WO2024013621A1

WO2024013621A1 - Discharge valve for slidable material and processing plant for slidable material provided with such a discharge valve

Info

Publication number: WO2024013621A1
Application number: PCT/IB2023/057002
Authority: WO
Inventors: Rinaldo Piva; Daniele ZANON
Original assignee: Pegaso Industries S.P.A.
Priority date: 2022-07-12
Filing date: 2023-07-06
Publication date: 2024-01-18

Abstract

A discharge valve (1) for slidable material, which is configured to extract from a pipe (10) at least a portion of the slidable material (100), comprises: - a body (2) which is intended to be fixed to the pipe (10) and which is provided with an inlet (2A) which is open inside the pipe (10), and an outlet (2B) which is open outside the pipe (10), - a closure member (3) which is received inside the body (2) and which comprises a channel (30) which extends as a through-channel between a first opening (3A) and a second opening (3B) which are formed in the closure member (3). The closure member (3) can be moved between an opening configuration (V1) of the valve (1), in which the channel (30) places in communication the inlet (2A) and the outlet (2B) in order to allow the slidable material to be discharged from the pipe (10), and a closing configuration (V2), in which the closure member (3) closes the inlet (2A) so as to prevent the introduction and the stagnation of the slidable material (100) in the body (2).

Description

Discharge valve for slidable material and processing plant for slidable material provided with such a discharge valve

DESCRIPTION

Technical field

The present invention relates to a discharge valve for slidable material and a processing plant for slidable material provided with such a discharge valve.

The invention is used, preferably though not exclusively, in the field of processing of granulated plastics material.

Technological background

In the field of processing slidable materials, it is sometimes necessary to take a sample of material at one or more predefined locations of the processing process in order to verify the compliance of the material with one or more parameters. For example, in the field of transforming granular plastic materials by means of extrusion or moulding, it is desirable to control that the plastic material introduced into the mould or extruder has a number of well-defined properties in order to ensure an adequate level of quality of the moulded product. For example, it is important that the plastic material has a desired level of humidity. However, this requirement is difficult to reconcile with the high levels of hygroscopic properties of some plastics materials which are widely used in the sector, such as, for example, materials based on polyethylene terephthalate (PET) or polyamide (PA) or polycarbonate (PC) based material or materials based on some copolymers, such as ABS (acrylonitrile butadiene styrene).

Therefore, these plastics materials, before being subjected to extrusion or moulding processes, have to be adequately dried in suitable drying plants, where the water content of the granules is reduced to the minimal quantities required by the transformation process.

In a commonly used process, the drying of the granular polymer material is carried out inside a hopper, in which the material to be dried is contained and in which a continuous flow of warm and dry air is introduced.

However, it is also desirable for the drying level not to be too extreme. In fact, a plastic material which is dried to an excessively low humidity level can bring about problems in the subsequent extrusion and moulding steps because the excessively dry plastic material can be poorly fluid when molten.

Therefore, there is the requirement to verify whether the drying conditions used are suitable for obtaining the desired properties in the plastic material which is conveyed to the processing steps after the drying. To this end, therefore, there is provision for carrying out samples of plastic material being discharged from the drying step and upstream of the moulding or extrusion step and for measuring the chemical/physical properties of the sampled material, for example, the humidity content thereof, in order to verify the suitability of the drying conditions used.

To this end, the plants for transforming granular plastic materials are provided with a discharge valve which is configured to take a sample of plastic material which has been dried and which is ready to be supplied, for example, to an extruder.

These valves usually comprise a valve body which is provided with an inlet and an outlet which is capable of placing in fluid communication the interior of the hopper or respectively, of the pipe on which the valve is mounted, with the exterior, where the plastic material removed from the hopper or the pipe can be collected and analysed. These valves further comprise a closure member which can be actuated in order to open/close the valve in order to permit/prevent the flow of plastic material through it.

However, the Applicant has noted that the known discharge valves have a number of disadvantages which can make the results of the analyses which are carried out on the samples of granular material taken poorly reliable.

In particular, the Applicant has found that these valves are not suitable for ensuring a complete purging of the valve body with respect to the plastic material. On the other hand, when plastic material to be analysed is taken, a given quantity of residual plastic material remains inside the valve body.

This residual plastic material is naturally subjected to the surrounding conditions and, therefore, the chemical/physical characteristics thereof vary over time. For example, in the case of a drying hopper, the residual plastic material can be subjected to polymer degradation phenomena as a result of the long time spent at high temperatures.

Over time, therefore, the residual plastic material takes on chemical/physical characteristics which do not correspond to those of the plastic material being processed in the hopper. Therefore, it is important to prevent, in a subsequent analysis, the residual plastic material which remained in the body of the valve from being analysed.

Therefore, when it is desired to carry out a further analysis of the plastics material, it is necessary to discharge the residual plastic material so that it is not involved in the analysis to be carried out and does not influence the results thereof.

To this end, usually, it is possible to provide for rejecting a first quantity of plastic material taken from the valve, keeping for the analyses only a second quantity of plastic material which is taken from the valve afterwards.

This involves an evident waste of plastic material.

Furthermore, it is difficult to predict the quantity of residual plastic material which remained in the body of the valve and therefore to predict how much plastic material it is necessary to reject.

Since, as indicated above out, the residual plastic material influences the analyses, compromising the reliability thereof, it is preferable to reject a greater quantity of plastic material than the residual plastic material which could have remained in the valve.

This involves additional losses of plastic material.

Furthermore, some granules of residual plastic material can in any case become mixed with the new plastic material which is taken, influencing the results of the analyses. Therefore, in order to attempt to prevent influences of the residual plastic material during the analyses which are carried out and to obtain measurements which correspond to the effective characteristics of the plastic material being processed, there is provision for carrying out the analyses on a plurality of samples of plastics material.

However, this involves undesirable losses of time and greater implementation costs.

In addition to this, the Applicant has noted that the arrangements used are not suitable for eliminating the uncertainties relating to the measurements carried out.

Therefore, it is still necessary to provide a discharge valve for slidable material and a processing plant for slidable material which is provided with such a valve which is structurally and functionally configured to at least partially overcome one or more of the disadvantages set out above with reference to the cited prior art.

In the present description and in the appended claims, the definition "slidable material" is intended to be understood to mean a plurality of solid elements which are different and separate from each other and which have suitable dimensions and configurations in accordance with the processing to be carried out and the material used. The term "slidable material" is intended to include in particular slidable polymer material in granules, powder or flaks.

The term "pipe" is intended to be understood in the context of the present description to be an element which is suitable for conveying and receiving, at least temporarily, the slidable material, such as, for example, a conveying tube, or a supply hopper or drying hopper.

The term "movement direction" of the slidable material is intended to be understood to be the direction in which the slidable material is moved inside a pipe. The slidable material can move in the movement direction continuously or discontinuously.

Description of the invention

In a first aspect thereof, the invention is directed to a discharge valve for slidable material, which is configured to extract from a pipe at least a portion of the slidable material.

The discharge valve preferably comprises a body which is intended to be fixed to the pipe. The body is preferably provided with an inlet which is intended to be open inside the pipe, and an outlet which is intended to be open outside the pipe. Preferably, the valve further comprises a closure member which is received inside the body. Preferably, the closure member comprises a channel which extends as a through-channel between a first opening and a second opening which are formed in the closure member.

The closure member can preferably be moved between an opening configuration of the valve, in which the channel places in communication the inlet and the outlet in order to allow the slidable material to be discharged from the pipe through the valve, and a closing configuration , in which the closure member closes the inlet so as to prevent the introduction and the stagnation of the slidable material in said body.

In a second aspect thereof, the present invention is directed towards a processing plant for slidable material, comprising a pipe which contains the slidable material and a discharge valve for the slidable material, which is fixed to the pipe and which is configured to extract at least a portion of the slidable material outside the pipe, wherein the discharge valve is constructed in accordance with the first aspect of the invention.

As a result of the features set out above, the discharge valve of the invention prevents undesirable stagnations of plastic material from occurring inside the valve. In fact, when the closure member is moved into the closing configuration , the inlet of the body of the valve is obstructed by the closure member which prevents both the introduction and the stay of slidable material inside the body. In this manner, the slidable material which is extracted from the discharge valve can be considered, with all reasonableness, to be representative of what is effectively present or being conveyed inside the pipe, as a result of which it can be analysed to measure the characteristics of the plastic material currently being processed or moving (for example, the degree of humidity thereof), obtaining very reliable results.

Therefore, waste of slidable material and waste of sampling time is prevented without compromising the reliability of the analyses carried out as a result of any residual plastic material which remains in the valve and which can be withdrawn together with the plastic material being processed.

Furthermore, by positioning the valve in the closing configuration it is possible to prevent undesirable introductions of plastic material inside the body of the valve during the processing or the conveying of the slidable material.

As a result of the invention, it is further possible to carry out the closing/opening of the valve without interfering with the slidable material being processed.

In at least one of the aspects mentioned above, the present invention may further have one or more of the preferred features set out below.

Preferably, the closure member is configured in such a manner that, at least in the closing configuration , the closure member partially projects from the body through the inlet.

Since, in the closing configuration , the closure member projects from the inlet of the body of the valve towards the interior of the pipe, undesirable introduction of slidable material into the body of the valve, which may then stay therein, is prevented. The presence and the configuration of the closure member allow the valve to be substantially excluded from the path of the material, preventing undesirable introductions of material into the channel of the valve.

Preferably, the closure member is configured so as to also project partially from the inlet of the body of the valve towards the interior of the pipe also in the open configuration. In this manner, the channel projects with respect to the valve towards the pipe and the undesirable stagnation of slidable material in the valve is prevented. Preferably, the body of the valve extends in a main longitudinal direction which defines a longitudinal axis of the body.

More preferably, the body of the valve is substantially cylindrical with a pair of longitudinally opposite ends, between which a side wall extends.

Preferably, the inlet and the outlet of the body of the valve are defined at the longitudinally opposite ends of the body.

Preferably, the closure member is substantially cylindrical and more preferably it is coaxial with the body of the valve.

Preferably, the closure member is slidably received in the body so as to be rotatable about the longitudinal axis of the body in order to be moved between the open configuration and the closing configuration .

Preferably, the closure member can be rotated through an angle of approximately 180° in order to be moved between the open configuration and the closing configuration .

Preferably, the valve is configured so that the outlet of the body of the valve is positioned outside the pipe both in the closure position and in the open position of the valve.

Preferably, the closure member comprises a solid body in which a channel is formed.

Preferably, the channel is a through-channel which extends parallel with the longitudinal axis of the body of the valve.

The channel preferably has a circular cross-section.

Preferably, the channel has a diameter which is smaller than the external radius of the body of the valve, more preferably the channel has a diameter between approximately 30% and 70% of the external radius of the body of the valve, for example, approximately 50%.

Preferably, the channel is eccentric with respect to the longitudinal axis of the body of the valve, more preferably the channel is configured in such a manner that the longitudinal axis is outside the channel, in particular there is provision for the distance between the longitudinal axis of the channel and the longitudinal axis of the body of the valve to be greater than the radius of the cross-section of the channel.

Preferably, the inlet of the body of the valve is partially delimited by a base wall which is provided in the region of the longitudinal end of the body.

The base wall is preferably in the form of an extension piece which extends from the side wall of the body of the valve so as to partially close the longitudinal end of the body of the valve.

Preferably, the base wall is formed in a circular segment-like manner, more preferably as a semi-circle.

Preferably, when the closure member is moved into the closing configuration , the first opening of the channel is obstructed by the base wall.

Preferably, the inlet of the body of the valve is further partially delimited by a side wall of the body of the valve.

Preferably, the inlet of the body of the valve comprises a recess which is formed in the side wall of the body.

In the open configuration of the valve, the first opening of the channel is positioned in the region of the inlet of the body of the valve and the second opening of the channel is positioned in the region of the outlet of the body of the valve so as to allow the passage of slidable material through the channel between the inlet and the outlet of the body of the valve. In the closing configuration of the valve, the first opening of the channel is positioned in the region of the base wall while the second opening of the channel remains in communication with the outlet of the body of the valve. In this manner, the introduction of additional slidable material into the channel is prevented, in any case allowing the emptying of the channel through the outlet of the body of the valve.

Preferably, the valve comprises an actuation device for moving the closure member between the open configuration and the closing configuration of the valve.

The actuation device may be manual or electronically controlled.

The actuation device preferably comprises a handle which is fixedly joined to the closure member and which extends radially outside the body of the valve. Preferably, there are provided guide means for guiding the actuation device between the open configuration and the closing configuration . The guide means preferably comprise a through-slot which is formed in a circumferential portion of a side wall of the body of the valve. The slot preferably extends over a circumferential portion of the body corresponding to an angle of approximately 180°. The handle preferably extends through the slot.

Preferably, the closed longitudinal ends of the slot act as a locking element for the handle in the open configuration and closing configuration of the valve, respectively.

The valve can further comprise a blocking device for blocking the valve in the open and/or closing configuration . In some embodiments, there is defined a movement direction of the slidable material in the pipe.

The movement direction may be a vertical, inclined or horizontal direction.

According to a preferred embodiment, in the open configuration the channel extends in a sliding direction which is inclined with respect to the movement direction.

This configuration allows, in the open configuration, the slidable material being moved in the pipe in the movement direction to be introduced into the channel of the valve and to slide therein with a laminar profile sliding. Therefore, turbulent movement profiles are prevented.

In particular, the sliding direction is preferably inclined with respect to the movement direction at an angle (6) of at least 30°, more preferably at an angle between 30° and 60°, for example, approximately 45°.

Preferably, the outlet of the body of the valve is positioned downstream of the inlet of the body of the valve with respect to the movement direction.

This arrangement allows the introduction of the slidable material into the valve to be promoted with a laminar sliding profile, preventing turbulent flows.

Preferably, the valve is configured in such a manner that the outlet of the valve is positioned at a vertical height less than the vertical height of the inlet.

Preferably, the valve is configured in such a manner that the outlet of the valve is positioned at a vertical height less than the vertical height of the inlet both in the closing configuration and in the open configuration of the valve.

Preferably, the channel is inclined downwards at an angle of at least 30° with respect to a vertical axis, more preferably an angle between 40° and 60° with respect to a vertical axis, even more preferably at an angle of approximately 45°.

This arrangement allows an improvement of the flow of the slidable material into the channel.

This configuration allows the "automatic" emptying of the slidable material present in the channel even when the valve is moved into the closing configuration , given that the second opening of the channel remains in communication with the outlet of the body of the valve. In this manner, stagnations of slidable material inside the channel are prevented.

Preferably, the base wall is provided upstream of the inlet of the body with respect to the movement direction, more preferably it is positioned at a vertical height which is higher than the inlet. Slidable material is thereby prevented from stagnating between the inlet of the body of the valve and the closure member. Preferably, the base wall is positioned in such a manner that, in the open configuration, the channel is positioned at a vertical height which is lower than the base wall.

Preferably, the base wall is positioned so as to guide the slidable material in the channel of the open configuration of the valve. This allows the flow of slidable material in the channel to be facilitated.

Preferably, the valve is fixed to an external wall of the pipe so as to extend outside the pipe.

In this manner, the valve is fixed to the pipe so that the inlet opens inside the pipe, but develops outside the pipe. This allows any slidable material which remains in the channel to be prevented from deteriorating. Furthermore, the slidable material from the channel is prevented from being able to be reintroduced into the pipe. Preferably, the outlet of the valve is positioned outside the pipe both in the open configuration and in the closing configuration of the valve.

Preferably, the valve is positioned in such a manner that the outlet of the valve is at a vertical height which is lower than the inlet so as to be able to use the forces acting in an inclined plane both in the open configuration and in the closing configuration of the valve for the sliding of the slidable material.

Brief description of the drawings

The features and advantages of the invention will be better appreciated from the detailed description of a preferred embodiment thereof, which is illustrated by way of non-limiting example with reference to the appended drawings, in which:

- Figure 1 is a schematic, cross-sectional view of a portion of a processing plant for slidable material which is provided with a discharge valve which is constructed according to the present invention, with the discharge valve in a first operating configuration;

- Figure 2 is a schematic, cross-sectional view of the portion of a plant of Figure 1 with the discharge valve in a second operating configuration;

- Figures 3 and 4 are two perspective views of the plant portion of Figure 2.

Preferred embodiment of the invention

With reference to the appended Figures, 100 generally designates a portion of a processing plant for slidable material comprising a discharge valve 1 which is constructed according to the present invention.

The slidable material is preferably granular plastic material and the processing plant 100 (not illustrated in its entirety) may be a drying and moulding plant, where the discharge valve 1 is positioned in a pipe 10 which extends between a drying hopper of the plastic material and an extruder, where the plastic material is molten before being injected into the die.

Notwithstanding that particular reference will be made below to plastic material, the valve of the invention may advantageously be used in a processing plant for a slidable material of a different type.

The pipe 10, which is only partially shown in the Figures, comprises a hollow body inside which the plastic material is conveyed in a movement direction which is indicated in the Figures with the arrow F.

The pipe 10 is positioned with a vertical orientation in such a manner that the movement direction F is substantially parallel with gravitational force.

In other versions which are not shown, the pipe may be positioned with a horizontal or inclined orientation with respect to the vertical.

The discharge valve 1 comprises a body 2 which is fixed as a through-member to a wall 11 of the pipe 10.

The discharge valve 1 is fixed to the wall 11 of the pipe 10 so as to extend from the wall 11 in a direction away from the pipe 10, that is to say, externally with respect thereto.

The body 2 has a substantially cylindrical form which extends along a longitudinal axis X between opposite longitudinal ends where there are provided an inlet 2A, which opens inside the pipe 10, and an outlet 2B, which opens outside the pipe 10, respectively.

The inlet 2A is delimited by a side wall 2C of the body 2 and a base wall 20, which is substantially semi-circular and which extends perpendicularly from the side wall 2C so as to partially close the longitudinal end of the body 2 internally with respect to the pipe 10. On the contrary, the outlet 2B extends over the entire longitudinal end of the body 2 so that the entire base of the cylinder which is formed by the body 2 is open and represents the outlet 2B.

The inlet 2A therefore has a smaller aperture with respect to the outlet 2B.

Independently of the orientation of the pipe 10, the discharge valve 1 is fixed to the wall 11 of the pipe 10 in such a manner that, with respect to the movement direction F, the outlet 2B is positioned downstream of the inlet 2A.

In particular, in the preferred embodiment described and illustrated here, the pipe 10 has a vertical orientation along a vertical axis Z and the outlet 2B is positioned at a vertical height Z1 which is lower than the vertical height Z2 of the inlet 2A.

In other words, the valve 1 is positioned in such a manner that the outlet 2B is interposed between the ground, or a support plane, and the inlet 2A. Furthermore, the body 2 is fixed to the pipe 10 in such a manner that the base wall 20 is positioned at a vertical height Z4 which is higher than the vertical height Z2 of the inlet 2A.

The body 2 is internally hollow and has a circular cross-section with an internal diameter D so as to receive a closure member 3 of the valve 1 in a slidable manner.

The closure member 3 also has a substantially cylindrical configuration and it is coaxial with the body 2 and comprises a solid body 31, in which there is formed a channel 30 which extends as a through-channel between a first opening 3A and a second opening 3B.

The channel 30 is substantially cylindrical with a circular cross-section and has a longitudinal axis X' which extends parallel with the longitudinal axis X of the body 2.

The channel 30 is eccentric with respect to the longitudinal axis X of the body 2 so as to be external with respect to the longitudinal axis X of the body 2.

The diameter DI of the channel 30 is less than half of the diameter D of the body 2, for example, it represents approximately 35% of the internal diameter D of the body 2 and approximately 30% of the external diameter D2 of the body 2.

The channel 30 is positioned in such a manner that the longitudinal axis X' thereof is positioned at a distance dl from the longitudinal axis of the body 2 which is greater than half of the diameter Dl of the channel 30.

The first opening 3A of the channel 30 is provided in the region of the longitudinal end of the body 2 where the inlet 2A is formed, while the second opening 3B is provided in the region of the longitudinal end of the body 2 where the outlet 2B is formed. The first opening 3A is positioned at a vertical height Z3 which is higher than the vertical height Z3' of the second opening 3B.

The closure member 3 can be rotated inside the body 2 about the longitudinal axis X between an open configuration VI of the valve 1 (illustrated in Figure 2), in which the channel 30 places in communication the inlet 2A and the outlet 2B, allowing the discharge of the slidable material from the pipe 10 through the discharge valve 1, and a closing configuration V2 (illustrated in Figure 1), in which the closure member 3 closes the inlet 2A so as to prevent the introduction and stagnation of the slidable material inside the body 2.

The closure member 3 is formed so as to partially project both from the outlet 2B, in an outward direction, and from the inlet 2A, towards the interior of the pipe 10. In particular, the closure member 3 projects from the inlet 3A as a result of the provision of a recess 21 which is formed in the side wall 2C at the side opposite the base wall 20.

In the open configuration VI, therefore, the channel 30 projects from the inlet 2A towards the pipe 10 and the slidable material passes through the discharge valve 1 from the interior of the pipe 10 to the exterior, only flowing only in the channel 30, while in the closing configuration V2 the solid body 31 projects from the inlet 2A towards the pipe, the first opening 3A of the channel 30 is completely closed by the base wall 20 and the second opening 3B is open in the region of the outlet 2B.

In this manner, undesirable stagnations of slidable material on the body 2 of the valve 1 are prevented.

In the open configuration VI, the longitudinal axis X' of the channel 30 defines a sliding direction Fl of the slidable material through the valve 1. The sliding direction Fl is inclined with respect to the movement direction F (parallel with the vertical axis Z) at an angle 6 of approximately 45°.

The valve 1 further comprises an actuation device 50 for actuating the closure member 3 inside the body 2. The actuation device 50 allows actuation of the closure member 3 in order to move it between the open configuration VI and the closing configuration V2 of the valve 1 and vice versa. The actuation device 50 allows rotation of the closure member 3 inside the body 2 about the longitudinal axis X of the body 2.

The actuation device 50 comprises a handle which is fixed to the solid body 31 of the closure member 3 and which extends radially from the closure member 3 towards the exterior and which is able to be gripped by the operator in order to move the valve 1 from the closing configuration V2 to the open configuration VI, and vice versa.

By actuating the handle, it is possible to rotate the closure member 3 about the longitudinal axis X in the two opposite directions in order to open or close the valve 1.

Preferably, the closure member 3 is rotated by a rotation angle of approximately 180° about the longitudinal axis X in order to be moved between the closing configuration V2 and the open configuration VI.

The handle comprises a rod 52 which is fixed at a first end to the solid member 31 and which is provided at the opposite longitudinal end thereof with a knob 53 which is able to be gripped by a user in order to actuate the actuation device 50.

There is provided on the body 2 a slot 24 which is intended to slidingly receive the rod 52 during the movement between the open configuration VI and the closing configuration V2 of the valve 1.

The slot 24 extends through the thickness of the body 2 and is delimited by two opposing side walls which act as a guide during the movement of the rod 52 between the open configuration VI and the closing configuration V2, while the opposite ends of the slot 24 act as travel limit stop elements for the movement of the rod 52.

The slot 24 extends on the body 2 over a circumferential arc which corresponds to an angle of approximately 180°.

The valve 1 is normally maintained in a closing configuration V2 with the channel 30 positioned in such a manner that the first opening 3A is positioned behind the base wall 20 (Figure 1). When it is necessary to carry out analyses of the plastic material, by taking it from the pipe 10, an operator provides for gripping the handle in order to rotate the closure member 3 inside the body 2 about the longitudinal axis X. Since the channel 30 is eccentric with respect to the longitudinal axis X, by rotating the closure member 3 the channel 30 is rotated about the longitudinal axis X so as to gradually bring it into the region of the inlet 2A, leaving the base wall 20.

During rotation, the rod 52 is moved in the slot 24 until moving into abutment against the end of the slot 24.

In this position, corresponding to the open configuration of the valve 1, the first opening 3A of the channel 30 is positioned completely at the inlet 2A so as to allow the introduction of the granules of plastic material inside the channel 30. After entering the channel 30, the plastic material slides inside the channel 30 between the first opening 3A and the second opening 3B as a result of the effect of gravitational force.

A desired quantity of plastic material can therefore be collected at the outlet 2B of the body 2.

After the desired quantity of plastic material has been taken, the operator provides for closing the valve 1 by gripping the handle 53 and rotating it as far as the closing configuration V2.

In the closing configuration V2, the first opening 3A is again placed in the region of the base wall 20 and is closed thereby so as to prevent the introduction of new plastic material inside the channel 30.

Since the channel 30 is inclined with respect to the vertical axis and the second opening 3B is open in the region of the outlet 2B, the plastic material present inside the channel 30 is also discharged from the outlet 2B so as to prevent any stagnation of plastic material inside the channel 30.

Preferably, the channel 30 is positioned with such an inclination as to ensure that the resultant force acting on the plastic material exceeds the friction forces and/or the viscous forces so as to allow the plastic material to slide and to prevent the stagnation thereof in the channel 30.

It may further be noted that, as a result of the configuration of the body 2 and the closure member 3 which allows the closure member to project from the inlet 2A, even when the valve is in the closing configuration , it is not possible for the granules of plastic material to become deposited and to remain at the opening of the inlet 2A of the body 2 of the valve.

Claims

1. Discharge valve (1) for slidable material, which is configured to extract from a pipe (10) at least a portion of the slidable material (100) and which comprises:

- a body (2) which is intended to be fixed to the pipe (10) and which is provided with an inlet (2A) which is intended to be open inside the pipe (10), and an outlet (2B) which is intended to be open outside the pipe (10),

- a closure member (3) which is received inside the body (2) and which comprises a channel (30) which extends as a through-channel between a first opening (3A) and a second opening (3B) which are formed in the closure member (3),

- wherein the closure member (3) can be moved between an opening configuration (VI) of the valve (1), in which the channel (30) places the inlet (2A) and the outlet (2B) in communication in order to allow the slidable material to be discharged from the pipe (10) through the valve (1), and a closing configuration (V2), in which the closure member (3) closes the inlet (2A) so as to prevent the introduction and the stagnation of the slidable material (100) in the body (2).

2. Valve according to claim 1, wherein said closure member (3) is configured in such a manner that, at least in said closing configuration (V2), the closure member (3) partially projects from the body through the inlet (2A).

3. Valve according to claim 1 or 2, wherein the body (2) extends along a longitudinal axis (X) and said inlet (2A) and said outlet (2B) are defined at opposite ends of said body (2) with respect to said longitudinal axis (X).

4. A valve according to any one of the preceding claims, wherein said body (2) extends along a longitudinal axis and said channel (30) is a through-channel which extends parallel with said longitudinal axis (X).

5. Valve according to the preceding claim, wherein said channel (30) is eccentric with respect to the longitudinal axis (X) of the body (2), the channel (30) being configured in such a manner that the longitudinal axis (X) is outside the channel (30).

6. Valve according to any one of the preceding claims, wherein the inlet (2A) is partially delimited by a base wall (20) which is provided in the region of a longitudinal end of the body (2) and, when said closure member (3) is moved into the closing configuration (V2), said first opening (3A) of said channel (30) is obstructed by said base wall (20).

7. Valve according to the preceding claim, wherein said inlet (2A) is delimited by said base wall (20) and by a side wall (2C) of the body (2).

8. Valve according to any one of the preceding claims, wherein said inlet (2A) comprises a recess (21) which is formed in said side wall (2C) of said body (2).

9. Valve according to any one of the preceding claims, wherein said body (2) and said closure member (3) are substantially cylindrical and coaxial relative to each other.

10. Valve according to the preceding claim, wherein said closure member (3) is rotatable in said body (2) about the longitudinal axis (X) of said body (2) in order to be moved between the closing configuration (V2) and the open configuration (VI).

11. Valve according to the preceding claim, wherein said closure member (3) is rotatable in the body (2) through an angle of approximately 180° about the longitudinal axis (X) of said body (2) in order to be moved between said closing configuration (V2) and the open configuration (VI).

12. Processing plant (100) for slidable material, comprising:

- a pipe (10) containing the slidable material,

- a discharge valve (1) for the slidable material, which is fixed to the pipe (10) and which is configured to extract at least a portion of the slidable material outside said pipe (10), wherein said discharge valve (1) is in accordance with any one of the preceding claims.

13. Plant according to the preceding claim, wherein there is defined in the pipe a movement direction (F) of the slidable material and wherein, in the opening configuration (VI), said channel (30) extends in a sliding direction (Fl) which is inclined with respect to said movement direction (F).

14. Plant according to the preceding claim, wherein said sliding direction (Fl) is inclined at an angle (6) of at least 30°, preferably an angle comprised between 40° and 60°, with respect to said movement direction (F).

15. Plant according to claim 13 or 14, wherein the valve (1) is fixed to the pipe (10) so that the sliding direction (Fl) is inclined with respect to the vertical axis (Z), preferably at an angle (6) between 30° and 60°, preferably of approximately 45°.

16. A plant according to any one of claims 12 to 15, wherein in said pipe (10) is defined a movement direction (F) of the slidable material, and wherein said outlet (2B) is positioned in said pipe downstream of the inlet (2A) with respect to the movement direction (F).

17. Plant according to any one of claims 12 to 16, wherein said outlet (2B) of the body (2) is positioned at a vertical height (Zl) less than the vertical height

18. Plant according to any one of claims 12 to 17, wherein said base wall (20) is provided upstream of the inlet (2A) of the body (2) with respect to the sliding direction (Fl) so as to prevent the slidable material from stagnating between the base wall (20) and the closure member (3).

19. Plant according to any one of claims 12 to 18, wherein the base wall (20) is provided upstream of the inlet (2A) of said body (2) with respect to the movement direction (F) so as to prevent the stagnation of the slidable material between said base wall (20) and said closure member (3).

20. Plant according to any one of claims 12 to 19, wherein said valve (1) is fixed to a wall (11) of the pipe (10) so as to extend from the wall (11) outside the pipe (10).