Abstract: A waste management system for plastic or other material floating on the surface and in the subsurface of a body of water. A shredding device will reduce the size of the particles of waste. Ocean water is removed by a drying device. The dried waste material is frozen to a temperature at or below minus fifty degrees Fahrenheit, using liquid nitrogen or other suitable means. The frozen waste material is then pulverized and ground into a powder. The powder may then be sprayed into a gas-filled chamber and heated. Temperature, pressure and humidity are maintained within the chamber for more than one minute. Microwave or other radiation and catalysts may be used to enhance the process of extraction. The processed material is then removed from the chamber. Carbon may be recycled or used as fuel by the ship. Water may be used by the ship or returned to the ocean.

Abstract: The invention relates to a beverage preparation machine comprising an apparatus for frothing or heating milk, which apparatus is connected via a milk suction hose to a milk container, and a cleaning apparatus for cleaning the milk suction hose and the apparatus for frothing or heating milk by means of a flushing fluid. The milk can be sucked from the milk container into the apparatus for frothing or heating milk by means of a vacuum which can be generated in the apparatus for frothing or heating milk.

Abstract: The present invention relates to a butter making device comprising a butter containing section containing a basic butter product to be processed further, a dosing unit for adding additives to the basic butter product, and a flow restricting and generating device disposed at the butter containing section for passing butter from the butter containing section for further processing the basic butter product to the dosing unit, wherein at least one further dosing unit and at least one further flow restricting and generating device disposed at the butter containing portion for passing basic butter containing section to the at least one further dosing unit.

Abstract: The present invention relates to a frozen confectionery product and to a method of manufacturing same. It furthermore relates to an apparatus for manufacturing a frozen confectionery product by rotary vertical extrusion. Said apparatus comprises a nozzle at least one ice cream passage with at least one inlet port and an outlet portion, and at least one chocolate passage with respectively an inlet port and an outlet port. The outlet ports are provided in the nozzle and have elongated cross-sections, and each chocolate outlet port extends in parallel to an ice cream outlet port, so as to form annular or helical chocolate layers upon rotation of the nozzle and the container with respect to each other.

Abstract: An appliance for the treatment of a liquid food comprises a container (2) for the liquid food, a support (3) for the container (2), a cover (4) to close container (2), a hermetically sealed chamber (6) within the cover (4), a tool (5) rotating inside the container (2) for the treatment of the liquid food, a primary electrical winding (9) held by the support (3) and suitable to transfer energy by magnetic induction to a secondary electrical winding (7) positioned inside the hermetically sealed chamber (6), and a motor (8) driving the rotation of the tool (5) positioned within the hermetically sealed chamber (6) and electrically powered by the secondary winding (7).

Abstract: A milk frother has a base and a removable stainless steel jug. The contents of the jug may be aerated with a magnetic frothing disc.

Abstract: The present invention relates to a frozen confectionery product and to a method of manufacturing same. It furthermore relates to an apparatus for manufacturing a frozen confectionery product by rotary vertical extrusion. Said apparatus comprises a nozzle (14) at least one ice-cream passage (20, 22) with at least one inlet port (24, 26) and an outlet port (28), and at least one chocolate passage (30, 32) with respectively an inlet port (34, 36) and an outlet port (38, 38?). The outlet ports are provided in the nozzle (14) and have elongated cross-sections, and each chocolate outlet port (38, 38?) extends in parallel to an ice cream outlet port (28), so as to form annular or helical chocolate layers upon rotation of the nozzle and the container with respect to each other.

Abstract: The invention provides a device (100, 200, 300, 600) for agitating a liquid, e.g. a milk frother, comprising: a main body (110) comprising an opening (116) adapted to releasably receive an inner container (120), which inner container is suitable for receiving the liquid; an agitation element (136) for agitating the liquid when the liquid is received in the inner container and the inner container is received in the opening of the main body; a driving element (132) for driving the agitation element; and an electrical connection (154, 152, 111) for providing electrical energy to the driving element. By providing an opening for releasably receiving an inner container, a separate container can be used in conjunction with the device. This container is releasable, so it can be put in a dishwashing machine or a sink with water without any risk of damaging the electrical components of the device. In this way, the container can be easily, hygienically and conveniently be cleaned.

Abstract: A machine for the treatment of food mixtures with an improved performance includes a container or cylinder for collecting a food mixture, integral with a frame structure and equipped with an upper lid, for closing the container and hinged to the frame, so as to be in a closed or open position on an upper opening of the container, in the container there being a rotating shaft, which is coaxial to the container and which supports in rotation scraping and mixing blades at the bottom and sides of the inner and bottom walls of the container, a blender being positioned in an opening of the lid. Particularly, the blender can be positioned so to be freely removable.

Abstract: A device for foaming milk with a motor arranged in a housing, for driving a driving shaft in rotation, and a foaming element arranged on a first housing end outside of the housing, coupled to the driving shaft, which set in rotation by the latter about a rotation axis. The device includes a supporting means arranged on the housing, on which means the device can be set down with first housing end located in a low position such that the foaming element rotates freely, and wherein the rotation axis extends at an inclination with respect to the vertical. The device for foaming milk, designed in this manner, produces a milk foam which is of a quality that can be generated in apparatuses of the state of the art, wherein at the same time the handling is simplified for the operator, and requires less attention from him/her.

Abstract: A milk frothing device comprises a housing (2) including a container (10) for receiving the milk to be frothed, and a frothing means (20), wherein the container comprises a side wall (11), a bottom portion (13) and an inclined wall portion (12), wherein the inclined wall portion is inclined with respect to the side wall and is confined by the side wall and the bottom portion, wherein the container and the frothing means together form an asymmetrical arrangement.

Abstract: An apparatus is disclosed for cutting cheese curd mass in a curd vat. The apparatus comprises a first cutting frame that cuts the cheese curd in a first direction along one plane of the curd vat. The first cutting frame comprising one or more cutting wires extending in one or more directions. The apparatus further comprises a second cutting frame comprising one or more cutting wires extending in one or more directions.

Abstract: A cheese vat for at least preparing curd for soft fresh cheese, comprising at least one cutting frame provided with a cutting wire system, which has a frame which has at least two opposite frame parts between which cutting wire sections extend, which frame parts are provided with openings form receiving a cutting wire, wherein the ends of a cutting wire are each fastened via pull relief means.

Abstract: A cutting frame for use in a curd vat, which cutting frame comprises substantially parallel frame girders, between which is situated a lattice formed from longitudinal knives and transverse knives, of which the transverse knives are mounted on the frame girders by welding and have aligned openings, in which the longitudinal knives are received, wherein the longitudinal knives are strip-shaped knives having a length dimension and a width dimension and having at least one sharp cutting edge extending in the length dimension, which cutting edge is formed by at least one obliquely ground cutting face, wherein the width of the longitudinal knives is smaller than the corresponding dimension of the openings of the transverse knives, and wherein means are provided for substantially preventing displacement of the longitudinal knives in the length dimension, wherein at least a number of openings of at least a number of transverse knives is provided with supporting elements which substantially lock the longitudinal kniv

Abstract: Compact machine for making cheese, other milk-derivatives and tofu comprising a shell (1) in which an impermeable basin (3) is inserted, a collecting container (2) in which a permeable basket (6) is inserted for collecting the product and a support structure comprising a lower base member (10) having two side arms (8). The machine comprises, furthermore, a motor (7) integral to the shell (1) for operating a stirring member (5), and heating means (4) adapted to heat to various temperature the content of the basin (3). The basin (3) and the permeable basket (6) are open and coupled with respect to each other, in a releasable way, one against the another. The coupled basin (3) and the permeable basket (6) are adapted to be integrally rotated, in order to be moved alternatively between a first position (A), where the basin (3) is down and the basket (6) is up, and a second position, where the basket (6) is down and the basin (3) is up.

Abstract: An appliance for conditioning a liquid made of or based on milk, in particular for preparing heated liquid or a cold or heated frothed liquid. The appliance includes a tank for receiving the liquid that is to be conditioned; a closed compartment secured to the tank; and an electric device located therein for imparting a conditioning effect to the liquid. The compartment is made water impervious and washable under running water without infiltration thereof into the compartment containing the electric device.

Abstract: A cheese process vat is disclosed. The cheese process vat includes an enclosure and a shaft assembly, preferably a shaft assembly having a shaft and a plurality of agitator panels arranged on the shaft in a planar fashion. The agitator panels are preferably arranged on the shaft such that the shaft assembly is balanced in both weight and agitator panel surface area around the centerline of the shaft.

Abstract: A soft-serve confection freezer incorporates a set of modules in a circular array and separately replaceable in a magazine. Each module supports a container storing a dry food ingredient in solid particulate form, and has a motor driven product impeller for controlled discharge of particulates from the container to a blender assembly. The blender assembly has a housing and screw-type auger of cooperating configurations and which cooperate with a central passageway for frozen confection flowing from the freezer, to blend particulates from one or more containers into the confection and discharge into a customer's cup for immediate consumption. A further version incorporates a magazine for injection and blending of one or more flavored liquids into the frozen confection. Control panel selection of ingredients and flavors and dispensing by the operator according to the customer's order, or selection and dispensing by the customer himself/herself, is provided. Components are arranged to facilitate cleaning.

Abstract: A machine for producing ice cream shop products comprises a whipping and freezing unit (2) with a horizontal axis (A) and a removable head (10) forming an end wall (11) of the whipping and freezing unit (2), there being in the wall (11) an inlet (12) for ingredients intended to constitute the ice cream shop products, and an outlet (13) for the ice cream shop product prepared.

Abstract: A curd preparation vat provided with a sealing construction for a shaft passing through a wall of the vat, which sealing construction has at least one receiving space and a sealing ring included therein in operation, surrounding the shaft, wherein the sealing ring has an annular body which is provided with a sealing lip which cooperates with a radially extending surface of the sealing construction, and wherein the annular body furthermore has an axially inner surface abutting against first positioning means of the sealing construction, wherein the sealing lip of the at least one sealing ring extends both radially and axially obliquely outwards from a both radially and axially outer edge area of the annular body, and wherein between the sealing lip and the inner surface of the annular body that abuts against the shaft, an axially outer surface of the annular body is situated, which cooperates directly with second positioning means, which leave the lip clear, for fixing the at least one sealing ring between the

Abstract: A machine for making ice-cream products comprises at least a motor operatively connected to a rod-shaped element so as to drive the rotation of the latter about its own axis of extension, grip means for moving the motor and/or the rod-shaped element at least along the axis of rotation of the rod-shaped element so that the rod-shaped element is at least partly immersed in a containment tank. The machine comprises means for activating the motor, preferably contact sensors, positioned on the grip means.

Abstract: A cheese vat for at least preparing curd for soft fresh cheese, comprising at least one cutting frame provided with a cutting wire system, which has a frame which has at least two opposite frame parts between which cutting wire sections extend, which frame parts are provided with openings form receiving a cutting wire, wherein the ends of a cutting wire are each fastened via pull relief means.

Abstract: Tempering apparatus having disc-free stirring tool (8) with plate-shaped arms (12, 13). The upper side (14) of each arm (12) has a different geometrical configuration than the lower side (19) thereof. Each neighbouring arm (13) has the opposite configuration of the upper and lower sides (23 and 24). The mass is thereby given an intermittent up- and downwards movement in the mass treatment chamber (2) and the tempering capacity of the apparatus is improved.

Abstract: Apparatus for cutting and stirring curd, comprising a curd vat with a shaft drivable for rotation, which shaft comprises a number of cutting frames extending radially from the shaft and having a number of strip-shaped transverse knives and longitudinal knives, the longitudinal knives each having an inner end situated near the shaft and an outer end situated near the wall of the curd vat, while at least a number of longitudinal knives of at least one of the cutting frames are provided, at the outer end situated near the wall of the curd vat, with a knife end section which has at least one portion extending transversely to the longitudinal direction of the longitudinal knives.

Abstract: Apparatus for cutting and stirring curd, comprising a curd vat with a shaft drivable for rotation, which shaft comprises a number of cutting frames extending radially from the shaft and having a number of strip-shaped transverse knives and longitudinal knives, the longitudinal knives each having an inner end situated near the shaft and an outer end situated near the wall of the curd vat, while at least a number of longitudinal knives of at least one of the cutting frames are provided, at the outer end situated near the wall of the curd vat, with a knife end section which has at least one portion extending transversely to the longitudinal direction of the longitudinal knives.

Abstract: Improvements are provided in an apparatus and a method for shredding blocks of cheese. The apparatus includes an elongated cheese chamber having an open side face for the admission of a block of cheese, which is urged into the elongated cheese chamber by a loading piston, a longitudinally-extending side plate and a floor surface for slidingly-engaging a block of cheese. An extruding piston is provided to force the cheese downstream within the elongated cheese chamber. The improvement includes an extrusion grid plate which is fixed at the downstream end of the elongated cheese chamber having a plurality of elongated, parallel, horizontal and vertical, knife-edges constituting a plurality of rectangular openings. A rotatable shredder assembly including an overlapped disc is sited immediately downstream of, and is in longitudinal abutment with, the extrusion grid plate, to prevent undesired escape of the extruded cheese.

Abstract: An apparatus has a tank with a vertical carousel holding blocks of cheese. The carousel moves in a closed path which submerges and flips over the blocks of cheese in a chilled brine solution contained in the tank. The movement of the carrousel ensures that the cheese is cooled uniformly without deformation. While the cheese block are held in the carrousel a fluid circulation system forces chilled brine through the tank.

Abstract: Apparatus for cutting and stirring curd, comprising a curd vat with a shaft drivable for rotation, which shaft carries a number of cutting frames extending radially from the shaft and arranged on the shaft in staggered relation, each cutting frame having two frame girders, which extend radially from the drivable shaft and between which a lattice work is situated formed from longitudinal knives and transverse knives, the transverse knives being mounted on the frame girders by welding. The transverse knives form openings which are in line, in which the longitudinal knives are received with ample play, while means are provided for substantially preventing displacement of the longitudinal knives in the longitudinal direction.

Abstract: Apparatus for cutting and stirring curd, comprising a curd vat with a shaft drivable for rotation, which shaft carries a number of cutting frames extending radially from the shaft and arranged on the shaft in staggered relation, each cutting frame having two frame girders, which extend radially from the drivable shaft and between which a lattice work is situated formed from longitudinal knives and transverse knives, the transverse knives being mounted on the frame girders by welding. The transverse knives form openings which are in line, in which the longitudinal knives are received with ample play, while means are provided for substantially preventing displacement of the longitudinal knives in the longitudinal direction.

Abstract: Apparatus for cutting and stirring curd, comprising a curd vat with a shaft drivable for rotation, which shaft carries a number of cutting frames extending radially from the shaft and arranged on the shaft in staggered relation, each cutting frame having two frame girders, which extend radially from the drivable shaft and between which a lattice work is situated formed from longitudinal knives and transverse knives, the transverse knives being mounted on the frame girders by welding. The transverse knives form openings which are in line, in which the longitudinal knives are received with ample play, while a device are provided for substantially preventing displacement of the longitudinal knives in the longitudinal direction.

Abstract: A cheese processing vat of the type having a pair of interconnected generally cylindrical wall portions with agitator panels rotating therein to sweep generally cylindrical volumes includes agitator panels which are driven to rotate in opposite directions such that the panels move through a common swept volume between their axes of rotation in the same direction. The panels are mounted such that one panel leads the other during movement through the common swept volume.

Abstract: A molds is filled with cheese by an apparatus that includes an extruder which injects cheese through the opening in the mold. A plunger is located adjacent to the mold and is contacted by moveable wall of the mold as cheese fills a mold cavity. An actuator may be provided to varying the position of the plunger in order to accommodate different size molds. A sensor coupled to the plunger measures the force exerted by the cheese against the moveable wall. Aa controller receives a force signal from the sensor and produces an output signal when the force reaches a predetermined level. The output signal activates a knife blade which cuts off further injection of cheese into the mold cavity.

Abstract: A device for moulding cheese includes a vessel (1), for containing a mixt of curds and serum, and a series of moulding cups (11), a distribution trough (3) into which mixture from the vessel (1) flows, and a hopper (5) including a row of openings (16) located above the series of moulding cups (11), and disposed at the distribution trough (3) outlet. A mechanism moves the hopper (5) and the series of moulding cups (11) in a horizontal direction relative to each other.

Abstract: A method of forming a continuous ribbon of cheese from precheese is described. A conveyor belt system is used, modified to retain and transport the liquid precheese which, over the course of conveyance, solidifies to form the continuous cheese product discharged at the end of the conveyor.

Abstract: The apparatus comprises a vat having a lateral wall and a bottom for pasteurizing, maturing and maintaining a product. A cover adjacent to the lateral wall and to the bottom controls the temperature of the product present in the vat. A first heat-exchange circuit is defined by the cover and by the vat. A heat-exchange fluid circulates in the first heat-exchange circuit. The first heat-exchange circuit includes a heat generator for the heating of the heat-exchange fluid and includes a first heat exchanger for the cooling of the heat-exchange fluid. A second heat-exchange circuit has a tank. A diathermic liquid circulates in the second heat-exchange circuit. A second heat-exchanger is disposed in the tank, and a refrigeration group is connected, in a heat-exchange relationship, to the second heat-exchanger. The second heat-exchange circuit is connected to the first heat-exchanger by a by-pass conduit parallel to the first heat-exchanger.

Abstract: The curd ripening apparatus comprises two perforated, semicylindrical baskets (12, 30), rotatably supported on a common horizontal axis, one within the other. Curds are poured into the inside basket, and the outside basket is then rotated of 180.degree. with respect to the other and is latched with latching means (26, 28, 40) to make it integral with the other basket (12, 24) in an angular position opposite to it, so that a closed barrel is formed. One or two motors (36, 38; 136, 138) can rotate both baskets together, so that the curds are rolled until ripe. The inside basket is preferably provided with internal, parallel, transverse blades (42).

Abstract: A process for producing pumpable foodstuffs, wherein raw foodstuffs such as raw cheese is pre-comminuted, mixed with further ingredients, thermally treated by steam injection, subsequently cooled and creamed or emulsified and then fed or passed to a further working or processing operation. The present invention further relates to an apparatus for producing pumpable foodstuffs, such as processed cheese, having a treatment apparatus for raw foodstuffs, a mixer, a device or unit for heating and subsequently cooling the cheese mass and having feed pumps for the cheese mass.

Abstract: A dispenser of foodstuff is particularly well adapted to deliver cheese for pizza making. A refrigerator contains a bin which may be completely removed from said refrigerator for cleaning, as in a dishwasher, for example. The bin features inwardly sloping walls so that the cheese does not normally stick to the wall. An auger delivers the cheese to a spout where a star wheel meters flow and breaks up any clumps in the cheese. A spring biased trap door closes the spout, especially when the bin is removed from the refrigerator. The refrigerator contains parts which control the opening and closing of the trap door and the turning of the auger. The entire system operates under the control of a programmable microprocessor which includes means for detecting when the bin is empty or is failing to delivery the cheese.

Abstract: A device is described relating to separating mixed substances of differing flowabilities, in particular for the purpose of processing foodstuffs. The processing takes place in a device by which an elastic presser belt is pressed onto the periphery of a hollow separating drum with a perforated wall, so that the substance to be processed consisting of the previously mentioned composition and located between the presser belt and the hollow separating drum is separated into a phase of easily and a phase of less easily flowable components. The present concept provides for the use of two presser belt systems, which are operative one in series with and downstream of the other and influence a hollow separating drum, thus offering the possibility of using presser belts of different softness as well as, in the case of offset arrangement of the presser belt systems, use of varying perforations in the respectively associated circumferential areas.

Abstract: A curdling tank includes two upright, mutually intersecting, circular tank sections, each of the circular tank sections having a concentrically operated stirring system. The bottom portions of each of the circular tank sections are shaped to include sloping sides to form respective concentric bottom grooves with a downwardly pointed cross section, the lowermost portions of the grooves meet or overlap each other midway between the two shafts. The grooves are arranged in the shape of a figure of eight and the grooves achieve an effective emptying through a single outlet.

Abstract: An apparatus for separating of flowable and non-flowable constituents mixed with each other, particularly for the purpose of preparation of foodstuffs, operates with an elastic presser belt which is held pressed against the circumferential surface of a separating drum and which is guided between laterally bounding walls. For reducing the unavoidable leakage flow in the region of the radial sealing gap located between the perforated drum and the presser belt, the sealing gap is provided with a radial recess, which extends over the region of the separating drum encompassed by the presser belt and has an opening in the region of the entry wedge which connect said recess with this region.

Abstract: A cheese-making tank comprising a cylindrical container provided with a first cutting frame with cutting wires forming a netting, said cutting frame being displaceable forwards and backwards along the lower portion of the container from a first position at one end of the container to a second position at the other end of the container. It is further provided with a second cutting frame with radially extending cutting wires, said cutting frame being pivotally arranged about a longitudinal axis and with stirring means to be lowered into the lower portion of the container in order to carry out stirring movements therein. When being in the second position, the first cutting frame can be turned into the upper portion of the container while the stirring means are working.

Abstract: A method of centrifuging cheese milk that involves skimming it in a self-emptying centrifuge, returning some of the separated cream to the skim milk to adjust it to the desired level of fat, and centrifuging it again to precipitate microorganisms and dirt particles. The method uses only one centrifuge. The raw milk is preliminarily simmed down to a desired fat content in one section of a separation space, the accordingly standardized milk is forwarded to the periphery of another section of the separation space, where it is purified of microorganisms and dirt while flowing radially inward through the section, and the standardized and purified milk is extracted from the processing space inside the centrifuge by w ay of a peeler.

Abstract: For the metered addition of copper ions in cheese production in a stainless steel kettle(a) CO.sub.2 is introduced into the added water,(b) copper ions are produced electrolytically in the added water by means of electrodes immersed in the added water,(c) the enzymes necessary for the cheese production are added to the added water containing CO.sub.2 and copper ions and(d) the added water containing CO.sub.2, copper ions and enzymes is added to the raw milk for the cheese production.An apparatus for carrying out this procedure is characterized by(a) an electrolyzing tank (10) having an anode (11), a cathode (12) and a vent (13),(b) means (1, 2, 3, 4, 6) for feeding added water into the electrolyzing tank (10),(c) means (5, 7, 8, 9) for the metered addition of CO.sub.

Abstract: This invention concerns a process for applying a liquid release agent, especially an alginate, to the outside of a thin wide strand of cheese (30) on a revolving cooling roll (2) characterized in that the release agent is pressed onto the outside of the cheese strand (30) in the form of a film (34) which is fed at the rate of travel of the cheese strand (30).

Abstract: An enclosed food processing vat is provided having two or more generally horizontally-oriented partial cylindrical inner wall sections, each inner wall section conforming to a first portion of an swept volume created by the rotation of an agitator means about a horizontal shaft, the distance between the shafts being slightly greater than the radius of the swept volume so that a second portion of the swept volume for each shaft intersects and overlaps the swept volume of adjacent shafts. Each shaft is provided with a series of combined cutting and stirring paddles comprising a series of blades arranged both perpendicular to the shaft and parallel to the shaft that are sharpened on one side only and fixed so that when the shaft is rotated in one direction cutting will take place; whereas, when the shaft is rotated in the other direction stirring will take place.

Abstract: An apparatus for stretching dough comprising two pairs of rollers and means for imparting vibrations to the dough positioned between the pairs of rollers is provided. In this apparatus, vibrations are imparted to dough, which causes the thixotropic effect in the dough. Such dough can be readily stretched by being subjected to a tensile stress caused by the difference in the peripheral speed of the pairs of rollers. Therefore, dough can be stretched without subjecting it to high pressure during the stretching process.

Abstract: An extrusion die for producing hollow extrusions from material which is difficult to solidify quickly, e.g. chocolate, the die comprising an outer die part secured to the end of a supply pipe, a central aperture in the outer die part within which an inner die part having a multiplicity of spaced air injectors is provided, so that during extrusion chocolate forced through the apertures surrounds the injectors to produce an extrusion product having a plurality of longitudinal passages therein. A fluid, e.g. air, is passed through the injectors and into the longitudinal passages to prevent collapse of the passages before the chocolate has set. Relative rotation between the outer and inner die parts may be effected.

Abstract: A counterflow washer and cooler for processing cottage cheese curd and whey material comprising a horizontal housing, and a material and fluid blender rotatable mounted in the housing. The blender includes a rotatable shaft having at least one material lifting and conveying assembly rigidly mounted thereon having a material supporting surface and a guiding and conveying wall for moving material longitudinally through the housing in counterflow to the direction of flow of a washing and cooling fluid passing through the housing.

Abstract: Apparatus for cutting and stirring curd, comprising a curd vat with a shaft drivable for rotation, which shaft carries a number of cutting frames extending radially from the shaft and arranged on the shaft in staggered relation, each cutting frame having two frame girders, which extend radially from the drivable shaft and between which a lattice work is situated formed from longitudinal knives and transverse knives, the transverse knives being mounted on the frame girders by welding. The transverse knives form openings which are in line, in which the longitudinal knives are received with ample play, while means are provided for substantially preventing displacement of the longitudinal knives in the longitudinal direction.