Gas separation: apparatus – Apparatus for selective diffusion of gases – Plural separate barriers
Reexamination Certificate
2001-01-16
2003-04-01
Spitzer, Robert H. (Department: 1724)
Gas separation: apparatus
Apparatus for selective diffusion of gases
Plural separate barriers
C095S052000, C096S010000
Reexamination Certificate
active
06540817
ABSTRACT:
TECHNICAL FIELD TO WHICH THE INVENTION PERTAINS
The present invention relates to a hollow fiber membrane dehumidification device that dehumidifies compressed air by means of hollow fiber membranes.
1. Prior Art
Since the compressed air that is employed for a drive source for all kinds of devices becomes the cause of early corrosion of the devices when it contains a large amount of moisture ordinarily it is employed as the drive source after it has been dehumidified by a dehumidifier. A freezing type and an adsorption type are generally adopted for this kind of dehumidification device, but in recent years hollow fiber membrane type dehumidification devices have attracted attention based on the facts that they have been miniaturized, made lighter, and had their maintenance operations simplified.
Previously the above-mentioned hollow fiber membrane dehumidification devices involved as shown in
FIG. 5
the positioning of multiple hollow fiber membranes (
52
) in a housing chamber (
53
) inside a housing (
51
), and the sending in of compressed air from one end of these hollow fiber membranes (
52
), and while this compressed air was caused to flow through the inside the moisture in the compressed air was selectively discharged to the housing chamber (
53
) owing to the pressure difference between the partial pressure of the water vapor of the compressed air and the partial pressure of the water vapor of the outside housing chamber. Then, after the compressed air has been made into dehumidified air by dehumidifying it in this manner, it is discharged from the other end of the hollow fiber membranes, and made into a drive source by emitting it to the air tank at the rear stage, etc. In addition, it has been composed such that it is usually possible to dehumidify the compressed air with an excellent dehumidification function by causing a portion of the dehumidified air that is exhausted to flow back to the housing chamber (
53
) in a fixed constrictor amount through the medium of the reflux route (
54
) as purged air and by maintaining the partial pressure of the water vapor inside the housing chamber (
53
) in a low state by means of this purged air.
2. Problems that the Invention Attempts to Solve
However, as in the above-mentioned prior art, in the case of a composition that causes the reflux of a portion of the dehumidified air by a fixed constrictor amount as purged air, there is the problem that it becomes impossible to emit dehumidified air to the air tank at the rear stage, etc. at a pressure above that prescribed, even in the event that the pressure of the compressed air deviates slightly from the normal fluctuation range and declines.
In other words, when the dehumidified air formed by dehumidifying compressed air is emitted to the air tank at the rear stage, etc., a portion flows back to the housing chamber as purged air, so it causes the pressure to fluctuate while being subjected to the effects of the pressure fluctuations of the compressed air and the pressure fluctuations in response to the reflux amount of the purged air. At this time, when the pressure of the compressed air declines, the reflux amount of the purged air declines together with the pressure of the dehumidified air in tandem with this, so the effect whereby the purged air causes the pressure of the dehumidified air to decline ends up decreasing, but since the constrictor volume of the purged air is fixed the effects of the decline of pressure of the purged air ends up being relatively large in the relationship between the compressed air and the purged air. As a result of this, even in the event that the pressure of the compressed air deviates slightly from the normal fluctuation range and declines, the pressure of the dehumidified air ends up declining by a wide extent due to the effect of the purged air, so when this dehumidification device is incorporated in an air source system it is easy to fall into a fatal state wherein it is not possible to send the dehumidified air to the air tank at the rear stage, etc., at a pressure above that prescribed.
Therefore, the purpose of the present invention is the provision of a hollow fiber membrane type dehumidification device that can emit dehumidified air to an air tank at the rear stage, etc. at the highest possible pressure, even in the event that the pressure of the compressed air has declined by a wide margin.
3. Means for Solving the Problems
In order to solve the above-mentioned problems, the invention is a hollow fiber membrane dehumidification device characterized by the fact that it possesses (a) hollow fiber membranes that cause the compressed air supplied from one end to the interior to flow through and at the same time discharges the moisture in said compressed air to the outside, and by so doing exhausts said compressed air to the other end as dehumidified air; (b) a reflux route that causes a portion of the dehumidified air exhausted from said hollow fiber membranes to flow back to the outside of said hollow fiber membranes as purged air; and (c) a variable restrictor that is provided on said reflux route that increases or decreases the opening-closing volume in accordance with the increase or decrease of the pressure of the compressed air that flows through the interior of said hollow fiber membranes.
In the above-mentioned composition, a portion of the dehumidified air is flowing back as purged air, so the pressure of the dehumidified air undergoes the action of the pressure fluctuations of the compressed air itself supplied from the front stager and that of the pressure fluctuations in response to the reflux amount of the purged air. Therefore, when the constrictor amount of purged air is fixed (fixed constrictor) as in the prior art, the decline in pressure due to the purged air ends up exerting a great action on the decline in pressure of the dehumidified air, even in the event that the reflux amount of the purged air declines in accordance with the decline in pressure of the compressed air itself. As a result of this, when a hollow fiber membrane type dehumidification device is incorporated in an air source system, it is easy to fall into a fatal state as an air source system wherein it is not possible to send the dehumidified air to the air tank at the rear stage, etc., at a pressure above that prescribed, even in the event that the pressure of the compressed air deviates slightly from the normal fluctuation range and declines.
Compared to this, according to the above-mentioned composition of the invention of the present application, when the pressure of the compressed air that flows through the interior of the hollow fiber membranes declines, the opening-closing amount of the variable constrictor decreases, and due to this the reflux amount of the purged air decreases. Owing to this, the decline in pressure due to the purged air is more strongly controlled than in the case of the fixed constrictor, and due to this an excessive decline in pressure of the dehumidified air is prevented. As a result, in the event that a hollow fiber membrane type dehumidification device is incorporated in an air source system, it is possible to send the dehumidified air to the air tank of the dehumidification system at the highest possible pressure even if the pressure of the decompressed air ends up declining to a great extent.
In addition, the invention is characterized by the fact that it possesses (a) a primary flow route and a secondary flow route that split the reflux route into 2 branches; (b) a first orifice that is provided on said primary flow route and that controls the flow of purged air in said primary flow route; and (c) a flow volume regulation valve that has been made capable of opening the valve part based on the opening-closing volume in response to the pressure differential of the purged air that flows back through said primary flow route and said secondary flow route, and that causes said primary flow route to be linked to said reflux route through the medium of said valve part.
According to the above-mentioned composition, since it compr
James Ray & Associates
Nabco, LTD
Spitzer Robert H.
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