US1738794A - Method and apparatus for saturating fibrous articles - Google Patents

Description

Dec. 10, 1929. PARKER 1,738,794

METHOD AND APPARATUS FOR SATURATING FIBROUS ARTICLES Filed March 6, 1925 3 Sheets-Shee l Dec. 10, 1929. PARRER 1,738,794

METHOD AND APPARATUSFOR SATURAI ING FIBROUS ARTICLES Filed March 6, 1925 3 Sheets-Shee 2 H. PARKER Dec. 10, 1929.

METHOD AND APPARATUS FOR SATURA'IING FIBROUS ARTICLES 5 Sheets-Sheet 3 Filed March 6, 1925 Patented Dec. 10, 19 29 PATENT OFFICE.

HOWARD PARKER, OF BERLIN, NEW HAMPSHIRE, ASSIGNOR TO BROWN COMPANY, OF

BERLIN, NEW HAMPSHIRE, A CORPORATION OF MAINE METHOD AND .AJPPARATUS FOR SATURATINGI- FIBROUS ARTICLES Application filed March 6, 1925. Serial No. 13,664.

In the manufacture of articles such as tubes or pipes from fibrous material as cellulosic pulp, it is often desired to saturate the material after it is formed into the desired shapes with saturants capable of iII1- parting certain desirable qualities to the finished articles. For example, if fiber tubes or pipes are to be used for underground conduits for electric Wires, the saturant should be such as to impart insulating and moisture proof qualities. A saturant commonly employed to impart these-qualities is pitch, and in order to saturate the pipes, tubes or other articles, it is necessary to heat the pitch to decrease its viscosity as much as possible Without, however, raising its temperature sufiiciently high as to injure the fibrous articles immersed therein, whether from burning of the fibers or warping, cracking, or

other damage.

In order to render the saturation as complete as possible, it has also been found de sirable to subject the articles, while immersed in the hot saturant, to pressure above atm0spheric. Before being satur'ated articles formed of cellulosic pulp contain, besides air and other gases, more or less moisture, even though they have been subjected to apparent 1y complete drying, and this moisture, when the articles are immersed in the hot saturant,

' is converted into steam which with the air and other gases escapes from the articles and produces more or less violentfoaming of the saturant. Of course the escape of this gaseous matter from the articles should be per- .mitted since its removal provides voids into which the saturant may be made to penetrate, but it adds to the difiiculties experienced in efi'ect-ingthe saturation since it opposes the penetration of the saturant and produces foaming thereof;

This invention, therefore, relates to an improved method and apparatus for accom plishing the saturation wherein the escape of steam and other gases from the material is permitted, the saturant being then forced into the resultant voids in the material. In brief," this method comprises bringing the articles immersed in the saturant up to the saturating temperature and permitting foaming to take place during that time. The articles and saturant are then subjected to pressure conditions for some time and then the pressure is released and further foaming permitted for a certain period, the length of whichdepends upon the character of the articles being treated. .The articles immersed in the saturant are then again subjected to pressure conditions for a period, afteuwhich the pressure is released and the saturant is drawn off. If the foaming period after the first pressure treatmenthas been of sufficient length, there should be no foaming after the second pressure period. If there is foam at this time, it should be allowed to escape before the saturant is drawn off, or it will leave the surface of the articles dirty or covered with spots or small masses of the saturant. Foaming after the final pressure period does not aid in the penetration of the saturant, it

being necessary to subject the articles and enter the tank containing the articles and saturant during a part only of the tinie of drawing off, or by restricting the entry of on during substantially the entire drawmg oflt' time.

structional features of the apparatus, such as, for example, mechanism for preventing the saturant from contact with the pressure regulating devices.

For a more complete understanding of this invention, reference may be had to the accompanying drawings, in which Figure 1 is a plan, partly in section, of one form of apparatus designed-for the saturation of fiber tubes according to the method of this invention.

Figure 2 is a view, partly in elevation and partly in section, of the same.

This invention also comprises certain con- Figure 3 is a detail section through a pressure regulator protecting device.

Figure 4 is a fragmentary view partly in section, showing a temperature regulating mechanism.

For the purposes of illustration, this invention has been shown in connection with an apparatus of the general type disclosed in the patent to O. B. 'Brown et al. No. 1,488,974, granted April 1, 1924, although it should be recognized that many features of this invention are not restricted to any specific apparatus. This apparatus comprises a plurality of treating tanks 1 within which the articles to be saturated are placed, being held in cages 2 perforated for the passage of the saturant. These cages containing the articles may be let down into the tanks or removed therefrom by any suitable hoisting mechanism, the dome shaped tops 3 of the tanks being removable to facilitate such action. with the series of treating tanks 1 is a saturant supply reservoir or storage tank 5 from which saturant may be forced by means of a pump 6 positioned within a charging tank 7, there being one charging tank for each treating tank. Each of the pumps may be driven individually as by means of a motor 8. The discharge end of each pump is connected with a pipe 10 which discharges at the upper end of the corresponding treating tank, as at 11, The saturant may return from the lower end of each treating tank through a large pipe 12 to the corresponding charging tank. The intake of the pump 6 has a multi-way valve 15 therein which may be turned to permit the pipe to draw either from the storage or supply tank 5, or from the lower portion of the charging tank so that after a supply of saturant has been taken from the storage tank 5, this tank may be shut off from the pump 6 and the treating tank placed in communication therewith so that further action of the pump 6 serves to circulate the saturant through the treating and charging tanks, being passed into the treating tank at the top and out at the bottom continuously. The pipe 10 is also provided with a multi-way valve 16 which the flow therein may be directed through the pipe 17 to return the saturant into the storage tank so that when desired the saturant may be drawn off from treating tanks. valves and 16 inay be actuated by suitable hand wheels 20 and 21, respectively. also connmmicating with the storage tank ire pump 2 (see Figure 1) by t may be pr" ed from the .arough a .o pressure 27. T e line is pro leading back 8 having a 'e' so that 2? may be Associated mits the saturant to settle out from the foam,

thesteam and other gases escaping, the saturant thus settling out being pumped back to the storage tank by means of a pump 40 communicating through a pipe 41 with the lower portion of the foaming tank and with a pipe 42 leading to the storage tank. In order that the operator may be able to judge of the amount of foaming, each pipe 35 may be provided with a small branch pipe 45 having a control valve 46 therein, the end of this pipe 45 projecting downwardly so that a pail or other suitable receptacle 47 may be placed thereunder. By opening the valve 46 and noting the character ofthe discharge into the pail, the operator may determine readily whether foaming is taking place.

During the period of saturation it is, of course, necessary that the saturant be maintained at the proper temperature to reduce its viscosity to the required extent. For this purpose heating mechanism comprising steam coils has been provided, the steam being supplied through a steam line 50 to coils 51 in each of the treating tanks, coil 52 in the charging tanks, and coils 53 in the storage tank. The temperature to which the saturant is raised may be regulated by any suitable regulating means as pointed out in the Brown et al. patent above mentioned.

As shown this regulating means comprisesa steam supply regulating valve and a valve for controlling the release of the water of condensation from the heating coils in the treating and charging tanks, this mechanism being shown in detail in Figure 4. The supply of steam to each of these coils is controlled through the valve normally held open by means of a spring 61. Positioned in each charging tank is a bulb communicating w th diaphragm member which actuates ti justa can- 67 valve 68 co pressure from a co sseo. r pipe 69 through a pipe 70, iearang to the diaphragm mechanism 71, adir'.,sion such air by the opening of ii e val: perature of t e b ll valve 60 to shut e close the the heating nnected to ding to a sting through an M and cnar n endenser T5 ha 1 member adjustable cam 78, a valve 79 controlling pressure'from the pipe 69, through thepipe 80 to the diaphragm actuating portion 81 of the valve 82 controlling the outlet of condensate from the condenser 75. This valve 82 is normally held open by means of a spring 83 so as to permit the condensate to pass from the coils, but if the temperature rises sufiiciently the valve 79 is elevated, permitting air to pass through the pipe 80 so as to close the valve 82.

The pressure regulating valve 29 above referred to may be controlled by an automatic pressure regulating device as at 90, but it is important that the saturant itself shall not have access to this mechanism, necessarily of a somewhat delicate character, which the saturant would injure. In order to prevent the saturant from contacting therewith and yet permitting the pressure of the saturant to be effective in controlling this device, mechanism has been provided for maintaining a fluid column between the saturant and the device, this fluid being of such a nature that it will not injure the regulating device or mix with the saturant. For this purpose air under pressure is satisfactory. The device for maintaining this column of air is illustrated in detail in Figure 3. At a suitable position in the pressure line 27, preferably adjacent to the relief pipe 28, is positioned a chamber 91 jacketed as at 92 to permit steam from the heating system to pass therearound in order to maintain in fluid condition saturant extending thereinto from the pressure line 27. Projecting into this chamber 91 is an air pipe 93 which extends tothe pressure regulating device 90 and to the recording device, if one is used, as at 94. In order that the saturant may not pass into this pipe 93, air under pressure is supplied to the upper portion of the chamber as through a pipe 95. This air may be derived from the pipe 69 and should be of a pressure slightly in excess of 1 that desired for the pressure in the pressure line 27 in order that it may balance the pressure in the pressure line and also provide for leakage of air through the regulating device 90. This pressure of air supplied to the pipe 95 may be regulated by any of the well known pressure regulators or reducing valves and can readily be kept quite accurately at the desired point, or, if desired, such a regulator might be employed adjacent to the chamber 91 without affecting the pressure in the pipe 95.

The saturant is kept in the storage or supply tank 5 slightly above the temperature of treating which, for pitch, may reach from it 260 to 310 Fahrenheit, but is preferably between 280 and 295 Fahrenheit. This provides for the cooling effect when the pitch is pumped into the comparatively cooler tank containing the cages with the articles, such as tubes, contained therein. After the articles have been placed in the treating tanks and these tanks closed, the pitch is pumped into the treating tanks and circulated therein; during all this time the valve to the foam tank being open so as to permit free foaming of the saturant due to the escape of steam, air and other gases from the voids of the fibrous articles. In the foaming tank the saturant may settle out from the foam, the air and gases passing out through the vent 39, so that it may be pumped back into the storage tank. Of course the foaming tank should also be kept hot with any suitable type of steam coil (not shown) in order to prevent the saturant from becoming solidified therein.

After this circulation of saturant has been effected for a certain length of time, the valves 35 to the foam tank are closed and pressure of, say, pounds per square inch is applied from the pressure line, which pressure, of course, may be varied to satisfy the requirements of the particular articles being treated. It is not necessary to wait for all the foaming to be completed before the pressure is applied. This would take a considerable length of time and it is found that it apparently makes little difference in the saturation. The pressure is continued for a suitable length of time, and the pressure supply line then being closed, the valves 35 are opened into the foam line, whereupon the pressure immediately reduces and foaming commences. The length .Of time in which this foaming takes place varies with different articles and different cellulosic fibers. In some cases practically all of the saturant will foam out of the treating tanks into the foam tank, and in such cases it is necessary to again fill the treating tanks .with saturant and repeat the procedure from pumping in to the foam period to insure a satisfactory treatment. If the treating tanks are not foamed in this manner, penetration of the saturant is not uniform, portions nearer the center not containing as much saturant as those nearer the surface, and it is also found that a simple relief of the pressure without opening the treating tanks and permitting foaming is not sufficient. Afterthe foam period of the required duration has been completed, depending on the character and density of the fibrous articles, pressure is again applied and after this pressure period the pressure is released into the foam line. If the previous foam period has been of sufficient extent, no foaming should be expected meats..-

spotted with small masses of the saturant.

l lowever, pumping out of the treating tanks may be more expeditiously accomplished and without the necessity of permitting foaming to be complete it the entrance of air to the tanks is greatly restricted. H entrance of air is shut oil altogether, the resultant partial vacuum in the tanks as the pumping proceeds may tend to slow down the pumping somewhat. This slowing action, however, may be eliminated by permitting restricted passage of the air into the tank during the pumping operation. This may be done either by restricting the passage of air throughout the entire period of pumping or opening up the tank freely during a portion of the pumping and closing it entirely during the remainder. By restricting the entry of air in this manner, the saturant is maintained nearer to its treating temperature than if air at atmospheric temperature were allowed free access thereto, and consequently is maintained in a more fluid condition. After the excess saturant has thus been removed from the tanks, they may then be opened freely to theair and allowed to stand until the articles have cooled sufficiently to produce the required surface color due to the solidification of the saturantj Having thus described an embodiment of this invention and its method of use, it should be evident to those skilled in the art that various changes and modificationsmight be made therein without departing from its spirit or scope as defined by the appended claims.

I claim:

1. The method of saturating fibrous articles which comprises immersing such articles in heated saturant and permitting gases to es cape from thevoids thereof, subjecting the articles so immersed to pressure above atmospheric, then reducing the pressure and per mitting more gases to escape, again increasing the pressure above atmospheric, drawing ofi the saturant, reducing the pressure to atmospheric, and permitting the articles to cool freely in the air.

2. The method of saturating fibrous articles which comprises immersing such articles in heated saturant, and alter the articles have been heated therebysubjecting the articles and saturant alternately to higher and lower pressures and permitting the escape of gases from the voids of the material during the periods of lower pressure, withdrawing the saturant, and then permitting the articles to cool freely in the air.

3. The method of saturating fibrous articles which comprises immersing the articles in heated saturant, circulating the saturant until the articles have reached substantially the temperature of the saturant while permitting the escape of gases therefrom, confining the articles and saturant and subjecting them to pressure ahove etmospl ieric re ducing the pressure and permitting the escape of more gases and then again confining and subjecting the articles and saturant to pressure above atmospheric, partially reducing the pressure while drawing ofi tree saturant, reducing the pressure to atmospheric, and permitting the articles to cool while permitting free access of air.

l. The method of saturating fibrous articles which comprises immersing the articles in heated saturant, circulating the saturant until the articles have reached substantially the temperature of the saturant while. permitting the escape of gases therefrom, confining the articles and saturant and subjecting them to pressure above atmospheric, reducing the pressure and permitting the escape of more gases and then again confining and subjecting the articles and saturant to pressure above atmospheric, and then drawing otl the free sat-urant while restricting access of air at atmospheric temperature to the articles and saturant.

5. The method of saturating fibrous articles which comprises submerging such articles in melted saturant, circulating the saturant about the articles until they have reached substantially the temperature of the saturant and permitting foaming to take place, alternately subjecting the articles and saturant to higher and lower pressures and permitting foaming while at the lower pressures, drawing off excess saturant, and permitting the articles to cool freely in the air.

6. Themethodof saturating fibrous articles which comprises submerging said articles in melted saturant, circulating the saturant about the articles until they have reached substantially the temperature of the saturant and permitting foaming to take place, and alternately subjecting the articles and sat urant to higher and lower pressures and permitting foaming while at the lower pressures, andthen drawingofi' the excess saturant while restricting access of air' at atmospheric temperature thereto.

7. lfhe method of saturating fibrous articles which comprises immersing the articles in melted saturant, circulating the saturant until the articles have reached substantially the temperature of the saturant while pe mitting the escape of gases therefrom, con fining the articles and saturant and subjecting them to pressure above atmospheric, reducingthe pressure and permitting the escape of more gases, again confining and subjecting the articles and saturant to pressure above atmospheric, withdrawing the saturant while permitting access of air at atmospheric pressure during portion of the withdrawing operation, releasing the pressure to atmospheric, and permitting the articles to cool freely in the air.

8. An apparatus of the class described comprising a tank for containing articles to be saturated, a saturant supply reservoir, means for circulating saturant between said tank and reservoir, a foam tank, means for relieving said saturating tank into said foam tank, and means for returning saturant in said foam tank to said reservoir.

9. An apparatus of the class described comprising a tank for containing articles to be saturated, a saturant supply reservoir, means for circulating saturant between said tank and reservoir, a foam tank, means for relieving said saturating tank into said foam tank, means for returning saturant in said foamtank to said reservoir, and means for subjecting the contents of the saturating tank to pressures different from atmospheric.

10. An apparatus of the class described comprising a tank for containing articles to be saturated, a saturant supply reservoir, means for circulating saturant between said tank and reservoir, a foam tank, and means for relieving said saturating tank into said foam tank.

11. An apparatus of the class described comprising a tank for containing articles to be saturated, a saturant supply reservoir, means for circulating saturant between said tank and reservoir, a foam tank, means for relieving said saturating tank into said foam tank, and means for subjecting the contents of the saturating tank to pressures different from atmospheric.

. 12. In an apparatus of the class described, a tank for containing articles to be saturated, means for establishing pressure in said tank different from atmospheric, a pressure regulating device for controlling such pressure, and means for prevent ng saturant in said tank from access to said device.

13. In an apparatus of the class described, a tank for containing articles to be saturated, means for circulating saturant through said tank, means for establishing pressure in said tank different from atmospheric, a pressure regulating device subjected to pressure of the saturant for controlling such pressure, and means for preventing saturant from having access to said device.

14. In a saturating apparatus having a saturatingtank, means for establishing pressure conditions different from atmospheric in said tank, and a device responsive to pressure of said saturant for controlling sald means,

the method of preventing the saturant from contacting with said device which comprises maintaining. a column of fluid immiscible with the saturant under pressure between said saturant and said device.

15. In a saturating apparatus, a tank for containing saturant and articles to be saturated, means for establishing pressure conditions different from atmospheric in, said tank, a device responsive to pressure of said saturant for controlling said means, a chamber interposed between saiddevice and tank and into which saturant from said tank may pass, and means for establishing a column of air under pressure between said device and the surface of the saturant in said chamber to prevent the saturant from contacting with said device. 16. In an apparatus of the class described, a tank for containing articles to be saturated, a saturant supply, pipe connections between said tank and supply, means for forcing saturant through said connections from said supply to said tank, a bypass from the pressure side of said means to said supply, a valve in said bypass, a pressure responsive device for controlling said valve, a chamber in communication with said connections and into which saturant may flow, connections between the upper portion of said chamber and said device, and means for maintaining said pressure in said chamber counterbalancing the pressure on said saturant for preventing the saturant in such chamber from contacting with such device- 17. In an apparatus of the class described, a tank for containing articles'to be saturated, a saturant supply, pipe connections between said tank and supply, means for forcing saturant through said connections from said sup ply to said tank, a bypass from the pressure side of said means to said supply, a valve in said bypass, a pressure responsive device for controlling said valve, a chamber in communication with said connections and into which saturant may flow, connections between the upper portion of said chamber and said device, means for maintaining said pres sure in said chamber counterbalancmg the pressure on said saturant for preventing the saturant in such chamber .from contacting with such device, and means for heating the saturant in said chamber. I

In testimony whereof I have aflixed my signature.

HOWARD PARKER.

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