WO2001066953A1

WO2001066953A1 - Air conditioning apparatus

Info

Publication number: WO2001066953A1
Application number: PCT/SE2001/000462
Authority: WO
Inventors: Gunnar Berg; Dan ÖRTENGRAN
Original assignee: Pm-Luft Ab
Priority date: 2000-03-09
Filing date: 2001-03-06
Publication date: 2001-09-13
Also published as: AU2001237874A1; SE522560C2; EP1261807A1; AU2001237873A1; NO20024282D0; SE0000788L; WO2001066952A1; NO20024282L; SE0000788D0

Abstract

The present invention relates to an air conditioning plant comprising a fan with double inlet (2), whereby the plant comprises a space (6) which is substantially quadratic in a cross-section perpendicular to the fan shaft (3); that the fan shaft (3) is provided with an engine (8) having direct or belt transmission, whereby the engine (8) is arranged on a foldable bridge (10).

Description

TITLE

AIR CONDITIONING APPARATUS

DESCRIPTION Technical field

The present invention relates to an engine support for belt driven fans, in particular radial fans with double inlet of air treatment apparatus.

The object of the present invention is to obtain an engine support at belt driven fans in order to facilitate a rational maintenance of the fan and engine.

Background of the invention

There are different types of fans present in air treatment apparatuses. The most common one is radial fan with double inlet provided with a helically shaped fan house. Other types are axial fans and chamber fans.

Radial fans with double inlet are built as free standing units. It is common that the fan deliverer delivers these units to different producers of air treatment apparatuses for further installation. The installation measures can vary. Two different types of fan impellers are used in these fans. Fan impellers having blades bent forward, and fan impellers having blades bent backward. Fan impellers having blades bent backward become more and more common due to a better consciousness of energy issues and one requires a higher yield. Fans having blades bent forward have, however, that advantage that they can be manufactured more compact than fans having blades bent backward with regard to a given air flow.

One has high requirements on isolation of vibrations when it comes to a fan unit. To obtain a good isolation space is required between the fan unit and the housing of the apparatus. The height of the fan unit is thereby considerably reduced as space is required both above and under the unit to provide a good isolation.

Radial fans with double inlet having a helical fan house have a high and uneven outlet speed. This requires a straight channel upstream of the fan to minimize systemic losses. The fan allows however different outlet directions, forward, upward, and downward but requires a large space due to the required straight channel after the fan house. The space in fan rooms is, however, normally relatively small and thus one is forced to add an channel bend or another disturbing means such as channel silencer close to fan outlet providing an increased pressure drop as a consequence in spite of the different outlet directions. With regard to axial fans the situation is even more troublesome when only forward exists as outlet direction. Furthermore there is required some sort of flow director not to obtain a rotating flow which gives still higher pressure drop in the subsequent channel system and components.

The space after the fan impeller in a chamber fan can be regarded as a pressure box. The outlet area can be made large and any disturbance, such as a channel bend can be mounted directly at the outlet without any increased pressure drop.

In the Nordic countries one normally provides an air treatment apparatus with some type of heat reclaiming means. One of the most common ones is a rotating heat exchanger. It has the highest temperature yield. A common type of apparatuses are the so called unit apparatuses. These apparatuses are construed with regard to rotating heat exchangers. The cross-section of the apparatus is quadratic and in height, split into two air streams, to and fro streams. The advantage using these apparatuses are that they have an even width and are compact. The same advantages are achieved using a module apparatus if it is similarly construed If all apparatuses can be built as module apparatuses this means a considerable reduction of the number of articles to be produced, as well as the fact the building constructor well knows the measures which will be due.

The working point of a fan in an air conditioning plant is calculated client specifically. Any variation of the working point leads to a variation of the rotational speed and the effect demand of the fan, which in turn leads to a uniquely selected engine and driving conditions. Of these the substantial amounts of radial fans with double inlet of air conditioning plants provided with belt driving to provide a simple adjustment of the rotational speed.

Fans of air conditioning plants are almost solely driven by electric engines which are standardized, easy obtained and do not discard any pollution into the ventilation air stream.

The technical problem Building in of fan units in attic spaces often leads to the fact that the space available for maintenance is restricted, and a demand is thus to obtain fan units which provides for maintenance, including exchange of fan/fan engine in a simple and rational way.

Thus a problem at fan units is the maintenance situation, i.e., the possibilities of cleaning and exchanging engine and fan impeller in a built-in unit, often in a module system, where one has very restricted spaces to work in. Here there are requirements for specific measures to be able to facilitate the work and provide for best possible working environment/working position to the one carrying out the maintenance.

Description of the present invention

It has now surprisingly turned out possible to meet these requirements and to solve outstanding problems by means of the present invention which is characterized in that the engine is placed on a foldable bridge.

By integrating a fan into the plant part there is created more space for a larger diameter of the fan impeller. This also calls for the fact there is space to place the fan impeller in a ring diffusor. Using the diffusor dynamic pressure is recovered as static pressure. This leads to less pressure losses and thereby the yield increases.

The present invention will be described more in detail in the following with reference to the accompanying drawing showing a preferred embodiment of the present invention, however, without being restricted thereto, and wherein FIG. 1 shows a side view of a fan unit, and FIG. 2 shows a detail of the attachment of the engine.

1 denotes a module unit in general, in which a radial fan with double inlet 2 is arranged onto a shaft 3 connected to a belt transmission 4. The radial fan with double inlet 2, which is provided with blades 8 bent backward, is provided with a diffusor created between two diffusor sheets, suitably circular discs whereby the diffusor has a diameter which is at least 50% larger than the diameter of the fan, and preferably 55 to 80 % larger than the diameter of the fan impeller. Outside the diffusor discs there are inlet sheets 9 which are isolated from the inlet wall by means of sleeves and, further there are supply air channels for feeding the fan, which channels end in an inlet opening around the shaft 3 of the radial fan with double inlet. The fan 2 is centrally placed in a space 6 (fan housing) which has a quadratic cross- section in a plane perpendicular to the shaft 3 of the radial fan with double inlet 2. In any direction out from this space there is an outlet opening which normally takes the whole side of the unit 1 in front of the radial fan with double inlet 2. The size of the opening can of course be varied upon demand. A channel tube (not shown) can be connected directly to the opening, whereby such a channel tube can be bent directly if the space thus requires.

The fan 2 is driven by a motor 8 which transfer the rotation to the fan 2 via a belt transmission connected to the shaft 3 of the fan 2.

In a particular embodiment of the invention there is obtained an engine support for radial fan with double inlet in air conditioning plants. For the fan part of an air conditioning plant there are a number of construction requirements, such as that the fan part, i.e., the housing comprising the complete fan with driving unit shall be as short as possible due to the normally existing lack of space to the air conditioning plant; the fan part shall be possible to inspect from alternative sides seen in the direction of the air flow; the fan part shall be belt driven to be able to vary the size of the motor and rotation speed of the fan; fan parts shall be able to be mounted vertically; engine support with its engine is not allowed to influence the inlet flow of the fan aerodynamically; the fan part shall independent of engine support be given a possibility of different outlet directions; fan part with motor shall be vibration isolated; the engine support shall be adaptable to different engines; the engine support shall allow a careful alignment of belt transmission; the engine support shall allow a simple inspection and maintenance of the fan part; and the fan part shall be able to be cleansed.

By tradition the engine is placed on or between beams whereby the beams are vibration isolated on their insides towards the housing of the plant, most often closest to its bottom. Usually, the engine is placed upstream the fan which provides for a simple and rugged construction whereby, however, the drawback is that the fan part becomes longer. Alternatively, the engine can be placed at the side of the fan, but this can only be done when the fan part has enough width. The problem is hereby to make the construction enough torsional stiff without increasing the costs of the construction. At a vertical mounting of the fan part a torsional moment exists due to the weight of the fan insert as the vibration isolation is adapted to a horizontal mounting between beams and the bottom of the plant housing.

If one places a substantially large engine beside the fan part an unsymmetric air flow is created which gives raise to a vortex at the inlet of the fan, which inlet is placed on the engine side, which leads to a reduced fan capacity.

Further the shift of an engine of a fan part an environmental problem as heavy engines shall be placed therein with precision in narrow spaces. In particular fan parts of radial fans with double inlet are difficult to cleanse due to beams and hollow profiles in the building of the plant.

The problem has been solved by placing the engine 8 on a foldable bridge 10. The bridge 10 is thereby mounted on a support 11 comprising two beams 12 running in parallel, which beams 12 at their lower ends 13 are pivotally, rotatably arranged to a holder 14 and at its upper ends 15 are releasably mounted to a holder 16. From a production technical point of view the holders 14 and 16 are identical whereby the mounting of the beams 12 are carried out in different ways. The holders 14 and 16 comprise in this embodiment on one hand a hole 17 for a pivotal, rotational mounting of a journal 18 through the beams 12, on the other hand a slot 19 for tensioning the belt between the engine 8 and the belt disc 4. The engine 8 is thereby secured to the adjustment slots 19 via securing screws 20 running in said slots 19 and which screws are fastened to the upper ends 15 of the respective beams 12. By eliminating the securing screws 20 the engine can be folded forward passing the fan unit 2. The holders 14 and 16 are, in turn, fixedly mounted to a tubular support 11 arranged to receive a torsional moment created by the engine 8 during work. The tubular support 11 is further arranged to the fastening beams of the air conditioning plant via dampening attachments 22 to eliminate vibrations to its support, such as a building.

Claims

1. Air conditioning plant comprising a fan with double inlet (2), whereby the plant comprises a space (6) which is substantially quadratic in a cross-section perpendicular to the fan shaft (3); that the fan shaft (3) is provided with an engine (8) having direct or belt transmission, characterized in that the engine (8) is arranged on a foldable bridge (10).

2. Air conditioning plant according to claim 1, characterized in that said bridge (10) is mounted to a systems of beams (12) which system in its lower end

(13) is pivotally, rotatably mounted in a point (14) and in its upper end (15) is releasably mounted in adjustment slots (19).

3. Air conditioning plant according to claim 1, characterized in that the engine, in vertical direction, is substantially centrally placed regarding the unit having a horizontal air flow.

4. Air conditioning plant according to claim 1, characterized in that the engine support is substantially made of a hollow profile.