GB2266138A - Boiler associated with a ventilator - Google Patents

Abstract

A gas-fired appliance 74 e.g. a boiler is associated with ventilating apparatus 80 mounted over an air vent 78 in a wall the apparatus 80 having a fan and an air flow sensitive switch, the arrangement being such that when the appliance is switched on e.g. by a time switch 76, the fan is first brought into operation to draw air through the vent in quantities sufficient to activate the air flow sensitive switch which then allows ignition of the gas in the appliance. The vent 78 is a standard size wall air vent. The apparatus 80 may include a thermostatically actuated electric and/or water-to-air heater and a dust or insect filter. The water-to-air heat exchanger may be shaped like a grille and adapted to fit over the air vent. <IMAGE>

Description

AIR SAFTY APPARATUS This invention relates to air heating apparatus being guarnteed inside a building. For gas boilers which requires air bricks (ventilation). 5000 btu's = 1 sq inch.

Many buildings for domestic occupation include an air vent through which air can circulate between the inside and the outside of the building. In particular, where gas appliances are used inside the building it is necessary that air be allowed to enter the building to replace the air consumed by combustion, and it is a legal requirement that an air vent be present so that air can be drawin in.

However when air is drawn in in this way, the incoming air is cold air from outside the building and this provides an undesirable heat reduction inside the building. Thus on occasions are blocked which is "dangerous".

It is a first object of this invention to gurantee air coming in through such a vent. It is the first object of this invention to provide a way of checking that a vent exists and is open before gas can be ignited in a gasfuelled heating device.

According to a second aspect of the invention, there is provided air heating apparatus having an air inlet, an air outlet and a heating element, wherein the air inlet is adapted to be connected to an air vent in an external building wall, and where the element is arranged to heat air flowing through the apparatus from the inlet to the outlet.

The apparatus preferably has a housing which can be fitted to a building wall, with an aperture in the rear face of the housing of a dimension such as to register with an air vent in the wall. Air vents come in standard sizes, and the aperture in the back wall of the housing can therefore be of corresponding standard size.

The heating element may be an electrically powered heating element, or may be a heat exchanger in which hot water circulates in order to give up its heat to air passing through the heat exchanger.

Still further, the heating element may be a combination of an electrically heated component and a water to air heat exchanger.

The apparatus has included a fan to draw air in through the air vent and to force the air out through the heating element. (If heated part is fitted, ie heat exchanger).

A thermostat may be included in the apparatus to switch on the heating element automatically in the event that the incoming air through the vent is below a temperature such as 2"C.

The apparatus may include a filter to prevent dust or insects from outside being blown into the building.

According to a second aspect of the invention, there is provided air heating apparatus in the form of a heat exchanger adapted to fit over an air vent in an external building wall such that all the air passing through the vent also passes through the heat exchanger.

In the first aspect of the invention, there is provided a gas-fuelled heating installation comprising a gas-fuelled heating device located in a room, an air vent through a wall of the room through which air can be drawn into the room to replace air consumed by operation of the heating device, a fan communicating with the vent, and an air flow sensitive switch mounted in series with the fan, the components being interconnected so that when the heating device is switched on, the fan is brought into operation to draw air through the vent in quantities sufficient to activate the air flow sensitive switch, and activation of the air flow sensitive switch allows ignition of the gas in the heating device.

This installation ensures that the legally required air vent into the room is open before the gas of the heating device can be lit. This is an important safety feature.

The fan being part of an air handling unit which includes means for heating the air which enters the room through the vent. The heating means may be an electrically powered heating element, or may be a heat exchanger in which hot water circulates in order to give up its heat to air passing through the heat exchanger.

The gas-fuelled heating device may be a boiler which heats water, eg for a central heating system. However the installation is also applicable to other types of heating device.

The installation may include a time clock for switching on the heating device.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a cross section through a wall on which a heating apparatus in accordance with the invention is mounted; Figure 2 is a front view of the heating apparatus of Figure 1, with a front panel removed; Figure 3 is a rear view of the apparatus of Figure 1; Figure 4 shows a blanking plate for use at the rear of the apparatus shown in Figure 3; Figure 5 and 6 are respectively elevation and side views of a heat exchanger in accordance with the invention; Figure 7 is a diagrammatic representation of a heating installation in accordance with the third aspect of the invention; and Figure 8 is a cross-section though an air handling unit for use as part of an installation in accordance with the third aspect of the invention.

Figure 1 shows an external wall 10 of a building, with 12 indicating the exterior and 14 indicating a room in the interior of the building. A vent opening 16 is provided to allow air to flow from the outside of the building to the inside, in a known manner. This vent opening may be closed for example by an air brick 18 at the exterior face of the wall 10, or may be constructed in any other known manner.

Safty apparatus 20 is mounted on the internal surface of the wall 10 over the vent opening 16. Air flowing in through the vent 16, as indicated by the arrows 22, passes into the housing 20 and out through a housing opening 24. In following this path, the air passes over one or two heating elements 26, 28 where it is heated. Thus the air entering the room 14 is heated before it passes into the room.

The heating element 26 can be an electrical heating element, and the heating element 28 can be a heat exchanger where hot water passes in heat exchange relationship with the flowing air.

Under normal conditions, air will be drawn in through the vent opening 16 whenever the pressure on the inner side of the wall is greater than the pressure on the outer side of the wall. This will happen for example when a fire with a chimney is in operation, and when hot gases from the fire pass up a chimney. Cold air will be drawn in through the vent opening to replace the air which passes up the chimney.

In the absence of the heating apparatus as shown and described here, the air which will be drawn in will be cold air, and this will cool down the room 14. Such cooling is particularly not desired when a fire is operating elsewhere in the room. This is where a heat exchager could be fitted.

(Room temperature will raise quicker also stop draughts).

However by including heating elements 26 and/or 28 in the flowpath of the air through the vent, this incoming air can be heated to increase the temperature in the room.

The heating apparatus as shown here can itself be used to introduce a flow of air through the vent opening 16. If the heating elements 26 and/or 28 are operating, then there will be a convection flow of air through the heater and out through the opening 24, and a corresponding amount of air will be drawn in through the vent opening 16.

A fan 30 will be included to provide a positive throughflow of air, either when the heating elements 26, 28 are operating or when they are not operating.

An insect screen 32 can be placed in the vent opening to prevent dust or insects being drawn into the building. (Not important could be included) A thermostat 34 can be included in the housing 20 to detect low temperatures and to switch on the heating elements 26, 28 when low temperatures are detected in order to prevent interior temperatures which might lead to freezing. Such a thermostat is often referred to as "froststat". Part two of safty (will reduce insurrance claims).

The rear face of the housing 20 is shown in Figure 3 and is in the form of a plate 36 which has a cut-out 38. The dimensions of the cut-out are those of a standard size vent opening 16, for example a 9" by 6" opening. A blanking plate 40 can also be provided to cover part of the cut-out 38 in the event that the vent opening 16 is of a smaller size. The back plate 36 also has holes 42 for fastenings 44 which secure the heater to the wall.

7 Figures g and g show an alternative form of heating apparatus. This apparatus may be included in a housing 20 as shown in Figure 1, or may be used on its own. The 7 apparatus unit shown in Figures S and g is a heat exchanger with an internal water passage which can be connected into a hot water circuit in the same manner as a conventional central heating radiator. The heat exchanger has water passages 50 in the form of a grille which surrounds air passages 52. An air vent 54 is mounted at the top of the heat exchanger and inlet and outlet tappings 56, 58 will accept pipe connections and/or valves as desired.The heat exchanger can be secured over a vent opening 16 by means of screws or other fastenings extending through holes in flanges 60. The heat exchanger can be connected up as part of a conventional central heating circuit, or can be mounted in a separate circuit.

The invention thus provides a facility to heat air entering a building through an air vent. The air vent may be an existing vent, or one specially made to provide an air input guarntees air flow and reduces risks of burst pipes to a heater as described here. The apparatus makes use of standard components and the fitment of the apparatus will require no more than conventional fitters skills.

The invention will also be installed as a safety feature whereby if the vent/air intake is blocked, then the boiler or gas appliance will not operate. A pressure switch will be fitted to detect air flow through the vent. In this type of installation, it is not essential to have a heating element associated with the vent.

Figure 7 illustrates an installation of this type. A building 70 has a room 72 which contains a gas-fired cental heating boiler 74 controlled by a time switch 76. In one external wall of the room, there is an air vent 78. Mounted over this air vent is an air handling unit 80 which includes a fan 82, a motor to drive the fan in a direction which will pull air into the room through the vent and a flow sensitive switch 86 (see Figure 8).

In operation, the time switch 76 will be set to start the boiler at a specific time. When that time arrives, the time switch will operate and will first of all start the motor 84 which drives the fan 82. This will cause air to be drawn in through the vent to achieve a certain air flow. The flow sensitive switch 86 will monitor this flow and if the flow is above a threshold value, then the switch 86 will return a signal to the boiler 74 to allow the boiler to start and the gas to be ignited. If the flow through the vent 78 is below the threshold value (possibly because the vent has become blocked), then the boiler will not be allowed to start.

Figure 7 also shows a heating element 84 in the air handling unit 80, as it is preferred to include such an element.

Claims (10)

1. The air safty apparatus is a unit for positive air air ventilation and which is made of basic materials ie fan, motor, switches and a heat exchanger fan could have a variable speed motor

2. In Claim one when all these components ie fan, motor etc, are assembled in a special designed casing in the correct order this now becomes the basic air safty apparatus

3. In Claim two the air safty apparatus is designed to fit on a existing air brick (giving ventilation to a required area ie normall house lounge kitchen etc) on the internal side of an outside wall (explained in drawings)

4. In Claim three when the air safty apparatus is fitted to a internal wall there will be access through the unit ie cut out so when the fan runs fresh air will be drawn in from the outside atmosphere by the fan to the required area ie lounge

5.Claim four when the fan is running the air is drawn in (force by the fan) the air pressure will force an electrical switch ie hair switch to make a circuit to a required switch ie gas valve, room stat

6. In Claim four when the air safty apparatus is fitted the unit needs an electrical supply from the unit requiring ventilation ie gas boiler and when in Claim four the switch is made a circuit. this circuit is now the main electrical supply to the required appliance ie gas boiler

7. In Claim six the electrical circuit is made by the fan forcing a hair switch or pressure switch. If the fan fails or the vent (air brick) should get blocked the circuit is broken and the required appliance requiring ventilation fails so that the required appliance will not fire (ie gas boiler without fresh ventilation.The object of the air safty apparatus is to give positive ventilation to a required area with a fuel requiring fresh air to burn correctly

8. A heat exchanger is fitted if required between the fan and the hair or pressure switch and is simply connected to the existing flow and return heating pipes if this is not possibale a electrical element may be fitted as an alternative

9. The air safty apparatus may also incorporate a frost protection device which will be located above the heat exchanger. The frost stat will overide the fan and pressure switch to enable the pipes from freezing

10. Basic operation of air safty apparatus (1) Main switch is calling to bring on appliance ie gas boiler (2) Main switch is commonly a time clock (3) Switch is made and electrical current runs from time clock to air safty apparatus fan (4) Fan triggers hair or pressure switch (5) Switch is now made and electrical current will fire up gas boiler (or oil) (6) When heating is required the air safty apparatus heat exchanger will heat to boiler temp giving heated ventilation thus room temperature rasies quicker