GB2516464A

GB2516464A - Macerators

Info

Publication number: GB2516464A
Application number: GB201313124A
Authority: GB
Inventors: Luke A C Shepherd
Original assignee: Haigh Engineering Co Ltd
Current assignee: Haigh Engineering Co Ltd
Priority date: 2013-07-23
Filing date: 2013-07-23
Publication date: 2015-01-28
Also published as: WO2015011476A1; GB201313124D0

Abstract

A macerator has a maceration cavity, opening, closeable cover, water admission means, slurry outlet, and sensor arrangement which determines a value for products inserted into the macerator, and a control arrangement which can control at least one of the starting of maceration, the duration of maceration, and the stopping of maceration. Also disclosed is a corresponding method of normal usage of the macerator. The value determined, may be aÂ number of products, a height value, a volume value, a mass value. The start may be delayed until a minimum value has been exceeded, and as such the macerator may be more efficient in its use of water, by not starting with only a small quantity of material to be macerated. The duration of maceration may be adapted to the quantity of material, also to increase efficiency of the use of water.

Description

Macerators The present invention relates to macerators. In particular, the present invention relates to improvements in or relating to the operation of macerators of the type used for maceration of clinical and similar waste.

Macerators process solid waste products by reducing the solid product to a slurry in water, which can then be more readily disposed of through conventional drainage conduits. Clinical waste typically disposed of by maceration includes pulp fibre trays and containers contaminated by bodily waste or fluids. The macerator includes a chamber in which the solid product is shredded and mixed with water and an outlet through which the slurry produced passes to waste. A rinse step rinses the macerator chamber clean for the next cycle.

Known clinical waste macerators operate with a fixed cycle in which the duration of the maceration process and the volume of water used are predetermined for a specific model of macerator. That is to say, the macerator operates for the same amount of time and uses the same amount of water on each cycle, irrespective of the mass or volume of products to be disposed of. This is wasteful of water, power and also of time before the macerator is available for the next load.

Accordingly, there is a need to overcome the problems with existing macerators.

In its broadest sense, the present invention provides a macerator having a maceration cavity having an opening for insertion of products into the cavity; a closable cover to the opening; and water admission means and a slurry outlet in fluid communication with the cavity.

The macerator is characterised in that it further comprises a sensor arrangement to determine a value for products inserted, in use, into the cavity.

Preferably, the macerator further comprises a control arrangement adapted, in response to a value determined by the sensor arrangement to control at least one of: i) a start of a maceration step; ii) a duration of a maceration step; and iii) a volume of water admitted to the cavity for a maceration step.

In one embodiment, the value determined for products inserted into the cavity is a numerical value for the number of products inserted into the cavity. Suitably, the sensor arrangement includes a sensor associated with the cavity opening or with the closable cover to the opening.

In a second embodiment, the value is a height or volume value determined by a height of products in the cavity or a volume of products in the cavity. Suitably, the sensor arrangement includes a sensor mounted to or adjacent the cavity.

Suitably, the sensor is an IR sensor, a non-IR light sensor, an acoustic sensor or a mechanical sensor.

In a third embodiment, the value is a mass value, determined by a mass of products inserted into the cavity. Suitably, the sensor arrangement includes a load mass sensor associated with the macerator cavity.

Conveniently, the sensor arrangement is adapted to terminate the rnaceration step in response to the presence of particles falling below a predetermined level.

According to a further aspect of the invention there is provided a control method for a macerator, the macerator having a maceration cavity for macerating products and a sensor arrangement for determining a value for products inserted in the cavity, the method comprising the steps of:-determining a value for products inserted into the cavity using said sensor arrangement; and controlling at least one of: i) a start of a maceration step; ii) a duration of a maceration step; and iii) a volume of water admitted to the cavity for a maceration step, said controlling step being governed by the measured value for products inserted into the cavity.

Preferably, the control method further comprises determining said value for products based on one or more of a mass of inserted product, a volume of inserted product, a height of inserted product or numerical number of inserted product.

The above and other aspects of the present invention will now be described in further detail, by way of example only.

Typically, a clinical waste macerator includes a macerator cavity into which products to be macerated are placed. The cavity is adapted to rotate the products against a shredding surface to reduce the product to small particles. Water is introduced to the cavity to aid decomposition of the products and aid flow of the slurry so products from the cavity at the end of the maceration step. Once maceration is complete, further water is introduced into the cavity to rinse the apparatus clean. The macerator includes a cover or lid to the cavity to provide a fluid seal and to prevent contamination from the clinical waste.

In a conventional macerator, the duration of the maceration step and the volume of water used are predetermined, by experimentation by the manufacturer, for any particular macerator. For example, maceration durations of 1 to 3 minutes and water volumes of 20-30 litres are typical. For any particular machine, the duration will be the same and the volume of water used will be the same irrespective of whether the machine is being used to dispose of a single, small waste product, or multiple or large products.

In accordance with the present invention, a sensor arrangement is provided to determine the number of products inserted into the macerator cavity, or the height of products within the cavity or the volume of products in the cavity. Those skilled in the art will be readily able to determine suitable sensor arrangement to achieve this objective. For example, the number of products inserted into the macerator can be determined by means of a sensor, such as an IR or other optical sensor.

Suitably, this can be mounted in the underside of the lid or around the opening of the cavity, the count products as they pass the sensor.

The height or volume of products in the cavity is considered to act as a better indicator of the amount of clinical waste inserted and thereby a better indicator of the amount of maceration required. The sensor arrangement can include a single sensor to provide a simple binary determination of the height of products within the cavity -whether the height is above or below a predetermined value; or the arrangement can include a plurality of height-aligned sensors to provide a more accurate determination of the content of the cavity in two dimensions; or a sensor arrangement adapted to provide a three-dimensional determination of the volume of products within the cavity.

In a further embodiment, the sensor arrangement includes a load mass sensor associated with the macerator cavity to determine the mass of products within the cavity.

Once the product content of the cavity has been determined, a control assembly, such as a control circuit, is caused to adjust the duration of the maceration step, to increase or decrease the maceration period as appropriate; and to adjust the volume of water used in the maceration step, to increase or decrease the volume of water, with respect to predetermined periods and volumes determined for the macerator.

Alternatively, the control assembly is adapted to delay the start of the maceration step until a predetermined value for the number, height, volume or mass of products has been inserted into the cavity. However, it will be appreciated that clinical waste cannot be left to accumulate indefinitely and must be disposed of promptly. As such, the control assembly is advantageously configured to provide a limited predetermined delay period after expiry of which, if the predetermined value remains unsatisfied, the macerator step is started.

Claims

Claims 1 A macerator comprising a maceration cavity having an opening for insertion of products into the cavity; a closable cover to the opening; and water admission means and a slurry outlet in fluid communication with the cavity; and further comprising a sensor arrangement to determine a value for products inserted, in use, into the cavity; and a control arrangement adapted to control at least one of: i) a start of a maceration step; U) a duration of a maceration step; and Hi) a volume of water admitted to the cavity for a maceration step.
2 A macerator as claimed in claim 1 wherein the value determined for products inserted into the cavity is a numerical value for the number of products inserted into the cavity and wherein the sensor arrangement includes a sensor associated with the cavity opening or with the closable cover to the opening.
3 A macerator as claimed in claim 2 wherein the control arrangement is adapted to control a start of a maceration step and delay the start of the maceration step until the number of products inserted is equal to or exceeds a predetermined number of products.
4 A macerator as claimed in claim 2 wherein the control arrangement is adapted to adjust at least one of: i) a duration of a maceration step; and H) a volume of water admitted to the cavity for a maceration step in response to the numerical value determined.A macerator as claimed in claim 1 wherein the value is a height value and the sensor arrangement the sensor arrangement includes a sensor mounted to or adjacent the cavity to determine a height of products in the cavity 6 A macerator as claimed in claim 1 wherein the value is a volume value and the sensor arrangement the sensor arrangement includes a sensor mounted to or adjacent the cavity to determine a volume of products in the cavity 7 A macerator as claimed in any preceding claim wherein the sensor is an IR sensor, a non-IR light sensor, an acoustic sensor or a mechanical sensor.8 A macerator as claimed in claim 1 wherein the value is a mass value indicative of the mass of products inserted into the cavity and wherein the sensor arrangement includes a load mass sensor associated with the macerator cavity.9 A control method for a macerator, the macerator having a maceration cavity for macerating products and a sensor arrangement for determining a value for products inserted in the cavity, the method comprising the steps of:-determining a value for products inserted into the cavity using said sensor arrangement; and controlling at least one of: i) a start of a maceration step; U) a duration of a maceration step; and iii) a volume of water admitted to the cavity for a maceration step, said controlling step being governed by the measured value for products inserted into the cavity.A control method as claimed in claim 9, further comprising determining said value for products based on one or more of a mass of inserted product, a volume of inserted product, a height of inserted product or numerical number of inserted product.