US1757081A - Wet-bulb thermostat - Google Patents

Description

May 6, 1930. w. FLEISHER WET BULB THERMOSTAT Filed Nov. 23, 1927 2 Sheets-Sheet l INVF"TOP.

ATTORNEYS.

May 6 1930. w. FLEISHER 1,757,081

WET BULB THERMOSTAT Filed Nov. 23, 1927 2 Sheets-Sheet 2 a INVENTOR. Mu ax-WV A TTORNEYS.

' ratus should be small so that the actual mois- Patented May 6, 1930 UNITED STATES PATENT OFFICE,

WALTER L. FLEISHER, OF NEW YORK, N. Y., ASSIGNOR TO THE COOLING & AIR CON- DITIONING CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK WET-BULB THERMOSTAT Application filed November 23, 1927. Serial No. 235,357.

This invention relates to ventilating system and with regard to its more specific features to apparatus responsive to the wet bulb temperature within an enclosure, either for the purpose of indicating that temperature or for the purpose of operating other apparatus accordingly.

In modern ventilating systems it is recognized that two of the most important factors involved are the total heat content, and the moisture content, of the air. These are closely related and the accurate determination of either generally involves a measurement of the wet bulb temperature of the air.

In many ventilating systems, the air brought into and out of the room is conditioned by having its moisture content and its temperature, adjusted in accordance with both the wet and dry bulb temperature of the air. Accurate maintenance, however, of the conditions is dependent upon theaccuracy of the reading of the wet and dry bulb temperatures. The wet bulb instrument, however, when constructed as an ordinary thermometer or thermostat having a wet covering upon the thermo-responsive element, over which the air passes, has many limitations which affect the accuracy, for if the wick or cloth or porous sleeve becomes clogged with dust or dirt its capillary action is affected and the evaporation from its surface no longer maintains the elements at the wet bulb temperature. a

In accordance with this invention, it has been found that a true reading of the wet bulb temperature may be obtained by measuring the temperature of a small bod of water which has been brought into intimate and efiicient contact with the air to be measured. This contact results in the water assuming the wet bulb temperature even though it be 1nsufficient to bring the air to the .wet bulb temperature if the water be small enough 1n quantity to respond readily to temperature changes. Where the apparatus is used for measuring the temperature of the atmosphere within a room, it is preferred that the appature given off to the room is not a material room and so that the water supply is not lost by evaporation to an extent to defeat the purpose.

The invention accordingly comprises the features of construction, combinations of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

Fig. 1 is a vertical section through an apparatus involving this invention.

Fig. 2 is a section along the line 2-2 of Fig. 1.

Fig. 3 is an illustrative ventilating system embodying the invention.

In the drawings, the numeral 1 comprises a pan adapted to contain a small body of water, and the numeral 2 designates a cylindrical casing having an upwardly turned and outwardly flared end or skirt 3. This casing is supported from the pan 1 by bolts 4 in coaxial relation with the pan, but with the skirt 3 spaced from the flared sides 1? of the pan to provide an air outlet between them,

as shown at 5. Resting upon ,the top of the casing is a cover 6 adapted to support a motor 7 by means of bolts 8, the motor itself carrying upon its shaft a fan 9 and a cone 10. The cover 6 is provided with a groove 11 to receive the top of the. casing 2 so that the motor, fan and cone are maintained in co-axial align,- ment with the casing 2 and with the pan 1.

The cover 6 is provided with large openings 12 which serve as air inlets. The fan 9 is preferably arranged to occupy the greater portion of the space between the motor 7 and the casing 2 so that the rotation of the fan will create the maximum draft downwardly through-the casing 2 and outwardly through the air outlet 5.

The cone 10 is preferably supported upon a spider 14 attached to the shaft and is supported in position to have its nose or apex 15 extend well below the water level within the sump. This nose is preferably open as at 15 to permit the water to flow upwardly on the inside of the cone. The upper edge of the cone may be flared outwardly as shown at 16, if desired. With the construction shown, as the motor 7 is operated the fan and cone are revolved and the fan draws air downwardly, as previously described, while the cone draws up the water upon its inner and outer surfaces and throws a spray of water in a horizontal sheet stretching outwardly from the edge 16. This edge is so situated that the air coming downwardly from the opening 12 comes in intimate contact with the spray. As illustrated, the sheet issuing from the edge is slightly below the lower edge 17 of the casing 2, so that the air, as it passes around this lower edge, is compelled to pass downwardly through the spray and upwardly through it again, thus causing the air to traverse the spray twice. The water issuing from the spray, except for the small portion which is evaporated, is caught by the flaring edge 1 of the pan and returned to the sump.

This apparatus is constructed in small size such that the volume of water within the pan may have its temperature changed readily in response to room conditions and in this manner the quantity of moisture added to the air of the room by the apparatus is, in general,negligible in so far as it afiects room humidity conditions. The apparatus does, however, in spite of this fact, cause the water within the sump to assume the true accurate wet bulb temperature, so that the indication of the wet bulb temperature or the control of any portion of a ventilating system by it may be readily accomplished by inserting a thermo-responsive element 18 below the waterlevel within the pan. .This may conveniently be accomplished by clamping the element to one of the posts 4. When the device is used as an indicating element, there may be associated with this thermostatic element an indicating device 19 to read the wet bulb temperature directly on the face of a dial. When, however, the device is intended to be used as a control apparatus, the thermostatic element will appropriately be connected to the mechanism to be controlled.

Referring now to Figure 3, which shows a practical application of the invention, the numeral 50 comprises a room having an air inlet 51 and an outlet 52. Conditioning apparatus are provided which, as illustrated,

comprise a fresh air intake 53, a fan 54, a tempering coil 55, a mixing chamber 56, an air washing apparatus 57 a second mixing chamber 58, a fan 59, all connected in series and connected to the inlet '51 by a conduit 60. The air outlet is connected to the mixing chambers 56 and 58 by suitable conduits 61 and 62 respectively, each of which is controlled by a' damper 63 and 64 respectively. The spray chamber contains a spray nozzle 65 fed with water by a conduit 66 supplied by 'passed on to the pump for use in the spray nozzles and a valve 72, and operating mechanism controls the admission of steam to the heater 55. Both of these valves, through the medium of compressed air in conduits 73 and 74, are under the control of a wet bulb thermostat 75 such that, with a rising wet bulb temperature, the heat is first cut ofi from the heater 55 at the valve 72 and if this proves insuflicient to keep down the temperature of the wet bulb thermostat, the valve 71 is automatically operated to introduce cold or refrigerated water to the sprays.

The conduit 62 is preferably provided with a heater 7 6 which is supplied with steam through a valve and operating mechanism 77 from the same main 78 which supplies the heater 55, and the damper 64 and the valve 77 are both operated by compressed air in conduit 80, and are controlled from the dry bulb thermostat 81. The nature of this control is such that as'the dry bulb temperature rises, the steam is first cut off from the coil 76 through the medium of the valve 77. Thereafter, if this prove insuflicient to readjust the conditions, the damper 64 is also operated, to reduce the amount of return air.

The wet bulb thermostat comprising a control apparatus similar to that described in Figure 1 is provided in any convenient location and as illustrated, it is mounted in the exhaust duct 61'. This device may have its operating motor directly connected to the power mains to supply the power necessary for its operation and its thermostatic element may be connected with the valve 72 control-' ling the steam coil 55 and the valve 71 controlling the water for the spray chamber of the system.

In view of the foregoing, it'would be clear that the accuracy of maintenance of the conditions of the room is greatly increased by reason of the fact that the wet bulb temperature is at all times accurately known. In installations of the character referred to, this is a matter of great importance.

- Since certain changes in carryingout the above process and in the constructions set forth, which embody the invention may be made without departing from its scope, 1t 1s intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the ge- III . of language,

neric and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. The process of indicating the wet bulb temperature of an atmosphere which comprises bringing a small body of water to the wet ,bulb temperature by atomization and contact with the atmosphere without materially aliecting the humidity conditions thereof and indicating the temperature by registering the temperature of the water body.

2. The process of'indicating the wet bulb temperature of an atmosphere which c0mprises circulating a small stream of water in a closed circuit including a spray, maintain ing an air circuit of the atmosphere through said spray, said air stream being insufficient to have an appreciable effect upon the moisture content of the atmosphere and thewater stream being of such small volume as to respond readily to temperaturechanges and indicating the temperature by registering the temperature of the water body.

3. The process of ventilation which comprises feeding air to a room, maintaining adjacent to the room a body of water of small size bringing said body. of water into intimate contact with air from' the room by spraying it therethrough to bring its temperature to the wet bulb temperature of the air in the room, said contact being insuflicient materially to affect the moisture content of the room and varying the humidity conditions of the incoming air stream in accordance with the temperature of the said body of Water.

l. The process of ventilation which comprises feeding air to a room, bringing air from the room into intimate contact with spray from a body of Water so small as to respond readily to temperature changes and controlling the humidity conditions of the incoming air by the temperature of the body of water.

5. An apparatus of the character described including, in combination, a container for a body of water of such small volume as to respond readily to temperature changes, an atomizer on the container for circulating the Water therein in a closed-circuit including a spray, means on the container for operating circulate in intimate contact with said spray the air in the room, atomizing means for bringing the Water in said container into intimate contact with the air in the room at a rate suflicient to bring the water to the wet bulb temperature without appreciably altering the conditions in the room, and means for indicating the temperature of the water.

7. An apparatus of the character described comprising a vaporizer, a water container mounting said vaporizer and adapted to hold a small body of liquid, a fan on the container for circulating a steam of air through spray formed by the vaporizer and eject the air-from the container, and means for measuring solely the temperature of the Water to indicate changes in temperature caused by the current of air passing in contactwith the-spray.

an enclosure, means for drawing a current of n a system of the character described air from said enclosure to be conditioned, a

vaporizer in the path of the air drawn from said enclosure, a small body of water in the vaporizer adapted to be brought in intimate contact with air from said enclosure, and means for causing the water 1n the container to assume the wet bulb temperature of the air from the enclosure, whereby an indicating device will respond to changes in the temperature of the water in the container.

9. In a system of the character described an enclosure, means enclosure and enclosure at desired conditions of tempera- In testimony whereof I aflix my signature.

for drawing air from the furnishing air to the enclosure, :1 conditiomng devlce for supplying air to the to changes in the tem- WALTER L. FLEISHER.

the atomizer and for causing an air stream to 7 whereby the spray readily assumes the-wet bulb temperature of the air. stream, and means for measuring the temperature-0f the water within said container.

6. Means for indicating the wet bulb temperature comprising, a vessel adapted to contain a body of water of small size 'relativeto

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