Surgery – Respiratory method or device – Means for supplying respiratory gas under positive pressure
Reexamination Certificate
1998-11-03
2001-04-17
Lewis, Aaron J. (Department: 3761)
Surgery
Respiratory method or device
Means for supplying respiratory gas under positive pressure
C128S204180
Reexamination Certificate
active
06216691
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a mounting body for mounting a flow generator assembly within an external housing and an apparatus for providing breathable gas to a patient.
The invention has been developed primarily for use in breathable gas supply apparatus used in, for example, the Continuous Positive Airway Pressure (CPAP) treatment of Obstructive Sleep Apnea (OSA) and similar sleep disordered breathing conditions. The invention also finds application in breathable gas delivery systems used for assisted ventilation and mechanical respiration.
BACKGROUND OF THE INVENTION
The pressurised gas supplied in CPAP treatment of OSA serves to pneumatically splint open the patient's airways. The pressure of the supplied gas may be constant, bi-level (in synchronism with patient breathing) or auto-setting in level. Throughout this specification any reference to CPAP is intended to incorporate a reference to any one of, or combinations of, these forms of breathable gas supply.
CPAP treatment is generally administered whilst the patient and any bed partner are sleeping. As the gas supply apparatus is normally located within a few meters of the patient it is desirable to minimise the noise produced by that apparatus to minimise sleep disturbance.
CPAP breathable gas supply apparatus generally comprise a plastics housing or casing having a gas flow generator assembly and an electrical control and power supply system therein. A flexible conduit connects the outlet of the apparatus (at a point on the housing) to a nose and/or mouth mask worn by the patient to communicate the supplied gas to the patient's airways.
The flow generator assembly usually consists of a brushless electric motor driving a fan or turbine. The noise produced by the flow generator assembly has three basic transmission paths to surrounding atmosphere. It is radiated from the apparatus housing, transmitted from the turbine outlet to be propagated along the conduit that connects the outlet of the apparatus to the patient mask and transmitted from the turbine inlet to be propagated along the gas inlet path (in the opposite direction to the gas flow) to the housing gas inlet and so to atmosphere.
In a prior art approach, the flow generator assembly has been mounted to the apparatus housing by fastening the turbine housing to mounting feet integrally moulded with the apparatus casing with cushioning rubber washers disposed between the housing and feet. In addition to having acoustic air paths for noise emanating from the flow generator through the conduit and housing, vibration produced by the flow generator assembly is transmitted through the feet to the housing, which acts as a panel radiator, and radiates noise therefrom. The vibration energy reaching the casing can also result in a buzzing noise or the like that can be particularly disturbing to the patient and any bed partner.
An attempt to reduce noise radiated from the housing has involved attaching numerous, for example about ten, blocks of acoustically absorptive foam to the inner surfaces of the apparatus housing. However, this increases the complexity, and thereby the cost, of assembling the apparatus.
Another approach is used in the applicant's bi-level CPAP apparatus model VPAPII. The VPAPII includes a sound enclosure within the apparatus housing having an outlet chamber mounted therein. The metal sound enclosure has a first and second chamber, each having a port to allow the passage of air into the first chamber through to, and then out of, the second chamber. The flow generator assembly and the outlet chamber are located in the second chamber. Air is drawn past a baffle and into the first chamber which includes a step-like labyrinth baffle allowing the free flow of air through the first chamber into the second chamber whilst attenuating the noise from the flow generator assembly propagating along the air inlet path. The internal surfaces of the sound enclosure are lined with sound absorbing polyurethane skinned foam.
In one version of VPAPII, the flow generator assembly is mounted within the sound enclosure and attached to the outlet chamber by a rigid metal mounting bracket. In another earlier version, the flow generator assembly sat on one inner face of the second chamber and was cushioned by EVA foam that was in turn adhered to the second chamber inner face. In both versions, the blower air path outlet is secured to the inlet port of the outlet chamber by way of a silicone rubber conduit.
The outlet chamber is formed as one substantially rectangular chamber moulded from “ignition resistant” ABS. Foam is adhered to the outlet chamber's internal surfaces but otherwise the outlet chamber is ‘empty’ in that it has no labyrinthine or tortuous path.
The VPAPII, whilst being quieter than previous apparatus, requires expensive materials to produce, is complex in both manufacture and assembly and does not allow for rapid reassembly after servicing. It also utilises steel components which are relatively heavy and affect the portability of the apparatus.
It is an object of the present invention to substantially overcome or at least ameliorate one or more of the deficiencies of the prior art.
SUMMARY OF THE INVENTION
Accordingly, in a first aspect, the present invention discloses a mounting body for mounting a flow generator assembly within an external housing, the body being formed from a compliant material and adapted to be fixed with respect to said housing and including a recess of substantially complementary shape to said flow generator assembly to receive and locate same.
In a second aspect, the present invention discloses an apparatus for providing breathable gas to a patient, the apparatus includes an external apparatus housing, a flow generator assembly, and a mounting body of compliant material fixed with respect to said housing including a recess of complementary shape to said flow generator assembly to receive and locate same.
In the present specification, the terminology “compliant material” is intended to encompass any material having the ability to absorb vibrations, for example in the manner of an acoustic dampening foam, as well as being sufficiently structurally rigid to achieve a mounting function and support the weight of the flow generator assembly.
Examples of compliant material are:
(1) Polyurethane, being a foamed thermo-setting plastic. The foam can be, for example, polyester-polyurethane foam or polyether-polyurethane foam; and
(2) An elastomer such as foamed silicone.
Preferably, the mounting body includes one or more external surfaces adapted to be complementary to, and engage with, adjacent internal surfaces of the housing to locate the body with respect to the housing.
The mounting body is preferably produced from a single piece of compliant material. Alternatively, the body may be formed from a plurality of compliant components fitted, adhered or otherwise bonded to one another.
The flow generator assembly is preferably snugly received, and desirably substantially enveloped, within the recess of the body. Any exposed surfaces of the flow generator assembly are preferably covered by a filter foam insert of complementary shape to the recess.
The body is preferably adapted to mount the flow generator in isolation from any contact with the housing.
The flow generator recess in the body preferably includes an orifice for allowing gas to communicate with the inlet of the flow generator,
In an embodiment, the mounting body preferably includes at least one wall disposed, after assembly, adjacent an internal wall of said housing, said body wall including channel means which co-operate with said housing internal wall to provide an inlet duct from atmosphere to said orifice. If desired, a layer of compliant material can be disposed between the housing wall and the body, the layer co-operating with the channel means to form the inlet duct
In another embodiment, the inlet duct is formed internal of the mounting body.
The inlet duct is preferably a tortuous path to reduce noise propagating from the flow gene
Kenyon Barton John
Kwok Philip Rodney
Sapula Marek Tomasz
Virr Alexander
Wickham Peter John Deacon
Lewis Aaron J.
Mitchell Teena
Pillsbury Madison & Sutro LLP
ResMed Limited
LandOfFree
Mounting body does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Mounting body, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mounting body will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2504958