US2184473A

US2184473A - Drier

Info

Publication number: US2184473A
Application number: US188741A
Authority: US
Inventors: Chester J Scanlan
Original assignee: New York Blower Co
Current assignee: New York Blower Co
Priority date: 1938-02-04
Filing date: 1938-02-04
Publication date: 1939-12-26
Anticipated expiration: 1956-12-26

Description

Dec. 2.6, 1939. c:.` J. sANLAN DRIER Filed Feb. 4. 1958' Patented Dec.V 26, 1939 UNITED STATES DRIER Chester J. Scanlan, Bloomington, lll., assignor to The New York Blower Company, Chicago, Ill.

Application February 4, 1938, Serial No. 188.741

1 Claim.

This invention relates to a drier and more particularly to an apparatus for drying wood. grain and other materials.

One object of the invention is to provide a 5 drying apparatus wherein the grain or other material to be dried is placedl in a chamber and air circulated through the chamber so that the circulating air will absorb moisture from the material, means being provided for controlling the temperatureof the air and also releasing air after it reaches a certain point of humidity and admitting a supply of fresh air. It will thus be seen that with this improved apparatus the air may be continuously recirculated through the drying chamber until a certain quantity of moisture has been absorbed, at which time ahumidostat will effect opening of a damper or closure at an outlet for air so that moist air may escape from the drying chamber and at the same time open a` damper in an 4inlet through' which fresh air may enter a conduit leading to a circulating fan, .the dampers being automatically closed by action of the humidostat when the humidity of the air has been reduced to a desired point regardless of temperature.

It is another object of the invention to pro-V vide an apparatus of this character wherein a valve for a steam pipe leading to a heating coil is adapted to be adjusted through the medium of a thermostat disposed Within the drying chamber, thus permitting the heat to be adjusted and the temperature within the drying chamber maintained within predetermined limits. It will thus be seen that the temperature within the drying chamber and the humidity of the air passing through the drying chamber may be controlled and these two factors have a definite relation to each other which will permit the rate at which moisture is absorbed to be controlled and a relatively slow or rapid drying of the material in the drying chamber effected.

The invention is illustrated in the accompanying drawing, wherein the gure is a vertical sectional semi-diagrammatic View of a drier construeted in accordance with this invention.

The chamber I of the improved drying apparatus may consist of a room in a building or a specially erected structure. A false bottom or platform 2 extends horizontally in the chamber in vertical spaced reation to the bottom 3 thereof, and through this platform or false 'bottom are formed a suitable number of openings 4 through which air passes upwardly from the space `ii be!- ktween the platform and the bottom of the chamber. Any suitable means may be provided'within the chamber for supporting grain or the like over the platform 2, or if lumber or similar bulky ma- 5 terial is to.be dried, it may be piled or stacked upon the platform in such a manner that air may pass upwardy through and around it and ab,- sorblmosture from the material to be dried. An air outlet neck or pipe 6 is fitted through anvlO opening 1 formed-in the Wall 8 of the chamber, and in this pipe is disposed a damper 9 which is pivotally mounted, as shown at Ill, for movement from the closed position, indicated by dotted line to the opened position shown in full line. The 15 wall II at the opposite side or end of the chamber from the wall 8 is formed with an opening I2 through which a pipe or conduit I3 extends,

and adjacent the open outer end of this conduit is a damper I4 which is pivotally mounted, as zo shown at l5, for movement from the opened position, shown in full line to the closed position indicated by dotted line. A branch pipe I6 extends downwardly irom the conduit- I3 intermediate the length thereof, and this branch pipe 25 leads to the inlet of a blower ll which is mounted externally of the drying chamber and provided with a discharge pipe or neck I8 snugly received in an opening I9 formed in the wall I I below the platform 2. By this arrangement of-parts air 30 may be forced'from the blower into the chamber below the false bottom or platform 2, and this air will then move upwardlyI through the openings 4 for passage upwardly through and about the grain or other material to be dried. The dampers Ailv and I4 are normally closed and. when the air reaches the upper portion of the chamber, it will pass through the conduit I3 and then down through the branch' pipe I6 back to the blower for recirculation through the drying chamber. The air must be heated before it is 'delivered into the space 5 below the platform 2,

and in order to do so, there has been provided a heating coil 20 which extends vertically and transversely through the neck I8, as shown in the 5 figure. This coil forms a portion of a steam pipe 2l through which steam o'ws from a suit- I air controlled. The valve is to be opened and closed in response to variations in a thermostat 23 mounted within the drying chamber, and there has been provided valve adjusting mechanism of a conventional construction, indicated in general by the numeral 24, and operatively connected with the thermostat, as shown by the dotted line 25. This valve adjusting mechanism is not illustrated in detail as it is of a conventional construction. vided a humidostat 2li` of a conventional construction which is mounted within the space 5 under the platform `2 and operatively connected with the dampers, as indicated by the dotted lines 21, so that, when predetermined variations in humidity of the air takes place, the dampers may be opened or closed.

During use of the drier, the air which is driven wardly through the openings 4 and absorbs moistur from the material, after which it is returned to the blower and recirculated until sufficient moisture has been absorbed to cause the humidostat to be aiected. When this takes place, the dampersl are opened and moisture-laden air escapes through the pipe 6 While, at the same time, fresh air enters through the open outer end of the conduit I3 and ows to the blower I4. The

humidity of the air will'thus be reduced toa point at which it m`ay again absorb moisture from the material being dried and the humidostat will then again be affected and cause closing of the dampers. The temperature of the air has a direct effect upon the amount of moisture which can be taken. up and by properly setting the thermostat 23 the temperature of the air in the drying chamber may be maintained within predetermined bounds.

In order todene any condition of atmospheric air relative to its ability to absorb moisture, two temperatures'must be designated, namely, the dew point Atemperature and the dry bulb temperature. For a given dry bulb temperature, the

higher the dew point temperature the less the moisture absorbing capacity. 'I'his relationship between dew point and dry bulb temperature can b e controlled by means of a humidostat controlling the relative humidity, which is dened as the actual moisture (in percent) content at any given dry bulb temperature in relation to the moisture content at saturation for the same dry bulb temperature.

For example: Let us assume a drying temperature of 110 F. D. B., which is used for seed corn and many other products, the following table There has also been prof gives the drying rate or capacity based on dry air.

Relative humidity egggcgy Persan! n ment may be heated by steam or be a direct red unit, such as a hot air furnace. This recirculation causes the relative humidity to build up as ,moisture is removed from the product to be dried.

When the desired relative humidity is reached, corresponding to the required drying rate, a humidostat opens two dampers, one on the suction of the blower and one on'the discharge. This operation may be by means of compressed air motor or an electric motor turned on and ofi by humidostat controlled actuating means.

Having thus described the invention, what is claimed as new is:

In a drier, a drying chamber, said drier having a false bottom defining an air inlet space, said false bottom having openings, an outlet pipe carried at one end of the drying chamber, a damper in the pipe, a conduit carried at the opposite end of the drying chamber, a damper in the conduit at its outer end, said conduit having a branch pipe, a blower connected with the branch pipe and having a discharge pipe communicating with the air inlet space, means for automatically effecting the opening and closing of the dampers, said means including a humidostat within the space beneath the chamber, means for heating air. delivered through the forward discharge pipe, and means for automatically controlling said heating means, said last-mentioned means including a thermostat within the drying chamber.

CHESTER J. SCANLAN.