CA3005762A1

CA3005762A1 - Inlet valve, mixing device and control method for introducing a powdery substance into a liquid

Info

Publication number: CA3005762A1
Application number: CA3005762A
Authority: CA
Inventors: Mikkel MORK NIELSEN; Torben Marcussen; Bjarne Darre; Uwe Schwenzow
Original assignee: GEA TDS GmbH
Current assignee: GEA TDS GmbH
Priority date: 2015-11-23
Filing date: 2016-03-03
Publication date: 2017-06-01
Anticipated expiration: 2036-03-03
Also published as: DE102015016766A1; AU2016359638A1; EP3380220A1; EP3380220B1; CA3005762C; DK3380220T3; WO2017088938A1; DE102015016766B4; NZ742733A; PL3380220T3

Abstract

The invention relates to an inlet valve, a mixing device and a control method for introducing a powdery substance into a liquid present in a container of the mixing device. The present invention has the object of developing the inlet valve, the mixing device, the control method and the method so as to avoid the formation of dead space in the region of the internal wall of the container at the entry point for the powder, and clumping and blocking of the powder at the entry point and in the inlet valve, and so as to ensure reliable and smooth introduction of the powder into the liquid and simple adaptation to different powdery substances. Furthermore, the configuration of the inlet valve aims for a low-wear and replacement-friendly arrangement of the seat seal. This is achieved, in terms of the device, with an inlet valve in which, inter alia, · the valve seat (2a) forms a seat opening (2b) through which the powdery substance (P) is introduced into the liquid (F), · the seat opening (2b) with the valve plate (8a) can be changed between fully closed (shut position) or fully opened (open position), · the seat opening (2b) is arranged in and flush with a region of extent of a wall of the container jacket (100.1) or of the container bottom (100.2), · the valve closing member (8) can be transferred by means of the control device (30) into the shut position and into the open position, · the control device (30) has at least one signal receiver (16), · the at least one signal receiver (16) is a measurement device for the mixing parameters composition and nature of the powdery substance (P), throughflow of the powder (P) in the inlet valve (20), pressure in the mixing device (1000) in the region of the seat opening (2b) and/or temperature of the liquid (F), and · the shut position or the open position of the inlet valve (20) can be set during the introduction procedure depending on the mixing parameters.

Description

INLET VALVE, MIXING DEVICE AND CONTROL METHOD FOR
INTRODUCING A POWDERY SUBSTANCE INTO A LIQUID
TECHNICAL FIELD
The invention relates to an inlet valve for introducing a powdery substance into a liquid that is present in a container of a mixing device according to the preamble of claim 1, a device for introducing a powdery substance into a liquid according to the preamble of claim 6, a method for controlling the introduction of a powdery substance according to the preamble of claim 7 and a method for introducing a powdery substance into a liquid according to the preamble of claim 8.
PRIOR ART
Mixing devices are known, so-called vacuum mixers, that have a container with a stirring apparatus, in which a liquid is present that is mixed with a powdery substance. The free surface of the liquid, which can have a fluid level with a height of 0.4 to 4 m in the container, for example, is subjected to a vacuum relative to atmospheric pressure of, for example, 0.2 to 0.8 bar, which is accordingly associated with this height range, so that the liquid in particular in the base region of the container experiences a vacuum relative to atmospheric pressure under all operating conditions.
The container usually consists of a substantially cylindrical container jacket and an upper and a lower container bases. The lower container base can preferably be conical, i.e. tapering downward, in particular configured as a cone. The introduction of the powdery substance into the container occurs via an opening in the container wall, preferably either at the lowest point in the preferably cylindrical container jacket or, in a container base that tapers downward, preferably in the upper region of the container base. This opening continues in a tubular inlet nozzle toward the outer side of the container, to which a pipe leading to a powder storage container is connected. The inlet nozzle and thus the pipe are configured such that they can be shut off so that, on the one hand, the mixing device can be closed off from its environment via this path and so that, on the other hand, an amount of the powdery substance present in the powder storage container can be added to the liquid when required. As a rule, this is carried out in a so-called batch method, in which the amount of powder present is admixed into the amount of liquid provided in the required mix ratio in the mixing device and, as a rule, they are mixed together by means of a stirring apparatus.
Heretofore, a disc or ball valve that functions as a check valve has been arranged in the inlet nozzle to control the supply of the powdery substance. Because of the design of a disc or ball valve, the valve seat is located at a more or less large distance from the internal wall of the container due to the respective closure member configuration and kinematics, and so a dead space is formed in the inlet nozzle up to the respective valve seat as a result. Powder can build up in this dead space and remain there, causing a blockage that cannot or can only insufficiently be swept away by the action of the stirring apparatus. This risk arises in particular when the inlet nozzle is located in the downwardly tapering container base, and this arrangement may form a sump up to the valve seat of the respective valve.
Moreover, it is a disadvantage in disc and ball valves for the required seat seals to be arranged on the housing side and thus to be constantly exposed to the fully developed pipe flow. As a result, the seat seals are subjected in an exposed manner to the sometimes very abrasive powders, such as lactose, and are thus liable to increased wear. A publication on the Internet by TYCO International Ltd., Tyco Flow Control, Hygienic Products UPDATE, in conjunction with an F250 Powder SKI-JUMP Valve, for example, includes an indication of this substantive matter. A ramp ("ski jump") that is formed annularly around the valve housing of this disc valve and upstream of the seat seal in the flow direction of the powder channels the abrasive powder particles over the rubber seal, whereby abrasive wear of the rubber seal should be reduced.

2 The two valve designs, the disc and ball valves, also have in common that, when the valve is closed, the powder is located upstream of the respective closure member as viewed in the transport direction of the powder and can agglomerate there and thus block the supply and the entry into the container. To be able to replace each worn-out seat seal, the valve has to be uninstalled from the pipe in which it is arranged. In the case of disc valves, it is also a disadvantage that the disc-shaped closure member is located in the flow path of the powder flow and thus represents an additional obstacle.
The object addressed by the present invention is that of developing at least one generic inlet valve for introducing a powdery substance into a liquid that is present in a container of a mixing device, or a generic device for introducing a powdery substance into a liquid, or a generic method for controlling the introduction of a powdery substance into a liquid, or a generic method for introducing a powdery substance into a liquid such the formation of a dead space in the region of the internal wall of the container at the inlet point for the power as well as agglomerations and blockages of the powder at the inlet point and in the inlet valve are avoided and such that a reliable and trouble-free introduction of the powder into the liquid and a simple adaptation to various powdery substances are ensured.
Moreover, an objective is to achieve a configuration of the inlet valve that includes a low-wear and easily exchanged arrangement of the seat seal.
SUMMARY OF THE INVENTION
With regard to the device, this object is solved by the inlet valve for introducing a powdery substance into a liquid with the features of claim 1 and by a device for introducing a powdery substance into a liquid with the features of claim 6.
Furthermore, the object is solved with regard to the method by the method for controlling the introduction of a powdery substance into a liquid with the features of claim 7 and is solved with regard to the device and to the process by the features of claim 8.

3 The invention proposes for the first time an inlet valve for introducing a powdery substance into a liquid that is present in a container of a mixing device, said inlet valve being configured as a globe valve, wherein the container consists of a preferably cylindrical container jacket as well as an upper and lower container base.
The lower container base preferably tapers downward and is preferably configured conically or cone-shaped and is joined seamlessly to the container jacket. A
valve housing of the inlet valve is arranged with a valve closure member on the container jacket or the container base. Said valve housing has a valve seat, which interacts with a valve plate of the valve closure member. The valve seat forms a seat opening, through which the powdery substance is introduced into the liquid. By means of the valve plate, the seat opening can be adjusted between completely closed and completely open, i.e. a closed position and a completely open position can be implemented. The seat opening is arranged in and in alignment with an extension area of a wall of the container jacket or the container base.
Concretely, this means that, to the greatest extent possible, the valve seat and thus the seat opening formed by it are flush with the internal wall of the container jacket or the downwardly tapering container base. A control apparatus, by means of which the valve closure member can be shifted into the closed or the open position, is associated with the inlet valve. The control apparatus has at least one signal receiver, which is a measuring apparatus for the mixing parameters = composition and consistency of the powdery substance, = flow rate of the powdery substance in the inlet valve, = pressure in the container of the mixing device in the region of the seat opening, = and/or the temperature of the liquid.
The aforementioned pressure can be measured indirectly in the head space of the container above the surface of the liquid or directly in the region of the seat opening.
The closed or the open position of the inlet valve can be selected as a function of the mixing parameters during the introduction of the powdery substance.

4 For the seat opening to be as flush as possible with the internal wall of the container jacket or of the preferably downwardly tapering container base, a further development of the inlet valve is proposed in which the container-side end of the seat opening is oriented perpendicular to the stroke direction of the inlet valve and is flush with the inner side of the wall of the container jacket or container base. Here the flush fit of the container-side end of the seat opening should be understood to mean that this end represents an integral part of the inner contour of the container wall in this region, wherein the contact surface between the seat opening and the associated seat seal in the valve closure member is disposed as close as structurally possible to the end of the seat opening.
The aforementioned arrangement can also be executed with a valve seat in which the valve seat and the valve closure member are sealed off from each other without a discrete seat seal. This can be a pairing of metal on metal or a metallic valve seat that interacts with a valve closure member with sealing properties (suitable plastic).
What is essential here, too, is that the contact surface between the seat opening and an associated sealing surface on the valve closure member is disposed as close as structurally possible to the end of the seat opening.
A further advantageous embodiment of the inlet valve provides that a part of the valve housing that accommodates the seat opening is surrounded radially externally by a disc-shaped connecting element or expands into this connecting element, wherein the connecting element extends in the plane of the seat opening and perpendicular to the stroke direction of the inlet valve. Thus the connecting element, on the one hand, is a radial external component of the valve housing, in which the seat opening is configured and, on the other hand, functions advantageously as a weld-on part to be introduced into the wall of the container and thereby becomes an integral part of this wall.
Another further development of the connecting element provides that a front surface of the disc-shaped connecting element that faces the interior space of the container

5 is flush and in alignment with the inner side of the wall of the container jacket or the container base. This container-internal-side closure and the orientation aligned with the internal wall prevents the formation of a dead space in this region, and the valve seat with its seat opening and the associated seat seal in the valve closure member is not only brought up close to the extension area of the wall but is positioned in it, to the extent that this is possible.
In order to ensure that there are no dead and hollow spaces in the valve housing, it is proposed that, at least in the region upon which the powder impinges, the valve closure member be configured as a cylindrical bar with the same diameter, on which the valve plate is molded with the same diameter. This means that the valve plate connects to the cylindrical bar seamlessly and with the same diameter. Based on this embodiment, when the inlet valve is in its fully open position, the valve closure member with its valve plate is moved as far as possible out of the fully developed flow of the powdery substance, and so it, on the one hand, does not constitute an obstacle to flow and, on the other hand, a seat seal, which is accommodated in the valve plate, is disposed near the wall of the valve housing and thus outside of the fully developed flow region of the pipe flow, and it is therefore at most touched only tangentially by the stagnating flow near the wall in this edge region.
According to the invention, the device for introducing a powdery substance into a liquid has an inlet valve with the features described above.
With regard to the process, the object is solved by the method according to the invention for controlling the introduction of a powdery substance into a liquid. The powdery substance is introduced into the liquid present in a container of a mixing device by means of an inlet valve. The powdery substance flowing through the inlet valve enters into the liquid via the seat opening. The closed or the open position of the inlet valve is adjusted during the introduction process as a function of the mixing parameters. The mixing parameters are understood to include the composition and the consistency of the powdery substance, the flow rate of the powdery substance

6 in the inlet valve, the pressure in the container of the mixing device in the region of the seat opening and/or the temperature of the liquid.
The composition and the consistency of the powdery substance also determine the diameter of the seat opening and thus the nominal diameter of the inlet valve.
The control of the inlet valve, especially the duration of its opening, is determined by the presence or absence of the powdery substance, in particular in the inlet region of the inlet valve. When a flow rate can no longer be detected here, the suction of air into the container via the inlet valve must be avoided, and the inlet valve must be shifted into its closed position by the control apparatus.
According to the invention, the method for introducing a powdery substance into a liquid is performed using a device according to the invention and with at least one of the stated method steps from claim 7.
All of the features and advantages disclosed for the inlet valve according to the invention and the device according to the invention similarly apply to the method according to claim 7 of the invention as well as its advantageous further development according to claim 8.
Further features and advantages of the present invention arise from the following description in conjunction with the figures of the drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
A more comprehensive representation of the invention arises from the following description and the included figures of the drawing as well as from the claims. While the invention is implemented in the most diverse embodiments, a preferred exemplary embodiment of a mixing device for introducing a powdery substance into a liquid by means of an inlet valve according to the invention is described in the drawing. In addition, a method is indicated that can be performed with the inlet valve

7 in conjunction with the mixing device. The following is shown:
Figure 1 in a schematic representation, a mixing device with an inlet valve in conjunction with a control apparatus;
Figure la in an enlarged representation, a section in the region of the inlet valve and the adjacent wall region of a container of the mixing device, identified in Figure 1 with "A";
Figure lb in a further enlarged representation, a second section from the first section according to Figure la, identified in Figure la with "B";
Figure 2 in a perspective representation and in half-section, the inlet valve according to Figures 1 and la without a control head housing; and Figure 3 in a perspective representation, the inlet valve according to Figure 2, wherein, in contrast to Figure 2, the control head housing is additionally shown.
A mixing device 1000 (Figure 1) includes, inter alia, a container 100, which consists of a preferably cylindrical container jacket 100.1 and an upper container base, which is not shown, and a lower container base 100.2. The lower container base 100.2 preferably tapers downwardly, usually in the shape of a cone or circular cone, and has an outlet 100.3 at the lower end. In the container 100, a liquid F is present which forms a free level N, above which a pressure p, usually a vacuum relative to the atmospheric pressure, normally prevails in the mixing device 1000 in question (vacuum mixer). A valve housing 2 of an inlet valve 20 is arranged on the container jacket 100.1 or container base 100.2. A control device 30 is associated with the inlet valve 20, which serves to introduce a powdery substance P into the liquid F.
Disposed within the container 100 is a stirring apparatus 24, preferably mechanical, that extends down into the region of the lower container base 100.2. The required mixing effect can also be achieved by fluid-mechanical means, such as by pumping the liquid F through a circulation line and the tangential entry of the liquid into the container 100.

8 According to the invention, the inlet valve 20 is configured as a globe valve (Figures 2 and 3). In its valve housing 2, it has a valve seat 2a and a valve plate 8a that interacts with it and that is configured on a valve closure member 8.
As a rule, the valve closure member 8 accommodates a seat seal 10, which brings about the sealing effect in the closed position of the inlet valve 20 in conjunction with the valve seat 2a. Alternatively, it is also possible to implement seat configurations without a seal, in which the pairing of metal on metal or metal against a valve closure member 8 with sealing properties, such as a suitable plastic, results in a sufficient seal.
The valve seat 2a has a seat opening 2b, through which the powdery substance P
is introduced into the liquid F. The liquid F, which is present above the connection point of the inlet valve 20 that is arranged in the wall of the container 100, forms a height h with its fluid column, and so the static pressure in the region of the connection point and thus of the seat opening 2b is composed of the vacuum p and the static pressure resulting from the height of the fluid column h. In a vacuum mixer having, for example, a vacuum of p = 0.2 to 0.8 bar and a height of the fluid column h = 0.2 to 4 m in accordance with this pressure range, there is always a vacuum relative to the atmospheric pressure in the region of the seat opening 2b, and so the seat opening 2b is suctioned out of the container 100.
The seat opening 2b can be adjusted by means of the valve plate 8a between completely closed, i.e. the closed position, and completely open, i.e. the open position. According to the invention, the seat opening 2b is arranged in and in alignment with an extension area of a wall of the container jacket 100.1 or the container base 100.2 (Figures 1a, 1 b). The container-side end of the seat opening 2b is oriented perpendicular to the stroke direction of the inlet valve 20 and, in the best possible embodiment, which is not shown in Figure lb, is flush with the inner side of the wall of the container jacket 100.1 or the container base 100.2.

9 A part of the valve housing 2 that accommodates the seat opening 2b is surrounded radially externally by a disc-shaped connecting element 2c that extends in the plane of the seat opening 2b and perpendicular to the stroke direction of the inlet valve 20 (Figures 1 b, 2,3 and 1). The connecting element 2c is arranged in a wall opening 100.4 of the container 100 and is preferably materially bonded, preferably by welding, to its wall. A front surface of the disc-shaped connecting element 2c that faces the interior space of the container 100 is flush and in alignment with the inner side of the wall of the container jacket 100.1 or the container base 100.2.
The valve closure member 8 can be shifted into the closed or the open position by means of the control apparatus 30. Said control apparatus 30 has at least one signal receiver 16 (Figure 1). The at least one signal receiver 16 is a measuring apparatus for the mixing parameters of composition and consistency of the powdery substance P, flow rate of the powdery substance P in the inlet valve 20, pressure in the mixing device 1000 in the region of the seat opening 2b and/or the temperature of the liquid F. A pipe connection 2d on the valve housing 2 is connected via a supply line 18 to a powder storage container 26, in which an appropriate amount is kept for a preferably batchwise introduction of the powdery substance P into the liquid F. The measuring apparatus 16 is located in the supply line 18, preferably in the immediate vicinity of the pipe connection 2d, and here it preferably detects the flow rate of the powdery substance P. The presence or absence of the powdery substance P leads to a corresponding signal, which is transmitted from the measuring apparatus 16 via a signal line 22 to the control apparatus 30. Depending upon the signal from the measuring apparatus 16, the control apparatus 30 transmits a control command to a control head housing 14 of the inlet valve 20 via a further signal line 22. During the introduction, the closed or the open position of the inlet valve 20 can be selected as a function of the aforementioned signal from the measuring apparatus 16.

In a similar manner, further measuring apparatus can additionally or alternatively be provided to record the other mixing parameters so that it is also possible to select the closed or the open position of the inlet valve 20 using these mixing parameters.
The valve housing 2 is connected to a drive housing 6 by a lamp housing 4 to drive the valve closure member 8 (Figures 2 and 3). This is preferably a spring/piston drive that is charged with pressurizing medium, wherein a return spring 12 shifts the valve closure member 8 into its closed position when the drive is not charged with pressurizing medium, preferably pressurized air. A valve rod 8b, which engages with the valve plate 8a of the valve closure member 8 and is guided through the drive housing 6 and into the control head housing 14, serves to guide the valve closure member 8 axially on the drive side.
It is apparent from Figure 2 that, at least in the region upon which the powder impinges, the valve closure member 8 is configured as a cylindrical bar with the same diameter, on which the valve plate 8a is molded with the same diameter.
As a result of this structural configuration, hollow and dead spaces in the valve housing 2 are avoided in the movement area of the valve closure member 8, wherein the valve closure member 8 with its end-side valve plate 8a and the associated seat seal 10 can be largely withdrawn from the region of the valve housing 2 through which the substance is fully flowing.
The device, namely the mixing device 1000 described above, for introducing the powdery substance P into the liquid F has the previously described inlet valve with its likewise previously described further developments.

The method for controlling the introduction of the powdery substance P into the liquid F provides that the powdery substance P be introduced into the liquid F
that is present in the container 100 of the mixing device 1000 by means of the inlet valve 20 described above. In this way, the powdery substance P flowing through the inlet valve 20 enters the liquid F via the seat opening 2b, and the closed or the open position of the inlet valve 20 is adjusted during the introduction process as a function of the mixing parameters. The mixing parameters are understood to include the composition and the consistency of the powdery substance P, the flow rate of the powdery substance P in the inlet valve 20, the pressure in the container 100 of the mixing device 1000 in the region of the seat opening 2b and/or the temperature of the liquid F.

REFERENCE SIGN LIST FOR THE ABBREVIATIONS USED
20 Inlet valve 30 Control apparatus 1000 Mixing device 100 Container 100.1 Container jacket 100.2 Container base (conical; cone-shaped) 100.3 Outlet 100.4 Wall opening 2 Valve housing 2a Valve seat 2b Seat opening 2c Connecting element 2d Pipe connection 4 Lamp housing 6 Drive housing 8 Valve closure member 8a Valve plate 8b Valve rod Seat seal 12 Return spring 14 Control head housing 16 Signal receiver 18 Supply line 22 Signal line 24 Stirring apparatus 26 Powder storage container F Liquid N Level P Powdery substance h Height of the fluid column p Pressure above the fluid column

Claims

1. An inlet valve (20) with a container (100) and a control apparatus (30) for introducing a powdery substance (P) into a liquid (F) that is present in the container (100) of a mixing device (1000), said inlet valve being configured as a globe valve, .cndot. with a container base (100.2) that is configured on the container (100) and that is attached to a container jacket (100.1), with a valve housing (2) of the inlet valve (20), which is arranged on the container jacket (100.1) or container base (100.2) and which has a valve closure member (8), .cndot. with a valve seat (2a) in the valve housing (2), .cndot. with a valve plate (8a) that is configured on the valve closure member (8) and that interacts with the valve seat (2a), .cndot. with the valve seat (2a), which forms a seat opening (2b), through which the powdery substance (P) is introduced into the liquid (F), .cndot. with the seat opening (2b), which can be adjusted by means of the valve plate (8a) between completely closed (the closed position) and completely open (the open position), .cndot. with the valve closure member (8), which is configured, at least in the region upon which the powder impinges, as a cylindrical bar with the same diameter, on which the valve plate (8a) is molded with the same diameter, .cndot. with the valve closure member (8), which with its end-side valve plate (8a) can be largely withdrawn from the region of the valve housing (2) through which the powdery substance (P) is fully flowing when the inlet valve (20) is in the fully open position, .cndot. with a control apparatus (30) that is associated with the inlet valve (20), .cndot. with the seat opening (2b), which is arranged in and in alignment with an extension area of a wall of the container jacket (100.1) or the container base (100.2), .cndot. with the valve closure member (8), which can be shifted into the closed or the open position by means of the control apparatus (30), .cndot. with the control apparatus (30), which has at least one signal receiver (16), .cndot. with the at least one signal receiver (16), which is a measuring apparatus for the mixing parameters of composition and consistency of the powdery substance (P), the flow rate of the powdery substance (P) in the inlet valve (20), the pressure in the container (100) in the region of the seat opening (2b) and/or the temperature of the liquid (F), .cndot. wherein the closed or the open position of the inlet valve (20) can be selected during the introduction as a function of the mixing parameters.

2. The inlet valve with a container (100) and a control apparatus (30) according to claim 1, characterized in that the container-side end of the seat opening (2b) is oriented perpendicular to the stroke direction of the inlet valve (20) and is flush with the inner side of the wall of the container jacket (100.1) or the container base (100.2).

3. The inlet valve with a container (100) and a control apparatus (30) according to claim 1 or 2, characterized in that a part of the valve housing (2) that accommodates the seat opening (2b) is surrounded radially externally by a disc-shaped connecting element (2c) that extends in the plane of the seat opening (2b) and perpendicular to the stroke direction of the inlet valve (20).

4. The inlet valve with a container (100) and a control apparatus (30) according to claim 3, characterized in that a front surface of the disc-shaped connecting element (2c) that faces the interior space of the container (100) is flush and in alignment with the inner side of the wall of the container jacket (100.1) or the container base (100.2).

5. A device (1000) for introducing a powdery substance (P) into a liquid (F), wherein the device (1000) has an inlet valve (20) with a container (100) and a control apparatus (30) according to one of claims 1 to 4.

6. A method for controlling the introduction of the powdery substance (P) into a liquid (F), wherein the powdery substance (P) is introduced into the liquid (F) that is present in a container (100) of a mixing device (1000) by means of an inlet valve (20) with a container (100) and a control apparatus (30) according to one of claims 1 to 4, .cndot. wherein the powdery substance (P) flowing through the inlet valve (20) enters into the liquid (F) via the seat opening (2b), .cndot. wherein the closed or the open position of the inlet valve (20) is adjusted during the introduction process as a function of the mixing parameters, and .cndot. wherein the mixing parameters are understood to include the composition and the consistency of the powdery substance (P), the flow rate of the powdery substance (P) in the inlet valve (20), the pressure in the container (100) in the region of the seat opening (2b) and/or the temperature of the liquid (F).

7. The method for introducing a powdery substance into a liquid using a device according to claim 5 and with the method steps according to claim 6.