GB2459683A - Swelling polymer filled bag actuator - Google Patents

Abstract

The actuator comprises a flexible water permeable material pouch 19 a movable member held in contact with the pouch. The pouch contains a water absorbing polymer, e.g. a swell gel, which swells on contact with water and moves the movable member to an activated position. A valve used to enable shipping containers to sink if lost from a ship may incorporate the actuator. The valve comprises a vented splash-proof outer housing 14 connected across a container wall 18 by a pipe 15 to an inner housing 16 with identity chip 13. The pipe is closed by a valve member 23 on a pivoted arm 21 under influence of a heavy sponge closing spring 26. If submerged water enters the outer housing swelling bag and opening the valve. A raised interior housing lip or pipe 30 helps prevent water ingress if the valve opens in heavy seas on deck. The bag may be of nylon and quilted to optimize swelling. A deactivating pin may be provided.

Description

IMPROVEMENTS IN ACTUATORS

The invention relates to improvements in water triggered actuators, in particular for a valve incorporating such an actuator which can be used to enable shipping containers to sink.

There are up to eight million shipping containers at sea at any given moment. They are often stacked, one on top of another, up to six high on the decks of the vessels that carry them. A stack of six is generally the maximum due to the structural limitations of the bottom container (in holding up to five above it) and this can lead to weight distribution and stability issues on the vessel.

Depending on the source of the figures, between ten and twenty thousand containers fall off these vessels per annum.

This is due to a number of factors, but high seas, waves and bad weather in general are the main causes. Of course foundering ships are also known to drop containers, the "MSC Napoli" lost just under a tenth of its 2400 containers off the Dorset coast in January 2007.

It seems to be agreed generally that around 50% of these lost containers sink immediately, mainly due to their weight, but sometimes due to structural defects or damage caused by the fall or collision with other containers en-route to the water.

Depending upon the source of the figures available (whether these are sourced from the "losers" of the containers or the "sufferers" of the subsequent losses to property caused by them being afloat on the open sea) the remainder sink at some point between a "period of days" and never. By definition, most of these floating containers are in the major shipping lanes for some time, presenting a significant hazard to sea borne vessels.

Some containers (particularly ones carrying buoyant materials) will never sink, at least until they are dashed on reefs or rocks and break up. Others can take many weeks, months or even years to sink. A great many of them end up neutrally buoyant, semi submerged, a couple of inches beneath the surface of the sea. For as long as they are there they are a serious danger to shipping, particularly leisure craft and small to medium sized vessels. Shipping containers have even been reported as causing damage to submarines; one submarine recently hit a container "hanging" stationary at a depth of lOOm head-on.

The way this problem is currently dealt with is avoidance. In others words, watches are posted to look out for containers. There are sonar and even infra red systems available to detect objects floating just beneath the surface, but again these are systems designed to spot and alert of the danger not to minimise its presence.

In the past, air forces and navies have used containers (particularly ones located in major shipping lanes) as target practice, in order to sink them. However this practise is no longer widespread due to environmental concerns.

The present invention therefore aims to resolve this problem by providing an actuator, which is triggered on contact with water, which may be used in a valve which is water operated to allow water to flow into a container immediately it comes into contact with the sea to enable it to sink.

The invention therefore provides an actuator comprising a pouch made from a water permeable flexible material and a movable member held in contact with the pouch in a deactivated position, said pouch containing a water absorbing polymer which swells on contact with water and moves the movable member to an activated position.

The invention will now be described, by way of example only, with reference to and as shown in the accompanying drawings in which:-Figure 1 is a schematic view of a shipping container fitted with a valve incorporating the actuator of the present invention; and Figure 2 is a side sectional elevation of a valve of the present invention.

As shown in Figure 1, a shipping container 10 is provided with a plurality of two way valves 11 which comprise the actuators of the present invention. The actuators cause the valves 11 to open on contact with water allowing water to flood into the container 10. When not in contact with water, the valves 11 allow air to escape from within the container 10 if under pressure. Thus the valves 11 also give simultaneous protection to the cargo within the container 10 from ingress of humidity and water in bad weather.

The valves 11 can be retro-fitted to existing containers 10 and also designed into new ones.

Each container 10 preferably has a minimum of four valves 11 placed close to opposing corners 12 of the container 10 in such a way that, if a container 10 is floating, at least two valves 11 will be at the lowest point and submerged (allowing water to flow in), whilst the other two are above either also submerged or out of the water (for air to escape) whatever the orientation of the container 10.

If a container 10 is able to sink when filled with water, the valves 11 will ensure that this happens swiftly.

The valves 11 preferably also incorporate a microchip 13 which is potentially also available for use by Customs and Excise or Port Authorities for identification and tracking of containers 10.

Each valve 11 may be fabricated out of plastic, and comprises an outer housing 14, a pipe or tube 15 that extends through an aperture in the wall 18 of the container and an inner housing 16 that can prevent accidental ingress of water and also contains the microchip 13 mentioned above.

The actuators of the valves 11 comprises a pouch 19 of a flexible water permeable material, for example resembling a small quilted teabag, containing a small amount of a water absorbing polymer 20 (commonly known as a "swell gel") fixed in place under a movable member in the form of a lever 21.

One end 22 of the lever 21 is pivotally connected to the outer housing 14. The other end 25 of the lever 21 is provided with a rubber sealing member 23 that firmly closes the mouth 24 to the pipe 15. This sealing member 23 is held firmly in place either by the shape of the lever 21, which is preferably slightly sprung, or a spring 26, preferably made of a heavy sponge, held in place by a wall 27 of the outer housing 14.

Instead of using a lever the valves 11 may use a plunger operated by a circular quilted pouch of the gel.

The inner and outer housings 16, 14 and the pipe 15 use a one way gripping system 28 to retain them together and in place on either side of the container wall 18. This system 28 is preferably in the form of a washer or collar that has a number of tiny "blades" 29 that are set at an angle and "grab" the outer surface of the pipe 15 when slid along it, actively locking the components in place. This type of system 28 is widely used in "push-fit" and other plumbing systems.

The inner housing 16 is designed to deflect glancing blows during container 10 loading and contains a small length of pipe 30 that points upwardly in much the same way as a snorkel.

When a valve 11 is submerged, water floods through the outer housing 14 and the gel 20 of the actuator swells, pressing against the lever 21. The pressure produced by the swelling gel 20 overcomes the spring bias of the lever 21 or the spring 26 which maintains the seal 23 with the pipe 28 to move the lever 21 away from the pipe 28 and thereby open it to allow water to flow into the container 10.

The seal does not need to be broken by much for full flow to be possible through the pipe 15, for example a 15mm diameter pipe (similar to a garden hose) only needs the rubber seal 23 to be lifted by some 3.8mm in order to achieve full flow.

Additionally, the valve(s) 11 on any opposing corners to the submerged valve(s) 11 which are out of the water are also opened. The air pressure produced by the water flooding into the container 10 is enough to overcome the bias of the spring 26/lever 21 and force the seal 23 open from within allowing air to escape.

The outer housing 14 is designed in such a way as to deflect as much incidental water as possible from the valve 11 within in high seas or bad weather, ideally only allowing water inside when actually submerged. The inner housing 16 is designed to prevent water dripping into the container 10 through the system if it is accidentally triggered in very bad weather or high seas. Water will only travel up the pipe or "snorkel" 30 and out Thto the contaTher 10 f t s under pressure due to the container 10 being submerged beyond this pipe's height. In the case of an accidental trigging, the system simply resets itself as the gel 20 dries out.

The pouch 19 in which the gel 20 is stored is preferably made of nylon and is preferably quilted. The reason for the quilting is because the gel 20 is so efficient at swelling on contact with water that, if this pouch 19 had smooth side walls, the outer parts of the gel would swell and cut off water supply to the inner parts of the gel 20 in the pouch 19, thus making the system inefficient. The quilting ensures an even spread of the gel and the separate pockets allow uniform activation and spread of force. In tests a very efficient pouch 20 was made from nylon stocking material, which provided good containment and was easily expanded by the gel 20, typically around four times its original size.

As the expansion of the gel 20 is so efficient, a disabling mechanism is preferably included to disable the system. This is of interest because deck sidings on some container ships can stop water from freely draining. In this case the bottom containers 10 in the stack (the least likely to fall) can regularly be submerged in 0.5 to 1 metre of water in high seas. A suitable disabling mechanism would comprise a pin inserted through a hole in the lever 21 locking it in place and keeping the pipe 15 sealed. If triggered, the gel 20 on the outside of the pouch 19 swells closing down the water supply to the centre of the pouch 19 and therefore preventing the valve 11 from fully triggering.

Pins with fluorescent high visibility warning tape could be inserted to temporarily disable valve 11 in these situations. The tape provides a visual aid to check this has been done and also to draw attention to the fact that the valve 11 is still disabled on a subsequent voyage if not removed.

The microchip 13, which is optionally built into the inner housing 16, can be used to identify an original valve 11 built under license. This necessitates a unique encoded number in each individual valve 11 located on the inside of the container 10. If the container 10 is sealed by a trusted agency, identification and processing by authorities electronically reading the number (from the outside of the container 10) could help in the targeting of resources in the detection of illicit imports/exports etc. The advantage of using the hydraulic properties of a "water absorbing polymer" (or "swell gel" as it is better known) is that the valve 11 can be triggered and operate automatically, at sea with no power source.

There are a number of other potential applications for the actuators of the present invention. One application in which the actuator might be used could be the automatic triggering of roadside "Flood Alert" signs or to raise a defensive curtain against flood water to protect property.

Such an actuator comprises a number of gel containing quilted "doughnut" shaped pouches 19 may be placed around a central pin in layers. When the gel 20 comes into contact with water, enough force is created by the gel swelling to project a tube placed over the same pin.

Other applications include the remote triggering of safety systems and alarms.

Claims (16)

1. CLAIMS: 1. An actuator comprising a pouch made from a water permeable flexible material and a movable member held in contact with the pouch in a deactivated position, said pouch containing a water absorbing polymer which swells on contact with water and moves the movable member to an activated position.
2. 2. An actuator as claimed in claim 1 in which the pouch has a plurality of separate pockets.
3. 3. An actuator as claimed in claim 1 or claim 2 further comprising a disabling mechanism activatable to prevent movement of the movable member.
4. 4. An actuator as claimed in any one of the preceding claims in which the movable member is a sprung lever.
5. 5. An actuator as claimed in any one of claims 1 to 3 in which the movable member is biased into contact with the pouch by means of a spring acting on the moveable member.
6. 6. An actuator as claimed in claim 5 in which the spring is made of a sponge construction.
7. 7. An actuator as claimed in any one of claims 1 to 3 in which the movable member comprises a plunger.
8. 8. A valve comprising the actuator as claimed in any one of the preceding claims comprising a housing to which one end of the movable member is pivotally attached, a sealing -10 -member located on the movable member, wherein when the actuator is in the deactivated position said sealing member is biased into sealing contact with one end of a pipe which extends through the housing, said sealing member being moved out of sealing contact with the pipe when the movable member is in the activated position to allow fluid flow through the pipe.
9. 9. A valve as claimed in claim 8 further comprising a microchip enclosed within the housing.
10. 10. A valve as claimed in claim 8 or claim 9 in which the housing comprises an inner housing and an outer housing and means to clamp them together such that the pipe extends from the inner to the outer housing.
11. 11. A valve as claimed in claim 10 in which the clamping means comprise an annular member in or on each of the inner and the outer housings, said annular members comprising a plurality of inwardly directed angled gripping members which grip an outer surface of the pipe.
12. 12. A container comprising a plurality of walls and at least one valve as claimed in any one of claims 8 to 11 affixed to a wall with the pipe extending through the wall.
13. 13. A container as claimed in claim 12 in which the container has six walls and eight corners and at least four valves located at at least four opposing corners.
14. 14. An actuator substantially as hereinbefore described with reference to and as shown in the accompanying drawings. -11-
15. 15. A valve substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
16. 16. A container substantially as hereinbefore described with reference to and as shown in the accompanying drawings.