Abstract:
A method and apparatus for cheese block forming with vacuum separated tower sections is disclosed for use in producing large blocks of compressed cheese without having to halt delivery of cheese curd into the tower while discharging a block of cheese. The cheese block former has an upper tower section with an interior area for receiving a mixture of curd and whey under a negative pressure, and a lower tower section, also under a vacuum, for separating the whey from the mixture and pressing the remaining curd into a block of cheese. A vacuum separator is disposed between the upper and lower tower sections to allow the upper and lower sections to remain in fluid communication and, additionally, to allow different pressures therein. The vacuum separator thus provides for a continuous cheesemaking process.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to cheesemaking, and more particularly to a cheese block forming machine for continuously making compressed blocks of cheese with a tower having two sections capable of having different vacuum pressures simultaneously. 
     Cheese block formers are commonly used to produce large blocks of cheeses. They generally do so by providing a tower or column having a large interior area. At the top of the column, a mixture of curd and whey is fed into the column under a vacuum. As the mixture flows down through the column, the whey is drained out of the mixture and the curd, under its own weight, becomes a solid cheese pillar. At the bottom of the column, the pillar is cut into blocks using a cutting apparatus, such as a guillotine blade. The cheese is prepared for packaging and shipment. 
     To be effective, the machines must be rugged so as to minimize maintenance and labor expenses, efficient, and capable of producing a variety of cheese types (ie., cheddar, colby, monterey jack, mozzarella, brick or muenster). Further, the block formers must produce cheese blocks that have consistent weights from block to block and have a uniform moisture content. Finally, the block formers themselves should allow for independent operation, or for operation in conjunction with multiple cheese block formers. 
     There have been many attempts to properly mass-produce cheese blocks using large cheese block formers in the prior art, but most have fallen short in at least one of a number of categories. One example is that the prior art processes have not provided for continuous cheese block production. That is, when a cheese block is cut, the vacuum had to be shut off so as to accommodate the opening of the guillotine blade in preparation for cutting the cheese block. Once the vacuum was shut off, curd feed could not be drawn into the block former. After the guillotine was closed, the vacuum could be turned on again. However, time is required to achieve the vacuum necessary to allow curd feed to begin. Therefore, the prior art processes required a certain amount of downtime, and thus there lacked continuity in the cheese block forming processes. Further, downtime in general adds to production expenses and reduces overall efficiency. 
     Therefore, it would be desirable to have a cheese block former that solves the aforementioned problem, thus allowing large blocks of cheese to be produced continuously and without significant down time. 
     SUMMARY OF THE INVENTION 
     The present invention provides for an apparatus and method for cheese block forming with vacuum separated tower sections that overcomes the aforementioned problem. 
     In accordance with one aspect of the invention, the cheese block former has an upper tower section with an inner surface and an outer surface. The inner surface defines an interior area. The upper tower has a curd feed inlet at its top to allow curd to enter into the cheese block former. When the curd is inside the upper tower section, it comes in contact with the inner surface. The cheese block former also has a lower tower section that has inner and outer surfaces, as well as an interior area. The lower tower section is in fluid communication with the upper tower section, and has an inner screen along its inner surface. The inner screen is used to separate the whey from the cheese curd mixture under a vacuum. Finally, the upper tower section has a vacuum separator that serves to connect the upper and lower tower sections. The vacuum separator allows different pressures to exist simultaneously in the upper and lower tower sections to thereby provide continuous cheese block formation because as one block is being removed from the lower tower section, the upper tower section can be kept under high vacuum to draw in more cheese curd to keep the process operating continuously. 
     In accordance with another aspect of the invention, a cheese block former is disclosed to continuously make large blocks of bulk cheese from a cheese curd mixture, the block former again having an upper tower section. The upper tower section has top and bottom ends, inner and outer surfaces, and a curd feed inlet to allow curd to enter the interior area of the upper tower section. The block former also has a lower tower section having top and bottom ends. The block former further has separate vacuum sources for the upper and lower tower sections as well as a vacuum separator to permit different pressures to exist simultaneously in the upper and lower tower sections. The lower tower section also has at least one removeable perforated plate extending from the top to the bottom of the section. And finally, the lower tower section has a flange through which vacuum is provided. 
     In accordance with another aspect of the invention, a method for continuously making blocks of cheese is disclosed. A mixture of curd and whey are fed into an opening at the top of the upper tower section. The mixture is drawn into the tower by providing a vacuum source to the upper section of the tower. The whey is separated from the curd in a lower tower section by providing another vacuum source to the lower tower section. The whey is drained from the cheese through an area between a perforated whey separation screen and an inner surface of the lower tower section. The vacuum source of the upper tower section is separated from the vacuum source of the lower tower section. A solid cheese column is formed from the curd by applying pressure from the weight of the cheese column. Properly sized blocks of solid cheese are obtained while simultaneously feeding additional curd mixture into the upper tower section. 
     Accordingly, one object of the present invention is to provide a cheese block former which can continuously produce cheese blocks by providing a vacuum separation means between two sections of a cheese block former. 
     Another object of the invention is to provide a cheese block former which can produce larger cheese blocks of a variety of cheeses in a sanitary, efficient and reliable way by allowing a block of cheese to be discharged while at the same time drawing in fresh cheese curd. 
     Various other features, objects and advantages of the present invention will be made apparent from the following detailed description and the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings illustrate the best mode presently contemplated for carrying out the invention. 
     In the drawings: 
     FIG. 1 is an elevational front view of a cheese block former according to one aspect of the invention. 
     FIG. 2 is a detailed schematic view of a portion of FIG. 1 taken along line  2 — 2  of FIG.  1 . 
     FIG. 3 is a detailed view of one embodiment of a top portion of FIG. 1 having a straight-through upper tower and a rotary valve. 
     FIG. 4 is a partial cross-sectional view taken along line  4 — 4  of FIG.  3 . 
     FIG. 5 is a detailed view of another embodiment of a top portion of FIG. 1 having a straight-through upper tower without a rotary valve. 
     FIG. 6 is a partial cross-sectional view taken along line  6 — 6  of FIG.  5 . 
     FIG. 7 is an isometric view of a straight-through chute in accordance with one aspect of the invention. 
     FIG. 8 is a detailed view of a top portion of FIG. 1 having a cyclone-type hopper and a rotary valve. 
     FIG. 9 is a detailed view of a top portion of FIG. 1 having a cyclone-type hopper and with the straight-through chute of FIG.  7 . 
     FIG. 10 is a detailed sectional view of a portion of FIG. 9 taken along line  10 — 10  of FIG.  9 . 
     FIG. 11 is a cross-section of the lower tower taken along line  11 — 11  of FIG.  4 . 
     FIG. 12 is a detailed view of a portion of FIG. 11 taken along line  12 — 12  of FIG.  11 . 
     FIG. 13 is a detailed view of a portion of FIG. 11 indicated by line  13 — 13  of FIG.  11 . 
     FIG. 14 is a detailed cross-sectional view of a portion of FIG. 13 taken along line  14 — 14  of FIG.  13 . 
     FIG. 15 is a partial isometric detailed view of a portion of FIG.  14 . 
     FIG. 16 is a schematic cross-sectional view of a portion of a cheese block tower showing the lowering of the cheese within the tower. 
     FIG. 17 is a schematic cross-sectional view of a portion of the cheese block tower showing the discharging of a cheese block. 
     FIG. 18 is a schematic block diagram of a cheese block former system according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a cheese block former  10  according to the present invention situated on a finishing section  170 , which itself is mounted on a base  14 . The cheese block former is shown having a lower tower section  80 , a vacuum separator  60 , and an upper tower section  30 . The vacuum separator provides a vacuum separation between the upper and lower tower sections. The tower has a curd feed inlet tube  38  on an upper end  32  to supply curd feed into the upper end  32  of the cheese block former  10 . A vacuum port  40  is provided in the upper end  32  of the upper tower section  30  to draw curd into the cheese block former  10 . The lower tower section  80  has vacuum ports  90  and  92  that are used to draw whey from the curd, as will be described in detail hereinafter. In a preferred embodiment, separate vacuum sources (not shown) provide the vacuum to vacuum port  40  and vacuum ports  90  and  92 . A motor  46  is located on the vacuum section and drives a rotary star valve  62  (FIG. 4) according to one preferred embodiment of the invention. 
     FIG. 2 illustrates a sectioned schematic view taken along line  2 — 2  of FIG. 1 to show a taper in the lower tower section  80 . As indicated, a bottom end  100  has a wider cross section than a top end  102  which has a more narrow cross-section. The taper from the flange  86  to the bottom end  100  is provided to supply blocks of cheese of desired size and at the same time, limit the amount of curd entering the lower tower section  80 . 
     Referring to FIG. 3, the upper tower section  30  of the cheese block former  10  is shown in greater detail. The upper tower section  30  extends from an upper end  32  to the vacuum separator  60 , and has an inner surface  30   a  and outer surface  30   b  which define an interior area  36 . In this embodiment, the upper tower section  30  is shown with a rectangular-shaped hopper  34 , which has a cheese curd inlet  38  for allowing cheese curd to enter the upper tower section  10  under a vacuum supplied via a vacuum port  40  which is connected to a vacuum source (not shown). A curd level indicator  42  is attached to the upper end  32  about the vacuum port  40 . A motor  46  is positioned adjacent the upper tower section  10  and is mounted with supports  48  and  49 . The motor  46  operates a valve  62  within the vacuum separator  60  and is preferable a  1  HP motor. Below the vacuum separator  60 , the lower tower section  80  is partially shown. Two separate vacuum lines  90  and  92 , each connected to a vacuum source (not shown) to draw whey from the curd in an enlarged vacuum chamber  88  (which will be discussed in detail later). 
     FIG. 4 shows a detailed view of one embodiment of the vacuum separator  60 . In this embodiment, the vacuum separator  60  includes a rotary star valve  62  having a plurality of vanes  66  that rotate about a center hub  64  to provide a vacuum separation between the upper tower section  30  and the lower tower section  80  such that cheese block former  10  continuously can operate with different pressures in the upper and lower tower sections simultaneously. The plurality of vanes  66  rotate to transfer curd to the lower tower section  80 . Tower section  80  has an outer surface  80   a  and an inner surface  80   b,  the inner surface defining an interior area  82  extending down below the flange  86  into the lower tower section  80 . 
     Vacuum lines  90  and  92  are connected between vacuum sources (not shown) and to the interior area  82  of the lower tower section  80  through the flange  86  via vacuum inlets  90   a  and  92   a.  FIG. 4 also shows an inner whey separation screen  120  disposed along the inner surface  81   b  of the lower tower portion  80  below the flange  86 . The inner whey separation screen  120  further has a tapered upper portion  122  to create a vacuum chamber  88  below the flange  86  and between the tapered portion, the inner surface  81   b,  and the outer surface  95  of the extension chamber  94  that extends from the vacuum separator. All of these features are described and shown in greater detail in FIG.  10 . 
     The motor  46 , FIG. 3, is mechanically connected to drive the rotary star valve  62 , FIG. 4, during the operation of the cheese tower  10 . The vanes  66  of the rotary star valve  62  rotate to maintain the upper tower section  30  and the lower tower section  80  at separate pressures at all times in order to discharge cheese blocks at the finishing section  170  while drawing fresh cheese curd into the upper tower simultaneously. It should be noted that the upper and lower tower sections are allowed to remain in fluid communication with one another as the cheese block forming process proceeds. That is, as the vanes  66  turn, cheese is transferred from the upper tower  30  to the lower tower  80 , where the whey is drawn from the curd. 
     FIGS. 5 and 6 show an alternate embodiment of the upper tower section  30  with a rectangular-shaped top  34  having an interior area  36 , similar to FIGS. 3 and 4. Also depicted are the vacuum separator  60  and part of the lower tower section  80 . Here, however, the rotary star valve  62  has been replaced with a straight-through chute  130 . The straight-through replacement chute  130 , like the rotary star valve  62 , allows for fluid communication between the upper tower section  30  and the lower tower section  80 , but without requiring a movable mechanism such as the star valve  62  and motor  46 . It is understood that the straight-through chute disclosed and claimed herein may include a rectangular, circular, or oval-shaped chute, a cylinder, a tube, or any other similar type hollow material conveying apparatus. FIGS. 3 and 5 also show a viewing window  110  for inspecting the cheese curd mixture (not shown) after it passes through the vacuum separator  60 . 
     FIG. 7 illustrates an isometric view of the rectangular straight-through chute  130  used to replace the rotary star valve  62  discussed above. The chute  130  comprises a top flange  134  and bottom flange  136  to facilitate attachment of the chute into position within the tower  10 . Further, the chute  130  has an outer surface  131   a  and an inner surface  131   b,  the surfaces extending between the top flange  134  and the bottom flange  136 . The inner surface  131   b  defines an interior area  132  through which a mixture of cheese curd and whey (not shown) may flow. Together, the chute  130  and the mixture, which contacts the inner surface  131   b  provide an effective vacuum separator between the upper tower section  30  and the lower tower section  80 . 
     FIG. 8 illustrates a detailed view of the top portion of FIG.  1 . Here, however, another preferred embodiment is shown. The cheese block former  10  has a cyclone hopper  140 . The cyclone hopper has a conical portion  140   a  and a cylindrical portion  140   b,  the cyclone hopper connected to cheese curd inlet  38  and vacuum port  40 . The cyclone hopper is installed on top of the vacuum separator  60 , which comprises a rotary star valve  62  of the type discussed earlier. Vacuum ports  90   a  and  90   b  in the lower tower section  80  are also shown and they function for the purpose discussed previously. Also shown is a clean-in-place (CIP) sprayer  144  which is connected to the upper tower section  30  cyclone hopper  140  and just below the vacuum separator  60  via line  145  so as to flush and rinse the tower  10 , bypassing the rotary star valve  62 . CIP sprayer  142  (shown in dashed lines) facilitates cleaning of the cyclone hopper  140 . 
     FIG. 9 shows a detailed view of FIG. 1 again with the optional cyclone hopper  140  attached to the block former  10 . Here, however, the rotary star valve  62  has been replaced with the straight-through chute  130  as previously described (FIG.  7 ). In this preferred embodiment, the CIP sprayer  144  (FIG. 8) is not required, and thus, is not shown. 
     Referring to FIG. 10, an enlarged sectional view along line  10 — 10  indicates in greater detail the arrangement of the whey separation screen  120  within the lower tower section  80 . The whey separation screen  120  is disposed along the inner surface  81   b  of the lower tower section outer wall  81 , with a whey drainage area  89  therebetween. Further, the whey separation screen  120  has an inwardly tapered portion  122 , the screen tapering above and toward extension section  94  wall  95 , which extends down below the flange  86 . As noted earlier with reference to FIG. 4, the enlarged vacuum chamber  88  is located above the whey drainage area  89 , but below the flange  86  and between the inner screen tapered portion  122 , the lower section inner surface  81   b,  and the outer surface  95  of the extension chamber  94  that extends from the vacuum separator  60 . 
     FIG. 10 illustrates the enlarged vacuum chamber  88  connected to the vacuum port  90   a  at the top of the whey drainage area  89  which provides for optimal removal of whey from the cheese curd mixture in the lower tower section  80 . 
     Referring to FIG. 11, a cross-section of the lower tower portion  80  taken along line  11 — 11  is shown. The lower tower section  80  has an outer wall  81  with an outer surface  81   a  and an inner surface  81   b.  Shown here is that disposed along the inner surface  81   b  is the inner screen  120  having two distinct portions  120   a  and  120   b,  configured to remain unmated such that a rectangular cross-section is formed when the two halves  120   a  and  120   b  are inserted for use in the lower tower. The inner whey separation screen  120 , along with the inner surface  81   b,  defines a whey drainage area  89  therebetween, the vacuum drainage area extending from the top end of the lower tower section  102  to the bottom end of the lower tower section  100 . The whey drainage area provides a space for whey to be removed from the cheese curd mixture  16 . 
     Additionally, when the screen sections  120   a  and  120   b  are put in place such that they surround the interior area  82  of the lower tower section  80 , the size of the cross-section of the screen increases along the axial length of the lower tower portion from top to bottom. Therefore, the walls of the screen  120  are inclined outward at a small angle relative to the axis of the tower  10  in a downward direction (see FIG.  2 ). 
     FIG. 12 is a detailed view of the whey separation screen  120  taken along line  12 — 12  of FIG.  11 . Screen  120  is formed of two disjointed sections,  120   a  and  120   b,  which are disposed along the inner surface  81   b  of the lower tower section  80 . 
     FIG. 13 illustrates a detailed view of the inner whey separation screen indicated by line  13 — 13  of FIG.  11 . The screen portion  120   b  is bent to conform to two sides of the rectangular-shaped inner surface  81   b  of the lower tower section  80 . 
     Referring to FIG. 14, a cross-sectional view taken along line  14 — 14  of FIG. 13, the inner whey separation screen  120  is shown to have a flat base portion  160  and a plurality of protrusions  162  disposed along the entire area of the screen. The whey separation screen  120  covers substantially the entire inner surface  81   b  of the lower tower section  80 . The protrusions  162  form open areas  164  in the screen  120  providing fluid communication so as to allow whey to pass from the cheese curd mixture  16  in the interior area of the lower tower section  82  through the screen and into the whey drainage area  89 . 
     FIG. 15 shows an isometric detail of the inner screen  120  so as to more clearly indicate its features. The screen  120  has a flat base portion  160 , a plurality of protrusions of the kind indicated by  162  and open areas such as  164  formed in the base portion underneath the protrusions. 
     Referring to FIGS. 16 and 17, a finishing section  170  is shown having an inner chamber  174 , an elevator  178  having an elevator platform  180  and a lifting mechanism  182  such as a piston. Also shown is an ejection ram  186 , a guillotine apparatus  190  and a bottom portion  198  of a column of cheese  200 . An access door  176  which pivots between an open position (FIG. 16) and a closed position (FIG. 17) is also shown. The finishing section provides a sanitary area in which cheese block cutting, pressing, and packaging can take place. The guillotine apparatus  190  is comprised, in part, of a single linearly moveable blade  192  defined by a cutting edge  192   a,  a top surface  194   a,  and a bottom surface  194   b.  Piston  196  is used to actuate blade  192  which is moveable from a first position in which the opening at the bottom of the cheese block former  10  is closed off to a second position in which the opening at the bottom of the cheese block former  10  is unobstructed. In a preferred embodiment, the cutting edge  192   a  is beveled adjacent the top surface  194   a  to facilitate cheese cutting. 
     Again referring to FIGS. 16 and 17, an elevator  174  is positioned within the inner chamber  174  of the finishing section  170  below the block former  10 . The elevator  174  is operable by a piston  182  to move the elevator platform  96  along a path which is coaxial with the cheese block former and the cheese column  200 . A linearly moving ejection ram  186 , operable by a piston  188 , is also located within the interior chamber  174 . The ram  186  is aligned to extend through the cheese block  200  and the access door  176  when the ram is in the extended position and the access door is open (FIG.  17 ). Located outside of the inner chamber  174  and the adjacent access door  176  is a bag loader  202  which, when used, serves to hold a bag  204  for receipt of cheese blocks as they are ejected from the inner chamber  174 . Once a bag  204  has been filled with a cheese block, the bagged cheese block is released from the bag loader  202  and is then transported to another processing station (not shown). 
     The operation of the cheese block former  10  will now be described. At the start of the operational cycle, the guillotine blade  192  is in its closed position. A vacuum source  39 (shown schematically in FIG. 18) is used to evacuate the air through the vacuum port  40  such that a negative pressure is formed within the block former  10 . When a sufficiently high vacuum is obtained, the difference between the low pressure in the upper tower section  30  and the comparatively high atmospheric pressure acting on the curd in the curd source block  37 , FIG. 18, causes curd to flow into the interior area  36 . Curd flow can be stopped via curd feed check valve(not shown) when the curd level reaches a desired height as determined by sensing probe  42 . 
     The curd is then drawn down through the vacuum separator  60 , which in the preferred embodiments, comprises either a rotary star valve  62  or a straight-through replacement chute  130 . Below the vacuum separator  60 , the curd is drawn into the lower tower section  80 . In the rotary star valve embodiment, the motor  46  is actuated to move curd to the lower tower section  80 . In the straight-through chute embodiment, curd is transported by gravity feed. 
     Separate vacuum ports  40  and  90  (shown in FIG. 18) are connected to a vacuum source  39 , FIG.  18 . The whey is drawn from the curd into the open areas  128  of the screen  120  by the vacuum from ports  90   a  and  92   a.  The vacuum ports  90   a  and  92   a  extract whey and air from the vacuum chamber  96  and from the cheese curd mixture through the open areas  164  and into the enlarged vacuum chamber. The whey drains out of the tower through the drainage area  89  below the enlarged vacuum chamber  88 . Also, the weight of the curd within the tower compresses the curd even further to force whey out of the curd through the inner whey separation screen. Whey is then removed from the drainage area via whey drainage ports(not shown). 
     The base of the column of cheese rests on the top surface  194   a  of the guillotine blade  192 . At the top of the lower tower section  80 , the inner screen  120  is tapered inside an enlarged vacuum chamber  96  just below the flange  86  where the vacuum ports  90   a  and  92   a  are connected. As whey is drained from the curd, the weight of the curd and the resulting cheese begins to fuse the cheese into a continuous column. 
     When the column of curd in each tower has reached a predetermined height indicated by the tower&#39;s level probe  42 , the curd feed control valve (not shown) automatically closes and the elevator platform  180  is raised to a position adjacent to and abutting the guillotine blade  192  so as to begin the cutting and discharge sequence. Next, the blade  192  is withdrawn to its open position to allow the column to drop down onto the elevator platform  180 . Simultaneously, as the curd column is lowered, the curd feed control valve is automatically allowed to open to replenish the curd. This is accomplished because of the capability of providing the vacuum separator which allows different vacuum pressures in the upper and lower tower sections simultaneously. 
     The small outward pitch of the cheese block former  10  in the downward direction reduces the frictional resistance between the base portions  160  of the screen  120  and the curd during the downward movement of the column of curd. In the preferred embodiment, the lower tower section is provided with a 2 inch pitch, or in other words, the sides increase from a 9″×11″ at the top end of the lower tower section  102  to 11″×14″ at the bottom end of the lower tower section  100 . 
     The curd is then lowered into the inner chamber  174  of the finishing section  170  by the elevator  178  to a distance corresponding to the desired depth, and hence weight, of the block of cheese being processed. Once sizing is completed, the guillotine blade  192  is returned to its closed position, and in doing so, the blade cuts the block of cheese from the lower end of the column of curd. Exact weight tolerances can be achieved by keying appropriate size information into an electronic block weight adjustment system which can be connected to the block former. 
     Next, the elevator  178  lifts the platform  180  so as to force the cheese block upward against the bottom surface  194  of the guillotine blade  192 , thus pressing the cheese block for a predetermined amount of time. The bottom surface of the blade  192 , the top surface of the elevator platform  180 , an ejection ram  186  and the inner surface  176   a  of the access door  176  thus function as a mold for the cheese block. Molding provides the block with a finished surface that is suitable for packaging. 
     Once the cheese block is formed so as to be suitable for packaging, the access door  176  is opened and an ejection ram  186  is actuated so as to push the cheese block into an adjacent bag  204  inside a bag loader  202 . The bag  204  has been positioned over trays  206  that have been spread apart to facilitate bagging, which is done using heat and under a vacuum. The cheese block  201  is then ready to be transported for shipment. The door  176  closes and the entire cycle is ready to be repeated. 
     FIG. 18 is a schematic diagram to generally indicate the way in which the cheese block former operates in conjunction with other mechanical systems in practice to produce a cheese block. A vacuum source  39 , curd source  37 , cutter  170 , bagger  202  and conveyor  208  systems are shown as previously discussed. Of course the relative position of each mechanism is only exemplary. 
     The present invention has been described in terms of preferred embodiments, and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appended claims.