WASTE TANK ASSEMBLY

A waste tank assembly includes: a tank having a top end configured to be connected, in use, to receive waste via one or more ports, and an open bottom end, the tank defining an interior; a waste cartridge removably received in the tank interior and having one or more ports configured to be fluidly connected to the one or more ports of the tank to receive the waste in an interior volume of the cartridge; and a closure part for securing the waste cartridge inside the tank interior, the closure part openable to allow removal of the cartridge from the tank interior via the open end.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of European Patent Application No. 23461637.3 filed Aug. 14, 2023, the disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to ways of cleaning the interior of a tank such as, but not exclusively, a waste tank e.g. in an aircraft.

BACKGROUND

Tanks or reservoirs containing matter such as waste from a sanitation system, or other matter, which may be contaminated or hazardous or generally undesirable if left on the inner surfaces of the tank for a period of time often include a device that extends into and sprays water or some cleaning fluid around the tank to clean the tank. This can avoid the need for manual cleaning of the tank which can be unpleasant or even dangerous. Furthermore, the tanks are often too small to enable a person to access the interior to clean it properly, or the tank may be vacuum sealed and so not accessible for manual cleaning and/or access to the tanks may be too difficult for the tank to be cleaned by a person. Passenger aircraft include large tanks for human waste from the aircraft toilets. These tanks are emptied after a flight and the inside of the tank is cleaned. This is usually done by means of a device, known as a rinse nipple, having nozzles through which pressurised water or a cleaning solution is sprayed around the interior of the tank.

A conventional rinse nipple includes a housing part to which a rinse hose providing the cleaning fluid is connected. The housing extends through the tank wall. A rinse head is provided at the end of the housing located inside the tank. The rinse head is provided with multiple openings or nozzles and the pressurised fluid is ejected out through the nozzles to clean the tank. Some rinse nipples have a rotatable rinse head. To avoid the need for power to be supplied to rotate the rinse head, the openings or nozzles are angled and offset relative to the axis of rotation of the head. This positioning provides momentum about the axis to cause the head to spin about the axis thus maximising the coverage of the fluid inside the tank.

Whilst the multiple nozzles and spinning head ensures that the fluid is sprayed as much as possible around the tank interior, due to the presence of various components and fittings that may be provided on the tank walls, extending to the tank interior, there may be some areas that are effectively obstructed or hidden by these components and are not reached by the spray from the spinning head. Furthermore, particularly when the tanks are large. The fluid may not reach the bottom of the tank, or may not reach the bottom with sufficient force to provide effective cleaning. This can result in waste material or the like remaining in those areas where the pressurised fluid does not reach, and clogging or building up. The tank cannot, therefore, be fully purged of all of the waste, which can cause contamination of the tank.

There is, therefore, a need for a cleaning arrangement that can ensure improved cleaning of the tank in a simple and efficient manner.

SUMMARY

According to the present disclosure, there is provided a waste tank assembly. The assembly includes a tank having a top end configured to be connected, in use, to receive waste via one or more ports, and an open bottom end, the tank defining an interior; a waste cartridge removably received in the tank interior and having one or more ports configured to be fluidly connected to the one or more ports of the tank to receive the waste in an interior volume of the cartridge; and a closure part for securing the waste cartridge inside the tank interior, the closure part openable to allow removal of the cartridge from the tank interior via the open end.

A cleaning method is also provided.

DETAILED DESCRIPTION

A typical rinse device is shown inFIGS.1and2. A rinse nozzle3is shown mounted in the wall12of a tank2or vat or other reservoir. The rinse nozzle3is connected, in use, to a rinse port1from which rinse fluid is provided to the rinse nozzle from a rinse fluid supply (not shown).FIG.2shows, in cross-section, the rinse nozzle3mounted in the wall12of the tank2, at the top of the tank. Apertures or jets4are formed in the nozzle3such that as rinse fluid is provided to the nozzle3it is sprayed out through the jets4around the interior22of the tank to clean the tank. A typical nozzle3comprises a housing10, one end of which is provided with a fitting13arranged to be attached to a pipe or the like via which pressurised water or cleaning solution is provided. At the other end of the housing through which the pressurised fluid flows, which extends into the tank, is mounted a rinse head14mounted to rotate relative to the housing10. The rinse head is arranged to rotate about an axis of rotation X which is the axis through the housing from the one end to the other end.

The rinse head14is provided with a number of holes or jets4via which the pressurised fluid F forced through the housing is ejected into the tank. The jets can be positioned offset from the axis of rotation and at angles such that the ejection of the pressurised fluid F provides a force that causes the rinse head14to rotate relative to the housing about the axis X.

The pressurisation of the fluid and the rotation of the rinse head provides a good range of coverage of the interior of the tank with cleaning fluid. In some cases, however, areas may exist, due to the presence of other components on the inside of the tank, that fluid from the rinse head cannot reach. Alternatively, because the rinse nozzle is typically small and mounted into the top of the tank, the pressurized fluid F may not adequately reach the bottom or other locations in the interior of the tank, or at least not with sufficient force to adequately clean the tank. Furthermore, as can be seen inFIG.2, the jets do not clean the tank in a symmetrical manner.

The waste tank assembly according to this disclosure is designed to address these problems as will be described with reference toFIGS.3to11.

As seen inFIG.3, the waste tank assembly according to the disclosure has a modified tank100, having a top region102arranged to connect to the system from which waste is expelled into the waste tank, similar to existing waste tanks, and an open bottom end104; a cartridge200removably mounted within the tank, and a closure part300mountable to the open bottom end104of the tank100to secure the cartridge200within the tank, the closure part300being openable to allow removal of the cartridge from the tank from the open bottom end. The modified tank according to the disclosure is thus in the form of a sleeve, open at one end, the sleeve defining an interior108(FIG.4) configured to receive the waste tank cartridge. The cartridge, when inside the tank, therefore defines the interior210(FIG.4) of the waste tank, to receive the waste—the cartridge providing a barrier between the waste and the tank interior108. The cartridge connects to the top region102of the tank100such that the waste entering the tank assembly is directed into the interior210of the cartridge. The cartridge can then be removed from the tank e.g. when full or at other times when the tank assembly is to be emptied, by opening the closure part300and removing the cartridge from the open end104of the tank. The waste in the cartridge than then be disposed of either by emptying the cartridge or by disposing of the cartridge including the contained waste. If the cartridge is reusable, it can then be replaced in the tank and secured by the closure part. If the cartridge is disposable, a new cartridge can then be mounted into the tank which is then ready to receive more waste.

As mentioned above, the top region102of the tank100is provided with fittings for attachment to the system from which the waste is ejected into the tank. Various types of fittings are possible. In the example shown, the tank has an inlet port110which can receive an inlet pipe111which, in use, is connected to the system such that waste from the system passes along the inlet pipe111, through the tank inlet port110into the waste tank. The fittings may also include a port112for receiving some form of propeller system or suction device or demister113which can assist in forcing the waste into the waste tank. One or more additional ports114can be provided in the top region of the tank for other parts or accessories. For example, a level sensor may provide in an accessory tube115to detect the level of waste in the tank. These fittings may vary and can correspond to the fittings on known waste tanks for collecting the waste in the tank assembly.

In the assembly according to the disclosure, the waste is collected in a waste cartridge200located within the interior108of the tank100. The waste400is, therefore, not in contact with the interior of the tank itself, and so the tank interior does not become contaminated and does not need to be cleaned. All of the contamination is retained within the removable cartridge200.

The cartridge200may also be provided with ports212,214,216arranged to align with the ports110,112,114and fittings111,113,115in the top region of the tank, to ensure direct passage of the waste through the top region of the tank into the cartridge200.FIG.4shows waste400accumulated in the cartridge200.

To dispose of the waste from the tank assembly, the cartridge is removed from the open end104of the tank100by opening the closure part (e.g. a locking nut)300. The example shows the closure part300in the form of a locking nut that fastens, e.g. by a threaded/screw fastening, to the open bottom end of the tank and extends radially inwards sufficiently to provide a flange or ledge to prevent the cartridge passing the closure part when it is fastened. The nut can then be unscrewed and removed from the open end to release the cartridge. Other fastening or retaining means can also be envisaged for releasably securing the cartridge in the tank. The manner in which the cartridge200can be quickly disassembled from the tank for waste disposal can be seen, for example, inFIG.5.

In an example, the cartridge is mounted to a support500which acts as a holder for the cartridge and can also be configured to ensure that the cartridge is correctly fitted and oriented in the tank.

The support500defines a base510, on which the cartridge is supported from below, and an arm520and an attachment part530which together form a clip structure into which the cartridge is fitted and secured. The support provides structure for the cartridges as it is removed from the tank (as seen inFIG.5). The cartridge200is then unclipped from the support500to be emptied or disposed of, and the (reusable) cartridge or new cartridge can then be fitted into the support to be mounted into the tank for the next waste collection.

An example of such a support will be described with reference toFIG.6. At stage 1., the cartridge200, mounted in the support500, has been released from the tank11(as described above with reference toFIG.5). The dispose of the cartridge (or the waste in the cartridge, if reusable), the cartridge needs to be removed from the support500. In the example shown, the arm520and the attachment part530are arranged such that when the cartridge is secured in the support500, the attachment part extends over the top of the cartridge. The remove the cartridge from the support, the cartridge is lifted (in the direction of arrow A) relative to the support to allow release from the attachment part530and the cartridge is then slid out sideways (direction of arrow B) to free it from the support500.

The attachment part530in this example is in the form of a snap-fitting as best seen inFIG.8which shows the cartridge and support from a side view (as inFIG.6) and also from a top view, where the snap fitting530can best be seen. In this example, it can be seen that the attachment part includes two snap-fit arms532extending from the support arm part520, radially inwards across the top of the cartridge. The two snap-fit arms532are configured to extend either side of a part on the top of the cartridge, in this example, and have enlarged ends534that, when the cartridge is seated in the support, on the support base510, abut against the port so that the port can not move out of the attachment part. As the cartridge is lifted (FIG.6, stage 2.) however, the lower, narrower neck of the port can move sideways past the enlarged ends534as seen inFIG.6, stage 3.

To install the cartridge in the support, the procedure is the reverse ofFIG.6and the cartridge engages with the attachment part in a snap fit. This cooperation between the cartridge and the support is provided by a shaped connected to ensure a POKA-YOKE assembly—i.e. the design is such as to eliminate the possibility of error in assembling the cartridge. Only one, correct, orientation is possible.

The correct orientation and securement of the cartridge in the tank can be further improved by forming a shaped feature540e.g. a rib or protrusion on the support arm, and a corresponding shape e.g. a recess140on the tank interior as seen inFIG.9.

To avoid leakage or spillage of waste as the cartridge is removed from the tank, a seal or plug600may be provided to sealing close the ports212,214,216on the cartridge. Various types of seal or plug may be provided, including individual stoppers that are pushed into the ports by the maintenance personnel. One example of a suitable plug assembly is shown inFIGS.7and8. Here, a unitary plug600is provided shaped to fit over all of the ports. The plug may be pivotally attached to the top of the cartridge such that it remains with the cartridge at all times. While the cartridge is assembled in the tank, the plug600is pivoted away from the ports, so that the ports can be attached to the necessary fittings (left-hand side ofFIG.7). When the cartridge is removed, the plug600can be pivoted into position in the ports (right-hand side ofFIG.7)

Various configurations for the cartridge200are possible. In a simplest implementation, the entire cartridge, including the top part containing the ports212,214,216and the main body of the cartridge that contains the waste may be disposable.

Typically, the top part250, with the machined ports, is the most expensive part of the cartridge, and so, in some embodiments, this may be a detachable part of the cartridge, so that it can be re-used with a different cartridge body260. The top part250may be connected to the main body260by a sleeve270. In such examples, it is possible just to exchange the main body of the cartridge and keep the top part and the sleeve.

Alternatively, the entire cartridge may be re-usable. The main body of the cartridge may be, e.g. made of cleanable plastic or steel. The top part can be removed allowing access to the main body for cleaning before re-use.

In another implementation, the main body of the cartridge could be made of an expandable material such as rubber, that expands as the cartridge fills with waste.

The simplicity and the compact design of a waste tank assembly according to the disclosure can be seen in the comparison with the conventional assembly inFIG.11. The assembly according to this disclosure can avoid the needs for a rinse nozzle, rinse port and drain valve, as well as hydraulic tubes and fresh water. Tank cleaning is therefore simpler and quick using the exchangeable cartridge. The problem of incomplete cleaning of the tank interior is also obviated. Furthermore, the cleaning can be performed at a remote cleaning facility rather than where the tank is installed.

The arrangement according to this disclosure therefore provides a simple, inexpensive and effective way of thoroughly cleaning a waste tank, and of preventing contaminants coming into direct contact with the tank. This simplifies cleaning and also avoids any chemical reaction between the waste contaminants/other substances and the tank. Furthermore, it is possible for the cleaning process to be performed off-site and without the need for water and with the need for the various rinsing and spray components commonly required.