WO2014011038A1

WO2014011038A1 - Feed valve

Info

Publication number: WO2014011038A1
Application number: PCT/NL2013/050518
Authority: WO
Inventors: Dirk Klaas IWEMA
Original assignee: Stichting Energieonderzoek Centrum Nederland
Priority date: 2012-07-11
Filing date: 2013-07-09
Publication date: 2014-01-16
Also published as: NL2009170C2

Abstract

Feed valve (1) for transferring an amount of material from an inlet (2) to an outlet (3), having a housing (4), a passageway (5) extending through the inlet (2), the housing (4) and the outlet (3), and connecting the inlet (2) and the outlet (3). A spherical element (6) is rotatably disposed in the housing (4), the spherical element (6) having a central bore (7). A first actuator (8) is connected to the spherical element (6) for rotation thereof from a first to a second angular position. The feed valve (1) further has a piston element (9) moveably disposed in the central bore (7), and a second actuator (10) connected to the piston element (9) for moving the piston element (9) from a first to a second linear position in the central bore (7).

Description

FEED VALVE

Field of the invention

The present invention relates to a feed valve, more particularly to a feed valve for transferring materials from an inlet to an outlet. Prior art

US patent US-A-1, 763,487 discloses a machine provided with a valve for controlled filling of containers with a range of material. The machine comprises a reservoir and a rotatable valve in a casing, allowing material in the reservoir to be transferred to a container by the valve via an opening. The valve has a cylindrical shape and has a central bore with a linearly moveable plunger therein, for transferring the material.

US patent publication US2007/181604 discloses a dry product dispenser for supplying a predetermined amount of granulated dry material. The dispenser comprises a main body or reservoir, a loading and dispensing member or rotatable valve positioned in an internal cavity of a lower section of the dispenser. Material in the reservoir can be transferred by the valve via a discharge spout into a container. The valve is a cylindrical member and comprises a cylindrical receiving cavity provided with an adjustable piston (or portion control device). The piston does not move in relation to the cavity during rotation/actuation of the valve, which during use moves up and down in a rotational manner.

US patent US-A-4,058,240 discloses an automatic drain system for compressed air systems, etc. It comprises a rotary valve for draining contaminations in the system, which is provided with a ball which is rotatable inside a housing body using a spindle. Seals are provided to prevent leakage between the ball and the body. The ball is provided with a bore through the center of the ball and normal to the axis of the spindle, allowing condensed water to be transferred from a high pressure side of a system, to a low pressure drainage output. In a further embodiment, a moveable piston is provided in a bore extending all the way through the ball, the piston being able to move under the influence of gravity in combination with the pressure difference between system side and drainage output side.

U.S. patent publication 5,823,401 discloses a sampling and dispensing ball- valve, comprising a body with a through-bore having a first (inlet) and second (outlet) end. The through-bore has an inner surface lined with a two-part sleeve which partially embraces a ball. The ball is rotatably mounted in the sleeve and the ball includes a blind-bore of a known volume. The ball is adapted to rotate between a first position where the blind-bore registers with the first end, and a second position where the blind- bore registers with the second end. During rotation of the ball, a sealing engagement between the ball and sleeve is maintained to prevent the ball from transporting fluid other than that held by the blind-bore. Therefore, only a predetermined volume is transported from the first end of the valve body to the second end. US patent US-B- 6,766,924 discloses a similarly constructed metering ball-valve.

The above prior art ball-valve suffers from a number of disadvantages First, the predetermined volume of the blind-bore is fixed, so the amount of material sampled or dispensed cannot be changed or altered. Second, the ball valve is not able to actively dispense materials from the blind-bore, making it difficult to ascertain whether all materials have been dispensed, particularly sticky and/or low viscosity materials. Third, the blind-bore may not be adequately or completely filled in case the blind-bore comprises e.g. residual materials and/or gas pockets. Hence, to avoid partial discharges and/or the retention of materials inside the blind-bore, the ball valve should only be used for viscous fluids and dry bulk solids, granules, powders and the like. Fourth, the inlet pressure in this case should be higher or equal to the outlet pressure to avoid leakage from the outlet to the inlet

Summary of the invention

The present invention aims to provide a feed valve which is free of the above prior art limitations.

According to the present invention, a feed valve according to the preamble is provided, wherein the feed valve comprises a housing; a passageway extending through the inlet, the housing and the outlet, and connecting the inlet and the outlet; a spherical element rotatably disposed in the housing, the spherical element having a central bore; and a first actuator connected to the spherical element for rotation thereof from a first to a second angular position; wherein the feed valve further comprises a piston element moveably disposed in the central bore, and a second actuator connected to the piston element for moving the piston element from a first to a second linear position in the central bore, and a filling body disposed in the housing, wherein an inner surface of the filling body is congruent with an outer surface of the spherical element. The first angular position refers to an open end of the central bore being in register with the inlet, and the second angular position refers to an open end of the central bore being in register with the outlet.

The difference between the first and second linear position of the piston element defines a variable supply volume (or stroke volume) depending on the selected first linear position. More particularly, the selected first linear position corresponds to a bottom dead centre position of the piston element in the central bore. This solves the problem of having a pre-determined supply volume and increases the versatility of the feed valve as it now offers a variable transfer capacity. The second linear position of the piston element in the central bore refers to a top dead centre position which is typically not varied.

Moving the piston element from the first to the second linear position by means of the second actuator reduces the supply volume. This allows the compression of materials in the housing and/or when the materials are discharged.

In a further embodiment, the spherical end surface has the same radius as the spherical element. The second linear position of the piston element then refers to the top dead centre position where the spherical end surface of the piston element is in alignment with the outer surface of the spherical element. Consequently, the supply volume becomes zero and the existence of a dead supply volume is eliminated.

The feed valve according to this embodiment is able to discharge all materials when the piston moves from the first to the second linear position. Since there can be no retention of materials and/or gas pockets inside a non-existent supply volume, the adequate or complete filling of the supply volume is guaranteed when the piston element moves from the second to the first linear position.

In further dependent claims, and as discussed below with reference to the drawings, further details of elements of the feed valve according to the present invention embodiments are described.

The feed valve according to the present invention aims to be suitable for a number of materials to be transferred, such as non-Newtonian fluids, gases, vapors, bulk solids, granules, powders, slurries, and various other materials. Especially applications where materials are transferred from a low pressure side to a high pressure side in an installation can make advantageous use of the present invention

embodiments. The feed valve can be used in a variety of industries, such as the petrochemical industry, the pharmaceutical industry, the food industry, the bio industry, the renewable energy industry (e.g. organosolv processes) etc.

The feed valve may act as an explosion barrier and/or flame arrester in explosive zones, thus providing a high safety level.

The feed valve comprises a minimum of components and can be manufactured of any material deemed suitable for the application.

Short description of drawings

The present invention will be explained in further detail hereinafter based on a number of exemplary embodiments with reference to the drawings, wherein:

Fig. 1 is a cross sectional view of a first embodiment of a feed valve according to the present invention;

Fig. 2 is a cross sectional view of a detail of the feed valve shown in Fig. 1, in another operational position;

Fig. 3 is a cross sectional view of a second embodiment of a feed valve according to the present invention;

Fig. 4 is a perspective view of an embodiment of a feed valve component according to the present invention.

Detailed description of exemplary embodiments

Referring to the drawings, Fig. 1 shows a cross sectional view of a first embodiment of a feed valve 1 according to the present invention. The feed valve is arranged to transfer an amount of material from an inlet to an outlet with minimal leakage and internal retention of transferred materials.

Fig. 1 shows the main elements of the feed valve 1 : an inlet 2, an outlet 3, a housing 4, and a passageway 5 extending through the inlet 2, the housing 4 and the outlet 3. Furthermore, a spherical element 6 is provided having a central bore 7, a first actuator 8, a piston element 9 disposed in the central bore 7, and a second actuator 10.

In an embodiment, the inlet 2 and outlet 3 can be separate components connected to the housing 4 by means of e.g. known pipe nozzles/flanges or welding techniques, or as shown using simple bolts. Sealing between inlet 2 and housing 4 is implemented using an O-ring sealing element 24, and similarly sealing between outlet 3 and housing 4 is implemented using a further O-ring sealing element 25. In another embodiment, the inlet 2, the outlet 3, and the housing 4 may be integrally formed using e.g. known casting techniques or one-piece machining methods. The materials used for the inlet 2, the outlet 3, and the housing 4 can be selected on a per application basis, depending on various process parameters and requirements.

The passageway 5 extends through the inlet 2, the housing 4, and the outlet 3, and implements a transfer path through the feed valve 1 connecting the inlet 2 and outlet 3. That is, the passageway 5 allows for materials to be transferred through the feed valve 1, where the materials move through the inlet 2, through the housing 4, and through the outlet 3, or vice versa.

In an embodiment shown in Fig. 1, a part of the passageway 5 that extends through the inlet 2 and the outlet 3 may be substantially cylindrical for facilitating a seamless transfer path and congruent connection to known pipes and pipe components (e.g. standard pipes, nozzles, and flanges). A part of the passageway 5 in the housing 4 may be substantially spherical for accommodating the spherical element 6.

The spherical element 6 is rotatably disposed in the passageway 5 between the inlet 2 and outlet 3. More particularly, the spherical element 6 is rotatably disposed in the housing 4 to allow rotation over an actuator axis 30 from a first to a second angular position. In the embodiment shown, the inlet 2 and outlet 3 are aligned along a passageway axis 5a, and the first and second angular position are 180° shifted over the actuator axis 30. In an alternative embodiment, the inlet 2 and outlet 3 may be at a different angle with respect to the housing 4 than shown in the Fig. 1 embodiment, e.g. at 90°. The first and second angular position of the spherical element 6 is then congruent with that orientations, in the example mentioned a 90° shift over the actuator axis 30. The actuator axis 30 extends perpendicular to the passageway axis 5a in both mentioned alternatives.

The spherical element 6 comprises a central bore 7 with a length (or depth) Li. In a first embodiment, the central bore 7 is a blind-bore (or one-sided bore), wherein the central bore 7 comprises an open end and a closed end so that the central bore 7 only partially extends through the spherical element 6. In a second embodiment, shown in the cross sectional view of Fig. 3, the central bore 7 is a through-bore, having a length of L₂ as indicated, wherein the bore comprises two open ends so that the central bore 7 fully extends through the spherical element 6. In both embodiments, the central bore 7 is axially symmetric around its longitudinal axis (which coincides with passageway axis 5a in the embodiment and operational position shown in Fig. 3).

The central bore 7 is substantially cylindrical with a diameter which is less than, equal to, or larger than an inner diameter of the substantially cylindrical passageway 5 extending through the inlet 2, housing 4 and the outlet 3. The spherical element 6 is kept in a sealing engagement with housing sealing elements 31, both at the inlet side and outlet side of the housing 4, thus forming a sealed passageway 5. The sealing elements 31 may be adapted to ensure proper sealing of the passageway 5, dependent on the diameter of the central bore 7. The material of the sealing elements 31 may be chosen depending on the specific applications. E.g. when the feed valve 1 is used in an application where the bulk material is of a hard or sandy type, the sealing elements 31 may be provided as carbon sealing rings.

The feed valve 1 further comprises a piston element 9 moveably disposed within the central bore 7 of the spherical element 6, wherein the piston element 9 adjoins an inner surface of the central bore 7. This provides a substantially sealing engagement between the inner surface of the central bore 7 and the piston element 9, which may be enhanced using additional piston sealing elements 12, as shown in the embodiments of Fig. 1, 2 and 3. The piston element 9 is linearly moveable inside the spherical element 6 from a first to a second linear position relative to the central bore 7.

The piston sealing element 12 can be an O-ring or any other type of seal element deemed suitable for the application. The piston sealing element 12 is particularly useful for applications having a higher differential pressure in operation between the inlet 2 and the outlet 3. Other embodiments of the feed valve 1 may conceivably comprise a plurality of sealing elements 12 interposed between the piston element 9 and the inner surface of the central bore 7, allowing for e.g. very high differential pressures between the inlet 2 and the outlet 3, or low viscosity materials.

The height Hi (Fig. 1 embodiment) of the piston element 9 is less than the length Li of the central bore 7, thus creating a possibility to form an open transfer volume V when the piston element 9 is retracted in the spherical element 6 (indicated by the dashed line in Fig. 2). Similarly, in the embodiment shown in Fig. 3, the height H₂ of the piston element 9 is smaller than the length L₂ of the through hole bore 7, again allowing formation of a displacement volume on both sides of the piston element 9. In the embodiment shown in Fig. 1 and 2, the central bore 7 is a blind-bore and the piston element 9 disposed therein comprises a single spherical end surface 11 with the same radius as the spherical element 6. In the embodiment shown in Fig. 3, the central bore 7 is a through-bore and the piston element 9 disposed therein comprises two spherical end surfaces 11, each of which with the same radius as the spherical element 6. The latter embodiment allows a double operation speed, to be explained in detail further below.

In the embodiment where the central bore 7 is a blind bore, the spherical element 6 may be provided with conduits or other elements allowing air between piston element 9 and the bottom of spherical element 6 to escape or return, to allow movement of the piston element 9 in the spherical element 6 without compression of the air in the space between piston element 9 and spherical element 6.

The feed valve 1 further comprises a first actuator 8 associated with the spherical element 6 which operates by means of a first actuator shaft 16. The first actuator 8 is adapted to rotate the spherical element 6 from the first to the second angular position (e.g. using a flattened end of the first actuator shaft 16 and a corresponding aperture in the spherical element 6. The first actuator shaft 16 is journalled in the housing 4, in a manner known as such, e.g. using a sealing bearing 18 (or other first actuator sealing element). Exemplary embodiments of the first actuator 8 are e.g. manual, electro-mechanical (direct or indirect, e.g. using cog wheels or gears), hydraulic or pneumatic drive units. In a manually operated embodiment of the first actuator 8 as shown in Fig. 1, a first lever 22 is provided and connected to the first actuator shaft 16 by attachment elements known as such for rotating the spherical element 6.

The feed valve 1 further comprises a second actuator 10 associated with the piston element 9 which operates by means of a second actuator shaft 17. The second actuator is adapted to linearly move (e.g. reciprocate) the piston element 9 from the first to the second linear position in the central bore 7. The second actuator shaft 17 is journaled in both the housing 4 and the spherical element 6. In the embodiment shown, a second actuator primary sealing element 19 is provided between the second actuator shaft and the housing 4, and a second actuator secondary sealing element 20 is provided between the second actuator shaft 17 and the spherical element 6 Furthermore, attachment elements known as such may be used to rotatably attach the second actuator shaft 17 in the housing 4, such as using a pivot ring 27 and packing ring 26. Exemplary embodiments of the second actuator 10 are e.g. manual, electro-mechanical (direct or indirect, e.g. using cog wheels or gears), hydraulic or pneumatic drive units. In the embodiment shown, a second lever 23 is provided and connected to the second actuator shaft 17 for moving the piston element 9.

The sealing elements 18, 19, 20 described above may comprise a single O-ring, a plurality of O-rings, or any other type of seal component deemed suitable for the application. Providing a plurality of O-rings for each sealing element 18, 19, 20 is particularly useful when coping with e.g. high differential pressures, or low viscosity materials.

In the embodiments shown, an eccentric element 21 is provided at an end of the second actuator shaft 17 for moving the piston element 9 from the first to the second linear position. An axis 21a of the eccentric element 21 is offset from the actuator axis 30. By way of example, the eccentric element 21 can be seen as a cam element slidingly connecting with a cam surface in the piston element 9, imposing a

reciprocating movement when the eccentric element 21 rotates around the actuator axis 30. Of course, a variety of alternatives to the eccentric element 21 are conceivable, e.g. electro-mechanical, hydraulic, or pneumatic mechanisms interacting with the second actuator shaft 17 and the piston element 9. Actuator lines may e.g. be fed to the piston element 9 through the region of the spherical element 6 around the actuator axis 30.

In an embodiment, the feed valve 1 further comprises a filling body 13 disposed in the housing 4, wherein an inner surface of the filling body 13 is congruent with an outer surface of the spherical element 6. A typical embodiment of the filling body 13 comprises a spherical inner surface immediately adjoining the outer surface of the spherical element 6, providing a sealing engagement between the filling body 13 and the spherical element 6. As the name suggests, the filling body 13 prevents the existence of dead volume inside the feed valve 1, thereby avoiding internal retention of transferred materials in the feed valve 1.

The spherical element 6 and the filling body 13 can be of any material, though care must be taken with regard to wear between the contacting surfaces, which may necessitate different materials for the spherical element 6 and filling body 13.

Shown in Fig. 4 is a perspective view of an embodiment of a feed valve component according to the invention. In this embodiment, the filling body 13 comprises two halves 14, wherein each halve 14 comprises an interface plane 15. The halves 14 are disposed in the housing 4 and arranged such that the interface planes 15 coincide. The halves 14 further comprise recesses (e.g. semicircular recesses) for accommodating the first and second actuator shaft 16, 17 on the actuator axis 30.

The interface planes 15 are parallel to the actuator shaft 16, and parallel to the longitudinal axis of the central bore 7 when the spherical element 6 is in the first or second angular position. This particular orientation of the interface planes 15 ensures that during operation an open end of the central bore 7 always faces a smooth inner surface of the halves 14 (e.g. no ridges, grooves, crevices etc.) when rotating from the first to the second angular position. As a result, there is no scraping effect when material is transferred from the inlet 2 to the outlet 3, avoiding internal retention of residual materials inside the feed valve 1. Another advantage of this orientation is that material in the supply volume V cannot get stuck behind surface discontinuities when the spherical element 6 rotates. Accidental locking of the first actuator 8 is thus avoided, particularly when the materials in the supply volume V are being compressed by the piston element 9.

The feed valve 1 according to the present invention comprises four main (kinematic) operational positions, two of which are individually shown in Fig. 1. and Fig. 2. The remaining two operational positions can be clarified without reference to the drawings.

According to the first operational position shown in Fig. 1, the spherical element 6/ first actuator 8 is in the first angular position, which refers to the

configuration wherein an open end of the central bore 7 registers with the inlet 2. The piston element 9/second actuator 10 is in the first linear position, which refers to the configuration wherein the piston element 9 is bottom dead centre, i.e. a retracted position in the bore 7. The first angular position combined with the first linear position yields a supply volume V (see Fig. 2) defined by the spherical end surface 11 and the exposed inner surface of the central bore 7. This configuration defines a supply stage of the feed valve 1, in which material is received from the inlet 2 into the available supply volume V.

It is important to note that the first linear position of the piston element 9 may actually be selected not to be bottom dead centre, but at a distance above the bottom of the bore 7, so that a varying transfer capacity of the feed valve 1 is achieved by not utilizing the maximum attainable displacement of the piston element 9 inside the central bore 7.

According to the third operational position shown in Fig 2, the spherical element 6/ first actuator 8 is in the second angular position, which refers to the configuration wherein an open end of the central bore 7 registers with the outlet 3. The piston element 91 second actuator 10 is in this case in the second linear position, which refers to the configuration wherein the piston element 9 is at its maximum distance from the bottom of the bore 7. In this configuration, the spherical end surface 1 1 is in alignment with the outer surface of the spherical element 6, reducing the supply volume V to zero. The second angular position combined with the second linear position denotes the discharge stage of the feed valve 1, wherein the supply volume V equals zero and material is discharged through the outlet 3.

In addition to the supply and discharge stages of the feed valve 1, the remaining two operational positions:

- the second operational position refers to the second angular position of the spherical element 6/ first actuator 8 combined with the first linear position of the piston element 91 second actuator 10. In this position the central bore 7 registers with the outlet 3 and the piston element 9 is retracted, bottom dead centre;

- the fourth operational position refers to the first angular position of the spherical element 6/ first actuator 8 combined with the second linear position of the piston element 91 second actuator 10, , wherein the central bore 7 registers with the inlet 2 and the piston element 9 is extended (away from the bottom of the bore 7).

When controlling the first and second actuator 8, 10 to have the first to fourth operational position in sequence, material can be fed from the inlet 2 to the outlet 3.

In both embodiments of Fig. 1 and Fig. 3, the first and second actuator 8, 10 may either be implemented as single direction actuators, or as reciprocating actuators. When using single direction actuators, the spherical element 6 will always turn in the same direction during operation, whereas when using reciprocating actuators, the spherical element 6 will go back and forth between the first and second angular position. The latter is advantageous when the angular difference between the first and second angular position is less than 180°. Furthermore, the first actuator 8 and second actuator 10 may be linked in order to ensure proper sequencing of the various positions of the spherical element 6 and piston element 9. This may be implemented as a mechanical link, or may be implemented using an actuator control unit, which e.g. under software control, actuates the first and second actuators 8, 10.

The feed valve 1 according to any of the embodiments of the present invention are specifically suitable for use in applications where material needs to be transferred in a reliable and safe manner. An example of such an application is an organosolv process, where material in the form of feedstock is brought from a supply environment to a reaction environment. The reaction environment is usually at higher pressure and temperature. Furthermore, in such application it is important that the inlet side is very good separated from the outlet side, in order to prevent hazardous situations (possible explosive reactions, return from toxic materials to inlet side, etc.). As the sealing of the present feed valve 1 embodiments between inlet 2 and outlet 3 is very good almost no dangerous substances can get back from the outlet side to the inlet side.

In more detail, the feed valve 1 cannot prevent that air transfers from the inlet 2 to the outlet 3, as it is the intended purpose to transfer material in that direction. The transfer in the other direction (from outlet 3 to inlet 2) is effectively prevented as indicated. In specific applications, this may even be improved by flushing the transport space in the feed valve 1, e.g. using a gas which is inert or not harmful for the specific process. This may e.g. be implemented using an additional flushing stage of the feed valve 1, where the bore 7 is aligned with flush ports in the housing 4 (e.g. at 90° rotation of the spherical element 6). Flushing can be further augmented by actuation of the piston element 9.

A further advantage of the feed valve 1 is that in a specific embodiment the piston element 9/second actuator 10 is able to compress materials in the supply volume V between the supply and discharge stage and/or when discharging materials through the outlet 3. The piston element 9 discharges the materials to any desirable pressure within its designed range from bottom dead centre to top dead centre. In the embodiments described, the spherical end surface 11 and the spherical element 6 have identical radii, so that the supply volume V equals zero and a dead supply volume is avoided when the piston element 9 is top dead centre. Consequently, no materials will be transferred back to the inlet 2 when rotating the spherical element 6 from the second to the first angular position while maintaining the piston element 9 in the second linear position.

The supply volume V depends on many parameters, e.g. the length and diameter of the central bore 7, the height of the piston element 9, the difference between the first and second linear position etc. The feed valve 1 according to the present invention does not impose a lower or upper limit on the size of the supply volume V, as this is dependent on e.g. manufacturing capabilities, application requirements etc.

As mentioned earlier, the embodiments shown in Fig. 1 and Fig. 2 describe two main configurations of the feed valve 1. In actual operational the feed valve 1 typically passes through these four configurations described above during a single supply and discharge cycle.

Furthermore, Fig. 1 and Fig. 2 describe embodiments wherein the first and second angular positions are separated by a straight angle (i.e. 180 degrees), which implies that the passageway 5 defines a straight transfer path between the inlet 2 and outlet 3. However, the present invention does not impose a geometric limitation on the passageway 5 and other geometries are readily conceivable.

Indeed, according to a group of embodiments not shown, the first and second angular positions may be separated by e.g. an acute, right, or obtuse angle between a supply and discharge configuration. So the passageway 5 need not be straight and may define a curved transfer path. It is readily understood that various components such as e.g. the inlet 2, the outlet 3, the housing 4, and the halves 14 may need to be redesigned in order to facilitate such a curved passageway 5. As explained earlier, the halves 14 depicted in Fig. 3 are adapted for a straight passageway 5, and where the interface planes 15 are parallel to the longitudinal axis of the central bore 7 in the first and second angular position, which are separated by 180°. However, the halves 14 may need to be redesigned to accommodate a curved passage way 5, wherein the first and second angular position are separated by e.g. 90°.

According to another set of embodiments not shown, it is conceivable that the feed valve 1 comprises a plurality of passageways 5 connecting a plurality of inlets 2 and outlets 3, a plurality of central bores 7 in a spherical element 6 and so on. The feed valve 1 can thus be embodied as a multi-port feed valve.

The present invention embodiments have been described above with reference to a number of exemplary embodiments as shown in the drawings. Modifications and alternative implementations of some parts or elements are possible, and are included in the scope of protection as defined in the appended claims. E.g. the spherical element 6 need not be fully spherical, and can have any other shape (e.g. a disc shape), as long as a transport volume V can be provided using a piston element 9 which is moveable in the spherical element 6, and the transport volume can be rotated from the inlet 1 to the outlet 3.

Claims

1. Feed valve (1) for transferring an amount of material from an inlet (2) to an outlet (3), the feed valve comprising: a housing (4); a passageway (5) extending through the inlet (2), the housing (4) and the outlet (3), and connecting the inlet (2) and the outlet (3); a spherical element (6) rotatably disposed in the housing (4), the spherical element (6) having a central bore (7); and a first actuator (8) connected to the spherical element (6) for rotation thereof from a first to a second angular position; wherein the feed valve (1) further comprises a piston element (9) moveably disposed in the central bore (7), and a second actuator (10) connected to the piston element (9) for moving the piston element (9) from a first to a second linear position in the central bore (7), and a filling body (13) disposed in the housing (4), wherein an inner surface of the filling body (13) is congruent with an outer surface of the spherical element (6).

2. Feed valve according to claim 1, wherein the central bore (7) is a blind-bore.

3. Feed valve according to claim 1, wherein the central bore (7) is a through-bore.

4. Feed valve according to any one of claims 1-3, wherein the piston element (9) is provided with at least one spherical end surface (11) having the same radius as the spherical element (6).

5. Feed valve according to any one of claims 1-4, wherein a height (¾; H₂) of the piston element (9) is less than a length (Li; L₂) of the central bore (7).

6. Feed valve according to any one of claims 1-5, further comprising at least one piston sealing element (12) interposed between the piston element (9) and an inner surface of the central bore (7).

7. Feed valve according to any one of claims 1-6, wherein the first actuator (8) comprises a first actuator shaft (16) connected to the spherical element (6), and the second actuator (10) comprises a second actuator shaft (17) connected to the piston element (9).

8. Feed valve according to claim 7, wherein the filling body (13) comprises two halves (14), wherein each halve (14) comprises an interface plane (15) which is parallel to the first actuator shaft (16) and the longitudinal axis of the central bore (7) in the first and second angular position.

9. Feed valve according to claim 7 or 8, further comprising a first actuator sealing element (18) between the first actuator shaft (16) and the housing (4), a second actuator primary sealing element (19) between the second actuator shaft (17) and the housing (4), and a second actuator secondary sealing element (20) between the second actuator shaft (17) and the spherical element (6).

10. Feed valve according to claim 7, 8 or 9, wherein the second actuator shaft (17) comprises an eccentric element (21).

11. Feed valve according to any one of claims 7-10,wherein the first actuator shaft (16) is connected to a first lever (22) and wherein the second actuator shaft (17) is connected to a second lever (23).

12. Feed valve according to any one of claims 7-10, wherein the first actuator shaft (16) and/or second actuator shaft (17) are connected to electro-mechanic, hydraulic or pneumatic drive units.

13. Use of a feed valve according to any of claims 1-12 in a system utilizing an organosolv process.