US3616615A

US3616615A - Colloidal droplet collector

Info

Publication number: US3616615A
Application number: US857076A
Authority: US
Inventors: Robert L Woodbury
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1969-09-11
Filing date: 1969-09-11
Publication date: 1971-11-02
Anticipated expiration: 1988-11-02

Abstract

AN APPARATUS FOR THE DIRECT INTERCEPTION OF LIQUID WATER FROM CLOUNDS COMPRISING AN ARRAY OF OPEN END DUCTS IN JUXTAPOSITION, A GRID POSITIONED IN FRONT OF THE ARRAY, AND COLLECTING MEANS POSITIONED AT THE BOTTOM OF THE ARRAY.

Description

NOV. 2, 1971 R. WQODBURY 3,616,615

COLLOIDAL DROPLET COLLECTOR Filed Sept. 11, 1969 INVENTCR 8 25 Kobe/"f L.6/000by 26 [m- J 52W, W WWW ATTORNEY).

United States Patent 01 3,616,615 Patented Nov. 2., 1971 3,616,615 COLLOIDAL DROPLET COLLECTOR Robert L. Woodbury, Darlington, Md., assignor to the United States of America as represented by the Secretary of the Army Filed Sept. 11, 1969, Ser. No. 857,076 Int. Cl. B01d 46/00 US. Cl. 55-278 3 Claims ABSTRACT OF THE DISCLOSURE An apparatus for the direct interception of liquid water from clouds comprising an array of open end ducts in juxtaposition, a grid positioned in front of the array, and collecting means positioned at the bottom of the array.

The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to an apparatus for the direct interception of liquid water from clouds.

The obtainment of an adequate supply of water is a problem, for example, in miliary camps and fortifications on the mountain tops in South Vietnam. South Vietnam has two major weather patterns, the Northeast Monsoon from mid-October to late March and the Southwest Monsoon from mid-May to mid-October. In the Northeast Monsoon, warm moist air comes off the South China Sea. During the Southwest Monsoon, warm moist air comes off the Gulf of Siam.

As the result of this warm moist air, orographic clouds form and provide almost permanent cover over the mountains. These clouds are constantly being formed as the adiabatically cooled water vapor condenses at the upwind end of the cloud to form droplets. These droplets evaporate at the downwind end as the cooled cloud goes down the mountain and is again warmed. Such clouds are colloidally stable and do not produce rain.

It is an object of this invention to provide and disclose a simple apparatus and method for the extraction of water from clouds.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims taken in conjunction with the accompanying drawing in which:

FIG. 1 shows an upwind, prospective view of the droplet collector.

FIG. 2 shows downwind, prospective view of an alternative design of the droplet collector.

Referring now to FIG. 1 of the drawings, the present collector comprises an array of tubes or ducts 10 in juxtaposition. Illustrative, but without limitation, the present ducts are approximately square, e.g., by 5", and 50" in length, and open at both ends. The ducts may be con structed of any suitable material having wettable and aerodynamically rough surfaces so that an appreciable drag is produced when the moisture-laden air flows therethrough. The present collector utilized ducts constructed of Tulle. However, netting, plastic and metal screening have been found operable. .In addition to being easily wettable, the opening through the netting or screening are required to be large enough to allow water to flow and small enough to be bridged by a capillary film of water so that water impinging on the ductwall can flow downward in response to the pull of gravity.

Grid 12 is positioned in front of ducts 10. A segment of grid 12 has been stripped from the front of ducts in FIG. 1 in order to more clearly show said ducts. The grid may be constructed of a material identical to the ducts 10. The mesh length of grid 12 is in the region of about to of the size of ducts 10. The ducts may be inclosed on four sides by Waterproof sheath 14 as shown in FIG. 1. The sheath may be constructed of any suitable material, e.g., plastic, metal or wood The present collector utilizes a sheath of water repellant, ounce per yard spinnaker cloth.

Integral sheet 16, which extends from the bottom of the collector, is utilized to collect and conduct the Water to a place of storage or usage. Sheet 16 may be constructed of the same or similar material used in sheath 14.

A framework comprising 4 elongated vertically positioned stakes, designated 18, having traverse supports 20, is utilized to support the collector. The framework may be constructed of any suitable material common to the area, e.g., bamboo. Sheath 14 may be secured to the framework by any suitable means, e.g., ropes. Integral sheets 16 is supported by stakes 22. Sheet 16 may be secured to stakes 22 by any suitable means, e.g., ropes. The framework is supported by guywires 24 secured to ground stakes 26.

In the alternative, sheath 14 may be dispensed with as shown in FIG. 2. In addition, rigid elongated bars 28 may be attached to the edges of integral sheet 16 in order to provide an adjustable collecting means.

In addition, the effective cross sectional area at the up wind end of the collector may be increased by attaching truncated four-sided pyramidal structure 30 to the apparatus in order to increase the swept area, thereby increasing the arnount of water collected.

In operation, the collector is erected at an altitude above the highest level the bottom of the cloud reaches during the warmest portion of the day. As the moistureladen air moves through the ducts, the introduction of grid 12 at the upwind region of ducts 10 produces a von Karman vortex street. This vortex street increases the probability of droplets coalescing. The coalesced droplets will fall out, thereby reducing the loss of droplets that neither Wet the wall or normally coalesce. The introduction of a grid of the designated size in front of the array, results in each duct of the current device having turbulent flow for the greater part of its length, with homogeneous flow not established until the ends of the ducts have been reached.

The von Karman vortex street is described by A. M. Kuethe and I. D. Schetzer in Foundations of Aerodynamics, Section 14.1 and 16.2, 1950. At the wind velocities that can normally be anticipated, i.e., 1 to about 20 knots, collection of almost all of the available water in the moisture-laden air occurs.

Although I have described my invention with a certain degree of particularity, it is understood that the present disclosure has been made by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention.

Having described my invention, I claim:

1. A collector system for the direct interception of liquid water from clouds comprising an array of open end ducts in juxtaposition, a grid positioned on the external upwind side of the array of ducts, the ducts being constructed of a material having wettable and aerodynamically rough surfaces so that an appreciable drag is produced when moisture-laden air flows through, the opening through the material being large enough to allow collected water to flow downward in response to the pull of gravity, and means extending from the bottom of the system to collect the water.

2. A collector system in accordance with claim 1 wherein the mesh length of the grid is in the region of about to of the size of the ducts.

3. A collector system in accordance with claim 1 com prising a truncated four-sided pyramidal structure attached to the apparatus at the upwind section thereof.

References Cited UNITED STATES PATENTS Schmidt et al. 55-135 Bradley 55-157 Seipp 55-157 Hawley 55-396 X Beaver 55-119 Vlier, Jr. 55-126 X Boles 55-154 X FOREIGN PATENTS France 55-T CE DENNIS E. TALBERT, ]R., Primary Examiner US. Cl. X.R.