Water Spray Cooler TECHNICAL FIELD

The present invention relates to heat exchangers and, more particularly, is directed towards cooling devices for mines. BACKROUND OF THE PRIOR ART

Increased heat problems are encountered as mines are worked at greater depths. Generally, the working area of the mine is cooled by a heat exchanger having a plurality of cooling coils and fins through which air passes. Heat exchangers of this type suffer from the disadvantage that dust collects on the air side of the fins and results in inefficient operation. Extensive and costly maintenance procedures are required to keep such systems operational. BRIEF SUMMARY OF THE INVENTION

It is an object of the present invention to provide a heat exchanger which does not suffer from the heretofore mentioned disadvantages and limitations. Another object of the invention is to provide ^' a heat exchanger for efficiently cooling the working area of a mine. The heat exchanger embodying the invention is a direct contact air to water spray cooler having a pair of water collecting mesh structures and a nozzle assembly for spraying cool water. One of the mesh structures is adjacent an inlet port of the spray cooler and the other mesh structure is adjacent an outlet port. The nozzle assembly, which is disposed between the mesh structures, mists the air as it is directed from the inlet port to the outlet port. The mesh structure at the outlet collects mist from the exiting air. The mesh structure at the inlet collects large droplets which fall from the misted air. Warm air entering the inlet is cooled as it passes through the cool water spray and through each mesh struc- ture.

Other objects of the present invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the devices, apparatuses and systems, together with their parts, elements and interrelationships, that are exemplified in the follow¬ ing disclosure, the scope of which will be indicated in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A full understanding of the nature and objects of the present invention will become apparent upon consideration of the following detailed description taken in connection with the accompanying drawings, wherein:

Fig. 1 is a perspective view, partly cut-away, of a heat exchanger embodying the present invention; and

Fig. 2 is a sectional view taken along the lines 2-2 in Fig. 1. DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, particularly Fig. 1, there is shown a heat exchanger 10 made in accordance with the present invention. In the illustrated embodiment, heat exchanger 10 is a direct contact air to water spray cooler with a housing 12 having a lower inlet port 14 and - an upper outlet port 16 at opposite ends thereof. Housing 12 includes a central spray chamber 18 that is opened to an inlet chamber 20 and an outlet chamber 22. Inlet port 14 includes a circular to rectangular transition member 24 which is connected to housing 12 at the entrance of inlet chamber 20. Outlet port 16 includes a rectangular to circular transition, member 25 which is connected to the housing 12 at exit of outlet chamber 22. Inlet chamber 20 tapers upwardly and inwardly from inlet port 14 toward the outlet port end of sprayer 10. The lower end of inlet chamber 20 is provided with a sump 52 which collects water and ^" a drain 54 through which excess water and contaminates flow at a regulated velocity. That is, the flow through drain 54 is regulated so that the drain remains relatively full of water and no air escapes through the drain. Outlet chamber 22 tapers downwardly and inwardly from outlet port 16 toward the inlet port end of sprayer 10. A pair of lattice frameworks 26 and 28, for example, egg-crate struc-

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tures, which are mounted in inlet chamber 20, deflect air that enters inlet port 14 from the mine ventilation system or from a blower (not shown) toward spray chamber 18.

Spray chamber 18 includes a framework 30 which carries a support structure 32, for example, a stainless steel mesh frame. A plurality of vertical plates 34, which are dis¬ posed in substantially parallel planes, are mounted to sup¬ port structure 32 and form a plurality of compartments 36. Plates 34 define air flow straighteners that direct the air flow in chamber 20 upwardly into spray chamber 18. A water collecting stratum 38, e.g., a plastic mesh layer, is carried on frame.32 within each compartment 36. A plurality of nozzle -assemblies 40 are connected to a mani¬ fold 42 which is connected to a cold water supply (not shown) via a conduit 43. One nozzle assembly 40 is dis¬ posed in each compartment 36. A plurality of nozzle assem¬ blies 40 are connected to a manifold 42 which is connected to a cold water supply (not shown) via a conduit 43. One nozzle assembly 40 is disposed in each compartment 36. A spray of cool water from each nozzle assembly 40, e.g., a full 46° cone nozzle, is directed upwardly into spray chamber 18 and mists the air that has passed through plastic mesh layer 38.

Upper outlet chamber 22 is provided with a framework 44 that supports a water collecting or mist eliminating stratum 46, for example,' a stainless steel mesh layer. A plurality of nozzle assemblies 48, which are connected to a manifold 49 and the cold water supply via a conduit 50, are directed downwardly towards mesh layer 46. As hereinafter described, nozzle assemblies 48 are provided to back flush and clean mesh layers 38 and 46 of dust accumulation.

As best shown in Fig. 2, the interior sidewalls of housing 12 are provided with a series of outwardly project¬ ing triangular shaped fins 56 that are disposed in substan- tially horizontal rows within spray chamber 18. Any water that has collected on the sidewalls of spray chamber 18 drips toward the tip of fins 56 and into the air stream flowing within the chamber. In the illustrated embodiment,

by way of example, housing 12 is approximately ten feet long, four feet high and one and a half feet wide. Also, in the illustrated embodiment, housing 12 is composed of galvanized steel. .In an alternative -embodiment, housing 12 is composed of a synthetic material, for example a plastic.

In operation of the invention, fresh ventilation air traveling through the mine's ventilation tubing enters cooler 10 through inlet port 14. The air is turned up¬ wardly and evenly distributed by egg-crate structures 26 and 28 which define air guide vanes. As the air moves up¬ wardly through cooler 10, it first passes through mesh layer 38 and through spray chamber 18 where it is misted by the cold water spary from nozzles assemblies 40. Then, the air flows through mesh layer 46 which defines a mist eliminator. The cool air passing through mist eliminator 46 exits cooler 10 through outlet port 16.

It is to be noted that spray cooler 10 provides several stages of cooling and both parallel flow and counterflow cooling. As the incoming air flows upwardly through mesh layer 38, it is exposed to water flowing downwardly through the mesh layer to water sump 52 at the lower end of inlet chamber 20. The downwardly flowing water has f llen from nozzles assemblies 40 or has dripped from either upper mist eliminator 46 or fins 56. Since the downwardly falling water has been exposed to the upwardly flowing air in spray chamber 18, it is warmer than the water spray. However, this falling water is still colder than the incoming air. The air is cooled further as it is passed through the cold water sprays from nozzle assemblies 40 and the water drip¬ ping from mist eliminator 46. The air is cooled even fur¬ ther as it passes through upper mesh mist eliminator 46 which has collected some of the spray water from nozzle assemblies 40. In all cases, heat exchange is accomplished y direct contact between the warm mine ventilation air and the cooler water. For the illustrated embodiment, tests have shown that with an air flow rate of 4,000 cfm, inlet dry bulb temperature of 90°F-93°F wet bulb temperature of

80°F-83°F, the outlet dry bulb and wet bul.t temperatures are 75°F-76°F for an inlet water temperature of 50°F at a

2 flow rate of 12 gal/min. and a pressure of 100 lb/in .

As previously indicated, nozzle assemblies 48 are provided to flush cooler 10 of any accumulated dust.

Generally, the spray from nozzle assemblies 40 is sufficient to maintian mesh layers 38 -and 46 relatively free of dust.

In this way, cooler 10 is substantially self-cleaning.

However, in the event that dust does accumulate, nozzle assemblies 48 are energized to wash out both mesh layers

38 and 46. Inspection windows 58, composed of a transparent plastic, for example, are provided in the sidewalls of housing 12 for examining the condition of plastic mesh 38.

Since certain changes may be made in the foregoing disclosure without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description and depicted in the accompanying drawings be construed in an illustrative and not in a limit¬ ing sense. We claim:

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