GB1604277A

GB1604277A - Apparatuses having temperature sensitive elements for controlling dampers in ventilation systems

Info

Publication number: GB1604277A
Application number: GB17532/78A
Authority: GB
Original assignee: TEKNOTERM SYSTEMS AB
Current assignee: TEKNOTERM SYSTEMS AB
Priority date: 1978-03-21
Filing date: 1978-05-03
Publication date: 1981-12-09
Also published as: SE7803220L; CA1125566A; DE2821147A1; SE410803B; FR2420725A2; FR2420725B1

Description

(54) IMPROVEMENTS IN OR RELATING TO APPARATUSES HAVING TEMPERATURE SENSITIVE ELEMENTS FOR CONTROLLING DAMPERS IN VENTILATION SYSTEMS (71) We, TEKNOTERM SYSTEMS AB, a Company duly organized under the Laws of Sweden, of Hans Michelsensgaten 9,5211 20 Malmo, Sweden, do hereby declare the invention for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to an apparatus having a temperature sensing element for automatically controlling a damper in a venting duct of a building.

Outer air that penetrates especially around windows and doors is exhausted as natural ventilation through outgoing air ducts, usually from kitchens, water-closets and bathrooms. A very great percentage of the extant housing, int.

al. practically all detached houses, have natural ventilation systems of this type.

When the outdoor temperature is low and in particular if a wind is blowing at the same time, natural ventilation will be strong and result in great heat losses, unless the outgoing air ducts have draught limiting devices for counter-acting this increase in natural ventilation, which is unnecessary and uneconomical from the point of view of ventilation. It is certainly true that natural ventilation can be limited in winter by manual stepwise or complete shutting of the dampers, if any, in the individual rooms of the dwellings, but this method is impractical and too coarse. It results in either too ample or too meagre a ventilation.

The regulation of the dampers can not become economically efficient unless it is continuously adapted int. al. to weather variations that may occur in the course of the day.

It has already been suggested to arrange closable incoming air ducts and to place in an outgoing air duct a temperature sensing means having a sensitive element which by changing its dimension or configuration due to temperature variations in the ambient air gradually closes or opens a damper so that the amount of outgoing air is controlled to some extent. It has also been suggested to place the temperature sensing means at the outlet of the outgoing air duct so that also the temperature of the outdoor air will become a factor which may affect the dimension or configuration of the sensitive element and the capability thereof to close and open a damper in the outlet.

It has proved, however, that conventional apparatuses for limiting the amount of outgoing air do not realize any really energy-saving draught in the natural ventilation system.

When the outdoor temperature is low and a wind is blowing much more air will be exchanged than at the same low temperature and in calm weather. In dwellings ventilated by natural draught the resulting heat losses during the cold time of the year, i.e. during the sesson when buildings have to be heated, are approximately one third of the total heat losses. In cold weather, indoor air humidity tends to drop to unsanitarily low values. Low air humidity in dwellings during the heating season is experienced by many people as inconvenient. After being heated indoor to room temperature the originally cold air from otuside will acquire an uncomfortably low relative humidity. The greater the exchange of air allowed in cold weather the drier the air in the house.

A third weather factor of importance apart from outdoor temperature and wind force, is the intensity of thermal radiation. With intense solar radiation, the indoor temperature will tend to increase. One way of avoiding this is to increase the amount of outgoing air per unit of time.

The advantages and desiderata outlined above have respectively been eliminated and attained in a considerable degree by means of the apparatus for limiting or controlling outgoing air which is disclosed in GB-PS 1 535 980. This apparatus can control a damper in an outgoing air duct in response to all important factors, such as indoor and outdoor temperatures, wind force and heat and cold radiation.

The present invention has for an object to permit applying a similar control technique also to incoming air ducts, i.e., venting ducts normally leading air from outside to indoor premises, with a view to further reducing total energy production costs.

Thus the object of the present invention is to provide an improved apparatus that will be suited for automatic control of incoming air and for control of outgoing air as required, thereby allowing an effective, automatic optimum limitation of the exchange of air in a building to an economically and physiologically reasonable level regardless of prevailing variations in outdoor temperature and wind force.

Another object of the invention is to provide a compact, functionally reliable and automatically operating apparatus which is capable of keeping the volume of incoming air constant per unit of time and which, if desired, can be utilized to control outgoing air ducts.

For attaining the aforesaid objects the invention provides an apparatus adapted to be connected to a venting duct leading from outdoors to the interior of a building to control the flow of air out of said venting duct, comprising a housing having an inlet for connection to the venting duct and an outlet and defining an airflow passage between the inlet and the outlet, a movable duct closing member for controlling the flow of air through the passage, a temperature sensitive element exposed to a flow of air at the temperature prevailing on the outlet side of the passage and adapted to react to small temperature changes to thereby operate the duct closing member for closing and opening the passage in response to the temperature reactions of the temperature sensitive element, apertures for deflecting a part of the air flowing through the passage to flow into contact with the temperature sensitive element so that both said part flow and the air flow at the temperature prevailing on the outlet side of the passage are allowed to influence the temperature sensitive element and so that the influence exerted by the one of said flows on the temperature sensitive element increases with increasing outdoor wind force whereby the temperature sensitive element tends (a) to close the duct closing member with increasing outdoor wind force and/or decreasing outdoor temperature and (b) to open the duct closing member with increasing indoor temperature and/or decreasing outdoor wind force and/or increasing outdoor temperature, wherein said passage comprises a first chamber interconnecting the inlet and the outlet, and a second chamber separated from said first chamber by a partition containing the said apertures, the temperature sensitive element is arranged in said second chamber and the duct closing member operable by the temperature sensitive element is supported by the housing adjacent the inlet or the outlet thereof.

The apparatus according to the invention can replace or supplement prior art incoming air ventilation systems of the simpler type and also for instance considerably more expensive mechanical ventilation systems, optionally also in combination with heat recovery assemblies, and eliminates their disadvantages, but the apapparatus can also be used in connection with outgoing air ducts. In both cases the apparatus can, also during the cold season or the heating season, keep the exchange of air on an acceptable level with regard to both the temperature variations of the outdoor air and prevailing wind conditions and on an acceptable level also when solar radiation is intense and indoor temperature rises, which is a particularly difficult problem in otherwise cold weather.

When the apparatus is sued in an outgoing air duct, it operates substantially in the same manner as the apparatus disclosed in GB-PS 1 535 980, that is, the deflected part of warm outgoing air and, whereven applicable, cold outdoor wind influence the temperature sensitive element at the same time but in a varying degree depending upon wind force and the temperature and velocity of the outgoing air.

When a strong wind is blowing the temperature effect the wind exerts on the temperature sensitive element dominates and when a weak wind is blowing the effect of the warm outgoing air.

When a strong cold wind is blowing, the damper is closed more than when a weak wind of the same temperature is blowing, since in the first case the part flow of warm outgoing air is not given the possibility of heating the temperature sensitive element so much as it can do in the second case. The result thus is that the heating effect exerted by the warm outgoing air on the temperature sensitive element decreases with increasing wind force and increases with decreasing wind force and that the damper is gradually closed with increasing wind force and gradually opened with decreasing wind force, or is gradually closed with decreasing outgoing air and/or outdoor temperature and gradually opened with increasing outgoing air and/or outdoor temperature.

By reason of its compact construction the apparatus according to the invention is particularly useful in connection with an incoming air duct. From the flow of air which also in this case tends to increase with increasing wind force out-of-doors, there is deflected a part flow into contact with the temperature sensitive element which is thus influenced by the temperature of the cold outdoor air and in dependence on wind force (wind velocity), but the temperature sensitive element is also influenced by the movements of the indoor air (the air in the premises). With increasing wind force outof-doors the influence of the incoming air increases (by increasing flow of air into the passage) in relation to the indoor temperature and, wherever applicable, part of the indoor air flow can be deflected and caused to influence the temperature sensitive element. With increasing wind force and decreasing outdoor temperature the temperature sensitive element as a result is influenced for closing the damper to an ever increasing extent, but the temperature and flow of the indoor air into contact with the temperature sensitive element acts in the opposite direction, that is, for opening of the damper, the result being that the damper is set in a position which is dependent both upon the outdoor temperature and the wind force as well as the indoor temperature and possibly the indoor air flow. As a consequence, there is obtained also in this case the most economical aeration of a room in the building.With an apparatus which permits the area of the apertures for leading warm indoor air into contact with the temperature sensitive element to be preset, and/or presetting of the operating range of the temperature sensitive element separate rooms can be controlled differently and various personal wishes can be satisfied.

As in the apparatus according to GB-PS I 535 980 use can be made, as a temperature sensitive element in the apparatus according to the present invention, of a temperature sensitive bimetal strip shaped into a single helix. Such helix can moreover be arranged in a compact manner within the housing, said housing having walls with openings so arranged therein that air flows are deflected for influencing the temperature sensitive element. By this arrangement there is thus provided a compact apparatus which can be connected to extant venting ducts and can be used both for incoming air and outgoing air ducts.

When used for control of incoming air the apparatus according to the invention can readily be connected to the inner end of an extant incoming air duct such as on the inner side of a venting duct provided in an outdoor wall in conjunction with or near a window. Such a duct may be in the form of a slot in the window structure or in the outer wall in close conjunction with a window. Such ducts are often provided below the window sill and sometimes above the window in dwellings and are usually equipped with a manually adjustable damper. It is then a simple matter to substitute the apparatus according to the invention for said prior art damper.The bimetal element and the duct closing member are preferably mounted in a compact elongate housing which has its inlet arranged for connection with a slot-shaped ventilation opening and its outlet adapted to open into or be connected to the room inside the outer wall. The duct closing member to which the bimetal element is directly or indirectly connected preferably is in the form of a flap which controls the flow through the passage in the housing, and thus the flow between the ventilation opening in the outer wall and th outlet of the apparatus leading into the room inside the outer wall.

An embodiment of the invention will be described in greater detail hereinbelow with reference to the accompanying drawings in which: Figure 1 is a plan view, partly in horizontal section, of a ventilation controlling apparatus according to the invention of the slot covering and uncovering damper type, and Figure 2 is a cross section of the apparatus on line II-II in Figure 1.

In the drawings, 25 designates an outer wall which separates a room 26 in a residential buliding from outdoor air at 27. A horizontal slot 28 is provided in the wall 25 or the window section (i.e. frame and casement), for example above or, as shown, below a window (not shown). The invention is here embodied in the form of a very compact apparatus which is generally designated 30 and includes an apparatus housing 31 with two chambers 32, 33. One chamber 32 is in the form of a passage which is of substantially the same length as the slot 28 and is connected, on the one hand, to the slot 28 via an inlet slot 34 in a bottom plate 35 and, on the other hand, to the room 26 via an outlet slot 36 which is angularly deflected, preferably relative to the inlet 34, in a suitable discharging direction.

The bimetal element 37 is in the form of a single helix and is located in the chamber 33 which is delimited from the chamber 32 by a partition in the form of a rotary sleeve 38 mounted in an internally cylindrical part 31a of the apparatus housing 31. Said part 3 la of the housing 31 has one or more apertures 39, and the sleeve 38 has inlet slots or inlet apertures 40 as well as outlet slots or outlet apertures 41.

The inlet slot 40 connects the main chamber or main passage 32 to the bimetal chamber or bimetal passage 33, and the apertures 41 are in communication with the apertures 39 and via them with the room 26.

The sleeve 38 is rotatable by means of a handle 42 accessible from the room 26 so that the free cross-sectional area of the apertures 39, 41 can be controlled.

One end 37a of the bimetal element 37 is connected to the apparatus housing 31, preferably via a device 43 which permits adjustment of the angular position of the bimetal element in the sleeve 38, while the other end of the bimetal element is connected to an operating arm 37b or constitutes such an operating arm which is adapted to actuate a valve flap 44 shown in Figure 2 by full lines in a fully open position and by dash and dot lines in a fully closed position relative to the outlet 36 of the incoMing air passage 32.

In the illustrated embodiment the valve flap 44 is fixed in the apparatus housing in that an inner bead-shaped edge 44a of the flap 44 is fixed in a seat of circular section in the wall 31 of the apparatus housing. In this case, the flap 44 can be made from elastic material and arranged in such a way as to form an element which by its inherent elasticity tends to return from closed to open position, whereby it is constantly kept in engagement with the birrietal arm 37b; However, the flap 44 may instead be pivotally mounted such that its weight keeps it in engage ment with the bimetal arm 37b. Optionally, the flap 44 can be urged towards open position by a spring (not shown).

The bottom plate 35 of the apparatus housing 31 is meant to be fixed on the wall 25 by means of for example screws 45 and in the em bodiment illustrated has two parallel, inwardly directed ribs 46. Matching grooves are provided at the inner edges of the opposite side walls of the housing 31. With suitably shaped ribs 46 and matching grooves the housing 31 can be readily mounted on the bottom plate 35 by exertion of pressure on the housing for bringing about engagement between the housing 31 and the ribs 46 of the bottom plate. When the housing 31 is made from sheet steel, the bottom plate 35 can be of elastic material, for example plastic, which facilitates the abovedescribed mounting of the housing 31.

As a rule, the bimetal element 37 need not be of as great a length as the apparatus housing 31. In the illustrated embodiment the bimetal element 38 is approximately half the length of the housing 31 and the bimetal arm 37b acts substantially at a point between the ends of the valve flap 44.

In Figure 2 the flow of incoming air from outside is indicated by arrows 50, and the indoor air flow in the room 26 by arrows 51.

Part of the incoming air can flow through the chamber 33 as a part flow 52a, but warm air also can flow from the room 26 through the chamber 33 in the manner indicated by the arrows 52.

The air flows 50-51,52 52a fundamentally correspond to the air flows that may occur in the embodiment disclosed in GB-PS 1 535980.

At increasing wind force outside the wall 25 the flows in the direction 50, 52a may dominate. These cold air flows act upon the bimetal element 37 and cause the damper 36 to close depending upon air volume and air temperature. However, warm air also flows through the bimetel element 37 according to the arrows 52, and the bimetal element is thus actuated also in dependence on the temperature of the indoor air and the damper 44 is therefore adjusted in dependence on both the temperature of the indoor air (warm air) and the temperature and wind force of the outdoor air, whereby the control of incoming air takes both the outer and inner conditions into consideration.

By reason of the possibility to set the throughflows 39, 41 and the angular position (initial position) of the bimetal element 37 in the manner described, the apparatus 30 can readily be adapted to various aeration requirements.

In the illustrated embodiment the apparatus is employed in a room of a residential building with the inlet 34 connected to the slot 28 of the venting duct, but if desired, the apparatus can be placed at the outlet of an outgoing air duct with the inlet 34 connected to the outlet of the outgoing air duct. The construction according to the invention owing to its simplicity and compact design is extremely advantageous and can be utilized instead of the conventional, usually manually adjustable slot covering and uncovering damper type employed in conjunction with apertures in outer walls beneath or above windows.

It is advantageous to use both automatically controlled outgoing air dampers according to GB-PS 1 535 980 and automatically controlled incoming air dampers according to the present invention to realize full selfcontrol of residen tial buildings and other houses. Employed as an automatic incoming air damper the apparatus manages to control and limit the ventilation that arises straight through a house from the windward side to the lee side and that repre sents a large, earlier unchecked item of energy loss where noncontrolled slot covering and un covering dampers are used. The invention is also applicable to fan assisted ventilation systems, which is readily realized by those skilled in the art without any particular description.

In a house having several controlled dampers according to the invention the dampers are closed to a higher extent on the windward side than on the lee side, whereby maximum aera tion will always take place on the most favoured side of the house, which is an important advan tage.

In testing apparatuses according to the present invention it has been found that, serving as control apparatuses for incoming air ducts or ventilation slots in walls, they act surprisingly effectively as sound absorbers of sound that otherwise unim pededly penetrates into rooms through ventila tion slots in the walls of the rooms. An explana tion of this unexpected effect is that the air flow is deflected in the housing 30 and that the housing thereby acts as a sound damper. This sound damping effect can be strengthened by manufacturing the housing from a suitable material, such as plastic.

It should also be mentioned that the auto matically operating apparatus according to the invention when connected to highly placed venting ducts in rooms of residential buildings or other premises eliminate the problem of ar ranging readily accessible operating means, which is so difficult to solve in connection with conventional dampers. If one does not experi ence or attach any importance to such a problem, the duct closing member of the ap paratus can, on the other hand, be connected with a device, within reach of a person in up right position, for manual closing of the duct closing member whenever it is desired to close the venting duct despite the tendency of the bi metal element to keep the duct closing member in open position.

Further, the apparatus can be provided with a device for presetting a range in which the valve flap is automatically controlled by the bi metal element. A device of this kind can con sist for instance of one or a pair of adjustable stops for the bimetal element or the valve flap, or a device 43 for setting the initial position (angle) of the metal element for actuation of the valve flap.

It is also possible to dispose the valve flap in such a manner that, if it is influenced in cold weather, that is, at relatively low outdoor tem- perature, by strong short-duration wind shocks, it can be swung by said shocks towards closed position even if the temperature is not so low that the valve flap is closed by the bimetal element. This possibility is readily realized by a study of Figure 2. Assuming that the temperature sinks so that the bimetal element swings the valve flap closer to the outlet 36, and a strong wind gust occurs, the air pressure against the rear of the valve flap can swing the valve flap towards closed position. When the gust ceases and the wind force sinks the valve flap is returned by spring force, which in the case illustrated is the resilience of the valve flap material in the portion closest to the joint 44a.Flapping of the valve flap is damped by the resistance offered by the spring force.

WHAT WE CLAIM IS:- 1. An apparatus adapted to be connected to a venting duct leading from outdoors to the interior of a building to control the flow of air out of said venting duct, comprising a housing having an inlet for connection to the venting duct and an outlet and defining an air-flow passage between the inlet and the outlet, a movable duct closing member for controlling the flow of air through the passage, a temperature sensitive element exposed to a flow of air at the temperature prevailing on the outlet side of the passage and adapted to react to small temperature changes to thereby operate the duct closing member for closing and opening the passage in response to the temperature reactions of the temperature sensitive element, apertures for deflecting a part of the air flowing through the passage to flow into contact with the temperature sensitive element so that both said part flow and the air flow at the temperature prevailing on the outlet side of the passage are allowed to influence the temperature sensitive element and so that the influence exerted by the one of said flows on the temperature sensitive element increases with increasing outdoor wind force whereby the temperature sensitive element tends (a) to close the duct closing member with increasing outdoor wind force and/or decreasing outdoor temperature and (b) to open the duct closing member with increasing indoor temperature and/or decreasing outdoor wind force and/or increasing outdoor temperature, wherein said passage comprises a first chamber interconnecting the inlet and the outlet, and a second chamber separated from said first chamber by a partition containing the said apertures, the temperature sensitive element is arranged in said second chamber and the duct closing member operable by the temperature sensitive element is supported by the housing adjacent the inlet or the outlet thereof.

2. An apparatus as claimed in Claim 1, wherein the housing is elongate and substantially tubular having the end walls and the inlet is formed by an elongate aperture in one side of the housing, and the partition comprises a tubular element disposed within the housing on the side thereof opposite to the inlet, the interior of said tubular element forming said second chamber, the first chamber being a space between the tubular element and the inlet of the housing.

3. An apparatus as claimed in Claim 2, wherein the temperature sensitive element is a helix-shaped bimetal element which has substantially the same diameter as the inner diameter of the tubular element minus a sufficient amount to give the bimetal element the requisite mobility in the tubular element, one end of the bimetal element is preferably adjustably connected to the housing or to the tubular element, while the other end of the bimetal element has or is connected to a protrusion which extends through the opening interconnecting said second chamber and said first chamber, and which constitutes a means for actuation of the duct closing member.

4. An apparatus as claimed in Claim 2 or 3, wherein the outlet of the apparatus is an elongate aperture in the wall of the tubular housing opposite said first chamber, and the duct closing member is in the form of an elongated valve flap which is disposed on the inner side of the housing and is pivotally mounted in said first chamber toward and away from the outlet of the apparatus for controlling the cross sectional area of the outlet.

5. An apparatus as claimed in any of Claims 24, wherein the tubular element and the housing, in a semicylindrical part of the housing wall enclosing the tubular element, have apertures for connecting said second chamber to the outer side of said housing.

6. An apparatus as claimed in Claim 5, wherein the tubular element is mounted for rotation in said housing and adjustable by an adjusting device to permit relative adjustment of said apertures for connecting said second chamber to the outer side of said housing so that the passage through these apertures can be closed and opened, as desired.

7. An apparatus as claimed in any of the preceding claims, wherein a manual closing or presetting device is connected to the duct closing means.

8. An apparatus as claimed in any of the preceding claims, wherein said housing in the area of the inlet has a mounting plate which has an opening for the connection of said housing to the inlet from said venting duct, and said housing and said mounting plate are provided with means for releasably mounting, for instance clamping, said housing to said mounting plate.

9. An apparatus as claimed in Claim 4, wherein the valve flap is provided with a springloaded hinge means and is adapted to be actuated by the temperature sensitive element against the action of the spring force.

10. An apparatus as claimed in Claim 9, wherein the hinge means and the spring load are

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. weather, that is, at relatively low outdoor tem- perature, by strong short-duration wind shocks, it can be swung by said shocks towards closed position even if the temperature is not so low that the valve flap is closed by the bimetal element. This possibility is readily realized by a study of Figure 2. Assuming that the temperature sinks so that the bimetal element swings the valve flap closer to the outlet 36, and a strong wind gust occurs, the air pressure against the rear of the valve flap can swing the valve flap towards closed position. When the gust ceases and the wind force sinks the valve flap is returned by spring force, which in the case illustrated is the resilience of the valve flap material in the portion closest to the joint 44a.Flapping of the valve flap is damped by the resistance offered by the spring force. WHAT WE CLAIM IS:-

1. An apparatus adapted to be connected to a venting duct leading from outdoors to the interior of a building to control the flow of air out of said venting duct, comprising a housing having an inlet for connection to the venting duct and an outlet and defining an air-flow passage between the inlet and the outlet, a movable duct closing member for controlling the flow of air through the passage, a temperature sensitive element exposed to a flow of air at the temperature prevailing on the outlet side of the passage and adapted to react to small temperature changes to thereby operate the duct closing member for closing and opening the passage in response to the temperature reactions of the temperature sensitive element, apertures for deflecting a part of the air flowing through the passage to flow into contact with the temperature sensitive element so that both said part flow and the air flow at the temperature prevailing on the outlet side of the passage are allowed to influence the temperature sensitive element and so that the influence exerted by the one of said flows on the temperature sensitive element increases with increasing outdoor wind force whereby the temperature sensitive element tends (a) to close the duct closing member with increasing outdoor wind force and/or decreasing outdoor temperature and (b) to open the duct closing member with increasing indoor temperature and/or decreasing outdoor wind force and/or increasing outdoor temperature, wherein said passage comprises a first chamber interconnecting the inlet and the outlet, and a second chamber separated from said first chamber by a partition containing the said apertures, the temperature sensitive element is arranged in said second chamber and the duct closing member operable by the temperature sensitive element is supported by the housing adjacent the inlet or the outlet thereof.

constituted by a flexible resilient wall portion of the valve flap close to an edge portion of said valve flap, which is secured to the valve housing.

11. An apparatus as claimed in any one of the preceding claims, wherein the apparatus is mounted in direct conjunction with a slitshaped ventilation aperture, preferably a ventilation aperture in conjunction with a window or a wall close to a window.

12. An apparatus as claimed in any one of the preceding claims, wherein the inlet and the outlet of said housing are so arranged that the flow of air is angularly deflected in said first chamber before it escapes through said outlet, on the one hand, to realize a sound damping effect and, on the other hand, to lead away the flow of air in the desired direction.

13. An apparatus as claimed in any one of the preceding claims, wherein the duct closing member is so arranged in said housing that in partially closed position said duct closing means can be swung against the action of an elastic force towards closed position by strong wind gusts through the inlet of said housing.

14. An apparatus adapted to be connected to a venting duct leading from outdoors to the interior of a building to control the flow of air out of said venting duct, substantially as hereinbefore described with reference to the accompanying drawings.