US3041877A - Device for the continuous determination of the drying capacity of free air - Google Patents

Description

6 Sheets-Sheet 1 July 3, 1962 M ROSNER DEVICE FOR THE CONTINUOUS DETERMINATION OF THE DRYING CAPACITY 0F FREE AIR Filed Aug. 2s, 1957 m lmwzliiie :mfzf: o .352m Enot f mm m5 E En@ Con CM. W um T5125 25m2 mf ESSO@ EnEmww V July 3, 1962 M. ROSNER 3,041,877

DEVICE FOR THE CONTINUOUS DETERMINATION OF THE DRYING CAPACITY OF FREE AIR Filed Aug. 28, 1957 6 Sheets-Sheet 2 Fig.2.

INVENTOR.

MULOS Ro SNER ATT 0 RNEYS July 3, 1962 M. RosNER 3,041,877

DEVICE FOR THE CONTINUOUS DETERMINATION OF' THE DRYING CAPACITY OF FREE AIR Filed Aug. 28, 1957 6 Sheets-Sheet 3 akfobE 15 OUUS Sep e ber 15 1 5 15 3u1 1 1 35 #j 1 70 7580 an 35 #s 50 55 @65 7D a9 45 5o im f 451 60 go 0 zsz 35% 6o 65 70 75 85 29% @11 1 25% 26127: @28% rn 1an '"U'rh sf/,V op 1901 190 Us Zw 157 w Ulli 6 F/g. 3a

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INVEN TOR.

vuKLoS ROSNER MMM Figa. W\ mm July 3, 1962 M. RosNER 3,041,877

DEVICE F'OR THE CONTINUOUS DETERMINATION OF' THE DRYING CAPACITY OF FREE AIR Filed Aug. 28, 1957 6 Sheets-Sheet 4 C== MAIN ALLEYS c L b c Fig. 4

INVENTOR.

MxKLos RoSw-:R

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ATTO RNEYS July 3, 1962 M. RosNER 3,041,877

OEvIcE EOE THE CONTINUOUS DETERMINATION OF TEE ORYING CAPACITY OF FREE AIE Filed Aug. 28, 1957 e sheets-sheet 5 f: I I n I E E cu \1` ci C1 I l I l i L l A L l .5a. 5=1l4 F9-51 a=1l0 9 Windpermeubility index. INVENTOR "KLOS ROSNEiL 3,@4L877 Patented July 3, 1962 3,041 877 DEVICE FOR THE CONTINUOUS DETERMINA- TIN F THE DRYING CAPACITY OF FREE AIR Mikls Rosuer, Budapest, Hungary, assigner to Lgninipex Fa, Papr-s Tzelauyag Klkereskedelmi Vallalat, Budapest, Hungary Filed Aug. 28, 1957, Ser. No. 680,815 2 Claims. (Cl. 721-335) This invention relates to a process for the continuous determination of the drying capacity of free air and it has particular relation to the obtaining of advantageous in dications for the natural drying of materials, such as wood or other products, e.g. agricultural products.

It is well known to use air as a `drying medium in industrial processes, as well as in forestry and agriculture.

In natural drying, the free air is brought in contact with the materials to be dried in its natural condition, i.e. natural temperature, humidity, etc., while in artificial drying the temperature, humidity, velocity etc. of the air used for drying are modified in dependence on the predetermined conditions to Vbe met in each case. In both cases-i.e. in natural as well as -articial drying-the course of drying is determined by the three essential parameters of the air, i.'e. temperature, relative humidity and velocity.

The continuous measuring of these 3 parameters means the continuous observation or measuring of the drying capacity of the air. It will be understood, however, that in the case of natural drying, in view of the dependence of these parameters on uncertain weather conditions, the drying capacity and its `possible changes if at all became known always only subsequently, because no means for continuous comparison or utilization of the parameter values have been known from the art in connection with natural drying.

The main object of the present invention consists in providing `a process which permits to continuously obtain, by means of a simple device, the most advantageous indications for a Vgradual or total adapting the drying system with free air to prevailing atmospheric conditions. The measuring device used in carrying out the invention indicates `the drying capacity of free air in advantageously selected time intervals and, furthermore, automatically indicates the necessary adjustment of the drying arrangement usedfor example `adjustment of `piles of wood if "the system serves for drying wood-in order to actually attain the `desired intermediate degree, or iinal content `of moisture in the material treated, as well as the desired drying velocity and the like.

In carrying out the process of this invention, the above object is attained by arranging the measuring device in a space of the drying system, through which the free air can unobstructedly pass-for example in the staple space of a wood drying system-and said measuring device (a) `cancontinuously measure the dilference between the prevalent andthe meteorological average wind intensity, and (b) the reading scale (which `forms part of the measuring device) permits reading of the actual drying capacity of the free -air as well as the extent 'of the necessary adjustments, if any, whereby the adjustment may result in retaining the drying procedure originally planned or in the use of a dilierent drying schedule.

Thus, by the use of the `measuringdevice and reading of the reading scale, exact data are obtained in advance about the drying capacity 'of the free air which is utilized in the initially arranged system'in which the .product is dried, for example in the initially 'used piles of Wood, if

` Wood is supposed to be dried.

.from the columns 4-9 of the scale.

FIG. l represents a portion of a exchageable sheet of the reading scale;

FIG. 2 shows a measuring element as arranged in the drying system (lumberyard);

FIG. 3 shows the reading scale with a series of sheets;

FIG. 3a the rotatably arranged cylinder, with an applicated sheet as originally calibrated, in reading position;

FIG. 3b the other sheets of the actual series, the first of which a recalibrated one;

FIG. 4 the preferable layout of the drying system (in the case of air drying of lumber);

FIG. 5 an `arbitrarily illustrated staple-type, as a unit of the entire drying system of FIG. 4 (denoted stapletype 2);

FIG. 5a the basic staple pattern of staple type 2, denoted sub-type 2/A;

FIGS. Sb-Se modifications of the basic pattern, denoted sub-types 2/B2/E;

FIG. 6 staple sub-type 2/C having originally a windpermeability-index=l,6 adjusted like sub-type 2/A, resulting in a wind-permeability index=2,0;

FIG. 7 staple sub-type 2/D adjusted like sub-type 2/ C.

The measuring device used in carrying out the present invention consists of one or more measuring elements and one or more reading scales pertaining to said element. The measuring element consists of a wooden board having the preferable dimensions of 3000 x 200 x 25 millimeters, consists of wood of conifers, e.g. pine, or of poplar, or the like, which has a weight not exceeding 50() kilograms per m.3 in air dried condition. This measuring element should be freshly cut and `arranged preferably at a height of 3-8 meters `above the ground level and supported at least at 3 points if horizontally arranged, in order to render it freely exposed to the current of air in all directions (FIG. 2). The elements used as supports for the measuring element should consist of air-dry wood or other material of constant moisture content.

FIG. 3 illustrates, by way of example, a series `of sheets of chart-like reading scales which are preferably applied tothe jacket of a rotatably arranged cylinder, several reading scales being alternately applicable, if desired', to the cylinder jacket. Other forms of reading scales, which can be arranged on `any suitable support, e.g. positioned y -on the mentioned supporting elements carrying the measuring element on which they `are displaceable, adjustable or exchangeable, can `be likewise used. The reading scales may be also of tabular arrangement or form pages of a booklet.

The scale illustrated in the appended FIG. 1. represents a portion of an exchangeable cylinder jacket and contains the heading, an initial section, and a middle section of the text, selected at random.

The above mentioned essential parameters and thus the drying capacity of the free air, are measured lfrom time to time-eg. in prescribed and meteorologie-ally equal intervals (see in FIG. l in column 2 of the scale Day of insertion). The desired drying velocities, the intermediate and final moisture content, etc. can then be read If the contemplated velocities, etc. are higher or lower than those read-on the scale, the scale can be displaced Vand changed and thereby the necessary extent of adjustment in the drying system can be determined. By carrying 'out said adjustment automatically results in obtaining the newly read drying .data for the entire drying system, or a part of it, respectively.

It will be understood from the above that in carrying out the present invention all three meteorological data can be determined, but individual data such as the Velocity `of rthe air or the differential air velocity-also the degree of exposure-can be measured individually or separately.

It should be noted that there is no fixed connection between the measuring element and the reading scale of the measuring device. For example if the reading device consists of a series of sheets combined with each other in the form of a booklet, it can be carried by the operator of the drying system. If the reading device or scale has a cylindrical form it can be arranged e.g. on a table.

For the application of the process of this invention in connection with the natural `drying of wood a detailed example is given below.

The staples of wood in a lumber yard can be built in manyfold patterns of diiferent arrangements. These arrangements being denoted here staple type 1, staple type 2, etc. Said types can be carried out with said various modifications (patterns) whereby these modifications may be denoted l/A, l/B, l/C, l/D, l/E 2/A, 2/B, 2/C, 2/D, Z/E, etc. respectively and used for carrying out the above described adjustments of the arrangement in order to apply the invention. Each pattern requires a separate scale sheet. In FIG. l, arbitrarily selected for the purposes of illustration, a separate sheet shows the data denoted 2/ C. One unit of the drying system `exposed to the wind is selected as a measuring unit whereby any un-i-t of the system can be selected for this purpose. If the unit is provided with a roof as shown in FIG. 2, the said Wooden board serving as the measuring element is placed within Ithis unit in the manner already described above.

Depending on the drying system in question the series of scale-sheets is now selected, in connection with the basic arrangement (staple type and yard layout-FIG. 4) of the goods to be dried, the arrangement being in use or only contemplated to be used. From this series of scales the sheet corresponding to the pattern variant or state of adjustment, which applies to the prevailing case, e.g. scale-sheet No. 2/ C is selected and placed on the support for the scales (FIG. 3). If no such variant or no such adjustment is available, a sheet is selected corresponding to the basic staple pattern, e.g 2/A (FIG. 5).

The above mentioned placing of the measuring element should be carried out in accordance with the tabular scale on the next date in the column denoted Day of insertion of the measuring element of the selected sheet. This date should be for example September lst. The coordinated full-drying period of the measuring element, depending upon the average meteorological weather conditions (parameters), represents the Kvalue which has to be likewise read and this should be the underscored figure, i.e. in the present example 60.

After expiration of the half-time of the drying period which appears in the above mentioned column of the complex parameter K-i.e. in the present example 50/ 2 or 25 daysdetermination of the moisture content in the measuring element is to be carried out, whereby any suitable method of determination of the moisture content can be used. If such determination shows that the moisture content of the wooden board serving as the measuring element is not higher than the moisture content indicated in -the table and corresponding to the above mentioned 50 days periodi.e. in the present example 26 percent-then as the actual Kvalue of the drying system in question will be determined by 50 instead of the average meteorological value calibrated as 60. If, however, the measuring element is of a higher w-ater content, the measurement with the aid of the measuring element has to be repeated at predetermined intervals-in our example in 5 days-periods-until the corresponding humidity value is attained. Thus, in accordance with above, the actual Kvalue of the drying system is detinitely determined.

If a Kvalue is determined not corresponding to the meteorological average, i.e. a Kvalue which differs from 60 days in the present example, the actual K- value indicated by the measuring element must be conspicuously marked in the scale (in the present example 50 days), whereby calibration of the scale used for the actual or planned drying system is changed, based on the actual drying capacity. In conformity with this scale, calibration of all sheets of the respective series should be likewise changed. A further procedure in the present example is as follows.

If at any time between September l and 30th, wood is arranged in staples in accordance with the types or subtypes of the series of scales here in question from the sub-types of said series (2/A to 2/E) that individual type should be selected, in the case of which, in connection with the recalibrated Kvalue, the drying period values and moisture content values most suitable in the respective case can be read. In the case of staple pattern 2/C anda Kvalue of 50, it will be found that the preliminary drying of the material treated will take 65 days and the full drying takes 205 days. If this is not satisfactory, another page of the series of scales should be selected, automatically indicating the sub-type or adjustment of the drying system, which is adapted to the actual meteoro logical conditions.

In order to facilitate adjustments of the drying system based on the reading of scales, the data shown in lthe scales can be supplemented by stating the geometrical and mathematical equivalents of the permeability of a unit or of the complete drying system, c g. yard and piles or heaps. (FIGS. 4 and 5). The wind permeability index thus stated simultaneously gives a reliable indication in connection with the selection of the best suitable scale and the selection of the best drying system, in order to maintain the latter at the desired drying value, in spite of the occurrence of unexpected meteorological conditions.

It is advantageous to check the correctness of the K- value calibration from time to time for example once a year. It may happen that one or the other year is unusually dry or unusually wet or that the average wind intensity has changed and by checking the data of the tables correctness of the calibration can be increased.

It will be understood from the above that the present invention is not limited to the specied means, arrangements, steps and other details specifically described above and illustrated in the drawings and can be carried out with various modiiications within the scope of the invention as defined in the appended claims.

Some specific examples for the application of this invention Ivvill be stated as follows:

In a lumber manufacturing plant 25 mm. thick White pine lumber is dried by air ttor the purposes of construction work. A certain part ofthe green stock, however, graded for joinery purposes, should be predried by air only -before it is going to the kilns.

On the yard the individual piles of wood may be disposed exactly according to FIG. 4, the spaces between the piles being disposed with respect to the requirements of soft wood.

The measuring element can be placed under the roof of any pile not lower than the surrounding piles. If the yard has no uniform shape but in view of surrounding lbuildings etc., can be divided into certain sections, exposed homogeneously to the velocity of wind, it is advisable to place at least one measuring element in each homogeneous section for detecting the differences in wind velocities or those between exposures. If the piles lhave no individual roofs, but are placed in a shed, the measuring element could be hanged under the roof of the shed well exposed to the wind, -that is, at a distance from the roof and from the walls. The piles may be built according to staple type 2, live variants of which (2/A-2/C) are shown on FIG. 5.

A further application of the invention is the following:

Selected from the freshly cut stock the measuring elements should be inserted as stated above. 'The date of this should be, as already supposed, September 1. This date may be optional, however, and if the actual date (e.g. August 20) is not given ou the reading scale an interpolation is to be made bet-Ween the t-wo neighbouring insertion dates (August 15September l).

On the given day, for instance September l, the stock of 25 mm. thick lum-bers furnished to the yard may be piled or built up by unit packages `of lumber with forklifts according to sub-type 2/C. This is shown by the relating sheet in conformity with the actual pattern according to FIG. 3. lFIG. 3a thereof shows `the reading scale in cylindrical shape and FIG. 3b the series of the interchangeable sheets No. Z/A-Z/E. The actually used sheet illustrated on |FIG. 3a is corresponding to pattern 2C. From the 3rd column of said sheet it is to be seen that at first on the 50/2, that is on the 25th day, that is on September 25, the moisture content of the measu-ring element placed on September 1st is to be controlled. It the moisture content is above the corresponding 26 percent on the 55/ 2 or the 27th day, on September 27, a second measurement is to be carried out. If the moisture content is higher than the corresponding 27 percent, again at 60/2, that is, the 30th day it is to be measured again. If the measured value is now equal to the corresponding m.c. of 28 percent or even less, this will mean -that all lumber piled on September 1 or since is drying actually according to the average meteorological conditions. Consequently the shrinkage as to the lumber piled on September 1 will begin on the 50th day, that is on October 20. The above mentioned high grade stock which is to be predried, if its piling took place on September l will ybe achieved on the 75th day, i.e. November 15, as it is to be seen on the reading scale. 'Ihe stock will therefore have an average moisture content of 28 percent. The stock to be thoroughly air dried may reach a iinal moisture content of 17 percent in 215 days as indicated by the readings, that is March 30.

If, however, at 50/ 2 or the 25th day i.e. on the iirst measuring day, the measuring elements show a corresponding moisture content of 2'6 percent, or less, that would mean that the actual drying capacity of free air is actually more eicient than in the average, and the above example is thus met. lIn this case the sheet 2C and the other sheets are to be recalibrated in the manner mentioned above, etc. It may happen, however, that a faster seasoning schedule is inconvenient, e,g. the drying kilns, trucks and personnel should get overwhelmed. Since sheets No. 2A and 2B are indicating mo-re retarded seasoning rates, said recalibrated sheets shall be put on the cylinder to be inspected. As it is seen on FIG. 3b, the sheet 2A indicates the predrying period of 75 days, just as it was looked for. Now all the piles erected on September 1 and later for predryiug only, shall be readjusted into sub-type 2A, preferably according to FIG. 6. This vwill automatically result in obtaining the seasoning schedule as initially contemplated.

The drying capacity of the free air, however, may deviate from the `average to the contrary too. in such a case, for example the measuring element does not reach the corresponding moisture content as originally indicated by the scale that will mean r.for K/2=60/2 or 30 days, which is October 1, but for instance, for 80/2 or 43th day only. If the original kiln `drying program is aimed at, the predrying of said high grade stock is to be accelerated, since, if not, predrying of said stock will be achieved only on the 105th day, that is on December 15, instead of November 15 as contemplated initially.

Since an acceleration is aimed at, sheets 2D and 2E are to be used. Sheet 2D indicates a suitable acceleration, because the recalibrated K-value of 80 indicates a predrying period of just 75 days as needed, with a still acceptable average moisture content of 30 percent. 'Ihe necessary adjustment which may result in retaining the originally planned drying procedure may be carried out if 6 the piles for predrying were erected in a faster subtype than 2C, for instance 2E, 2D. If the piles were originally adjusted as in FIG. 7, and have accordingly attained the same -wind permeability index of other piles of sub-types 2C, they may conveniently be adjusted according to sub-types 2E, 2D.

These specific examples demonstrate that the adapting of the entire drying system or of a part of it to the prevailing atmospheric conidtions may be eiected at a desired graduation. 'Ihe iineness of graduation depends on the iineness of the measuring device (number of scaleseries, number of sheets in each series, intervals of recalibration). In this manner the measuring device permits to predetermine the effects of weather conditions (parameters) -to a desired degree, for every drying system.

The process for the continuous determination of the drying capacity of free air as applied for agricultural purposes may Ibe demonstrated by a lfurther specic example.

Freshly cut fodder on the meadow in heaps, etc. but also the vegetation itself during the process of ripening, represent drying systems anyway. The drying as well as the ripening depends upon the drying capacity of free air. The measuring device according to the invention may be installed anywhere not only in lumber yards. It is essential, however, to secure conditions (height over ground level, protection from rainfall and sunshine, free exposure to wind) identical with those mentioned for lumber yards.

In view of the fact that farmlands are generally not equipped with meteorological stations and, since the conguration of the terrain varies so that climate may differ from farm to farm, it is essential to know the actual drying capacity on each farm. The measuring device is suited for exact indication. It is sufficient, however, to place a single complete device consisting of measuring element and scale in a central spot. It is preferable to use a separate measuring element in each individual farm or terrain-section. If K/2 or K values indicated by these sep- -arate measuring elements are identical with those of the said central measuring element, the climates in question (the drying capacities of the sections) are also identical. The indications may be communicated at the above stated intervals, e.g. by telephone, and the operator of the central measuring device gives, also in the case of K-value deviations, the correspondingly evaluated readings. The readings may incorporate the degree of the deviation regarding the drying time, ripening period, actual and nal moisture content, and so on.

Having now particularly described and ascertained the nature of our invention and in what manner the same is to be performed, I declare that what I claim is:

1. A system for the continuous determination of drying capacity of the open air used for the natural drying of wood, agricultural products and other materials, comprising a measuring element consisting of wood able to evaporate moisture according to the momentary parameter values of the open air which is free of inliuen-ce by the arrangement or examination of said element; a reading scale, releasably supported, indicating the duration of the natural drying of the measuring element and the readings on the scale bringing the duration of the drying in relation to previously defined meteorological and other values.

References Cited in the le of this patent UNITED STATES PATENTS Kelly m Nov. 9, 1915 Woodling July 18, 1939 Woodling Feb. 20, 1940

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