Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Tlle presen~ invention relates to improvements in cheese making
methods and apparatus and is particularly (but not exclusively) applicable
to the production of cheddar cheese.
~ onventionally cheese making has involved a number of different
steps or stages which have normally been carried out in different apparatus
and transported either manually or with some mechanised aid between the
apparatus stages. The various stages include producing a slurry of cheese
curd and whey from a milk supply; draining most of the whey from the curd;
fusing or matting the drained curd together and allowing a period of time
for acid development in the so-called cheddaring stage; milling or cutting
the matted curd into small particles and applying salt to these partlcles
or chips; allowing a further period of time for mellowing of the salted
curd particles; and subsequently pressing the salted curd particles into
a coherent mass before packing into blocks. The quality of cheese produced
by these techniques has to a very large extent depended upon the skill and
experience of the cheese rrlaker in controlling the various operating
parameters and in particular in determining appropriate draining, acid
development and mellowing times.
Over recent years there have been several attempts (particularly
in cheddar cheese making) to mechanise the process by providing continuous
or semi-continuous installations. These developments have generally
involved trying to get a continuous flow through all or part of the
various stages of production and have normally used different types of
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conveyors for conveving the curd through and between the various stages.
These systems, although providing some advantages from the point of
view of improving the flow rate of material through the system, have not
proved altogether satisfactory in practice. Some of the disadvantages
of these known systems are listed below.
(I) They do not provide a continuous through flow of material
through all stages of the cheese rmaking process within one
machine, and in particular, a continuous through flow from the
cheddaring stage through a milling operation and the subsequent
salting and mellowing stages.
(II) They provide insufficient control of the variable parameters
involved in cheese making and in consequence the quality of
cheese produced suffers. Generally it is desirahle to be
able to vary the maturing or cheddaring time as well rs the
mellowing time in response to the acidity level of the cheese
at varying times throughout its development. Generally known
mechanised systerns do not allow for easy testing of the
acidity levels at the various critical pllases of production.
(III) One of the major problems with both ccnventional and the more
recent mechanised or semi-mechanised systems is the high
cnp;ta] expense of the installation. However, generally very
liltlc~ a~cl~ h;ls bcellrll;l(le to resLrict ~hc floor splce
requirc~d Lor thcse ins-allations and the higll cal)it.ll expense
of the rnachinery is aggravated by the high capital cost
of the floor space required for the installation.
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(IV) Known mechanised and semi-mechanised systems have generally
suffered from an inflexibility in that they are usually only
capable of producing one type of cheese.
One of the main objectives of the present invention is to
provide an apparatus for cheese production, capable of continuous through
flow from the production of cheese curd and whey to subsequent salting
and mellowing stage.
According to the present invention there is provided apparatus
for the continuous manufacture of cheese from raw curd comprising structure
defining a drying and de-wheying section, a fusing section, a cheddaring
section, a milling section, a salting section, and a mellowing section,
and including:
a) first conveyor means in said drying and de-wheying section,
b) means for feeding curd in a continuous stream onto said first
conveyor means,
c) agitator means operable to agitate curd on said first conveyor
means to facilitate drainage of whey tnerefrom,
d) second conveyor means in said fusing section, said second conveyor
means being arranged to receive curd discharged from said first
conveyor means and permitting fusion of the curd thereon into a
mat of curd,
e) third conveyor means in said cheddaring section, said third conveyor
means being arranged to receive the mat of curd discharging from
said second conveyor means and to effect lateral expansion of the
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mat of curd thereon so as to stretch the curd,
f) a milling device in said milling section arranged to receive curd
discharging from said third conveyor means and to cut the curd
into separate pieces,
g) fourth conveyor means arranged to receive curd discharged in
pieces from the milling device, said fourth conveyor means extending
through the salting and mellowing sections,
h) means for applying salt to the curd on said fourth conveyor means
during passage through said salting section, the salt being absorbed
into the curd during passage through said mellowing section,
i) agitator means operable to agitate the curd and salt on said fourth
conveyor means,
j) a plurality of trays arranged beneath each of said conveyor means
to collect whey drained from curd on the conveyor means, said trays
being so arranged to segregate whey of different acid levels drained
from the different sections of the apparatus, and
k) individual drive means operable to drive each of said conveyor means
at variable speeds independently of the speed of the other conveyor
means~ whereby acid development in the curd may be regulated by
controlling the residence time of the curd in each section in
accordance with the acid levels of the whey in said trays.
The apparatus can conveniently be completely enclosed in a
casing to enable the temperature of the curd to be maintained at a
substantially constant temperature and to avoid air-borne contamination.
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A cheese making apparatus according to the invention for
producing cheddar cheese, but which is also capable of being used for
producing other forms of cheese, will now be described by way of
example, with reference to the accompanying drawings, in which:
Figure 1 is a perspective view of the installation, with part
of the outer casing cut away to show details of construction.
Figure 2 is a cross sectional elevation view of the apparatus
taken from the other side to that shown in Figure 1,
Figure 3 is a plan view of the conveyor in the whey drainage
section of the apparatus showing in broken lines the side skirts for
retaining the curd on the conveyor,
Figure 4 is a plan view of the conveyor in the matting and
fusing section, showing the side skirts in broken lines,
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Figure 5 is a plan view of the conveyor in the ci-eddaring section,
showing the side skirts in broken lines, and
Figure 6 is a plan view of the conveyor ;n the salting and
mellowing sections, showing the side skirts in broken lines.
The cheese making apparatus sho~l in the drawings comprises a
frame 10 fitted with an ouLer casing 11 which completely encloses a
primary whey drainage section ~2, a matting and fusing section 13, a
cheddaring section 14, a milling section 15, a salting section `16 and a
mellowing section 17. The whey drainage section 12 and the matting and
fusing section 13 are positioned above the cheddaring section 14 which
is in turn positioned above the salting section ~ and mellowing section
17, so that the cheese curd flows in a cascade flow pattern from an
upper input level to a lower output level.
The primary drainage section 12 has a drainage unit 20
and a drainage conveyor 21. The unit 20 consists of a reservoir 22
for reception of a slurry of curds and whey, the reservoir having a weir
23, a drainage screen 24 inclined downwardly from the weir for reception
of slurry overflow;ng the weir, and a tray 25 for collec~ g whey drained
fro~ curd flowing down the screen. The curds travel by gravity downwardly
over the screen while a substantial portion of the whey is drained through
the screen and collected in the tray 5. The screen 24 comprises a
plurality of closely spaced parallel bars of wedged shaped cross section
whicll defille drlillagc apertures having opposing walls whicll are flared
outwardly from one another in the direction from the upper surface to the
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lower surface of the screen. The drainage screen is
curved so that the end of the screen adjacent the weir
lies at a steep angle to the horizontal and the end of
the screen remote from the weir lies at a shallow angle
of inclination to the horizontal. The reservoir, screen
and tray form a single unit mounted for pivotal movement
about a substantially horizontal axis so as to adjust
the angle of inclination of the screen to the horizontal.
The curd exits from the drainage screen 24 onto the
drainage conveyor 21. The drainage unit 20 is the
subject of our co-pending patent application No. 348,310
filed March 24, 1980.
The drainage conveyor 21 comprises an endless
slat conveyor (Figure 3) consisting of two endless drive
chains 26, a plurality of thin metal slats 27 extending
between and mounted on the chains, and two side skirts
28, 29 for retaining the curd on the slats, the side
skirts being fi~ed to the frame and in sliding contact
with the slats. The slats are provided with perfo-
rations for draining whey from curd on the conveyor, anda plurality of trays 30 are positioned below the con-
veyor to collect whey draining therefrom. Arranged
above the conveyor 21 are a number of peg stirrers 31
and spray nozzles 32 between the peg stirrers 31. The
stirrers 31 each comprises a shaft extending trans-
versely across the conveyor and rotatably mounted in
;- bearings on the frame 10, the shaft having radially
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extending pegs. or arms 33 spaced at equal angular
intervals around the shaft and arranged to engage curd
on the conveyor upon rotation of the shaft. The shaft
is driven by a motor (not shown). The pegs 33 may be
helically arranged along the shaft.
The matting and fusing section 13 has a
conveyor 35 consisting of two endless chains 36,
transverse slats 37 mounted on and extending
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between the chains, and side skirts 38, 39 for retaining curd on the
slats. The upper run of conveyor 35 is provided with peg stirrers
40 similar to peg stirrers 31 except that the pegs extend radially
on only about half the periphery of the drive shaft whereby the
stirrers may be parked in a non-operative position out of contact with
any material on the conveyor. The conveyor 35 extends from and slightly
beneath the conveyor 21, the direction of movement of the upper runs
of the conveyors 21, 35 being the same such that cheese curd (at this
stage being in loose particle form) passes directly from the conveyor 21
to the conveyor 35. The length and speed of the conveyor 35 is sufficient
to allow the initially particulate cheese curd to pile and fuse and mat
together, when the peg stirrers 40 are in the parked non-operative
position, such that at the end of conveyor 35 a substantially continuous
mat of cheese curd is formed. A plurality of trays 41 are positioned
below the conveyor 35 to collect whey from the curd on the conveyor, the
whey draining through the gaps between the slats of the conveyor.
The cheddaring section 14 comprises a conveyor 45 (Figure 5)
consisting of two endLess chains 46, transverse slats 47 on the chains, and
side skirts 48, 49 for retaining curd on the slats. ~ plurality of peg
stirrers 40 having pegs on only one half of the periphery of the stirrer
are spaced along the conveyor, the stirrers being positioned between
the drainage trays 41 of conveyor 35 to minimise the overall height
of the installation. The cheddaring conveyor 45 is arranged with its
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direction of movemellt opposite to that of the conveyor 35. A deflector
plate 50 is mounted on the frame at the end of conveyor 35 and arranged
to invert the mat of curd and guide it onto the upstream end of conveyor
45. A plurality of trays 51 are positioned below the conveyor 45 to
collect whey from the curd on the conveyor, the whey draining through
the gaps between tlle slats of the conveyor.
The milling section 15 is at the downstream end of the cheddaring
conveyor 45. The milling section comprises a cutting device 52 adapted
to cut the mat of cheese curd into small particles or chips ready for
salting. Salt is generally absorbed more quickly when the surface area
to volume of the cheese curd is relatively large and this ratio is increased
by decreasing the size particle or chip. The cutting device 52 comprises
a cylindrical drum having a transverse plate adapted to cut a strip across
tlle complete width of the cheese curd mat and shorter longitudinal
blades generally perpendicular to the transverse blade adapted to cut the
transverse strips into shorter "chip" lengths. Drive means are operable
t~ oscillate the drum between a cutting position anrl an inoperative
position genera]ly beneatll the curd mat. ]n tlle cutting position the
blades strike the curd mat against a cutting block arranged above the
mat. The length of travel of the oscillating blades need only be
fairly short such that movement of the blade occurs generally within
the lower left-hand quadrant as viewed in Figure 2. The cheese curd
cut in any one stroke of the cutting blade is generally dislodged by
curd cut in a subsequent stroke such that the curd chips fall by gravity
into the salting section 16. The cutting device 5? is of known construction
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and has not been illustrated in detail.
The salting section 16 has the upstream half
of a conveyor 55 which is positioned below the cheddar-
ing conveyor 45 and adapted to move in a direction oppo-
site to that of conveyor 45. The conveyor 55 (Fig. 6)consists of two endless chains 56, transverse slats 57
on the chains, and side skirts 58, 59 for retaining curd
on the slats. The salting section 16 is provided with
nozzles 60 for spraying whey saturated with salt on the
curd on the conveyor 55, and peg stirrers 31 operable to
agitate the curd to distribute the whey/salt solution
more uniformly throughout the curd. The slats 57 of the
conveyor 55 are apertured to facilitate drainage of the
whey/salt solution from the curd on the conveyor, and a
plurality of trays 61 are positioned below the conveyor
55 to collect the whey/salt solution. This method of
salting curd is described in more detail in our co-
pending application No. 357,017 filed July 25, 1980.
The mellowing section 17 comprises the
downstream half of the conveyor 55. This section is
provided with peg stirrers 40 having pegs on only half
the periphery so that the stirrers can be parked in a
non-operative position. The curd discharged from the
conveyor 55 falls into a vibratory conveyor 62 from
which curd can be drawn by vacuum into a tower (not
shown) for consolidating the curd into a block of natu-
ral cheese as described in British patent No. 1542844.
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The conveyors 21, 35, 45, 55 are each provided
with a separate drive motor and gear reduction mechanism
63 adjustable to enable each conveyor to be driven at
any desired speed. The conveyors are preferably of the
construction described and illustrated in our co-pending
patent application No. 348,311 filed March 24, 1980 in
which each slat comprises a thin elongated metal plate
having the longitudinal margins thereof bent through an
angle in excess of 90 and longitudinal strengthening
means in the form of a V shaped bar having the ends
thereof secured to the end portions of the plate, the
centre portion of the plate being supported by a strut
on the centre of the bar. Conveyors having slats of
this construction can provide a substantially flat upper
surface but nevertheless be several metres wide and
support a heavy load per unit area without the aid of
additional supports between the chains.
The side skirts 28, 29 of the drainage con-
veyor 21 are arranged as shown in Figure 3 to effect a
lateral compression of the curd as it travels along the
conveyor, and the side skirts 38, 39 of the matting con-
veyor 35 are arranged as shown in Figure 4 to effect a
further lateral compression of the curd in the upstream
portion of the conveyor, and then to permit expansion
of the curd in the downstream portion of the conveyor
35. The lateral compression of the curdr in conjunction
with agitation by the peg stirrers 31 assists in
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releasing whey from the curd, and the subs.equent
expansion of the curd in the downstream portion of the
con~eyor 35 assists in allowing the whey to ~ilter
down to thQ top surface of the conveyor and drain away
between the slats.
As explained previously, the curd at th~
downstream end of the conveyor 35 has fused into a
substantially continuous mat of curd, and the con-
veyor 45 is driven at a slightly higher speed than
: 10 conveyor 35 so as to effect longitudinal stretching
of the mat of curd as it is transferred from
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the conveyor 35 to conveyor 45. In addition, the side skirts 48, 49
of the cheddaring conveyor 45 are ~rranged as shown in Figure 5 to
permit a lateral stretching of the mat of curd under its OWIl weight.
Tlle stretching oL the curd assists in the cheddaring .ction.
The side skirts 58, 59 of the conveyor 55 whicll extends
through the salting and mellowing sections are parallel to one another. ~.
As shown in Figure 1 the whey collecting tray 25 of the drainage
unit 20 and the whey collecting trays 30 of the drainage conveyor 21
are connected to a separate outlet pipe 65. The whey collecting trays 41
of the conveyor 35 are connected to a separate outlet pipe 66. The
trays 51 under the upstream portion of the cheddaring conveyor 45 are
connected to an outlet pipe 67 and the trays under the downstream portion
of the conveyor are connected to a separate outlet pipe 68. The trays
61 under the upstream portion of the conveyor 55, that is the porti.on
extending through the salting section, are connected to an outlet pipe
69, and the trays ~1 under the downstream portion of the conveyor 55,
that is the porLi.on extending through the mellowing section, are connected
to an outlet pipe 70.
~ ach of the outlet pipes 65-70 are fitted with sensors (not
shown) adapted to measure the acidity level of the whey draining from
the collecting trays associated with the outlet pipe.
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The spray nozzles 32 on the conveyors 21, 35 are for use in
spraying water or other liquid onto the curd to wash away lactic acid from
the surfaces of the curd, and thereby arrest acid development in the curd.
In the manufacture of cheddar cheese with the apparatus shown in
the drawings, the peg stirrers 40 on the conveyors 35, 45 are held in their
inoperative positions to permit the curd particles to fuse together.
The peg stirrers 40 are operated when the apparatus is used for the
manufacture of Colby or Montery cheese and the curd has to be maintained
in a granular form. The spray nozzles 32 are used to spray water onto
the curd in the manufacture of cheese from washed granular curd.
Although the apparatus shown in the drawings is particular suitable
for the continuous manufacture of cheese, it may be used to process curd
in batches taken sequentially from a number of vats in which the curd and
whey is produced.
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