Fluid sprinkling – spraying – and diffusing – Including supply holder for material – Moving solid surface engages material to be sprayed
Reexamination Certificate
2002-05-13
2002-12-24
Ganey, Steven J. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Including supply holder for material
Moving solid surface engages material to be sprayed
C239S349000, C239S533150, C239S571000, C239S583000, C222S383100, C222S385000, C222S401000, C137S533000, C137S533230
Reexamination Certificate
active
06497373
ABSTRACT:
The invention relates to a device for producing high pressure in a fluid. It comprises a piston which is movable in a cylinder, and a valve, both preferably of miniaturised construction. The invention further relates to a high pressure atomiser which contains this device, and the use thereof, preferably for medicinal purposes.
One aim of the invention is to enable a device of this kind and the atomiser containing the device to be made simpler in design and cheaper to produce and suited to its function.
In liquid chromatography (HPLC), for example, generally relatively small quantities of liquid are conveyed at high pressure through the separating column. Moreover, in medicinal aerosol therapy, aerosols are obtained, by atomising or nebulising liquid drugs for treating diseases of the respiratory tract in humans or for treating asthmatic conditions. Here again, a high pressure is required in a, generally relatively small, quantity of fluid in order to produce the small droplet size needed for the aerosol. In the metered dose inhaler according to U.S. Pat. No. 5,497,944, (the entire contents of which are incorporated herein by reference) a predetermined volume of a fluid is sprayed through a nozzle with a small aperture under a pressure of between 5 and 40 MPa (about 50 to 400 bar) to produce an aerosol. The present invention is particularly applicable to such metered dose inhalers and similar devices.
According to one aspect of the invention there is provided a device, preferably of miniaturised construction, for producing high pressure in a fluid, comprising a piston which is movable in a cylinder, a high pressure chamber which is located in front of the piston inside the cylinder, and a valve, which device includes
a cylindrical hollow piston,
a valve member which is guided by the hollow piston and is mounted so as to be axially movable against the hollow piston,
a stop means on the hollow piston which holds the valve member to the hollow piston and
a defined (predetermined) sealing surface at the inlet end of the valve member, the valve member generally being restrained from rotation about any axis transverse to the piston axis.
According to another aspect of the invention, there is provided a device for producing high pressure in a fluid, preferably of miniaturised construction, comprising a cylinder, a hollow cylindrical piston which is movable in the cylinder and provides a path for fluid therethrough, a high pressure chamber which is located in front of the piston inside the cylinder and which is supplied with fluid through said path, and an inlet valve in said fluid path which moves with the piston but is also capable of limited guided movement along the piston axis between a closed position in contact with a valve seat provided by the piston and an open position spaced from the valve seat, the valve member being so shaped and guided that it cannot rotate about any axis transverse to the piston axis such that a predetermined surface thereof engages the seat.
In U.S. Pat. No. 5,497,944, there is described and shown a similar device in which the check valve member is a ball. With such an arrangement, the ball can rotate during multiple operations. It has been found that wear and distortion under the high pressure involved can permanently deform the ball so that if a different part of its surface is used during sequential closing and sealing operations (because the ball is free to rotate about a transverse axis) there is a tendency for leakage to occur. This can be avoided by using the same surface of the valve member each time thus allowing bedding down to ensure the desired seal. In the preferred embodiment according to the invention, at least a major part of the valve member is cylindrical and is guided in a chamber (which may, for example, be the pump chamber itself or may be a part of the interior of the piston) and the valve member cylinder has an end surface which co-operate with the valve seal provided by the piston. Another disadvantage of a ball valve which can be avoided using the invention is that the transverse area of the valve is necessarily considerably smaller than the diameter of the ball and thus the guide cylinder in which it moves; this leads to a reduction in the force applied by the valve member to the valve seat arising from fluid pressure generated during the pressure stroke (forward movement) of the piston. A high application of force of the valve member is desirable to slightly elastically deform the valve member and/or the valve seat to close any slight gaps between them.
In the specification which follows, the terms inlet and outlet side or inlet and outlet end are used in relation to the main direction of flow of the fluid within the device. The term fluid includes both gases and liquids but the present invention is mainly concerned with liquids.
The valve member is somewhat displaceable against the hollow piston but it moves substantially with the hollow piston.
The valve member is preferably uniaxially rotationally symmetrical in shape, e.g. it is a circular cylinder or a frustum. Its cross-section is somewhat smaller than the cross-section of the chamber in which the valve member is movably mounted. This is achieved by means of one or more channels preferably extending in the outer surface of the cylindrical valve member, or by a somewhat smaller diameter of the valve member in relation to the diameter of the chamber in which the valve member is movably mounted.
The valve member is guided in the chamber in which it is movably mounted; a cylindrical valve member can rotate about its axis as required, but its axis always remains parallel to the axis of the hollow piston. This produces a defined sealing surface at the inlet end of the valve member.
The distance over which the valve member can travel relative to the hollow piston is limited by a stop or stop means which holds the movable valve member together with the hollow piston.
In some embodiments of the invention wherein the stop is beyond the outlet end of the valve member, there may need to be at least one recess in the region of the outlet end of the valve member to enable the fluid to flow through between the stop and the valve member when the valve is open. The or each recess is located either in the valve member at the outlet end thereof or in the stop in the hollow piston.
In the position where the valve member abuts on the stop of the hollow piston, the valve is opened. In the position where the valve member abuts on the defined sealing surface, the valve is closed.
A valve member arranged inside the hollow piston has virtually no friction against the inner wall of the hollow piston. A valve member arranged directly in front of the end of the hollow piston may possibly rub against the wall of the main pump cylinder of the device. In this case, the valve is actively closed and opened as the hollow piston moves, on account of the friction between the valve member and the cylinder wall.
The cylinder preferably consists of plastics and the hollow piston of metal or plastics. The material for the valve member is selected, in terms of its hardness, to complement the hardness of the material for the hollow piston and may be metal, ceramics, glass, gemstone, plastics or elastomer. The valve member is preferably manufactured in one piece.
When the fluid is sucked in, the high pressure chamber is connected to the fluid supply by means of the hollow piston. During the intake stroke of the hollow piston the fluid flows through the hollow piston and past the valve member into the high pressure chamber of the cylinder. During the exhaust stroke of the hollow piston the valve seat is sealed in high pressure tight manner against the defined sealing surface of the valve member.
The device according to the invention for producing high pressure in a fluid is connected to the fluid supply at its inlet end. The high pressure chamber is connected to another device into which or through which the fluid is conveyed under high pressure. The hollow piston or the cylinder is attached to a drive which bring
Cirillo Pasquale
Eicher Joachim
Freund Bernhard
Geser Johannes
Jaeger Joachim
Boehringer International GmbH
Ganey Steven J.
Sterne Kessler Goldstein & Fox P.L.L.C.
LandOfFree
Device for producing high pressure in a fluid in miniature does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for producing high pressure in a fluid in miniature, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for producing high pressure in a fluid in miniature will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2993260