EP1348816B1

EP1348816B1 - Waste disposal apparatus and method of waste disposal

Info

Publication number: EP1348816B1
Application number: EP03251347A
Authority: EP
Inventors: Nigel R. C. Shepherd
Original assignee: Haigh Engineering Co Ltd
Current assignee: Haigh Engineering Co Ltd
Priority date: 2002-03-22
Filing date: 2003-03-06
Publication date: 2004-05-26
Anticipated expiration: 2023-03-06
Also published as: DE60300003D1; DE60300003T2; EP1348816A1; GB0206868D0; ATE267927T1

Abstract

A method of using a waste disposal apparatus which apparatus includes a macerating chamber (4) having a waste inlet (6) for the introduction of waste material, a waste outlet (12) for the removal of macerated waste material, a macerator (18), a water inlet (10) a water pump (26) coupled to the water inlet and a first and second drive (48,50) arranged to independently drive the water pump and the macerator, respectively; the method comprising, in sequence, a) switching on the first and the second drive to initiate maceration of the waste product in water: b) switching off the first drive for a predetermined period of time; c) switching on the first drive again for a further predetermined period of time; and d) switching off the first and second drive. The method provides a shorter maceration and chamber cleaning cycle than if the water pump and macerator are driven by a common motor. <IMAGE>

Description

This invention relates to waste disposal apparatus and in particular to such apparatus which includes a macerator.
One known waste disposal apparatus has a macerating chamber with a drain valve at the bottom of the chamber and a macerator. Waste is introduced into the chamber, the chamber filled with water to a predetermined level and the macerator switched on until the pulp product has disintegrated. The macerator is then switched off and the drain valve is opened to evacuate the chambers. Additional water may be introduced to clean the chamber.
Another known type of such an apparatus includes a macerating chamber having a waste inlet for the introduction of waste material, a waste outlet for the removal of macerated waste material, a macerator and a water inlet, a water pump coupled to the water inlet; an electric motor for driving both the water pump and the macerator and a controller arranged to control the motor.
Waste products such as soiled, pulp products, (bedpans/urinals), incontinence pads or food waste are introduced into the macerator chamber through the waste inlet. They are then mixed with water which is pumped into the chamber as the macerator operates, the macerated waste exiting the chamber through the waste outlet. The apparatus disintegrates or pulps the pulp products to produce an effluent of particulate matter in a water suspension which can be disposed of through a sewerage system.
In the early stages the solid waste is disintegrated and starts to flow with the water through the waste exit. Towards the end of the cycle all the pulp has been macerated and removed from the chamber so only water is swept round the hopper thereby cleaning the macerator chamber. At the end of this cycle the motor is shut down and there is a short 3 second delay as the pump acts to brake the macerator to a halt its motion whereupon a latched lid at the waste inlet is unlatched to allow access to the macerator chamber once again.
The present invention seeks to provide a waste disposal unit which can perform the maceration and cleaning cycle more quickly. US-A-4,275,848 is prior art to this application. WO93/17191 discloses an apparatus according to the preamble of claim 1. The present invention is characterized by the features of the characterizing portion of claim 1, that is in which the controller is arranged to stop the water flow and restart the water flow while the macerator drive is driving the macerator.
Because the water flow control device, eg. a water pump motor coupled to a water pump, and the macerator drive are independently controllable, the pump cannot act to slow the macerator down as is the case in the earlier described prior art apparatus in which one motor ran the pump and macerator. The result is the same macerator takes 15 seconds rather than 3 seconds to come to a stop. However, the provision of the independent control allows the water flow to be switched off and restarted allowing earlier removal of most of the waste from macerator chamber resulting in a significant decrease in the total time required for the disposal cycle. This benefits the operator by providing a machine which can dispose of the same number of products in less time thereby reducing the noise burden on the environment and so more suitable for nighttime use, for example, or dispose of more material in the same time for a given design of macerator chamber components.
The present invention, according to a second aspect, is a method of using a waste disposal apparatus comprising a macerating chamber having a waste inlet for the introduction of waste material, a waste outlet for the removal of macerated waste material, a macerator, a water inlet, a water flow control device for controlling the flow of water to the water inlet, a macerator drive for driving the macerator; and a controller arranged to control independently the macerator drive and the water flow control device, the method comprising, in sequence:
a) switching on the flow of water to the water inlet and the macerator drive to initiate maceration of the waste product in water;
b) switching off the flow of water to the water inlet for a predetermined period of time;
c) switching on the flow of water to the water inlet again for a further predetermined period of time; and
d) switching off the flow of water to the water inlet and macerator drive.
Optional features of the apparatus and method are recited in the dependent claims.
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings of which:
Figure 1 is a part sectional side view of a waste disposal apparatus according to the present invention;
Figure 2 is a top view of the apparatus of Figure 1;
Figure 3 is a part sectional front view of the apparatus of Figure 1 with the front panel removed;
Figure 4 is a timing chart showing the timing of operations of the apparatus of Figure 1.
Referring now to Figures 1 to 3, a waste disposal apparatus 2 includes a macerating chamber 4 of generally cylindrical form. The top of the macerating chamber 4 has a circular opening 6 closable by a hinged lid 8 which opening provides a waste inlet to the chamber 4. A water inlet 10 in the form of a water spray is sealed to an opening through the lid 8 so as to be centrally positioned in the chamber 4 when the lid 8 is in the closed position.
At the bottom of the macerating chamber 4 is a helical gulley 12 leading to a waste outlet 14. The gulley 12 surrounds a generally upwardly convex base 16 on which a macerator 18 is rotatably mounted. The macerator 18 includes a conical plate 20 which has outwardly and upwardly extending macerator blades (impeller blades) 22 fixed to its outer rim 24. The macerator 18 is removable from the macerator chamber 4 through the opening 6 for maintenance or replacement.
A water pump 26 has an inlet 27 coupled to a water supply pipe 28 from a water cistern 30 which is filled with water to a preset level via a mains water supply 32, via a solenoid valve 34 and pipe 36. The solenoid valve 34 is controlled by a level switch 38 mounted inside the cistern 30. The water pump 26 has an outlet 40 coupled by a pipe 42 to the water spray 10. The water pump 26 is mechanically coupled to an electric motor 48 constituting the water pump drive.
The macerator 18 is mechanically coupled to an electric motor 50, constituting the macerator drive, for rotating the macerator 18.
The waste outlet 14 is coupled to a p-trap 52 in turn coupled to drain pipe work (not shown).
The lid is mounted on a lid arm 54 hinged at a hinge 56 to a frame 58 to which the waste disposal apparatus components are mounted and can be locked in the illustrated closed position by a solenoid controlled locking mechanism 60 which holds a manually releasible latch 62 in a locked position when actuated.
The frame 58 also defines a control box enclosure 62 in which are housed a controller printed circuit board and relays shown generally as 64.
As shown in Figure 3, a handle is fixed to the water spray 10 for use in lifting the lid 8.
A front panel 68 is removably attached to the frame 58 to provide access to the interior of the frame 58 and components of the waste disposal apparatus 2. A forward facing face 70 of the control box enclosure 62 includes a panel 72 of control buttons including a start button 74 for initiating a disposal cycle and operation and fault indicator lights.
The operation of the waste disposal apparatus 2 of Figures 1 to 3 will now be described with additional references to the operation timing chart of Figure 4.
The lid 8 is lifted and the pulp products to be disposed of are dropped into the macerator chamber 4. The lid 8 is closed and automatically latched in the closed position by latch 62. The apparatus is now ready to start the disposal cycle which in this exemplary embodiment is as follows (with paragraph letters indicating the position of the operation timing chart of Figure 4).
At time equals zero the operator pressed the start button 74 which defines the start of the disposal cycle.
A) At time zero, the controller detects the operation of the start button 74 and immediately locks the lid 8 down by switching the latching solenoid 60, which is used instead of a normal solenoid so the lid 8 will remain locked in the event of a power cut when the macerator 18 may still be running. The controller also switches on the water pump motor 48 at time zero in this embodiment to inject water into the macerator chamber 4.
B) At time equals 2 seconds the controller switches on the macerator motor 50 to cause the macerator blades 22 to rotate thereby initiating the disintegration process.
C) At time equals 50 seconds most of the waste product has been disposed of but water and some waste product will still be swirling round the macerator chamber 4. The controller switches off the water pump motor 48 at this time with the macerator motor 50 still running. Over the next 10 seconds the macerator chamber 4 drains of water taking almost all the disintegrated pulp product with it. However, some might remain in the chamber 4 in the form of small bits of product flicked back by the macerator blades 22.
D) At time equals 60 seconds the controller restarts the water pump motor 48 to quickly flush any remaining fragments of waste product to the drain.
E) At time equals 65 seconds the controller switches off the macerator motor 50. Water is still being pumped into the macerator chamber 4 which helps slow down the rotation of the macerator 18 but the macerator blades 22 will continue to swirl water about the interior of the macerator chamber 4 cleaning it until is stops.
F) At time equals 77 seconds the controller switches off the water pump motor 48.
G) At time equals 80 seconds the lid latching solenoid 62 is released by the controller readying the apparatus for a new disposal cycle.
The timing sequences will be varied to suit the particular design of apparatus components. For example, an apparatus with a larger chamber and macerator may require a longer second cleaning period to allow the macerator to slow to a stop at the end of the cycle. Suitable values can be readily determined by straightforward trial and error. For example, a slightly longer cleaning and slow down period could result in the timing points A, B, C, D, E, F and G of Figure 4 being instead 1, 2, 50, 60, 68, 83 and 88 seconds after start time 0.

Claims

A waste disposal apparatus including:

a macerating chamber (4) having a waste inlet (6) for the introduction of waste material, a waste outlet (14) for the removal of macerated waste material, a macerator (18) and a water inlet (10); a water flow control device (34) for controlling the flow of water to the water inlet; a macerator drive (50) for driving the macerator; and a controller (64) arranged to control independently the macerator drive (50) and the water flow control device (34), the apparatus being characterized by the controller being arranged to stop the water flow and restart the water flow while the macerator drive (50) is driving the macerator (18).
An apparatus as claimed in claim 1 in which the water flow control device is a valve (34) for controlling flow of water to the water inlet (10).
An apparatus as claimed in claim 1 in which the water flow control device is a water pump drive (48) coupled to a water pump (26) in fluid communication with the water inlet (10).
An apparatus as claimed in claim 3 in which there is included a starter (74) for initiating a disposal cycle operable by an operator of the apparatus, the controller (64) being arranged to detect operation of the starter (74).
An apparatus as claimed in claim 4, in which the controller (64) is arranged such that on detection of operation of the starter (74) the controller switches on the water pump drive (48) and switches on the macerator drive (50).
The apparatus of claim 5, in which the controller (64) switches on the macerator drive (50) a predetermined period after switching on the water pump drive (48).
An apparatus as claimed in claim 6 in which the controller (64) is arranged to switch off the water pump drive (48), only, after a second predetermined period after switching on the water pump drive (48), and, optionally, in which the controller (64) is arranged to switch on, again, the water pump drive (48) after a third predetermined period after switching off the water pump drive (48), in which case, further optionally, in which, the controller (64) is arranged to switch off the macerator drive (50) a fourth predetermined period after the water pump drive (48) is switched on again, in which case, yet further optionally, in which the controller (64) is arranged to switch off the water pump drive (48) a fifth predetermined period after the macerator drive (50) is switched off.
An apparatus as claimed in any preceding claim in which the waste inlet (6) is closable by a lid (8) which is releasibly lockable under control of the controller (64), and, optionally, in which the controller (64) is arranged to lock the lid (8) prior on initiation of a disposal cycle and to unlock the lid (8) a predetermined period after the water pump drive (48) and macerator drive (50) have been switched off at the end of the disposal cycle.
A method of using a waste disposal apparatus including a macerating chamber having a waste inlet (6) for the introduction of waste material, a waste outlet (14) for the removal of macerated waste material, a macerator (18) and a water inlet (10); a water flow control device (34) for controlling the flow of water to the water inlet (10); a macerator drive (50) for driving the macerator; and a controller (64) arranged to control independently the macerator drive (50) and the water flow control device (34), the method comprising, in sequence:

a) switching on the flow of water to the water inlet (10) and the macerator drive (50) to initiate maceration of the waste product in water;

b) switching off the flow of water to the water inlet (10) for a predetermined period of time;

c) switching on the flow of water to the water inlet (10) again for a further predetermined period of time; and

d) switching off the flow of water to the water inlet (10) and macerator drive (50).
The method of claim 9, in which there is any one or any combination of:

i) the water flow control device is a water pump drive (48) coupled to a water pump (26);

ii) at step a) the macerator drive (50) is switched on after the water pump drive (48) is switched on;

iii) at step d) the macerator drive (50) is switched off before the water pump drive (48) is switched off; and

iv) the apparatus includes a lid (8) is lockable in a closed position to close the waste inlet (6), and in which the lid (8) is locked in the closed position prior to, or at, the start of step a) and is unlocked after step d).