GB2196820A - Heating device for eg hot water or steam - Google Patents

Abstract

A heating device (10) comprises a casing (12), electrodes (24A, 26A) mounted alternately in a spaced apart relationship on terminal rods (24, 26), a liquid medium inlet (22) and an outlet (not shown) at the upper end of casing (12) for the discharge of the heated medium. The electrodes (24A, 26A) have openings (24B, 26B) for the throughflow of liquid medium, and the terminal rods are connected to a source of electrical power. The medium flows in a single direction only past the electrodes. <IMAGE>

Description

SPECIFICATION Improvements in or relating to liquid heaters This invention relates to liquid heating devices for example devices using electric power to heat water and/or to create steam.

The present invention seeks to provide a liquid heating device which is relatively compact and provides a rapid rise in liquid temperature in a short time interval in an energy saving manner.

The present invention proposes a liquid heating device including a plurality of spaced apart electrodes arranged to be connected to a source of electric power, the liquid to be heated flowing past the electrodes in a single direction only.

The device may comprise an inlet arranged to discharge the liquid to be heated at the lower end of the device so that the liquid passes through or over the electrodes in an upward direction leaving the device at the upper end thereof.

The device may include an expansion space above the bank of electrodes and the electrodes may be maintained in spaced relationship by regular or irregular spacing means between adjacent electrodes. Each electrode can be in plate form and provided with a series of fluid passages through the section thickness of each plate to allow the liquid to be heated to flow therethrough. Also a series of additional fluid channels at the outer and inner edges of each electrode plate can be provided.

The rate of flow of liquid through the device can be controlled in dependence of the pressure and/or mass flow and temperature depending upon the energy input to the heating means and the required condition or temperature of the liquid leaving the device.

Alternate electrodes can be connected to terminal rods for ease of connection to a source of electric power.

The device may be employed for the purpose of heating water and further compatible liquids as may be required, to create vapour or steam by economical means, and also for the purpose of providing power to drive an engine from which the energy may be used to drive any load, for example a dynamo or generator or a turbine.

The liquid, fluid, or water supply which is introduced into the device, may be filtered by mechanical means prior to entry into the device so as to remove or dilute any effluent or soil particles, chemicals, salts, calcium or weeds, as may be contained within the supply source, and such filtration means may be connected into an inlet control unit so as to prevent deposit 'build up' upon the surface of the electrodes, and further harmful effects such as blockages within the water channels.

The present invention will now be more particularly described with reference to the accompanying drawings in which Fig. 1 shows a sectioned elevation of one form of liquid heating device according to the present invention.

Fig. 2 shows a further sectioned elevation of the liquid heating device shown in Fig. 1, Fig. 3 is a section through an electrode separator shown in Figs. 1 and 2, Fig. 4 is a view on arrow A in Fig. 3, Fig. 5 is a sectioned elevation of a further form of liquid heater according to the present invention, Fig. 6 shows a sectioned elevation of another form of liquid heating device according to the present invention, Fig 7 shows a series of liquid heating devices according to the present invention and, Fig. 8 shows diagramatically a group of devices according to the present invention coupled together.

Referring to the drawings, a liquid heater 10 comprises an outer insulated casing 12, a liner 14 and a closure cap 16 for the liner, the liner being secured within the casing 12. Liquid inlet and outlet connections 18 and 20 respectively are secured to the cap 16 and an inlet pipe 22 is attached to the cap 16 and extends into the interior of the lining 14. Also passing through the cap and extending into the interior of the lining 14 are two terminal rods 24 and 26 which each have brass terminals 28. Attached to each terminal rod are a number of electrode plates 24A and 26A respectively. These electrodes are individually provided with openings 24B and 26B respectively to allow the through-flow of liquid to be heated. The openings 24B, 26B are equispaced on three pitch circle diameters.Each electrode has a central opening to receive the pipe 22, an opening to receive the electrode on which it is mounted and a clearance opening through which the other electrode passes in a non-contacting manner. The electrodes can each be provided with additional fluid channels (not shown) at the inner and outer edges.

The electrodes 24B and 26B are maintained in a spaced apart relationship by spacers 30 which are shown in more detail in Figs 3 and 4.

Referring to Figs. 3 and 4, each spacer 30 has an aperture 32 to enable the spacer to be mounted on one or other of the terminal rods 24 and 26. Each spacer has two legs 34 terminating in feet 36. The feet 36 and the central portion which includes the aperture 32 are relative thicker than the legs 34 so that whilst adjacent electrodes are in contact with the feet and the central portion, there is a space between the legs and the central electrode. Also each leg 34 has an aperture 38 to allow for the free passage of the liquid to be heated within the lining 14. The spacers 30 are mounted alternately on the electrodes 24 and 26 as shown clearly in Fig. 2.

In operation, electric power is supplied to the terminals 28 of the rods 24 and 26 and suitable ducting for the liquid to be heated is connected to the inlet connection 18. The liquid to be heated flows down through the pipe 22 and flows upwardly through the openings 24B and 26B in the electrodes 24 and 26 respectively and through the openings 38 in the spacers 30, the temperature of the liquid being increased as the liquid passes over successive electrodes due to resistive heating and the creation of an electro-magnetic field through which the liquid passes.

The heated liquid passes into an expansion space 40 which is formed between the uppermost one of the electrodes 24 or 26 as the case may be and the interior surface of the cap 16. This interior surface may be spherical and the heated liquid flows out of the device through the outlet connection 20. The liquid to be heated may be water and may leave the device in a liquid or vaporous state.

The heating device can have a control at the inlet and outlet both to control the rate of liquid inlet and the rate of discharge of heated liquid or vapour. These controls can operate in dependence of the pressure, flow rate and temperature at the inlet and outlet and as a function of the electrical energy being supplied to the device.

In an alternative arrangement, shown in Fig.

5 which is intended to receive the heated output from outlet 20 of the device shown in Figs. 1 and 2, an inlet pipe 42 terminates at the internal surface of the cap 16 so that the liquid to be heated flows directly through and over the electrodes 26A, 268. At the lower end of the liner 14 is a chamber 44 having a non-returning valve 46. and being connected to a pressure chamber 48 having a pressure control valve 50 and an outlet 52. The pressure chamber 48 also has a safety valve 54.

Referring to Fig. 6, there is shown a heating device 54 which is intended to receive the output of heated medium from the outlet 52 of the device shown in Fig. 5.

The device 54 comprises a casing 56 containing a chamber 58 having an inlet 60 with a non-return valve 62. A stack of electrodes 26A, 268 mounted on rods 24, 26 in a similar manner to that shown in Figs. 1, 2 and 5 are contained within the casing which terminates in a cap 16 having an outlet 64.

Referring to Fig. 7 there is shown a power plant comprising the liquid heating devices shown In Figs. 1, 2, 5 and 6 arranged in series. The liquid heaters are coupled together by ducting 66, 68 so that the output of heated medium can be ducted to the input of the next heating device. The output of the heating device 56 which can be steam, can be used to drive a turbine which in turn drives a generator. The electrical output of the generator can be used as the source of the electrical power for the liquid heaters. A source of electric power is shown connected to each of the electrode rods of the heaters.

The water to inlet 18 first passes through a filter 65, and has a control means 66 which controls the rate of inlet mass flow, depending for example upon the inlet pressure and temperature and the amount of electrical energy input depending upon the desired state of temperature of the flow through the outlet 64.

Similarly the flow through the outlet 64 has a control 68 which operates in dependence of similar functions to that used to operate the control means 66 and there may also be a feed back loop 70 so that the control means 66 and 68 can operate in unison.

Fig. 8 shows a group of four devices 10 having a common fluid inlet 72 connected to each of the inlets 18, and a common outlet 74 connected to each of the outlets 20. The incoming supply is provided with a mechanical control valve 76 so as to adjust the flow of liquid into each of the respective devices 10 through the inlet 18.

The positioning of the electrodes 24A, 26A within the lining 14 can be adjusted to suit the desired results but in one arrangement it has been found beneficial for the expansion space 40 to occupy approximately a third of the volume of the liner, the electrodes to occupy a further third, leaving a space beneath the lower-most of the electrodes to take up the remaining third of the volume.

The electrodes 24A, 26A and 248, 26B can be sized and arranged in any convenient manner. In one arrangement of device according to the present invention, the liner 14 can be 80mm. in diameter and each electrode disc is a snug fit inside the liner. Each electrode can be 3mm. or 4mm. thick and spaced apart by approximately 5mm. to 6mm.

Each disc has a central 20mm. diameter opening and a 4mm. diameter opening to receive a spacer mounted on one of the rods 24, 26 and a 10mm. diameter opening so that the disc does not contact the rod 24 or 26 on which the adjacent discs are mounted.

The openings 24A, 26A can be 3mm. or 4mm. diameter and can be arranged on three pitch circle diameters (30mm, 50mm. and 67.5mm). It is preferable that a space of approximately 75mm. is left above the electrodes, the electrodes themselves being equally spaced over a distance of 105mm.

and the inlet 22 extending into the liquid to be heated by approximately 50mm.

All of these dimensions can be varied in proportion to the internal diameter and length of the heating device.

The electrodes are preferably formed from copper although precious metals can be used and whilst they have been shown as flat in section they can be any shape such as parabolic, conical, dished or corrugated, the latter being useful for increasing the surface area.

Claims (14)

1. A liquid heating device including a plurality of spaced apart electrodes arranged to be connected to a source of electric power, the liquid to be heated flowing passed the electrodes in a single direction only.

2. A device as claimed in claim 1 comprising a housing containing the electrodes mounted a spaced apart relationship, a liquid inlet and an outlet to discharge the heated medium, the liquid inlet terminating below the electrodes allowing the liquid flow upwardly passed the electrodes and leaving the device through the outlet at the upper end of the device.

3. A device as claimed in claim 1 or claim 2 in which an expansion space is provided above the electrodes.

4. a device as claimed in any one of the preceding claims in which each electrode comprises a plate arranged to be connected to one or other of a pair of terminal rods, each electrode being provided with a plurality of apertures for the throughflow of medium to be heated.

5. A device as claimed in claim 4 in which each electrode has fluid flow channels at either or both of their inner and outer edges.

6. A device as claimed in claim 4 or claim 5 in which spacing means are mounted on the terminal rods to maintain the electrodes in a spaced apart relationship, the spacing means and the electrodes being mounted alternately on the two terminal rods which are arranged to be connected to a source of electrical power.

7. A device as claimed in any one of the preceding claims in which the electrodes are made from copper.

8. A device as claimed in claim 1 having an inlet at one end and an outlet at the opposite end, the heated medium discharging into a chamber having an outlet controlled by a nonreturn valve.

9. A device as claimed in claim 8 in which the chamber is connected to a pressure chamber having an outlet controlled by a pressure control valve.

10. A device as claimed in claim 1 having an inlet at the lower end thereof and an outlet at the opposite end thereof, the flow through the inlet being controlled by a non-return valve.

11. A power plant including at least two heating devices as claimed in claim 1- arranged in series.

12. A power plant including at least two heating devices as claimed in claim 1 arranged in parallel.

13. A power plant as claimed in claim 11 or claim 12 including a power turbine arranges to be driven by the output medium of the heating devices.

14. A heating device constructed and arranged for use and operation substantially as herein described, and with reference to the accompanying drawings.