VENTILATION DEVICE

Abstract: Ventilation device with a heat exchange element, preferably for arrangement in an outer wall (13) of premises which are to be ventilated with balanced volumes of ambient air (15). The ventilation device comprises two separate ventilation passages (16, 19) with generally identical heat exchange elements (18, 22) at the ends thereof. A fan (24A, 24B) is located centrally between the pair of heat exchange elements in each passage.

Description: Ventilation device Background of the invention The invention relates to a ventilation device with a heat exchanger, more specifically a ventilation device as described in the introductory part of claim 1. The increasing importance of energy saving and demand for air exchange, particularly in polluted premises, has created a demand for efficient ventilation devices with heat exchange. Devices are known which involve an interchange operation wherein during one interval of operation one or more heat exchange elements are heated by exhausting room air and this heat is released to ingoing ambient air in a following interval of operation. Known ventilation devices with reversable fans for simultanously interchanging suction and exhaust, are not able to provide balance in the air delivery when the air direction is changed, as different pressure losses encountered with different directions create unequal air transport volumes. To achieve air balance during operation of the device, .velocity control of the reversable fans is needed. Adjustment of the instant difference in pressure loss by controlling the fan velocity requires complicated and expensive equipment, and is difficult to achieve. The object of the invention The general object of the invention is to provide a ventilation device with heat exchanger as described, being suitable for controlled air exchange with heat recovery in premises having high requirements noise and air balance, e.g. rooms of domestic dwellings. It is a particular object to provide a ventilation device with equal pressure distribution and equal air volumes in both directions and with low pressure losses to enable the use of low noise radial fans. The device should also be of simple construction and be easy to clean and service. The invention The invention is stated in the characterizing clause of claim 1. Further features are stated in the subsidiary claims. Examples In the following, the invention is described further with reference to the drawings, wherein Fig. 1 shows a vertical section centrally through one section of a ventilation device according to the invention, and Fig. 2 shows a front view of the inner part of the device in Fig. 1. In both Figures, a pivotable part of the device is showed by ghost lines in a lowered position. The pivotable section can also be arranged to pivot sideways, or the part including the fans and additional elements can be retracted linearly from the mounted position. This may be arranged to effect opening of the electrical supply circuit by internal contacts or by external switching. The illustrated ventilation device is denoted with reference numeral 11. It is installed in an opening 12 in a wall 13 dividing a room from an ambient area 15. The device can also be installed in a reverse manner. The ventilation device 11 comprises a first set of two identical tube shaped elements 16A and 16B adjacently arranged with parallel axes on a carrying plate 17 flush with the inner ends, and situated close to the inner surface of the wall 13. Inside each of the tupe shaped elements 16A and 16B, a heat exchange element 18A and 18B is arranged. Said elements may be manufactured by helically winding corrugated aluminium foil. Other known heat exchange elements may also be utilized. On the inner side of the tube shaped elements 16A and 16B relative to the room, a second set of tube shaped elements 19A and 19B with a corresponding carrying plate, tube shape and diameter as the first set of tube shaped elements is arranged. The second, inner set of tube shaped elements 19A, 19B are connected to the first elements 16A, 16B by a double hinge, 20A, 20B attached to the carrying plates at the lower edge of the elements. This enables the second set of tube shaped elements 19A and 19B, as well as attached parts, to be pivotted as shown by the ghost lines in the drawing. In the lowered position all parts are easily accessible for cleaning, maintenance and repair. On the inner side of the wall, a support bracket 21 is arranged in a position to support the lowered second set of tube shaped elements 19A, 19B with generally vertical axis. At the end of each of the inner elements 19A, 19B, is arranged a heat exchange element 22A, 22B which closely corresponds to the outer heat exchange elements 18A and 18B. The tube shaped elements in each pair, 16A, 19A, respectively 16B, 19B form a passage 23A, respectively 23B through the wall. Centrally in each passage, is arranged a fan assembly 24 A and 24B, each if which having one or an equal plurality of powered radial fanwheels. The fanwheels may be symmetrial or asymmetrically arranged. Each fan with corresponding motor is mounted on a bracket 25 in an annular opening in a wall extending across passages 23 A and 23B. This enables the passage area to be adapted to the fan cross section. An alternative embodiment for suspending the fan assembly is described in the following. In addition to the illustrated elements, the ventilation device may have cover screens, suitable latches to maintain the inner tube shaped elements in their operating position, drainage outlets etc. The ventilation device is provided with an electrical operating control system providing the following sequence of operations: The fans 24A and 24B are operated at identical speeds with opposite directions of rotation for a period of e.g. 15 seconds, whereafter the direction of rotation of both fans is reversed whereupon the fans operate for a corresponding period. A suction through one passage will be balanced by an equal supply of air through the other. Equal pressure conditions in both passages, independent of the direction of operation, and equal loss of pressure in both passages generally, will ensure balanced volumes of air and permanent even pressure conditons in the premises. The equal pressure conditions are mainly due to the fans being generally centrally located between two generally identical heat exchange elements with both fans being identical and in all phases being operated with the same characteristics with the same inlet and outlet conditions on both sides regardless of the air direction. Alternatives As an alternative to electrically reversing the fans, each fan 24 A, 24B can be arranged to be pivotable in intervals of 180°. In this case, a simultaneous and regular release of the pivoting movement has to be carried out by an electrical operating mechanism and corresponding latches (not shown) at the brackets 25. The brackets 25 may be arranged to turn 180° in a short time movement under the influence of the momentum of the fans. The fans could then rotate continously and unidirectionally. To avoid self rotation, a commmon connecting arm with latches, e.g. operated alternatively byth a solenoid and a spring operated return, can be arranged. As both fans are operated unidirectionally, fans with assymmetrical blades can be used. As in the first example, a time control mechanism is required to control the intervals operation. The central control systems may in both cases be of known construction and no further description is needed. In a further alternative, the ventilation passages are separately arranged in the walls of the premises. A passage may for example be arranged at each end of a wall or in opposite walls. In this way a balanced air exchange with a different air current pattern in the premises is achieved.

Claims: Claims: 1. Ventilation device for arrangement in an outer wall (13) of a room (14) which is to be provided with ambient air (15) with different enthalpy, particulaly at lower ambient temperatures and at higher ambient temperatures and air humidity, wherein each of two ventilation passages (23A, 23B) has a heat exchange element (18, 22) and a fan or a fan assmbly (24A, 24B) connected to a control system for regularly reversing the blow direction, characterized in that each ventilation passage (23A, 23B) has two separate and generally identical heat exchange elements (18, 22) and that the fan or fan assambly (24A, 24B) is arranged generally between the heat exchange elements. 2. Ventilation device according to claim 1, characterized in that each fan (24A, 24B) is arranged in a circular opening (26) in a dividing wall arranged centrally in each ventilation passage (23 A, 23B). 3. Ventilation device according to claim 1 or 2, characterized in that the fans (23A, 23B) are journalled for rotation about a transverse axis, and are provided with a latch device for regularly stopping self rotation at intervals of 180° . 4. Ventilation device according to anyone of the claims 1-3, characterized in that the two ventilation passages are divided lengthwise in two parts (16, 19), and are connected by a hinge (20) to permit pivoting of one part sidewise or downward.

Inventors: NILSEN TROND, NORMANN ERLING C, NILSEN, TROND, NORMANN, ERLING, C.
Applicants: NILSEN TROND, NORMANN ERLING C, NILSEN, TROND, NORMANN, ERLING, C.
Application year: 1992
Main classification: F24F7
IPC codes: F24F7, F24F12