Fluid handling – With indicator – register – recorder – alarm or inspection means – Fluid pressure responsive indicator – recorder or alarm
Reexamination Certificate
1999-05-28
2001-03-20
Chambers, A. Michael (Department: 3753)
Fluid handling
With indicator, register, recorder, alarm or inspection means
Fluid pressure responsive indicator, recorder or alarm
C137S883000, C137S884000
Reexamination Certificate
active
06202684
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pressure control system for use for example, in controlling fluid pressure in the pressure pads of an alternating pressure mattress of a medical bed.
2. Discussion of Related Art
A known pressure control system for an alternating pressure mattress is shown in FIG.
1
. The mattress is part of a medical bed and includes two series of inflatable cells which are interleaved, one series within the other. The cells are alternatively inflatable to support a patient at different locations to prevent the formation of decubitus ulcers, known as bed sores.
Typically, inflation and deflation cycles may last from under two minutes to over twenty minutes.
The pressure control system includes a compressor
1
for producing pressurised fluid, typically air, which is coupled to a rotor valve
2
via conduit
3
. The rotor valve
2
couples the air to either one or to both of the first and second supply conduits
4
&
5
. The conduits
3
,
4
&
5
are formed within a manifold which itself is formed from two plate like parts at least one of which includes on an internal surface a recess, the parts being coupled together to provide the conduits.
The manifold also includes a means of connecting directly thereto a fluid source and a pressure control means coupled to the input conduit
3
for controlling fluid pressures in the system. The pressure control includes a single bellows coupled to the input conduit
6
and a discharge conduit
7
able to discharge fluid from the input conduit which operates dependent on the fluid pressure in the bellows. An optional low pressure indicator is also able to be attached to the system which is dependent upon a micro-switch activating when the bellows is inflated or deflated.
Thus the pressure control system has been successful in use. However the pressure control, low pressure indicator and outlets require auxiliary components and tubing to the manifold which can sometimes lead to failures and the tubing provided in the system can be subject to fluid leaks which may be inherent or caused by damage in use.
SUMMARY OF THE INVENTION
The present invention seeks to provide an improved pressure control system.
According to an aspect of the present invention there is provided a pressure control system for controlling the pressure in at least a first and second fluid system, comprising an input conduit for receiving fluid from a fluid source, means for directing fluid from the input conduit to one or both of the first and second supply conduits, and a pressure control housing including a manifold assembly, the said conduits formed within the manifold assembly, the manifold assembly providing a connector interface for supplying fluid directly to the fluid system, a pressure control means coupled to the input conduit for controlling pressure in the fluid system and a low pressure indicator coupled to the input conduit for visual indication of low pressure in the system.
Preferably, the manifold assembly comprises two plate-like parts at least one of which includes on an internal surface thereof recesses, the parts adapted to be coupled together. Thus by use of the manifold assembly forming the conduits and providing connector(s) for supply of fluid directly to the fluid systems, the amount of tubing as required by prior art systems is reduced.
Advantageously, the pressure control means is located at the input conduit to reduce its complexity and is integrated into the manifold assembly for ease of manufacture. In the preferred embodiment, the pressure control means includes a spring housed within the manifold plate-like parts, an adjuster to adjust the biasing force of the spring and a valve means operable to discharge fluid dependent on the pressure in the system.
Preferably, the rotor valve assembly, which is of conventional design, is connected directly to the manifold assembly, further reducing auxiliary components and simplifying manufacture.
Advantageously, the low pressure indicator is integrated into the manifold assembly. The indicator is located at the input conduit and comprises a diaphragm which is adapted for relative movement in relation to the fluid pressure applied to the system. In a preferred embodiment, the low pressure indicator comprises a diaphragm sealed between the two plate-like parts of the manifold assembly, a spring controlling the movement of the diaphragm in response to a pressure applied to the system. The low pressure indication being the relative movement of the diaghragm away from a transparent window, which is also integrated within the manifold assembly.
It will thus be apparent that by integrating the low pressure indicator into the manifold assembly, and not using the bellows as in prior art systems, the system is much simplified.
Therefore, the overall system by integrating the pressure control, rotor valve, low pressure indicator and connectors into one manifold assembly, has a reduced number of component parts thereby simplifying manufacture and reducing costs.
According to another aspect of the invention, there is provided securing means to secure the manifold assembly to the pressure control housing. Preferably, the securing means includes a surround adjacent the connector(s) provided on the manifold assembly, the surround adapted to engage the housing and more preferably the surround is integral to the manifold.
Thus, by incorporating the securing features into the manifold assembly, the amount of tubing and auxiliary. components are substantially reduced.
REFERENCES:
patent: 4253379 (1981-03-01), Olson
patent: 4341237 (1982-07-01), Stauffer
patent: 4606391 (1986-08-01), Achterholt
patent: 4860638 (1989-08-01), Hosono et al.
patent: 5819782 (1998-10-01), Itafuji
Angel Geoffrey Dennis
Kemp Daniel
Brown & Raysman Millstein Felder & Steiner LLP
Chambers A. Michael
Huntleigh Technology PLC
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