, and the man in charge, by means of the press button switch 2!, causes the motor i and the cutting device to be reversed for a short time. Instead of, as hitherto, having to stop the disintegrator device, open it up and clean it by hand, the following simplified operation has been found much more effective: rotation of the knives 23 is not only interrupted at as regular intervals as possib1e, but also reversed. Thereby any substances stuck between the knives 23 and the grid 24 are loosened very easily and in a very short time. The more often this cleaning is done, the more effective it is, above all if it is done promptly when any choking starts. After running backwards for a short time, mostly for a few seconds. the device 23--25 becomes clean and can again be put into normal service.

As seen in Fig. 3 two

main switches

28 and 29 are provided, which switch the motor l5 on to and ofi from the supply lines so and are fitted in the box I9, Fig. 2. With switch 28 closed, as

28 is actuated by means of the relay 3i and the switch 29 by means of the relay 32, these relays closing the

switches

28 and 29 against the force of

compressed springs

33, 34 acting on the switchbars. The

switches

28 and 29 are operated by auxiliary switches 35 and 36 by hand, by means of the push buttons 3?, 38. Further, the switches 35 and 36 are also provided with self-

holding switches

39 and 4!} respectively, and the switches 4| and 42 serve for stop-ping the motor i5. The switch 4! is actuated by means of the push button 43; the switch 42 is opened by the excess current bobbin 44 if the current exceeds a maximum.

The method of working is as follows:

With the plant at rest, the

switches

28 and 29 are open. By pressing the knob 31 the auxiliary switch 35 closes the contacts 45 so that the electric wire 41 is connected through contacts 48 and the closed switch 4 l, and also through contacts 50 and the switch 36 with the electric wire 5! to the switch 3|, and through its bobbin to t e. wire 4 52 and through the switch 42 to the wire 53 and thereby to another phase.

The coil of the relay 3i is thereby energized and closes the switch 28 for the motor I5 rotating normally, and at the same time closes also the self-holding switch 39, so that when push button 37 is released, and pressed back to the left by the compressed spring, the switch 35 opens the contacts 45 and closes the contacts 45, the relay 3! receives current through wire 54 and the closed switch 39 which is thereby held in closed position.

For changing the direction of rotation of the motor l5, button 38 is pushed. The switch 36 opens the contacts 5!) and thus the wire 54 is disconnected from the wire dl and the current to the relay 3! is interrupted, the

switches

28 and 39 are opened and the motor I5 is without current, so that it comes to a standstill. Only when closing the contacts 4% in the end position of the switch it, the coil of the relay 32 receives current through the wire 55 and closes the main switch 29 and the self-holding switch 40. In this way, the relay 32 is connected through the wire 55 to the wire 4! and remains closed when the press button 38 is released. The wire 51 connects the relay 32 through switch 42 to wire 53. The motor l5 and the knives 23 then rotate backwards in order to loosen the substances which have become stuck in the knives.

If the man in charge then actuates the push button 31, the motor and knives are again switched in to rotate in the manner described. The operator can stop the disintegrator i l with the help of push button 43, since switch 4| interrupts the current for both relays 3i and 32. The excess-current coils open switch 42 if the current to motor 55 exceeds a predetermined maximum. This would occur if the demand for power of the device It became too great in consequence oi sudden choking, and the motor would be overloaded. When opening the switch 42, the relays 3i and 32 descend and the main switch 28 is opened.

Instead of changing the direction of rotation by hand, a device as shown in Fig. 4 effects this change automatically. The motor I5 is supplied with current from the network 3!! and a main switch 5% is provided in the conduits, which in the two positions I and III interchanges two phases with each other, whilst in the position II the current is interrupted. The switch 59 is controlled by the cam ti through the roller 68, the cam being driven by the control-motor 62 as soon as the man in charge operates the hand switch 53 and thus closes the electric circuit through the wire 54, the bobbin of the relay and the wire 66. The relay t5 then connects wire 64 to wire 5'5. Relay 65 remains closed only as long as the hand switch 63 is closed and turns motor 62 until connection is made between

conduits

54 and 67 through conduit iii, contact strip 68 and contact member 59.

By rotation of cam (H by motor $2 in the direction of the arrow roller till leaves track H, comes on to track 52 and turns switch 59 into the position II. Thus current to motor i5 is cutoff, so that it can come to rest. When cam ti is rotated further, the roller Si] is raised on to track l3 andthe switch 59 comes into position III; In this. Way the connections of the motor It to the two phases are interchanged and motor it; drives the knife 23 backwards. This continues until the cam track '53 has all rotated under the roller 6d and the latter comes on to track M; the switch 59 then again stands, in the position 11 and ourrent to the motor I5 is interrupted for a short time. The roller 60 then descends on to track TI, and the switch again comes into position I, and the cutting device 23 is driven in the normal direction of rotation. Since the cam E! has then turned through 360, the fixed contact 69 has left the contact strip 53 and motor 62 together with cam 6i come to rest. Consequently from that time motor [5 continues to run in the normal direction of rotation until the hand switch 63 is again operated.

In Fig. 5 the switching-in of the motor 52 is controlled automatically in accordance with the liquid level F3, for instance in the shaft 8, Fig. l, which communicates with the intake of the disintegrating device 14. If the device becomes choked, and the delivery from it diminishes, the liquid level 9 rises, the float 15 also rises and the rope Tl, loaded with the suspended weight it, operates the swtich lever 79 by means of the stop 78. The lever iii is removed from the stop 8| against the force of the spring 8i} and pressed on to the contact 82, so that coil 83 receives current and closes the relay 65. In this way the control motor 62 is switched on and, in the manner already described, causes the cam 6| to rotate through 360, thus bringing switch 59 from position I into positions II and III and back into position I. Continued rise of the liquid level 9 causes stop 18 to pass lever '19.

By that time, however, the aforedescribed operations are completed and the cleaned disintegrating device acts again with undimished throughput. The liquid level a in shaft 8 again falls to its proper value, so that fioat l5 and the stop ":8 descend. In consequence of the yielding of the rope H, the stop 18 now slides along the sloping edge 34 of the lever 19 into the position shown in the drawing, which is defined by a guide 85 for the rope 71.

In the arrangement according to Fig. 6 the motor 62 is actuated in dependence on a time switch whose disc 86 is driven by a clockwork (not shown) and makes a complete revolution within a certain time, for instance in 15 minutes. The disc 86 rotates in the direction of the arrow; in one of the holes 8'! a pin 88 is inserted which, in the position shown in the drawing, keeps the switch 83 closed against the force of the spring 98. Because of this, the relay 65 closes the circuit and current is supplied to the motor 52. Consequently the cam Bl turns once through 360 in the manner described, whereby the motor [5 is caused to run backwards for a short time, whilst it runs in the normal direction for the rest of the time. As soon as the pin 88 is rotated past the cam 9 i, switch 89 is again opened by the spring fill.

If the disc 86 is driven by means of a reduction gear from the shaft of the motor 15 instead of from a time switch, the switching takes place in dependence on a certain number of turns of the cutting knife 23.

In the system shown in Fig. 7 the switching is efiected when the torque of the motor I5 rises beyond a definite value, since the power required by the cutting knife 23 has increased in consequence of the choking. For this purpose a power meter 92 is fitted into one phase, its coil 93 being excited proportionally with the current passing through that phase to the motor 15. At a certain value of this excitation, which may be altered by means of the adjusting resistance 94, the coil 83 of the relay 55 is so strongly excited that the relay 65 closes, motor 62 receives current and the cam BI is rotated. When the motor 15 is 6 switched off by switch 59, the coil 93 is without current and the relay 55 opens. Meanwhile however, the contact member 69 has been connected to wire 54 through the strip 63.

The invention is not confined only to municipal or other waste water or sewage plants, but may be adopted wherever the substances carried over in a liquid must for any reason be reduced in size.

I claim:

1. A control system for the electric motor driving a sewage disintegrator, said system comprising an electric wiring system including a main switch having three operating positions: one in which the motor is rotated in normal operating direction, one in which no current is supplied to the motor, and one in which the motor is rotated oppositely to normal operating direction, a mechanism connected to and actuating said main switch, an auxiliary motor operating said mechanism, electric wiring connected with said auxiliary motor and including a momentary switch for starting said auxiliary motor and a rotating contact switch connected to and operated by said auxiliary motor and continuing supply of current to said auxiliary motor when said momentary switch is reopened, said rotating switch comprising disconnecting means for interrupting current supply to said auxiliary motor when said main switch is in normal main motor operating position said mechanism comprising a cam roller connected with said main switch, and a cam member engaging said roller and being connected to and rotated. by said auxiliary motor, the rotatin part of said contact switch being mounted on said ca-m member.

2. A control system as defined in claim 1, said cam member comprising a cam portion for holding said roller and main switch in position for normal operation of said main motor, and comprising another cam portion disposed substantially diametrically opposite said first cam portion for holding said roller and main switch in position for reverse operation of said motor.

3. A control system as defined in claim 2, said cam member comprising two additional cam portions interposed between said first and said other cam portion for holding said roller and main switch in position where no current is supplied to the motor of said disintegrator.

4. A control system for the electric motor driving a sewage disintegrator, said system comprising an electric wiring system including a main switch having three operating positions: one in which the motor is rotated in normal operating direction, one in which no current is supplied to the motor, and one in which the motor is rotated oppositely to normal operating direction, a mechanism connected to and actuating said main switch, an auxiliary motor operatin said mechanism, electric wiring connected with said auxiliary motor and including a momentary switch for starting said auxiliary motor and a rotating contact switch connected to and operated by said auxiliary motor and continuing supply of current to said auxiliary motor when said momentary switch is re-opened, said mechanism comprising a cam roller connected with said main switch, and a cam member engaging said roller and being connected to and rotated by said auxiliary motor and comprising a cam portion for holding said roller and main switch in position for normal operation of said main motor, said rotating switch comprising disconnecting means so connected with said cam member as to inter- REFERENCES CITED The following references are of record in the file of this patent;

UNITED STATES PATENTS Number Name Date Given Nov. 8, 1927 Nogosek July 25, 1933 Alexay Apr. 25, 1939 Lum Feb. 18, 1941 Brentz Jan. 20, 1942 Durdin Sept. 8, 1942 Blodgett Mar. 14, 1944-.