US1643972A - Steam-circulating system for driers - Google Patents

Description

0c n 1643972 t 4 1927. K J. o. wooDsoME v STEAM CIRCULATING SYSTEM -FOR DRIEIRS med June 16. 192s 2 sneezssmf. 1

Je? Co'mpressar @Ewig folzgz 0 Woadsgme Patented Oct. 4, 1927.

JOHN 0.woo-Dso1vrn, or NEW Yoan, n. Y. STEAMCVIRCULATING AsYsjs-inw: son nnrnns.v

Appneaacm inedl June is, lesa serial No. 116,307.rv

, for eiicient and economical use of the steam is the provision for rapid circulation of the steam through the drying cylinders without permitting appreciable loss through the escape of uncondensed steam. The use of y.low pressure steam yand, low back pressures on the. driers also 'increases the economy7 of the system.

yIt. is therefore an object of this invention l to provide a steam circulating system for f paper machine driers, wherein a'rapid cir-y culation of steamthrough the driers is ef`- fected by the use of Venturi type jet compressors and circulators and wherein loss f throughthe escape from the driers of uncondensed steam is prevented bythe use of nozzle separators. Y

It is a further important object of myinvent-ion to provide a steam circulating system for paper machinedriers, wherein both high and low pressuresteam maybe used in connection with jet compressors of the Venturi type to effect rapid circulation and wherein meansV are provided. for the reduc! tion of. the back pressure on the driers.

Other and further important objects of this invention will be apparent from the 4disclosures in the specification and the accompanying drawings.

This invention (in Aakpreferred form) is illustrated inl thel drawings and hereinafter nore fully described.

vIn the drawings:

.Figure 1 is an .end elevational View', withV parts section,"of a steam drying installation for paper making machine driers. Figure 2 is an end elevational view with parts in section, of a modiedtype Vof' 1n stallation. e

In the steam drying system illustra-ted by Figure 1 the reference numeral 1` indicates a steam drying cylinder ofthe usual typeI found on paper machines. lSaid cylinder 1 comprises a cylinder shell [2' and a head 3 at each end thereof, provided with journals 4 rotatably mounted in suitable bearings.

The rear journal ortrunnion, 4is commonly hollow to provide for the admission of steam to the drying cylinder 1. Steam is adapted to be admitted to the interior of the rierj drum 1 through a passavged fitting 5 on said condensate formed in the drier drum` 1 is suit-ably accomplished by a curved siphon I pipe G which extends from a point adjacent the lower portion of said cylinder 1 out through the'extended trunnion t and Asepa- .Y rate therefrom to an endvfitting 7 The refl moval of the condensate is of course .effected by yirtue of the steam pressure maintained within the drier drum 1, and iscontinuous throughout the drying operation.

Steam is supplied to the drying cylinder 1 l preferably from two sources, a high pressure steam header 8v anda low pressure supply header 9. The low pressure steam ordinarily is obtained from the exhaust of steam. engines and turbines used in other operations in the paper mill and the object is to use as much low pressure steam aspossible in order to reduce the cost of steam for the drying ops eration. At the same time, it is necessary in order to obtain an efficient. transfer of heat from the steam tothe drying cylinder to provide arapid circulation of the steam through the drying cylinder. In orderto accomplish bothkof these ends I employ a jet compressor l() in the inlet steam line 11 connecting thehigh pressure steam header 8 with the steam fitting 5 and join the low pressure header 9`.to said yjet compressorv by meansof piping 12. AThe purpose of. the jet compressor 1s to effect a high velocity of steam with the use of small quantities of pressure steam at the required rate. The iet compressor l() comprises an outer shell l13" flared outwardly and flanged atfhoth ends and provided at its restricted intermediate portion with a slightly enlarged portion 50 having a side aperture'lt threaded to receive the pipe 12. An inner conical shell 15 yis adapted. to be fitted within one end of said outer shell 13and is provided with a constricted orifice 16 at its reduced end which terminates adjacent the side aperture 14. A similar though preferably longer inner shell 17 is adapted to fit within the other end of said shell 13 and isprovided with a relatively larger orifi-ce`18` spaced 4apart a. short distance from the orifice 16. kThe flared -ends of said inner shells 15 and 17 are each provided with flanges v19 and QOfadapted to be received in corresponding recesses formed inthe flat ends of the outer shell 13. The inner shellsl 15 and 17 are thus made readily 1,643,972: `UNITED STATES ristrettiv orrics.

extendedv trunnion 4. The removal ofthe velf) llO compressor is to be used. Gaskets 21 may suitably be provided for each end of the 1 shell 13 to form a tight joint between the fiol fianged ends of said shell and flanged fittings 22 on lthe piping 11, said flanges being secured together as by the bolts 23.

A machine ldrain header 24 is connected to the steam fitting 7- by means of piping 25. In order to increase the velocity of the oo ndensate removed through the piping 25, a restriction nozzle 26 is preferably installed therein. Said restriction nozzle 26 is somewhatsimilar in lconstructionv to the jet compressor 10 but is provided with only `one inner shell 27 having a somewhat restricted orice 28 and having no side aperture such as inthe jet compressor.

In'order to prevent the building up of a 'back pressure within the drain header. 24

equalto or greater than the pressure in the supply header 9, an equalizing line 29 is provided joining said headers 9 and 24, and provided with a check valve 30 to prevent the flow of steam from the header 9 into the header 24. By this provision of an equalizing line, the back pressure on the driers can never exceed the pressure of the low pressure steam of the header 9. y

It will be understood that in the practical application of my jet compressor to any particular drying system, the size of the orifice 16 must be very carefully calculated to deliver the required amount of steam to the driers v1 and to maintain the required' differential of pressure between the inlet steam line 11 and the drain line 25 to insure rapid circulation of the steam.

The advantage of my jet compressor 'is that it effects the rapidcirculation of the low'pressure steam with the use of very small amounts ofl high pressure steam and without the necessity ofemploying pumps or other mechanisms having moving parts subject to wear.

In theform of installation illustrated in Figure 2, I provide in addition to a jet compressor 31 a Venturi circulator 32 connected in the inlet steam'line 33 and a nozzle sepa` rator 34 connected in the drain line 35 and connected to the Venturi circulator 32.

The jet compressor 31 as before is com nected in the inlet steam line 33 from the high pressure steam header S to the drying are provi'dedwith relatively different sized orifices 39 and 40y respectively. Said circulator 32 is also provided with a side aperture 41 adjacent the orifices 39 and 40 and threaded` to receivey a pipe 42 which connects said circulator to a side orifice 43 in the nozzle separator 34. Said nozzle sepa rator 34 comprises an outer substantially cylindrical shell 44 flanged at each end and secured to flange fittings 45 by bolts 46 passing through' rsaid fianged ends. Only one inner shell 47 is provided in said separator 34, said shell 47 being'conical shaped andhaving a restricted orifice 48 opening below P the side aperture`43. Said side aperture 43.

is positioned in a slightly enlarged central portion l49 of said separator 34. This con" struction permits the separation of. the uncondensed steam from the condensate, since the condensate being delivered through 'theV to continue in its Idownward path through" oriiices'48 below the side aperture43 tends the pipe 35 into the drain header'whereas the uncondensed steam is aspirated from the enlarged'portion 49 through the piping pressor part is concerned lto that already described in connection'with the first'installation. After the steam has passed through the `jet compressor it passes Vthrough the reduced `orifice 39,Y whichincreases its velocity rand decreasesits static pressure to the extent necessary to form a partial vacuum sufficient to draw the uncondensed steam from the separator 34 through the piping 42.V The confined steam then passes through the upwardly fiared inner shell 33 wherein the velocity is somewhat reduced,

pass out into the and throughthe piping 33 and the fitting into the interior of the drying cylinder 1. The pressure ofthe steam within the drying cylinder 1 forces'the condensate `out through the siphon 6 and the steam fitting 7 into the drain line 35. In its passage through the separator 34 the Auncondensed' steam 'is separated from the condensateas described and the condensate passes on into the drain header and is removed from the system. It is Obvious that the size of the various orifices must be carefully calculated to produce the required Velocity'of steam to the drier and the required drop in lpressure between the separator 34 and the circulator V32. For instance, with a 5 pound pressure` drop between points A and B,`the pres? sure at A being 6 pounds per square inch, a one inch throat correspon ing vto the ori- .tice 39 will deliver 12 pounds of steam per minute to the drier. By calculations from suitable charts that may be prepared showing the flow of steam to the drier using various sized orifices, the correct size of orifice for any particular installation of driers may be readily computed. Since the inner shells if the various Venturi fittings are according tov my construction interchangeable, it is a simple matter to cha-nge the capacities of the syste-m in accordance with varying needs. It will be understood that while I have described my steam circulating apparatus in connection with drying systems .for paper machines'thatsaid appara-tus is equally applicable to other systems of drying mechanisrns, as for instance in the drying of textile fabrics.

I am aware that many changes may be made, and numerous details of construction varied through a wide range without departing` from the principles of this invention, and I therefore do not purpose limiting the patent granted hereon, otherwise than necessitated by the prior art.

I claim as my invention:

l. In a steam drying apparatus, a steam drier, a high pressure steam line, piping connecting said line to said drier, a jet compressor of the Venturi type in said piping,

a low pressure steam supply header connected to said jet compressor at the constricted portion, a drain line from said drier, a Venturi iitting therein and a coinmunicating conduit between said drain line and said steam supply header to equalize the back pressure in said drain line.

2. Ina steam drying apparatus, a steam drier, high and low pressure steam lines connected thereto, anda jet compressor in said connecting line for the purpose of drawing the low pressure steam into the drier.

3. In a paper drier system, a drier drum, high and low pressure steam lines, a jet compressor having a restricted orifice and a sideV opening adjacent said orifice, said compressor being connected to said high pressure line and to said drier drum, a conduit connecting said low pressure line to said side opening, a return drain line, and a restriction nozzle in said return dra-in line.V

4. The combination with a paper machine drying cylinder, of a high and low pressure. steam supply header, a steam inlet line connecting the high pressure header with the interior of the drying cylinder, a Venturi type jet compressor in saidinlet line,

and a pipe from said low pressure header toV said compressor, whereby low pressure steam is drawn into said inlet pip-e.

5. The combination with a paper machine drying cylinder of high and low pressure steam supply headers, a steam inlet line connecting the high pressure header with the interior of thedrying cylinder, a Venturi type jet compressor in said line connected to said low pressure header, a drain header connected to the interior of said cylinder, and an equalizing line having a check valve therein between said drain header and ysaid low pressure steam supply header for JOHN O. WOODSOME.

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