GB2205393A

GB2205393A - Ventilating equipment

Info

Publication number: GB2205393A
Application number: GB08708973A
Authority: GB
Inventors: Terence Ernest Adkins
Original assignee: REYCOL SERVICE CO Ltd
Current assignee: REYCOL SERVICE CO Ltd
Priority date: 1987-04-14
Filing date: 1987-04-14
Publication date: 1988-12-07
Anticipated expiration: 2007-04-14
Also published as: GB2205393B; GB8708973D0

Abstract

A ventilator for a clean room comprises a fan (16) located in ducting 10, and a driving motor (26) connected to the fan by a synchronous drive (28). The motor (26) is positioned within a ventilated housing (24) which is positioned within ducting (10) in which the fan (16) is located and from which the smaller housing (24) is sealed. The ventilation air flow through the motor housing (24) via inlets 34 and outlet 38 is kept separate from the flow of conditioned air to and through the fan. The fan (16) and motor (26) are mounted on a common base (12) having anti-vibration mounts (14). <IMAGE>

Description

AIR HANDLING EQUIPMENT SPECIFICATION This invention relates to air handling equipment, and is particularly concerned with an air handling unit adapted for use in laboratories and manufacturing plants where very clean air is needed. In conditioned environments where the air supply must be guaranteed to be ultra-clean, it is necessary to remove from the air supply any potential source of pollutionwhich might enter the conditioned air stream.

For example, one of the problems of conventional systems where one has a fan which is supplying air downstream to the workplace is that the fan is driven by a belt drive from an electrical motor which is positioned adjacent to the fan.

This means that the electrical motor and the belt drive are within the air stream which is feeding through the fan.

Therefore, if there is any problem with the motor or with the belt drive which results in fumes or particles being generated, these fumes or particles will be picked up in the air flow and directed downstream to the workplace. Such fumes and particles can arise from erosion of the drive belt or from motor failure for example.

One conventional way to avoid this problem is to remove the electrical motor and the drive belt assembly from the area where the fan is operating, i.e. outside the air handling unit. However, this gives rise to problems.

Firstly, it is then necessary to have a fairly lengthy transmission system between motor and fan. Secondly, it may then be necessary to weatherproof the motor. Thirdly, if the motor and fan do not run completely synchronously, then problems of vibration can arise, with resultant excessive noise levels. It is known to position a plate separator between the motor and fan assembly, but this also can give rise to serious vibration problems.

It is an object of the present invention to provide an air handling unit by means of which one can ensure that the conditioned air supply delivered by the fan will be unpolluted.

It is a further object of the present invention to provide an air handling unit in which, additionally, vibration is kept to a very low level.

It is yet a further object of the present invention to provide an air handling unit by means of which one can maintain the air supply at a constant flow volume so that a laboratory for example can be kept at a pressure which is slightly greater than atmospheric.

Broadly in accordance with the present invention there is provided an air handling unit in which, instead of taking the motor well away from the fan the motor is kept close to the fan and is ventilated separately.

Broadly in accordance with the present invention the air handling unit comprises a motor arranged to drive a fan wherein the motor is housed within its own sealed, ventilated housing positioned within the general housing in which the fan is located. The motor enclosure is separately ventilated to the ambient atmosphere.

It is a preferred feature of the present invention that the motor and the fan are mounted on a common base within the air handling unit casing, with the base being mounted itself on anti-vibration mounting means. In this way one prevents any differential vibration such as might arise if the motor and fan are mounted on separate subframes. This feature therefore contributes towards smoother running and a less noisy unit.

Preferably, the connection of the motor to the fan is by way of a synchronous drive means which comprises bearing means free from air leakage.

In order that the invention may be fully understood, one presently preferred embodiment of air handling unit in accordance with the invention will now be described by way of example and with reference to the accompanying drawing which is a schematic plan view of the air handling unit.

The air handling unit shown in the drawing comprises a double-skinned casing 10 which is composed of a plurality of connected elements. Within the casing 10 is a base 12 which is supported on a plurality of anti-vibration mounts 14. In this embodiment, six such mounts 14 are shown. The base 12 is thus able to "float" and act as a vibration damping mechanism. Mounted upon the base 12 is a fan, indicated generally at 16. The fan illustrated in the drawing is a standard double inlet, forward curved fan with an extended shaft 18. The flow of conditioned air into the fan 16 for onward delivery downstream is indicated by the arrows on each side of the fan.Between the outlet of the fan and a transverse panel 20 which separates the casing 10 from the downstream passage is a flexible connecting member 22 through which the conditioned air is delivered at constant flow volume.

Also mounted on the base 12 is a sealed housing, indicated generally at 24. This housing 24, as well as being sealed airtight, is also insulated against changes in temperature. Contained within the housing 24 is a motor 26 which serves to drive the fan 16. The drive is by way of a synchronous drive system comprising a belt 28 coupled to the fan shaft 18 by suitable pulley means. A sealed bearing unit 30 is set into the wall of the housing 24 and prevents any leakage of air through this wall. The opposite wall of the housing 24, adjacent to the side wall of the casing 10, is provided with an air inlet which is connected by way of a flexible duct 32 to a fresh air inlet grille 34 in the wall of the casing. The top of the housing 24 is provided with an outlet which is connected by way of an insulated flexible duct 36 to a small extractor fan 38 set into the side wall of the casing.

In use, conditioned air passes into the fan 16 and onward to the downstream point of delivery. The motor 26 is ventilated by the inlet and discharge system associated with the housing 24. The motor air impeller draws fresh air into the sealed housing 24 through the inlet duct 32, and the air is extracted from the housing 24 by the extractor fan 38. Thus, any pollution generated within the housing 24, whether from the motor 26 or from the synchronous drive 28 or from any other source,will be extracted to the ambient atmosphere and will be unable to pollute the conditioned air.

It will be appreciated that with the arrangement of the present invention the motor 26 and synchronous drive 28 are close to the fan 16, thus requiring only a short transmission chain and assisting in the smooth running of the unit, as well as keeping the overall size of the unit to a minimum.

Claims

CLAIMS:

1. An air handling unit comprising a fan and a motor arranged to drive the fan, wherein the motor is housed within its own ventilated housing which is positioned within a larger housing from which the ventilated housing is sealed and in which the fan is located.

2. An air handling unit comprising a fan for delivering a flow of air to an output of the unit, a housing positioned within the air flow to the fan and sealed from said air flow, a driving motor within the housing and connected to drive the fan, and means to maintain ventilation of the housing by an air flow discrete from the air flow to and through the fan.

3. An air handling unit according to claim 1 or 2, in which the housing for the motor is ventilated to the ambient atmosphere.

4. An air handling unit according to any preceding claim, in which the motor and the fan are mounted on a common base support.

5. An air handling unit according to claim 4, in which the base support is mountedonanti-vibration mounting means.

6. An air handling unit according to any preceding claim, in which the housing for the motor has a forced air ventilation system.

7. An air handling unit according to any preceding claim, in which the connection of the motor to the fan is by way of synchronous drive means.

8. An air handling unit according to claim 7, in which the synchronous drive means comprises a belt coupled to a shaft of the motor and to a shaft of the fan by respective pulley means, and bearing means enabling the drive means to pass through the housing wall without air leakage from the housing containing the motor.

9. An air handling unit according to any preceding claim, in which the fan is arranged to deliver conditioned air at constant flow volume.

10. An air handling unit according to any preceding claim, in which the housing containing the motor is thermally insulated.

11. An air handling unit substantially as hereinbefore described with reference to the accompanying drawing.