GB2114720A

GB2114720A - Apparatus for heating liquids

Info

Publication number: GB2114720A
Application number: GB08303206A
Authority: GB
Inventors: Ronald William Middleton
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-02-11
Filing date: 1983-02-04
Publication date: 1983-08-24
Also published as: GB8303206D0; GB2114720B

Abstract

Apparatus for heating liquids comprising a housing (1) defining a chamber (2) having an inlet (3) and an outlet (4) for liquid, pump or impeller means (13) for directing said liquid from the inlet (3) to the outlet (4), and electrical resistance heating means (17) in said chamber (2) for heating liquid as it passes from said inlet (3) to said outlet (4). The apparatus is incorporated in the coolant system of an internal combustion engine for preheating the coolant prior to startup. <IMAGE>

Description

SPECIFICATION Apparatus for heating liquids This invention relates to apparatus for heating liquids and more particularly, although not exclusively, to apparatus for heating liquid coolant in an internal combustion engine of a vehicle for pre-heating the engine prior to start-up.

When starting a vehicle internal combustion engine from cold, particularly under winter conditions, the engine will generally need to run on choke until it has reached a required minimum operating temperature and during this time the fuel consumption is extremely high. Thus, where a vehicle is only regularly used for comparatively short journeys, e.g., to and from a persons place of work, the fuel consumption will be extremely high and a great deal of fuel will be wasted because the vehicle is running with the engine on choke for probably a greater part of each journey.

Moreover, during the time that the engine is running on choke, wear and tear on the engine is at its highest because the fuel rich mixture tends to wash lubricant from the wall of the combustion chambers and during the initial part of the journey the vehicle will be operating without its heating and demisting systems working properly with adverse effect on comfort and safety. The present invention has as its object to provide apparatus for heating liquids which is particularly suitable for heating a liquid coolant in an internal combustion engine of a vehicle to pre-heat the engine prior to start-up and which also has uses in other fields where it is required to heat a liquid in a closed circuit system.

The present invention provides apparatus for heating liquids comprising a housing defining a liquid chamber having an inlet and an outlet, pump or impeller means for directing said liquid from the inlet to the outlet, and electrical resistance heating means in said chamber for heating liquid as it passes from said inlet to said outlet.

Said housing may be a cylindrical housing having an inlet at one end thereof and an outlet at the other end thereof, said pump or impeller means being mounted in one end of the chamber and said electrical resistance heating means extending into said chamber from the other end thereof.

Preferably the electrical resistance heating means is connectable, as by means of a suitable plug and socket connector, to a source of mains electricity and the pump or impeller means comprises an impeller driven by an electric motor which operates from the same source of mains electricity. In order to avoid problems of sealing the electric motor and impeller are preferably of a glandless type which enables said housing to be completely closed except for said inlet and outlet.

Thus, for example, the electric motor may be a shaded pole motor the stator of which is mounted around an end portion of the housing and the rotor of which is mounted within the housing on a shaft which also carries the impeller. Said shaft may be journalled at one end in a bearing provided in an end wall of said housing and intermediately of its length in a bearing provided by a perforate bearing disc or washer mounted in the housing.

Suitable bracket or other means may be provided for mounting the heating apparatus of the present invention within the engine compartment of a vehicle and said inlet and outlet may comprise hose connectors so that the heating apparatus can readily be plumbed into the liquid cooling circuit of a vehicle, e.g., as by cutting a flexible hose of the cooling system at a suitable point and connecting one cut end of the flexible hose to the inlet and the other cut end of the hose to the outlet.

The invention will be more particularly described with reference to the accompanying diagrammatic drawings, in which: Fig. 1 is a sectional elevation illustrating one embodiment of apparatus for heating liquids according to the present invention, and Fig. 2 is a sectional elevation of another embodiment of apparatus according to the present invention.

Referring to Fig. 1. of the drawings it will be seen that the heating apparatus illustrated therein comprises a cylindrical housing 1 defining a liquid chamber 2, the cylindrical housing 1 having an inlet conduit 3 at one end thereof and an outlet conduit 4 at the other end thereof. The housing 1 has a reduced diameter end portion 5 which is closed by an end wall having a blind cylindrical recess 7 therein in which is journalied one end of a shaft 8. Further bearing support is provided for the shaft 8 intermediate the length thereof by a perforate bearing washer or disc 9 having around the outer periphery thereof a resilient O-ring or the like 10 which locates the bearing washer 9 within the housing portion 10 and which acts as a self-centering device for the shaft 8.The shaft 8 has fixedly mounted thereon the rotor 11 of a shaded pole electric motor the stator 12 of which is mounted around the exterior of the casing portion 5. Whilst a shaded pole motor is preferred it will be understood that any other suitable form of electric motor may be used, e.g., a suitable electric motor driving the impeller on the shaft 8 through a magnetic coupling. Also mounted on the shaft 8 for rotating therewith is an impeller 1 3 which in the illustrated embodiment has axially extending impeller blades 14 but which could be a centrifugal or other suitable form of impeller.

The O-ring 10 on the bearing washer or disc 9 seals the outer periphery of the impeller to prevent liquid flowing back around the outside of the impeller. A spacer 1 5 is mounted on the shaft 8 between the rotor 11 and the bearing washer 9.

The opposite end of the cylindrical housing 1 is closed by an end wall 1 6 on which is mounted an electrical resistance heating element 17 connectable by way of the contact pins 1 8 of a plug and socket connector to a source of mains electricity. The electrical resistance heating element 1 7 may be of any suitable size but as an example a three kilowatt heating element has been found to be satisfactory in use for preheating the engine of a passenger car prior to start-up. The contact pins 1 8 of the plug and socket connector, as well as being electrically connected to the heating element 17, are also connected to the electric motor so that the electric motor will be energized when the heating element 1 7 is energised.So that there will be a minimum of electric leads externally of the heating apparatus, a conduit 1 9 is provided which extends longitudinally within the chamber 2 and the interior of which is isolated from the chamber 2. The conduit 1 9 serves to house the electrical leads (not shown) which extend from the pins 1 8 to the electric motor. As an alternative the impeller could be driven from a separate source, e.g., could be driven by a 1 2 volt electric motor adapted to operate off the battery of a vehicle to which the heating apparatus of the invention is fitted. Preferably the heating element 1 7 is thermostatically controlled e.g., as by means of a thermal cut-out 20.

In the use of the heating apparatus of the present invention, the apparatus is mounted within the engine compartment of a motor vehicle by means of suitable brackets or the like (not shown) and the apparatus is connected into the liquid coolant circuit of the vehicle engine by cutting a flexible hose of the coolant circuit at a suitable location and forcing the cut ends over the inlet and outlet conduits 3, 4, suitable hose clips being tightened around the end portions of the hose so as to clamp them tightly to the inlet and outlet conduits 3, 4.At a suitable interval of time before it is desired to start-up the engine of the vehicle the heating apparatus of the present invention is connected to a source of mains electricity using the aforesaid plug and socket connector and a suitable mains lead so as to energise the heating element 1 7 and the electric motor 11, 12. As a result the liquid coolant contained in the vehicle engine is caused to circulate through the heating apparatus of the present invention by means of the impeller 13 so that it flows over the heating element 1 7 and is heated.

In a modification of the apparatus illustrated in Fig. 1 the housing end portion 5 together with the shaft 8, rotor 11, impeller 13, and associated parts is formed as a seperate end assembly whilst the heating element 1 7 is carried by a second end assembly, the said end assemblies being a tight sliding fit with the cylindrical housing 1. The pins 1 8 form part of an electric plug and socket connector which is separate from the remainder of the apparatus and is connected to the heating element 1 7 by a suitable insulated electric lead or leads.In this embodiment the conduit 19 for housing the electrical leads connecting the electric motor in circuit with the heating element is omitted and instead the end assemblies are assembled to the cylindrical housing by means of hollow tie bars which extend between the end assemblies exteriorily of the cylindrical housing and the said electrical leads are housed in these hollow tie bars. Also, in this modification, the end wall 6 is provided by a cup-shaped closure member which is adhesively or otherwise secured in the open end of the housing portion 5 and which is centrally recessed to provide the bearing 7 whilst the bearing 9 is provided by a further cup-shaped member which is adhesively secured in the housing portion 5 and which is centrally apertured to provide bearing support for the shaft 8, thus obviating the need for the O-ring 10.

The inlet and outlet conduits 3 and 4 may comprise suitable unions, e.g., screw threaded unions, to facilitate the connection of hoses thereto.

Preferably the mounting arrangement for the modified apparatus is such that the apparatus, with the exception of said plug and socket connector, can be mounted in the engine compartment of a motor vehicle. The said electric plug and socket connector may be of any suitable kind, e.g., of the kind commonly used on electric kettles. That part of the plug and socket connector carrying tlie pins 1 8 adapted to be mounted to the exterior of the vehicle, e.g., to the outside of the radiator grille or on the exterior bodywork of the vehicle, e.g., using suitable clamp or bracket means, whilst the other part of the plug and socket connector is adapted for connection to a suitable source of mains electricity.This arrangement enables the two parts of the plug and socket connector to be connected together from the exterior of the vehicle without the necessity for the user to gain access to the engine compartment. If desired a screw cap or other suitable removable cover member may be provided for closing that part of the plug and socket connector containing the pins 1 8 when the apparatus of the invention is not in use. Having the plug and socket connector accessible from the exterior of the vehicle is not only more convenient but has the additional advantage that if a person should inadvertently drive away whilst the apparatus of the present invention is still connected to a source of mains electricity the two parts of the plug and socket connector will in all likelihood simply pull apart without any damage being done.

If desired the apparatus of Fig. 1 or of the modification described above may be "potted" or encapsulated in a suitable plastics or other material.

In the embodiment shown in Fig. 2, in which like parts have been given like reference numerals, the apparatus of the present invention is incorporated as part of a heat-exchange unit which comprises a heater for a motor vehicle. The heat-exchange unit comprises a casing 30 housing a heat-exchanger 31 by means of which air is passed in heat-exchange relationship with the engine coolant liquid so that the air will be heated by the waste heat from the engine when the engine coolant liquid is hot. The casing 30 has an inlet 32 for engine coolant liquid, an outlet 33 for engine coolant liquid, an air inlet 34 in which is mounted a fan 35 driven by a thermostatically controlled electric motor 36 and an air outlet 37.

The apparatus of the present invention is mounted in a chamber 38 in the lower part of the casing 30 and comprises an impeller housing 5a with which the inlet 32 communicates and which has an open outlet end 39 which discharges into the chamber 38. The heating element 1 7 is provided in the chamber 38 whilst the pins 1 8 are housed in a socket portion 40 formed in a side wall of the casing 30. Alternatively the pins 1 8 could form part of a separate plug and socket connector as described above in connection with the modified embodiment of Fig. 1.

The apparatus of the present invention is connected in circuit with the motor 36 of the fan 35 by way of a thermostatically controlled switch (not shown) so that, when the apparatus is in use, the motor 36 will not be energised and the fan 35 not operate until the engine coolant liquid has reached or falls below, a predetermined temperature, e.g., of about 800C.

If desired the apparatus of the present invention can be controlled by a suitable timer mechanism which enables the heating element and electric motor to be energised at a predetermined time in the future, thus enabiing the timer to be set, say, in the evening so that the heating element and electric motor will be energised at a predetermined time the following morning. In this way a user can connect the apparatus to a source of mains electricity and then set the timer and know that the engine of his vehicle will be pre-heated at a time when he wishes to use the vehicle, e.g., to drive to his place of work in the morning. The timer mechanism can be such that it can also be set to switch-off the supply of electricity to the heating element and electric motor after a predetermined period of time.

It has been found that using apparatus according to any of the above described embodiments fitted with a three kilowatt heating element 17 the average passenger car engine can be adequately pre-heated in minutes to a point where no choke will be required on a start-up.

Because the engine starts without the need for any choke, there is a considerable saving in fuel which far outweighs the cost of the electricity required to pre-heat the engine. In addition other benefits are gained, including easier and more reliable starting of the vehicle engine, less engine wear because there is no rich mixture to wash away lubricant from the walls of the combustion chambers, and immediate availability of the heating and demisting systems of the vehicle to provide greater driver comfort and safety through not having to drive initially with a badly misted windscreen. For vehicles having diesel engines cold weather starting problems can be overcome or mitigated.

Whilst the heating apparatus of the present invention is primarily intended for pre-heating the internal combustion engines of vehicles it will be appreciated that it also has utility in any other field where rapid heating or pre-heating of a liquid in a closed circuit system is required.

Claims

1. Apparatus for heating liquids comprising a housing defining a chamber having an inlet and an outlet for liquid, pump or impeller means for directing said liquid from the inlet to the outlet, and electrical resistance heating means in said chamber for heating liquid as it passes from said inlet to said outlet.

2. Apparatus according to claim 1, wherein said housing is a cylindrical housing having an inlet at one end thereof and an outlet at the other end thereof, said pump impeller means being mounted in one end of the chamber and said electrical resistance heating means extending into the chamber from the other end thereof.

3. Apparatus according to claim 1 when combined with a heat-exchanger unit comprising a heater for a motor vehicle, said unit comprising a housing, a heat-exchanger mounted in said housing, an inlet and an outlet in said housing for engine coolant liquid, an inlet and an outlet in said housing for air, and a fan for passing the air through the heat-exchanger in heat exchanger relationship with engine coolant liquid, said chamber being defined by the housing of the unit and having said engine coolant liquid inlet communicating therewith.

4. Apparatus according to claim 3, comprising a cylindrical impeller housing extending into said chamber, said inlet for engine coolant liquid opening into said impeller housing and the impeller housing having an outlet end which opens into said chamber.

5. Apparatus according to any one of the preceding claims, wherein said electrical resistance heating means is connectable to a source of mains electricity and the pump or impeller means comprises an impeller driven by an electric motor which operates from the same source of mains electricity.

6. Apparatus according to claim 5, wherein the electrical resistance heating means and said electric motor are connectable to a source of mains electricity of an electric plug and socket connector.

7. Apparatus according to claim 6, wherein one part of said electric plug and socket connector is connected to the remainder of the apparatus by an insulated electric lead or leads and is adapted for mounting on the exterior of the vehicle, the other part of the plug and socket connector is connectable to a source of mains electricity, and means is provided for mounting the remainder of the apparatus in the engine compartment of a vehicle, whereby said electric plug and socket connector can be connected and disconnected from the exterior of the vehicle without the need to gain access to the engine compartment.

8. Apparatus according to claim 5, 6, or 7, wherein said electric motor and impeller are of a glandless kind enabling said chamber or impeller housing to be completely closed except for the inlet and outlet thereof.

9. Apparatus according to claim 8, wherein said electric motor is a shaded pole motor having a stator mounted outside said chamber or impeller housing and a rotor mounted within said chamber or impeller housing on a shaft which also carries the impeller.

10. Apparatus according to claim 9, wherein said shaft is journalled at one end in a bearing provided in an end wall of said chamber or impeller housing and intermediately of its length in a bearing provided by a perforate bearing disc or washer mounted in the chamber or impeller housing.

11. Apparatus for heating liquids substantially as herein described with reference to Fig. 1 or Fig.

2 of the accompanying drawings.