GB2483275A - Housing with air vents that resists water ingress and suitable for an electronic controller - Google Patents

Abstract

An electronic controller comprising: a housing comprising rear 1 and front 3 mouldings enclosing a PCB 2 with a cover 4. At least one air vent 5 is formed in the housing and permits air flow from the exterior to the interior of the housing. The vent comprises a passage 6 between entrance 7 and exit 8 openings having at least one bend 9 arranged such that no line of sight exists between openings and thus from the exterior to the interior. The passage may have multiple bends and have a Z-shape (see figures 4 and 5 for variations). These vents thus limit external water ingress allowing the controller to be installed in areas where splashing water is possible. Preferably the passageway 6 in the vents 5 is orientated so that the bend 9 leads upwards when the housing is installed in use.

Description

Electronic Controller This invention relates to an electronic controller which provides an improved barrier to water ingress. Preferred embodiments of the invention relate to a thermostat ventilation system.

Control systems which include relays for switching medium to high loads (more than I amp) must include a ventilation system to keep them from both overheating and damaging the internal electronics as well as skewing the readings taken by internal or nearby thermistors. Most thermostats which carry a load ventilate themselves via a collection of holes built into the plastic housing of the thermostat itself. These holes allow cooler air to enter and warmer air to escape. Unfortunately, these same holes allow water to potentially enter the controller, damaging the unit and causing a potential safety hazard. Though some controflers have gone some way towards minimizing the amount of water that can enter the unit by limiting the size, location and angle of the ventilation slots, most thermostats provide only enough protection to stop vertical drips of water from entering. This limitation forces the installer to locate the thermostat well outside the range of any splashed water; bathrooms for example. Locating such controllers outside the bathroom is inconvenient to the user.

Considered broadly, vents according to the invention are of a type that limit water ingress to a greater extent than those currently employed, allowing them to safely be installed in areas where splashing water is possible. This ventilation system preferably comprises multiple vents, arranged side-by-side. Each vent may comprise an opening on the outside of the plastic housing of the controller, not more than 2mm across. These openings preferably lead to a multi-angled channel leading to the interior of the stat. The pathway of the individual channels is such that there is no straight line of sight path from the exterior to the interior of the controller. In profile, the paths may appear to be somewhat "1.-shaped" or "V-shaped". All openings and pathways are preferably angled upwards in relation to the vertical access. The advantage is that there is no unobstructed pathway for water to enter the stat and that water droplets will be forced from the pathways by gravity.

According to a first aspect, there is provided an electronic controller comprising: a housing; and at least one air vent formed in the housing and permitting air flow from the exterior of the housing to the interior of the housing, wherein the at least one air vent comprises a passage with an entrance opening and an exit opening and at least one bend, wherein the bend is arranged such that no line of sight exists between the entrance opening and the exit opening.

As there is no line of sight between the entrance opening and the exit opening, sprayed water cannot directly enter the interior of the unit from the exterior of the unit. This allows the unit to gain a higher ingress protection (IP) rating and allows the controller to be mounted closer to sources of water than would otherwise be allowed, for example the controller may be mounted within a bathroom rather than outside the bathroom, thus allowing electrical appliances (e.g. heated floors, heated towel rails, lighting, etc.) to be controlled and adjusted from within the bathroom without contravening electrical regulations. In the preferred embodiments of the invention, the controller can provide an IP rating of 1P21, more preferably 1P22 and yet more preferably a higher P rating.

Preferably at least one bend in the passage causes the passage to turn through at least degrees. This causes any object passing through the passage to lose a significant quantity of momentum. This reduces the chances of objects passing from the exterior to the interior of the unit even through indirect pathways, e.g. due to reflection off the passage walls.

The bend is preferably an angled bend. An angled bend causes more abrupt changes in direction as opposed to a smoothly curved bend, and thus further reduces the chances of guiding objects from the exterior to the interior of the unit.

The passage preferably comprises a plurality of bends. Although one bend may be sufficient in certain circumstances, for further protection against fluid ingress, a plurality of bends can be provided for taking more momentum out of the incoming fluid. This can protect the device against spray from higher pressure sources. More preferably, two bends are provided which are opposite in direction so as to form the passage into a "Z" shape. This causes multiple changes in direction for incoming fluid and corresponding energy losses and reductions in momentum, thereby reducing the chances of incoming particles transferring from the outside to the inside of the controller.

Preferably at least one section of the passage extends substantially vertically. With this arrangement, any incoming particle must traverse a section of passage against gravity.

Larger, heavier particles are less likely to have sufficient energy to surmount such an obstacle and are thus prevented from entering the interior of the unit.

Preferably at least one bend in the passage is arranged such that, in use, it causes a horizontal component of air flow through the passage to change direction. As described above, this reduces the momentum of incoming particles as energy is absorbed in the reflection processes. -Preferably a section of the passage adjacent to the entrance opening is arranged such that it slopes upwardly in use. With this arrangement, heavier particles which have been prevented from entering the unit fall back down under gravity and the slope ensures that these particles are directed back out of the passage via the entrance opening and do not block the passage against further air flow.

Preferably the controller comprises a plurality of vents. A plurality of vents allows greater movement of air in and out of the controller, thereby allowing for a greater cooling capacity. Also, if one vent becomes blocked, the remaining vents are still free to cool the unit and prevent the internal electronics from overheating.

Preferably the controller comprises at least one vent on each side of the controller. This encourages air flow to enter the unit from different or alternative directions and reduces the likelihood that the vents can end up in a stagnant patch of air, e.g. due to certain turbulence conditions.

Preferably the controller comprises at least one vent in the bottom of the controller. The bottom of the controller is the least likely area to be sprayed with water in normal use within a domestic bathroom and is therefore least likely to be blocked or restricted by water flows. Also, air rising in a hot environment will naturally be drawn into the controller through the bottom vents.

Preferably the controller is a thermostat controller. More preferably the controller is arranged to control an underiloor heating system.

Preferred embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings in which: Fig. I is a semi-diagrammatic, exploded view of a thermostat housing according to one embodiment of the invention, showing the vents as part of the rear moulding (1); Fig. 2 is an angled side elevational view, with some parts deleted for clarity of illustration, of the thermostat of Fig. 1 in assembled condition; Fig. 2A is a side view of the assembled thermostat, similar to Fig 2; measurements shown are in mm; Fig. 3 is a transverse cross-sectional view, showing measurements in mm; Fig. 4 is a cutaway close-up view of the vent arrangement; and Fig. 5 is a view similar to Fig. 4 illustrating an alternative embodiment.

As shown in Fig. I a thermostat controller comprises a rear moulding 1, a printed circuit board 2, an front moulding 3 and a face plate 4. The printed circuit board 2 is mounted behind the face plate 4 and the face plate 4 is mounted in the front of the front moulding 3. The front moulding 3 is then mounted onto the rear moulding I so as to form a housing for the printed circuit board. The vents 5 are formed by the front housing 3 and the rear housing I and provide fluid passageways 6 between the interior and the exterior of the housing.

In the particularly advantageous embodiments of the invention described here, the ventilation system is comprised of four sets of vents 5; one set on each side (eight vents per side) and two sets in the bottom in groups of six, set opposing each other. The vents are formed by the assembly of the front moulding 3 and the rear moulding 1, whereby the rear moulding creates three sides of the rectangular vent tubes 5 with the front moulding 3 providing the fourth side.

The left, right and bottom vents are identical except for their orientation. The right vents open to the right of the thermostat housing; the left vents open to the left of the thermostat housing. The two sets of bottom vents open downward. The pathway of the assembled individual right-hand vent tubes 5 begins with an opening of 6 mm wide by 2 mm high located on the right-hand side of the thermostat housing. The eight vents occupy the top two thirds of the side of the thermostat. The tubes continue upward at an angle of 30 degrees from horizontal for a distance of 6 mm before turning vertical for a distance of 4 mm upon which the exit point of the tube is reached. The tubes form a straightened 2-shape" when viewed in profile. The exit opening is 2 mm high by 6 mm wide and is vertically positioned. The eight vent openings are located 4 mm apart from each other. The left-hand vents are the mirror image of the right. The bottom vents shown in Fig. I are straight holes without bends as ingress protection is less important on the underside. However, for better ingress protection from underneath, it is preferred that the six right-hand bottom vents are identical to the right-hand side vents rotated 90 degrees clockwise. The left-hand bottom vents are mirrored versions of the right-hand bottom vents. The horizontal walls of all vents are 1 mm in thickness.

It will be appreciated that in the above description, the terms top, bottom, left, right, front and rear are all used in relation to a controller mounted in its normal, in use, orientation on a wall. The invention is not limited to the controller in use and the terms are used simply to define the relative orientations of the various components and features.

In the embodiment of Fig. 4, it can be seen that the vents 5 each comprise a passage 6 for passage of air from the exterior of the unit to the interior of the unit. Air enters the passage 6 through an entrance opening 7 and exits the passage 6 through an exit opening 8. The passage 6 comprises at least one bend 9. The bend 9 directs the air generally upwards (i.e. contrary to the direction of gravity).

It can be seen that the bend 9 ensures that no line of sight exists between the entrance opening 7 and the exit opening 8. This arrangement means that sprayed water from any direction cannot enter the interior of the controller directly.

It can also be seen that the slope of the passage 6 is such that any water entering the passage 6 in use will drain out under gravity, i.e. the passage 6 slopes upwardly as it passes away from the entrance opening 7.

In the embodiment of Fig. 5, the passage 6 comprises at least one bend 9. The bend 9 directs the air beyond vertical, i.e. the air is forced to change its horizontal direction of travel (i.e. its horizontal component of velocity is forced to change direction). This is achieved by forming the passage in the shape of a "V' or "L" in cross-section with a protrusion 10 protruding into the interior of the "V" or "12'.

These arrangements prevent heavier particles such as water droplets from entering the interior of the controller housing, while still allowing the much smaller and lighter air particles to navigate the passage against gravity and thus provide cooling to the electronics within the controller housing.

It will be appreciated that the description above his been given with reference to a thermostat controller as such controllers are often used to control bathroom (or other wet room) equipment. However the invention relates generally to electronic controllers and is not limited to use on thermostats. Such controllers may also be used to control humidifiers I dehumidifiers, fans, lighting, etc.

Claims (11)

1. Claims: 1. An electronic controller comprising: a housing; and at least one air vent formed in the housing and permitting air flow from the exterior of the housing to the interior of the housing, wherein the at least one air vent comprises a passage with an entrance opening and an exit opening and at least one bend, wherein the bend is arranged such that no line of sight exists between the entrance opening and the exit opening.
2. 2. An electronic controller as claimed in claim 1, wherein at least one bend in the passage causes the passage to turn through at least 60 degrees.
3. 3. An electronic controller as claimed in claim I or 2, wherein the bend is an angled bend.
4. 4. An electronic controller as claimed in any preceding claim, wherein the passage comprises a plurality of bends.
5. 5. An electronic controller as claimed in claim 4, comprising two bends which are opposite in direction so as to form the passage into a "Z" shape.
6. 6. An electronic controller as claimed in any preceding claim, wherein at least one section of the passage extends substantially vertically.
7. 7. An electronic controller as claimed in any of claims I to 5, wherein at least one bend in the passage is arranged such that, in use, it causes a horizontal component of air flow through the passage to change direction.
8. 8. An electronic controller as claimed in any preceding claim, wherein a section of the passage adjacent to the entrance opening is arranged such that it slopes upwardly in use.
9. 9. An electronic controller as claimed in any preceding claim, comprising a plurality of vents.
10. 10. An electronic controller as claimed in claim 9, comprising at least one vent on each side of the controller.
11. 11. An electronic controller as claimed in any claim 9 or 10, comprising at least vent in the bottom of the controller.