GB2144526A

GB2144526A - Flexible heated containers

Info

Publication number: GB2144526A
Application number: GB08416499A
Authority: GB
Inventors: Frederick Ralph Preston; Anthony Robert Hoare; Ronald Leslie Grosvenor
Original assignee: Marston Palmer Ltd
Current assignee: Marston Palmer Ltd
Priority date: 1983-06-29
Filing date: 1984-06-28
Publication date: 1985-03-06
Also published as: GB8317605D0; GB8416499D0

Abstract

A heating system for a flexible rubber tank 1 used to transport liquids liable to solidify or increase in viscosity at lower temperatures to a degree rendering pumping difficult. The heating system includes at least one immersion heater located in the tank, the immersion heater being supplied with hot water from an external electrically powered boiler and pump circulating unit 10. The use of hot water prevents damage to the tank and to the contents of the tank, which would typically be palm oil. The part of the heating system situated in the flexitank can also have heating fluid (either hot water or steam) circulated through it from a separate heater or boiler. <IMAGE>

Description

SPECIFICATION Container This invention relates to containers and has particular reference to flexible containers used for the transport and/or storage of liquids in bulk.

It is known to transport and store liquids in bulk and in British Patent Specification 1 51 2 033 there is described a demountable tank for the bulk transport of liquid goods in which the tank is provided with a heating blanket to heat the bottom of the tank. Many liquids become extremely viscose when cooled to ambient temperature and in some cases i.e.

palm oil solidified completely. Conventional liquids such as palm oil are shipped in drums of 45 gallon capacity and the drums are heated in an oven to melt the palm oil to permit it to be discharged.

The use of flexible liquid containers for the bulk transport of liquids is increasing in its attraction. Such flexible containers enable any lorry to become a tanker. There is no need to provide a dedicated tanker with the inflexibility which such a vehicle has. It has been proposed in German Offenlegungsschrift 28 1 3 064 to provide a heater mat at the bottom of a flexible container to heat liquids in the container. Such a container requires a double screened bottom and requires the use of a dedicated container.

By the present invention there is provied a container for the transport and/or storage of liquids in bulk, the container being formed of a flexible liquid impervious material and there being provided inside the container in contact, in use, with liquid inside the container, with means to heat liquid contained therein.

The flexible liquid impervious material may be a fabric reinforced synthetic or natural rubber material. The rubber material may be a nitrile rubber or a butyl rubber. The fabric may be rayon, Terylene (Registered Trade Mark for polyethylene terephthallate) or nylon.

The means to heat the liquid may be an immersion heater. The immersion heater may be heated directly by electricity or by a hot liquid, preferably hot water. The hot water or other liquid may be heated externally by an electrical heater. The hot water or other liquid may be circulated through the immersion heater via pipes. The pipes may be formed of a flexible material. The pipes may be connected to the immersion heater by quick release couplings. The hot water may be circulated by a pump. The pump may be located below the tank. The immersion heater may be in the form of a series of tubes interconnecting inlet and outlet headers. The electrical heating may be in parallel with an electrical circulating pump. The applied current may be direct or alternating. The applied voltage may be in the range 6 to 500 volts, preferably approximately 12, 24, 110, 240 or 450 volts.

The means to heat the liquid in the container may be adapted for continuous operation during transit or for discontinuous operating prior to discharge.

The means to heat the liquid may also be an existing sited boiler or heater delivering steam or hot water through the flexitank's heat exchanger.

The present invention also provides a method of transporting liquids in bulk which includes the steps of transporting the liquids in a flexible container and heating the liquids in the container. The liquids may be edible.

They may be chosen from the group palm oil, honey, waxes and tallow.

There may be two or more immersion heaters. The tank may be adopted to be transported in a standard ISO container of 20 feet or 30 feet or 40 feet in length by 8 feet in width. The tank may be restrained in the container by a harness.

By way of example embodiments of the present invention will now be described with reference to the accompanying drawings, of which: Figure 1 is a perspective view of a flexible container located in an ISO container; Figure 2 is an enlarged schematic view of part of the heating system illustrated in Fig.

1; Figure 3 is a perspective view of an alternative form of heating arrangement; Figure 4 is a schematic perspective view of a heat exchanger for use in Fig. 3; Figure 5 is a pespective view of a further form of heating system, and Figure 6 is a schematic view of the heating element shown in Fig. 5.

The present invention is concerned with the storage and/or transport of liquids in bulk. By "bulk" is meant transport of liquids in excess of 100 litres per container. Typically a container would have a capacity of 1 8 000 litres.

Referring to Fig. 1 this shows a flexible container generally indicated at 1 located in a standard ISO container 2. Typically the ISO container would be 8 feet wide by 20 feet in length. The height of the container would be approximately 8 feet. The flexible container is held in the ISO container 2 by means of a harness system 3. A pair of tapped inlet bores 4 and 5 are mounted and bonded into the flexible container 1 so as to be positioned at the upper end of the container when the container is installed in the ISO container.

Typically the flexible container 1 would be formed of a fabric reinforced butyl or nitrile rubber. Located in the tapped inlet bores 4 and 5 is a pair of immersion heaters which are connected by lines 6, 7, 8 and 9 to a central pumping and storage unit indicated generally at 10. The pumping and storage unit 10 has a water storage and expansion tank 11 and located beneath it an electrically powered pump 12. Water is heated in the tank 11 and pumped by the pump 1 2 through the lines 6 and 8 to the immersion heaters located in the flexible container. Water is returned via lines 7 and 9 to the tank 11 for further heating and recyciing.

Referring to Fig. 2 this shows the heating system in more detail. The immersion heater 1 3 comprises a series of spaced parallel tubes 14 which interconnect a header 15, a turnaround tank 1 6 and an outer header 1 7. The pipes 6 and 7 are made of a flexible material, such as rubber or a plastics material, and are connected to the headers 1 5 and 1 7 by quick connect couplings 1 8 and 1 9.

Water in the tank 11 is heated by means of an external heating tape 20 although an internal immersion heater may be used if required.

Electrical power for the pump 1 2 and the heating element 20 is supplied via lines 21 and 22. It will be seen that the heating element 20 and the pump 1 2 are connected in parallel. The container may be used to transport a liquid such as palm oil which becomes extremely viscous when it cools below 25to.

In use the heating system enables 10 kilowatts of power to be passed into the tank to maintain the palm oil in a sufficiently fluid state for it to be easily pumped out after significant periods of storage and/or transport. By using flexible pipes 6, 7, 8 and 9 to interconnect the immersion heater 1 3 and the heat source 10 surges of liquid within the tank, which inevitably occur during transport, can be accommodated. If fixed pipes were to be used in transport systems there would be a danger that they would become disconnected by the surging and movement of the tank which occurs during use.

A further alternative arrangement of components is illustrated in Figs. 3 and 4. Fig. 3 shows a general arrangement in which a container 23 has located therein a flexitank 24 which is restrained by a suitable harness 25.

A pair of tube bundles 26, 27 pass through the flexitank for heating purposes. As can be seen more clearly in Fig. 4 the tube bundle 26 interconnects an outlet header 28 with a tube bundle support 29. Similarly the tube bundle 27 interconnects an inlet header 30 and the tube bundle support 29. The headers 28 and 30 are suitably mounted in ports formed in the wall of the flexitank. A further port 31 provides access to the tube bundle support 29 so that the tube bundle support may be held up by a cord 32. A filler nozzle 33 is provided in the tank for normal filling purposes. The bundles 26 and 27 may be formed of flexible plastics tubing capable of withstanding the temperatures of the hot water or steam passing through the tube bundles.

The system illustrated in Figs. 3 and 4 would be left permanently in the flexitank and it will be appreciated that the tube bundles 26, 27 may be rolled up with the flexitank for transport and storage purposes. The systems illustrated in Figs. 3 and 4 are all self-contained. However, it is possible for the hot water or steam to be supplied from an external source. The heater may be operated continuously, semi-continuously or only prior to discharge.

A further alternative form of heating system is illustrated in Figs. 5 and 6. In this arrangement like parts to that illustrated in Figs. 3 and 4 are given like reference numerals. The system illustrated in Figs. 5 and 6 is, however, intended to be inserted into the flexitank when it is full. Clearly the contents of the tank must either be liquid or sufficiently fluid to enable the component parts to be inserted.

The immersion heater shown is in two portions 34, 35 and the portions are inserted separately through a suitable orifice 36. The arrangement is shown in more detail in Fig. 6.

It can be seen that the portion of the heater 34 is mounted in a half plug 37 and the portion 35 is mounted in a half plug 38. The portions are inserted individually by being pushed through the moulding 39 and the plug halves are then brought together and firmly pushed into the moulding 39. Hot water, steam or electricity is then passed through the elements in a conventional manner.

Although direct heating using an electrical immersion element may be used, by using an indirect heating system rather than a direct electrical immersion element certain advantages may be obtained. Thus overheating of the liquids contained in the tank may be avoided and the generation of local hot spots in an electrical immersion heater operating at high voltages and high currents, which hot spots may cause damage to the tank itself, can be avoided.

Although the liquid contained in the container has been described above as being palm oil, other materials may be transported which are susceptible to freezing or solidification on cooling, such as honey, tallow, wax or Cereclor used in the manufacture of soap.

Claims

1. A container for the transport and/or storage of liquids in bulk, the container being formed of a flexible liquid impervious material and there being provided inside the container in contact, in use, with liquid inside the container, with means to heat liquid contained therein.

2. A container as claimed in Claim 1 in which the flexible liquid impervious material is a fabric reinforced synthetic or natural rubber material.

3. A container as claimed in Claim 2 in which the rubber material is a nitrile or a butyl rubber.

4. A container as claimed in Claim 2 or 3 in which the fabric is rayon, nylon or polyethylene terephthallate.

5. A container as claimed in any one of Claims 1 to 4 in which the means to heat the liquid comprises an immersion. heater directly by electricity or by a hot liquid, preferably hot water.

6. A container as claimed in Claim 5 in which the hot water or other liquid is heated externally by an electrical heater.

7. A container as claimed in Claim 5 or 6 in which the hot water or other liquid is circulated through the immersion heater via pipes.

8. A container as claimed in Claim 7 in which the pipes are formed for a flexible material.

9. A container as claimed in Claim 8 in which the pipes interconnect inlet and outlet headers.

10. A container as claimed in any one of Claims 8 or 9 in which the pipes are formed of nylon.

11. A container as claimed in any one of Claims 1-10 in which the means to heat the liquid is adapted for continuous operation during transitor for discontinuous operation prior to discharge.

1 2. A method of transporting liquids in bulk which includes the steps of providing a flexible container having inside the container means to heat liquid in the container, filling the container with liquid so that the liquid is in contact with the heating means transporting the liquid in the container, heating the liquid by means of the heating means and discharging liquid from the container.

1 3. A method as claimed in Claim 12 in which the container is located inside a rigid box.

14. A method as claimed in Claim 1 3 in which the flexible container is restrained in the box by a harness.

1 5. A container substantially as herein described with reference to and as illustrated by Fig. 1 and Fig. 2 or Fig. 3 and 4 or Figs. 5 and 6.