FR2747891A1 - Blender for use in food industry containing two opposing helices - Google Patents

Abstract

Blender used in the food industry comprising a curved vessel (1), which is a cylinder closed at the rear end and open at the front end, and contains at least one plate (7) on the inside of the wall forming part of a helix so that in a first direction of rotation the product is mixed and is pushed towards the back of the vessel. There is also at least one counter-plate (9) also forming part of a helix such that in the first direction of rotation the product is pushed towards the front of the vessel to counter the effect of the first plate.

Description

 The present invention relates to a churn usable in the food industry.

 Churns of the type of that of the invention are already known.

They generally consist of a substantially cylindrical tank, closed at one end by a bottom wall and open at the other end by means of a frustoconical neck extending said tank. Inside the tank and the neck, there are respectively provided blades perpendicular to the internal walls of the tank and the neck. These blades have a propeller shape or part of a propeller.

 It will be noted that the pitch of said propeller in the tank may be several times that of the length of the churn so that said one or more blades of the tank have a substantially rectilinear shape offset at one end relative to a generator of the tank.

 Such a churn is thus provided for working in the two opposite directions of rotation. In the first direction of rotation, the blade allows the mixing of the product contained in the tank while pushing it towards the back of the churn. In the second direction of rotation, the blade pushes the product towards the neck of the churn and therefore towards its exit. The product contained in the tank is then extracted from the tank.

 We have seen that in such churns, when trying to mix several products with relatively different physical characteristics, the densest and therefore the least fluid products are found towards the rear of the churn while on the contrary the products the lightest and therefore the most fluid are found towards the entrance of the churn. For example, when you want to make a cryogenic coating of a sauce on a product, such as rice with pieces of meat, ham, chicken, etc., after a fairly short time, the rice is at the front of the churn while the other, larger pieces are found at the rear of the churn.

 It has been observed that this effect of segregation of the products between them is essentially due to the action of the brewing blade or blades. In fact, in the first direction of rotation, the densest products are driven more vigorously backwards than the lighter products, which has the effect of pushing the latter forward, hence segregation.

 It will be understood that this segregation effect is harmful in the search for homogeneity of the content to be mixed and that we have sought to solve the problem it poses.

 The object of the invention is therefore to propose a churn whose structure is such that it does not exhibit this segregation effect.

 To this end, a churn according to the invention is characterized in that it is provided with at least one counter blade in the form of a propeller part such that, in said first direction of rotation, the product contained in said tank and which is subjected to its action tends to be pushed forward of said churn so as to counterbalance the effect of said blade.

 A problem which then arises is that of the extraction speed which is significantly reduced. Indeed, in the second direction of rotation of the churn, direction corresponding to the extraction of the product contained in the tank, the counter-blade acts on the product unlike the blade. As a result, the product, subjected to the action of the counter blade, is, in this direction of rotation, pushed back towards the rear of the tank, thereby reducing the extraction speed accordingly.

 Another object of the invention is to propose a solution to this problem.

 To this end, the or each counter blade can pivot around an axis located at a certain distance from the internal wall of the tank so as to be able to take all the positions comprised between a first position where its free edge rests substantially on the inner wall of the tank and a second position where it is gaping.

Advantageously, said or each counter blade can pivot freely.

 Thus, in the second direction of rotation of the churn corresponding to the extraction of the product contained in the tank, the counter blade pivots under the action of the product and becomes without action on the product. As a result, the product extraction speed is not slowed down compared to a conventional churn without counterblade.

 The bowl of a churn is generally extended forward by a frustoconical neck which is provided with a helical blade extending said blade of the bowl. However, it has been noted that this helical blade also strongly contributes to the segregation phenomenon mentioned above. To solve this problem, the invention proposes that said churn includes a screen on the internal wall of said neck or on the internal wall of said tank and located behind said helical blade.

 According to advantageous features of the invention, said propeller part of said blade and the propeller part of said counter blade have substantially equal pitches.

 Said churn can also be provided with at least one stop so that said counter blade can be stopped with its free edge substantially in contact with the internal wall of said tank. Likewise, it can also be provided with at least one stop to limit the pivoting angle of said counter blade.

 According to another characteristic of the invention, the blade and the counter blade are respectively provided with beads provided to be able to guide the product contained in the churn respectively during the emptying of the product in the second direction of rotation of the churn and during the operation of mixing the product in the first direction of rotation of the churn.

The characteristics of the invention mentioned above, as well as others, will appear more clearly on reading the following description of an exemplary embodiment, said description being made in relation to the accompanying drawings, among which:
Fig. l is a front view of a churn according to the invention,
Fig. 2 is a sectional view along the plane II / II of FIG. 1 of a churn according to the invention,
Fig. 3 is a developed view of a churn according to the invention,
Fig. 4 is a front view of a churn according to the invention, and
Figs. 5a and 5b illustrate the operation of a churn according to the invention respectively in a first direction of rotation corresponding to the brewing phase and in a second direction of rotation corresponding to the extraction phase of the brewing product.

 The churn represented in FIG. 1 essentially consists of a cylindrical tank 1 at a first end of which, said subsequently the rear end, is welded a bottom wall 2 and at the other end of which, said front end, is welded a neck 3 having a frustoconical shape. At the front end of the neck 3, the latter has an opening 3a which allows, on the one hand, the introduction of the products to be brewed into the churn and, on the other hand, the extraction of the same products when they these have been brewed.

The churn rests, via a tread belt 4, on two rollers 5 at the same height (only the foreground one is visible in Fig. 1 and both are visible on the
Fig. 4) while it is rotated about its longitudinal axis by means of a pin 6 welded to its bottom wall 2.

 The churn of FIG. 1 includes, like most churns known to date, a fixed blade 7 which is welded to the internal wall of the tank 1, perpendicular thereto, as can be seen in FIG. 2. Relative to a generatrix of the cylinder forming the tank 1, the fixed blade 7 is inclined at an angle a as can be seen in the diagram of FIG. 3. Its rear end is thus offset relative to a generator.

 Note that it can be considered that the blade 7 has a partially helical shape whose pitch is several times greater than the length of the churn so that it then has a substantially rectilinear shape.

 The blade 7 has a bead 7a which is obtained by folding the blade on itself at its free end. This bead 7a has the function of guiding the product contained in the churn along the side of the blade 7 during its emptying, and this in the first direction of rotation marked with arrow A in FIG. 2.

 On the inner wall of the frustoconical part of the neck 3, a helical blade 8 is welded which is an extension of the blade 7. The winding direction of the blade 8 is the same as that of the blade 7. This direction winding is such that, when the churn rotates in the direction of rotation shown by arrow A, the product tends to be pushed towards the bottom 2 of the churn while, when it rotates in the direction of rotation shown by arrow B, the product tends to be pushed towards the neck 3 of the churn and then towards its opening 3a. In the latter case, the product contained in the tank 1 is extracted therefrom.

 We can see in Fig. 3 the helical blade 8 mounted on the neck 3.

 According to the invention, the churn comprises a counter blade 9 which is mounted so as to be able to pivot freely around an axis 10 situated at a certain distance from the internal wall of the tank 1 so as to be able to take all the positions included between a first position where its free edge 9a rests substantially on the internal wall of the tank 1 as shown in strong lines in FIG. 2 and a second position where it is gaping as shown in thin dashed lines in FIG. 2. In FIG. 2, the possible pivoting movement of the counter blade 9 has been shown by an arrow p. This counter-blade 9, when it is in the first position where it rests on the internal wall of the tank 1, is substantially symmetrical with the blade 7. This is particularly visible in FIG. 3 where it can be seen that the trace of the counter blade 9 when it is in this first position is inclined by an angle b of sign opposite to the angle a of inclination of the blade 7.

 Thus, when its free edge 9a is substantially in contact with the internal wall of the tank 1, the counter blade 9 has, like the blade 7, a partially helical shape. It will be noted that when the angle a and the angle b have equal values (but of opposite sign), the steps of said helix parts are equal, in absolute value.

Like the blade 7, the counter blade 9 is provided with a bead 9b which is obtained by its folding back on itself. This bead 9b is provided to guide the product contained in the churn on the side of the counter blade 9 during the mixing operation, and this in the second direction of rotation marked by the arrow B of the
Fig. 2.

It will be noted in FIG. 3, the arm 11 which supports, at its free end, the axis 10. This arm 11 is also visible on the
Fig. 1. At the rear of the churn, the axis 10 is supported directly by the base 2.

According to another characteristic of the invention, the churn comprises a screen 12 which, in the embodiment shown, is welded to the internal wall of the neck 3. This screen 12 is visible in FIG. 4 in which, the pivoting counter blade 9 has not been intentionally shown, for the clarity of this FIG. 4. On this
Fig. 4, we see on the other hand, the rollers 5 and the belt 4, the helical blade 8 and the blade 7. It will be noted that the screen 12 is placed behind the helical blade 8, as is also visible on the
Fig. 1.

We will now explain the operation of a churn according to the invention and this, in relation to FIGS. Sa and 5b. On these
Figs. 5a and 5b, only the tank 1 and the counterblade 9 and its pivot axis 10 are shown, and this in a single transverse plane. This plan is for example that of section Il / Il of the
Fig. 1. It has been shown by corrugations that the tank 1 contains a product P. In FIG. 5a, the tank 1 is subjected to a rotation in the direction shown by an arrow A. This direction corresponds to that which is used during the operation of mixing the product P contained in the tank 1. In FIG. 5b, the tank 1 is subjected to a rotation in the opposite direction shown by an arrow B corresponding to the direction used during the operation of extracting the product P from the churn by its opening 3a. In each of these Figs. 5a and 5b, there are shown eight different counter blade positions, marked by Roman numerals I to VIII.

 We will first consider Fig. 5a. In position I, the counter blade 9, by its own weight, is placed vertically with its free edge 9a which is distant from the internal wall of the tank 1.

It keeps this vertical position, at position II, where its free end begins to penetrate into the product contained in the tank 1. In position III, the counter blade 9 is subjected to the action of the product P, action symbolized by arrow Ac, which has the effect of rotating it according to arrow p. At position IV, it has completely pivoted and finds itself in abutment on the internal wall of the tank 1.

 We have symbolized by different points 13, a stop in the different positions I to VIII intended to receive the free edge 9a of the counter blade, but it is specified that this stop may not exist and, in this case, the counter blade 9 is stopped in its pivoting movement p by its sole contact with the internal wall of the tank 1, as can be seen in FIG. 2. If it exists, it is not necessarily arranged as shown, but rather in axis 10.

 In positions V and VI, the product always acts on the counter blade 9 and the latter is always in abutment on the wall of the tank.

 In positions VII and VIII, the product no longer acts on the counter blade 9, but it is its own weight which acts. The counter blade 9 therefore remains in abutment on the internal wall of the tank 1.

 Again in I, the counter blade 9 finds itself in an unstable position where, in a way pushed by the stop 13, it pivots to find itself vertical with its free edge opposite the wall of the tank 1. This pivoting is symbolized by an arrow marked q.

 It is noted that when it is immersed in the product P, that is to say in the positions marked III to VII, the counter blade 9 acts as if it were linked to the internal wall of the tank 1. It is released from this wall in positions I and II, but it will be understood that there it has no effect on the product P contained in the tank.

 Because it is mounted in the tank 1 so that, when it is in abutment on the wall of the tank 1, it is symmetrical with the blade 7, as previously explained, its action on the product P is opposite to that of the blade 7. In this direction of rotation of the churn, the action of the blade 7 is to push the product towards the rear of the churn, that is to say towards the bottom 2. Consequently, the counter blade 9 tends to push the product towards the front of the churn, which neutralizes the action of the blade 7.

 However, in this direction of rotation, the rear face of the blade 8 also acts, and significantly, to push the product back. This action is partially neutralized by the action of the screen 12 on the neck 3.

 We will now consider FIG. 5b. In position I, the counter blade 9 is vertical due to its own weight. It remains vertical in position II where its free end begins to come into contact with the product P contained in the tank 1. There, subjected to the action Ac of the product P, it pivots so as to be gaping and distant from the internal wall of the tank 1. A stop 14 can be provided to limit the pivoting angle of said counter blade 9. Like the stop 13, the stop 14 may not exist because the counter blade 9 naturally remains in a gaping position.

However, if it is provided, it is not necessarily arranged as shown, but rather in axis 10.

 The counter blade 9 remains in this open position as long as it is immersed in the product P contained in the tank 1, that is to say in positions III to VI. It will be noted that the two faces of the counterblade 9 are, in these positions, licked by the product P contained in the tank 1 so that no product can agglomerate on these faces.

 In position VII, the counter blade 9 has come out of the product P and, subjected to the action of its own weight, it pivots, as represented by the arrow marked p, so as to find itself vertical, position that it keeps until the end of the cycle.

 It can be seen that in this direction of rotation of the churn, the counter blade 9 has no action on the product contained in the tank 1.

It will be recalled that this direction of rotation is that of the extraction of the product through the opening 3a of the churn. It will be understood that this extraction is not hampered by the counter blade 9.

 As mentioned above, the screen 12 has an action in the direction of rotation of the churn which corresponds to stirring since it is located behind the helical blade 8. On the other hand, for the same reason, it has no action in the direction of rotation of the churn which corresponds to the extraction of the product.

 It will be noted that the action of the screen 12 may prove to be insufficient to avoid pushing the product towards the rear of the churn.

Also, it may prove necessary to provide two counterblades 9 and 9 ′ oriented in the same way, advantageously at the same angle, as shown in dotted lines in FIG. 3.

Claims (8)

 1) Churn usable in the food industry, of the type which consists of a horizontal tank (1) substantially cylindrical closed at one end, said rear end, and open at the other end, said front end, said tank being provided with '' at least one blade (7) on the internal wall of said tank (1) being in the form of a propeller part such that, in a first direction of rotation the product it contains is stirred and tends to be pushed backwards from said tank (1) and that, in a second direction of rotation, the product is pushed back towards the open end so that it can be extracted from said tank (1), characterized in that it is provided at least one counter blade (9) in the form of a propeller part such that, in said first direction of rotation, the product contained in said tank (1) and which is subjected to its action has tendency to be pushed forward of said churn so as to counteract the effect of said blade (7).  2) Churn according to claim 1, characterized in that the or each counter blade (9) can pivot about an axis (10) located at a certain distance from the internal wall of the tank (1) so as to be able take all the positions between a first position where its free edge (9a) rests substantially on the internal wall of the tank (1) and a second position where it is gaping.  3) Churn according to claim 2, characterized in that the or each counter blade (9) can pivot freely.  4) Churn according to claim 1, 2 or 3, said tank (1) being extended forward by a frustoconical neck (3) which is provided with a helical blade (8) extending said blade (7), characterized in that it further comprises a screen (12) on the inner wall of said neck (3) or on the inner wall of said tank (1) and located behind said helical blade (8).  5) Churn according to one of the preceding claims, characterized in that said propeller part of said blade (7) and the propeller part of said counter blade (9) have substantially equal pitches.  6) Churn according to one of the preceding claims, characterized in that it is provided with at least one stop (13) so that said counter blade (9) can be stopped with its free edge (9a) substantially in contact with the internal wall of said tank (1).  7) Churn according to one of the preceding claims, characterized in that it is provided with at least one stop (14) to limit the pivoting angle of said counter blade (9).  8) Churn according to one of the preceding claims, characterized in that the blade (7) and the counter blade (9) are respectively provided with beads (7a and 9b) provided to be able to guide the product contained in the churn respectively during the emptying of the product in the second direction of rotation of the churn and during the operation of mixing the product in the first direction of rotation of the churn.