US2665628A - Apparatus for treating liquids - Google Patents

Description

Jan. 12, 1954 A. H. BOILEAU EIAL APPARATUS FOR TREATING LIQUIDS 4 Sheets-Sheet 1 Filed Oct. 22. 1948 in Hi. I: T T =I RM 9% m M/ f .3 ht c F 1 u h a i m B a h F W A. H. BOILEAU ETAL APPARATUS FOR TREATING LIQUIDS Jan. 12, 1954 4 Sheets-Sheet 2 Filed Oct. 22, 1948 MW w 9 l 2 w I II I Q 3 nu V Jan. 12, 1954 A. H. BOILEAU EIAL APPARATUS FOR TREATING LIQUIDS 4 Sheets-Sheet 3 Filed Oct. 22, 1948 INVENTOR3: q/qrhurfi Boilcau Chan cs zf gqyfimfl fiarzcisi card 2 7m 4w 1954 A. H. BOILEAU ETAL 2,665,628

APPARATUS FOR TREATING LIQUIDS Filed Oct. 22, 1948 Sheets-Sheet 4 nvmvrons:

Patented Jan. 12, 1954 APPARATUS FOR TREATING LIQUIDS Arthur H. Boileau and Charles J. Rayman, Cedar Rapids, Iowa, and Francis S. Board, Chicago, Ill., assignors to Cherry-Burrell Corporation, Wilmington, Del., a corporation Application October 22, 1948, Serial N 0. 56,022

3 Claims.

This invention relates to improvements in apparatus and method for treating liquids while subjected to the effect of sub-atmospheric pressure in the presence of an attempering medium. More particularly, this invention relates to the improvements in apparatus and method for the continuous and rapid controlled treatment, such, for example, as pasteurization, steam distillation, and cooling of liquids, such, for example, as lacteal liquids, while flowing through a closed system and while in the presence of a heating medium, such, for example, as steam, and while subjected to the effects of sub-atmospheric pressures which may, if desired, be varied as the treatment progresses.

Devices of the general type contemplated by this invention and comparable methods of treating liquids generally do not contemplate sanitary arrangements in apparatus and sanitary process steps, whereby air may be purged from the liquid treating system and whereby the instantaneous discontinuance of the flow of untreated liquid into the processing apparatus or system, and the sealing of the processing chambers of the system, may automatically be effected upon the occurrence of certain conditions within one or more of the processing zones or chambers.

The primary objects of this invention, therefore, are to provide an improved method of treating liquid and improved apparatus for the practice of such improved method whereby and wherein excess air may be purged from the processing zone or zones and from the liquid supply conduit prior to the introduction of untreated liquid into the processing chamber or chambers; wherein air may automatically be admitted into the liquid supply conduit immediately ahead of the point of entry of the liquid into the first processing chamber in the event that the pressure of the incoming untreated liquid is less than a predetermined pressure, thereby to prevent the continued introduction of un treated liquid into the processing chamber; wherein the liquid is continuously supplied to the first processing chamber under pressure in excess of a predetermined pressure by a pump or equivalent mechanism automatically or manually operated responsive to certain conditions prevailing within the first processing chamber; and wherein the processing chambers are partially and controllably evacuated by evacuator mechanism which may be automatically sealed from the processing chambers upon the failure of the vacuum producing mechanism to operate according to a predetermined arrangement.

The foregoing and othzr objectives of this invention will be more apparent and will be more readily understood when read in connection with the drawings illustrating; the preferred embodiment of the apparatus contemplated by this invention, which apparatus, Without desire of limitation, will be described and illustrated as an improved type of vacuum pasteurizer for the treatment of such dairy products as milk or cream, and in which drawings:

Figure 1 is a diagrammatic representation of the preferred arrangement of the improved apparatus suitable and well adapted for the practice of the present invention. In the diagram the elements of the improved apparatus are arranged serially to illustrate the flow of liquid being treated in a closed system continuously according to the improved method.

Figure 2 is a vertical, sectional view of the improved pressure responsive valve for controlling the introduction of liquid into the processing chambers and for venting the liquid supply con- (iuit to the atmosphere and for admitting air into the liquid supply conduit upon the undue decrease in the pressure of the liquid being supplied to the first treatment chamber.

Figure 3 is a vertical, sectional view taken along line 3-3 of Figure 2 of the drawings and illustrates an inner view of the housing of the improved pressure responsive valve illustrated in Figure 2 of the drawings.

Figure 4 is a cross-sectional view, taken along line 4--4 of Figure 2 of the drawings, and illus-- trates a section of the lower portion of the housing of the valve illustrated in Figure 2 of the drawings.

Figure 5 is an enlarged, side elevational view, partially in broken-away section, of the passage intermediate the first and second treating chambers illustrated in Figure l of the drawings.

Figure 6 is an enlarged, fragmentary, vertical, sectional view, taken through one of the connections between the second processing chamber and the ejector condenser illustrated in Figure 1 of the drawings.

Figure 7 is an enlarged, fragmentary, vertical, sectional view of the upper portion of the first processing chamber, illustrated in Figure 1 of the drawings.

The improved apparatus according to the present invention and the improved method are readily adaptable in the treatment or processing of various liquids, in which the accurate control of the process steps and the relatively gentle handling of the product are important aspects.

The description of the invention, without desire of limitation, will be directed to an improved apparatus for the continuous processing of cream and the improved method wherein the cream is rapidly but gently treated while subjected to the effects of reduced pressure and while being gently intermingled and diffused with steam in a closed system for the pasteurization or steriliza tion, deodorization, steam distillation and prompt cooling of the cream to enhance the physical properties thereof and destroy harmful bacteria and spores.

After the improved apparatus has been properly cleaned and sterilized and assembled in the manner illustrated in Figure l or" the drawings, the apparatus may be operated and the process initiated by flooding the product discharge pump I with sterile water. The sterile water may be accumulated in the intake of the pump l to flood the pump as a result of the condensation incidental to steam sterilization of the apparatus or may have been manually introduced into the discharge portion of the apparatus ahead of pump I. Discharge pump 1 is then placed in operation and cool water circulated through the water jackets 2 and 3 of the processing chambers i and 5, respectively. Water supply pump 6 is then placed in operation to force the determined quantity of water, preferably cool water, at a predetermined pressure, through pipe i to and through the nested cones 8 of the compound or dual ejector condenser 9 housed in condenser chambers H] and II and mounted on standard 12. The temperature and pressure of the cooling water supplied by pump 6 will be indicated by the thermometer l3 and pressure gage Hi, respectively, and the temperature of the water discharged from the last cone or the ejector condenser 9 will be indicated by the thermometer l5.

As the entire apparatus is completely scaled from the atmosphere, the commencement of the operation or the ejector condenser will promptly create a reduced pressure condition in the ejector condenser chambers ill and H. The chamber l9 communicates with the final processing or vacuum cooling chamber by means of conduit 16, which is provided with a pressure or vacuum gage I1 and the chamber ll communicates with the intermediate processing or vacuum dcodorizing chamber 5 through conduit l8, which is provided with a pressure or vacuum gage If).

The volume and the pressure of the cooling; water supplied to the ejector condenser 9 by the pump 6 may be so controlled by the appropriate operation of pump 6 as to produce a vacuum when measured in inches of mercury of approxi mately 21 to 28 inches within the condenser cham bers l0 and II. Such vacuum condition will be clearly indicated by the gages I? and i9, respec tively. The same degree of exhaustion or vacuum prevailing in the ejector condenser chamber will also prevail in the final processing chamber 4 and the same degree of exhaustion or vacuum prevailing in the ejector condenser chamber II will also prevail in the intermedi ate processing chamber 5 and in the first processing chamber 2!), which is connected to the processing chamber 5 by means of the conduit 2|. Having thus evacuated the three processing chambers 4, 5 and 20, the reversally operating automatic pressure regulating valve 22, which communicates with the condenser chamber II, is adjusted to reduce the vacuum prevailing within the chamber II by the periodic or continuous admission of controlled quantities of air to the ejector condenser chamber II to reduce the vacuum therein to a vacuum preferably within the range of 15 to 20 inches of mercury, while the vacuum prevailing within the ejector condenser chamber H3 is maintained preferably at approximately 28 inches of mercury.

Having thus adjusted the operation of the ejector condenser 9, steam valve 23 in the steam pipe 24 is then opened to admit steam, preferably saturated steam, which has passed through a purifier 25 into the upper portion of the first processing chamber 22 The automatic steam pressure regulating valve 25 in pipe 24, intermediate the purifier 25 and chamber 20, is then adjusted so as to admit a predetermined, desired volume of steam. The necessary or desired volume of steam, in the first instance as before mentioned, is determined by observing the rise in temperature, as indicated by the thermometers l3 and I5, of the water which is being circulated at a constant volume through the ejector condenser 9. When such rise in temperature of the ejector condenser water indicates that the desired amount of heat is being supplied by the steam admitted into the upper portion of the first processing chamber 20, disregarding radiation losses, equilibrium valve 2': in the conduit 2| between the first and second processing chambers 20 and 5 is adjusted by tightening the spring loaded valve adjusting linkage 29 by the appropriate adjustment of the handwheel 29 until the predeter mined, desired temperature is indicated on the thermometer so in the passage 2| ahead of the valve 21. The temperature as indicated by thermometer (it would be the temperature prevailing in the first processing chamber 2i] ahead of valve 2'! and should correspond to a reduced pressure condition preferably within the range of 5 to 11 inches of mercury. The processing apparatus being thus adjusted, reduced pressure condition preferably within the range of 5 to 11 inches of mercury will prevail in the first processing chamber 26, a reduced pressure condition preferably within the range of 15 to 20 inches of mercury will prevail in the second processing chamber 5 and a reduced pressure condition preferably within the range of 2T to 28 inches of mercury will prevail in the last processing chamber 4.

Having thus adjusted the pressure conditions, and, oi necessity, the temperature conditions existing within the chambers 20, 5 and 6, which temperature condition will, of necessity, be within the ranges of approximately 199 F. to 200 F., and 162" i to 179 R, and 180 F. to F., respectively, the cream or untreated product supply pump 3i is placed in operation. Supply pump 3| is of the necessary type and has been so adjusted as to enable it to withdraw from a suitable source of supply through the intake pipe 32 a predetermined quantity of cream and deliver it through the conduit 33 at a predetermined pressure preferably in excess of atmospheric pressure, to and through the compound pressure inlet valve mechanism 34 into the upper portion of the S'Qfiiil processing chamber 20. The manner of controlling the operation of the pump 31 and the operation of the compound valve 35 will hereinafter be more fully described.

The cream entering the upper portion of the vacuum flash pasteurizing or sterilizing chamber 20 is discharged into a concentrating or centering funnel 35, from which it flows into a distributor 36, which has a finely perforated, lower distributing or diifusing section 31. The cone or funnel 35 is entirely surrounded by the distributor 36, which, in turn, is entirely surrounded by a steam deflector baffle 38. The cream is distributed by the plate 31 in minute droplets into the upper portion of the first chamber 20 within the confines of the bafile 38. While the droplets of cream descend through the chamber 20, they are gently intermingled and diffused with the steam supplied through the conduit 24 and rapidly heated to the temperature indicated by the thermometer 30, which, as hereinbefore indicated, would preferably be within the range of 190 F. to 200 F. corresponding to the reduced pressure conditions prevailing in chamber 20.

The heated and diflused mixture of cream and steam is drawn by the effect of the reduced pressure existing in the chamber 5 from the lower portion of the pasteurizing or sterilizing chamber 20, through the pipe 2|, past the throttling or equilibrium valve 21 into the upper portion of the intermediate or steam distillation and deodorizing chamber 5. The mixture of cream and steam enters the upper portion of the chamber 5 tangentially and boils appreciably due to the reduced pressure condition in chamber 5, and swirls downwardly over the inner wall of the chamber into the lower water jacketed portion wherein it accumulates.

Uncondensed steam and other gases are withdrawn from the chamber 5 into the chamber II of the ejector condenser through the communicating conduit l8, through which they enter by way of intake pipe 39. Pipe 39 extends downwardly into the chamber 5 from the upper portion thereof and is provided with an outwardly flared lower portion 40, surrounded by a collecting flange 4|. The flange 4| serves to collect small quantities of product which may impinge against the outer wall of the pipe 39 and the expanded portion 40 and drain downwardly thereover onto the flange 4|. Such a collected product is drained from the flange 4| through the spouts 42, which extend downwardly from the flange 4|, through the high velocity zone of escaping gases, thus preventing product from being entrained with the escaping gases.

The discharge of the product from the lower portion of the intermediate processing chamber 5 is controlled by the float valve 43 and when sufficient material has accumulated to operate the valve 43, the product is withdrawn therefrom through the conduit 44 into the upper portion of the third processing or cooling chamber 4 by the efiect of the reduced pressure existing in the chamber 4. The product enters the chamber 4 tangentially at the upper portion thereof in the same manner in which the product entered the chamber 5, and swirls downwardly into the lower water jacketed portion thereof where it accumulates after appreciable additional boiling produced by the reduced pressure condition existingin chamber 4. Released gases and uncondensed steam are withdrawn from the chamber 4 into the chamber H] of the ejector condenser through the communicating pipe l6, which, like unto the pipe I3, is also provided with depending intake pipe 39, which extends from the top portion of the chamber 4 downwardly centrally thereof. From chamber 4 the product is withdrawn through pipe 45 into the discharge pump I, from which, in turn, it is discharged to any desired station.

From time to time it may be necessary, particularly at the commencement of the operation of the apparatus, to make necessary adjustments of the operation of the water pump 6, the cream pump 3|, the steam regulator valve 26, the equilibrium valve 21, and the vacuum adjusting valve 22, so as to maintain the desired condition of reduced pressures and temperatures throughout the apparatus. To this end the various pumps must be of the type which lend themselves to such adjustment.

As hereinbefore mentioned, the processing of the product, according to the present invention, enables the accurate control of the conditions existing Within the various processing zones or chambers. Of primary importance is the control of the conditions existing within the first or pasteurizing or sterilizing chamber 20. The accurate control of the temperature of the product, immediately preceding the discharge thereof from the first chamber 20, past the throttling valve 21 into the second chamber 5, is directly related to the quantity of product supplied or being processed, the volume and pressure of steam being supplied to the first processing chamber 20, and the degree of vacuum prevailing within that chamber, and it is desirable to discontinue promptly the introduction into that chamber of untreated material to be processed in the event that any one or more of these conditions should be improper for securing the desired processing temperature.

The adjustment of the apparatus to maintain the desired operating conditions may obviously be accomplished manually. Automatic adjustment is in many instances more desirable. To this end the motor 46 which drives the cream supply pump 3| is controlled by a switch 41 which may be operated manually by the push button control 48 to open or close the power circuit for the motor 46. Switch 41 is also responsive, by means of suitable controls, to the temperature of the product as it is being discharged from the lower portion of the chamber 20 and to the vacuum prevailing within the chamber 20 and to the flow of the steam as it enters the upper portion of the chamber 20.

Suitable controls for the switch 41 of the type contemplated include the appropriately adjusted thermal unit 49, positioned in the passage 2| at the lower portion of the chamber 2|! and suitably connected in conventional manner to the switch 41, whereby to enable the opening or the closing of the power circuit for the cream supply pump 3| when certain predetermined temperature conditions prevail within the lower portion of the chamber 20. Similarly, a pressure sensitive element 50, communicating with the inner portion of the chamber 20, is also suitably connected to the motor switch 41, whereby to open or close the power circuit for the pump motor 46 by the appropriate actuation of the switch 41 upon the existence of certain predetermined conditions within the chamber 20, for which the pressure element 50 has previously been adjusted or set. In like manner, a pressure and/or flow responsive unit 5| communicates with the interior of the steam pipe 24 intermediate the automatic pressure regulating valve 26 and the chamber 20 and is, in turn, suitably connected to the motor switch mechanism 41, so that, when certain predetermined conditions prevail as to the pressure and flow of steam through the pipe 24 into the upper portion of the chamber 20, the power circuit for the motor 46 may either be opened or closed by means of switch 41 in response to the action of the unit 5|. By the use of such automatic controls involving the thermal unit 43, the vacuum responsive unit 5|) and the steam pressure and volume responsive unit 5|, it is possible to assure the operation of the cream pump 3| only when certain predetermined conditions of pressure and temperature exist within the processing chamber 25 and when a certain predetermined volume of steam at a predetermined pressure is flowing through the conduit 24 into the upper portion of the chamber 20.

The switch 41 may be operated manually by the push button control 48, which, independently of other controls, may be used to open or close the power circuit for the pump motor 46. The power circuit for the pump motor 46 may also be opened by the appropriate action of the switch 41 in response to any one or more of the automatic actuators 49, D or 5|. However, it requires the combined comparable action of all three of these automatic units 49, 55 and 5! to appropriately and automatically actuate the switch 41 to close the power circuit for the pump motor 46.

The compound valve mechanism 34, as clearly illustrated in Figure 2 of the drawings, includes a number of valve or fluid flow throttling elements. In the commencement of the operation of the processing unit as illustrated in Figure 1 of the drawings, the liquid supply pipe 33 is normally filled with air. Upon placing the pump 3i in operation, the pump will commence to force liquid through the pipe 33 and to compress the air contained therein. The pressure of the compressed air against the plunger 52 tends to raise the plunger within the lower branch 53 of the housing of the compound valve 34. As the plunger 52 rises, compressed air tends to escape past the outer edges of the plunger 52 through the channels 54 in the inner faces of the lower branch of the housing 53.

The passages 54, as clearly illustrated in Figures 2, 3 and 4 of the drawings, gradually increase in width and depth from the lower end thereof toward the upper end thereof. As the pressure of the air compressed in the conduit 33 below the plunger 52 increases, and as the plunger 52 rises, the volume of air which may escape through the channels 54 increases. As the air escapes through the channels 54 into the space in the housing of the valve34 between the plungers 52 and the spring biased plunger 55, reciprocally mounted in the upper branch of the housing of the valve 34, the pressure of the air again increases and the air escapes through the vent 55 in the housing of the valve 34.

The relative proportions of the channels 54 and the vent 58 are such that the air may readily escape from the pipe 33 ahead of the liquid being supplied thereinto by the pump 3|. When the pipe 33 has been purged of air and the liquid engages the plunger 52, the escape of the liquid through the channels 54 is not as rapid as the escape of the air therethrough, and the plunger 52 is rapidly forced upwardly. The upward motion of the plunger 52 carries with it the valve stem 53, the upper end of which is triangular in cross section and extends through the vent 53 and which is supported on the plunger 52. Such upward motion of the valve stem 58 continues until the valve 51 on the valve stem 58 is seated against the valve seat 53 in the housing of the valve 34 at the inner end of the vent 55, thus sealing the vent 56 and preventing the further escape of air or liquid through the vent.

The valve stem 58-, the upper portion of which extends through the vent 55, has a triangular cross section and permits the ready escape of gas through the vent 55batrat thesametimefunctions satisfactorily as a guide to accurately seat the valve 51 onto the valve seat 53. The lower portion of the valve stem 58 extends through a central aperture in the plunger 52, and is supported thereon by a spring 60 which is telescoped over the lower portion of the valve stem 58 intermediate the lower inner wall of the plunger 52, and the flange 6| on the valve stem 53. Such support of the valve stem 53 on the plunger 52 by the use of the spring 50 permits the continued upper motion of the plunger 52 in response to the pressure of the liquid in the supply conduit 33, after the vent 56 is sealed by the seating of the valve 51 against the valve seat 59. A spring retainer 52 is provided which extends intermediate the upper end of the spring 60 and the flange GI with the ends thereof extending downwardly and outwardly into sliding engagement in slots 53 in the walls of the plunger 52. Such an arrangement obviously permits the plunger 52 to move upwardly in the lower branch 53 of the housing of the valve 34 into such position as to permit the liquid to enter the enlarged upper portions of the channel 54, irrespective of the fact that the vent 55 has been sealed and valve stem 58 cannot be moved further upwardly.

With the plunger 52 thus raised into an elevated position by the pressure of the incoming liquid entering through the pipe 33 into the housing 01' the valve the pressure of the liquid intermediate the plungers 52 and 55 quickly becomes sufficient so that the effect of the pressure of the liquid in pipe 33 on the one side of plunger 55 and the effect of the vacuum in chamber 20 on the opposite side of plunger 55 will be to move the plunger 55 into the upper branch 54 of the housing of the valve 34 against the pressure of the plunger spring 55. Such motion of the plunger results in lifting the valve face 66 at the lower end of the plunger 55 from the complementary valve seat 51, to thus permit the flow of liquid through the intermediate branch 68 of the housing of the valve 34 into the upper portion of the first processing chamber 20.

It should be noted from the preceding description of the spring loaded pressure inlet valve 55 forming a part of the compound valve 34, illustrated in Figure .2 of the drawings, that all of the product which is supplied to the processing chamber 25 by the pump 3! is supplied through conduit 33 after the air has been purged therefrom and must be supplied under a sufficient pressure to raise the plunger 55 against the pressure of the spring 65, which necessary pressure has been predetermined by the selection of a spring of appropriate strength. The action of the liquid actuated plunger 55 of the compound valve 34 upon the discontinuance of the operation of the pump 3| or upon the occurrence of a sufficient drop in the pressure on the liquid in the supply line 33, as it may be supplemented or offset by the effect of the vacuum in chamber 20, is, in substance, the reverse of the operation just described for the flow of liquid in the forwardly direction from the pump 3| to the chamber 20,

When the pressure of the liquid in the line 33 drops either as a result of a stoppage or failure of the pump 3!, and the combined effect of the pressure of the liquid in the conduit 33 and the vacuum in the chamber 2!] is not sufiicient to overcome the pressure of the spring 55 and continue to raise the plunger 55, the plunger 55 will descend in the upper branch 34 of the valve mechanism 34 until the valve 66 engages the valve seat 61, thereby promptly stopping any further flow of liquid through the valve 34 into the upper portion of the chamber 20. Immediately upon the occurrence of such condition, if the pressure of the liquid in the line 33 drops sufiiciently, the plunger 52 will, as a result of the efiect of gravity, descend sufficiently to remove the valve element 51 from the valve seat 59, thus opening the air vent 5B, and permitting the entry of air into the valve housing 34 intermediate the plungers 52 and 55. Such entry of air through the vent 56 will permit the complete drainage of the pipe 33 through the pump 3!, pump 3| having such construction and operating characteristics and being so arranged as to permit such drainage upon stoppage of the pump 3 I Valve 3 is so constructed that when arranged for operation the valve stem 58 is vertical and the air vent valve seat 59 is at the same elevation or lower than the lowest portions of the valve seat 67. In the event that the drainage of liquid through the pump 3i is slow and the condition of vacuum still exists in the chamber 2!], the entry of air through the vent 56 into the portion of the valve housing immediately below the valve plunger 55 will prevent the withdrawing of liquid by suction from the housing of the valve 34 throughbetween the valve 66 and the valv seat 61 into the processing chamber 29. Such operation of the plunger 55 of valve 34 assures the exclusion from chamber 29 of any unprocessed liquid in the event of the stoppage of the pump 31 due to any of the hereinbefore mentioned conditions of temperature pressure or steam supply, each of which individually, or all simultaneously, could cause the discontinuance of the operation of the pump 3| in the manner hereinbefore described.

As hereinbefore described, the improved apparatus and improved method of processing liquids contemplates the continuous processing of a product, such as cream, under the influence of vacuum in a closed system. In the preferred embodiment of applicants invention, the vacuum generator has been illustrated as a water ejector type of steam condenser. As sometimes occurs in the operation of such mechanism, the operation of the ejector may fail for various reasons, thereby bringing about a failure of the vacuum, and, in some instances, such failure results in the accumulation of water under pressure in the condenser chambers. Such an accumulation of water in the condenser chambers l and H would obviously present a problem of flooding the productcontaining chambers 4 and 5, and the resulting damage of the product contained therein.

To prevent flooding the chambers 4 and 5, a check valve 69 is provided at the point of juncture of each of the conduits l6 and ill, with the chambers I0 and II, respectively, of the ejector condenser 9. Such a check valve 69 is clearly indicated by Figure 6 of the drawings. Each valve 69 is supported on its pivot 10, positioned above valve 89, so that the weight of the valve 69 will tend to seat the valve 69 against the valve seat H. Similarly, upon the discontinuance of the vacuum condition in either the condenser chambers H] or H, any accumulation of water under pressure in these chambers will tend to force the associated valve 69 against its seat II in the event that the water accumulates to a sufficient depth to engage the valve associated with the respective chamber. Similarly, if the stoppage of the condition of vacuum is sudden, the reduced pressure or vacuum condition existing within the chambers 4 and would also tend to draw the valve 69 against the seat H to seal the respective chambers 4 or 5 from the associated ejector condenser chambers ID or H.

As hereinbefore mentioned, the equilibrium valve 21 functions to regulate the relative pressure conditions existing between the first two processing chambers 28 and 5. The rapid flow of large volumes of gas and licuid past the valve 21, which is drawn toward its seat by the spring loaded linkage 28, may tend to cause a vibration of the valve 21. To reduce to some extent such vibration of the valve 21, and at the same time to permit the ready adjustment of the valve, and to seal the entry of the valve lever through the wall of pipe 2 l, the valve 21 is connected to a pivoted valve lever 12, which lever 12 is mounted on a spherical segment 13, supported in sectional pivot supports M. Supports M are housed in the passage [5 extending into the conduit 2|. The sectional pivot supports M are each provided with an axial aperture through which the lever 12 extends and in their adjacent faces are provided with depressions complementary to the spherical surface of the pivot 13. The inner section H of the pivot support abuts against a shoulder in the passage 1'5 and the outer sectional pivot support 14 is urged toward the inner sectional pivot support 1'4, by a compressed spring 15, held in position by an apertured cap 11 threaded to the outer end of the passage 15. By the appropriate adjustment of the cap 11 to suitably compress the spring it, the desired degree of friction intermediate the sectional pivot supports 14 and the pivot 13 may be secured so as to dampen the vibration of the equilibrium valve 2! and at the same time to maintain a suitable seal about the entry of the valve lever 1'2 into the passage 2|.

As is apparent from the hereinbefore described invention, the applicants have provided an improved apparatus and improved method of operation for the introduction into a vacuum type of processing device of liquid supply only under pressure in excess of a predetermined pressure, after first purging from the liquid supply conduit all of the air which normally would tend to interfere with the operation of a vacuum type of processing device. The invention also provides an improved apparatus and method of operation whereby the entry of untreated liquid into the processing chamber is automatically prevented in such instances wherein the pressure of the in-- coming liquid is less than a predetermined pressure, and whereby air is admitted into the liquid supply conduit in those instances where the pressure of the liquid in the supply conduit is abnormally low, so as to permit drainage of the liquid from the conduit back through the su ply pump to prevent the possible leakage of liquid past the inlet valve into the first processing chamber.

The improved device also provides for the completesealingof the processing chambers to prevent the contamination of the product being processed, in the event of the failure of the vacuum producin mechanism. It is important to note that in the operation of a device according to the applicents invention, wherein there is included the automatic pressure inlet and conduit venting valve, that such combined valve mechanism is responsive to the combined effect of pressure on the liouid within the supply conduit and the vacuum existing within the first processing chamber. The arrangement whereby the pump, which supplies the liquid into the supply conduit, is operated in response to the temperature and pressure conditions and in response to the flow of heat exchange medium into the processing chamber to assure the maintenance of the flow of a sufilcient quantity of heat exchange medium and the proper conditions of pressure and temperature in the chamber at all times while the raw ma terial is being supplied thereto, is a valuable advance in the art of processing liquids, such as milk or cream and other like food and beverage products.

Having thus described and illustrated the preferred embodiment and method of practicing the present invention, the invention is not to be restricted to the specific embodiment thereof as illustrated in the drawings and as hereinbefore described, excepting insofar as may be necessary in view of the disclosure of the prior art and the appended claims.

The invention is hereby claimed as follows:

1. In a device of the class described, the combination of an initial processing chamber, a subsequent processing chamber, a connecting duct interposed therebetween and communicating with said chambers, an external product supply duct communicating with the initial processing chamber at a place remote from said connecting duct, a processing medium duct communicating with said initial chamber adjacent to the product supply duct whereby suitable processing medium may be introduced into said chamber concurrently with the product to be processed and in proximity therewith, a product withdrawal duct communicating with said subsequent processing chamber at a place remote from said connecting duct, and an exhausting duct, communicating with said subsequent processing chamber for removing processing medium therefrom, said external product supply duct being provided with pressure operated valve means whereby product is admitted to said initial chamber at a predetermined pressure.

2. In a device of the class described, the combination of an initial processing chamber, a subsequent processing chamber, a connecting duct interposed therebetween and communicating with said chambers, an external product supply duct communicating with the initial processing chamber at a place remote from said connecting duct, a processing medium duct communicating with said initial chamber adjacent to the product supply duct whereby suitable processing medium may be introduced into said chamber concurrently with the product to be processed and in proximity therewith, a product withdrawal duct communicating with said subsequent processing chamber at a place remote from said connecting duct, and an exhausting duct, communicating with said subsequent processing chamber for removing processing medium therefrom, said external product supply duct being provided with pressure operated valve means whereby product is admitted to said initial chamber at a predetermined pressure, said external product supply duct being connected with a source of product under pressure and. having a cooperating pressure-operated valve through which product is introduced to said initial chamber, said valve being adapted to withhold product from said chamber when the product pressure is below a predetermined level.

3. In a device of the class described, the combination of an initial processing chamber, a subsequent processing chamber, a connecting duct interposed therebetween and communicating with said chambers, an external product supply duct communicating with the initial processing chamber at a place remote from said connecting duct, a processing medium duct communicating with said initial chamber adjacent to the product supply duct whereby suitable processing medium may be introduced into said chamber concurrently with the product to be processed and in proximity therewith, a product withdrawal duct communicating with said subsequent processing chamber at a place remote from said connecting duct, and an exhausting duct, communicating with said subsequent processing chamber for removing processing medium therefrom, said external product supply duct being provided with pressure operated valve means whereby product is admitted to said initial chamher at a predetermined pressure, said external product supply duct being connected with a source of product under pressure and having a cooperating pressure-operated valve through which product is introduced to said initial chamber, said valve being adapted to withhold product from said chamber when the product pressure is below a predetermined level and said valve having air bleeding means to insure removal of air from the product before supplying said prodnot to said initial chamber;

ARTHUR H. BOILEAU.

CHARLES J. RAYMAN. FRANCIS S. BOARD.

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