GB2516951A

GB2516951A - Bulk feeders

Info

Publication number: GB2516951A
Application number: GB201314200A
Authority: GB
Inventors: Peter David Wilson
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-08-08
Filing date: 2013-08-08
Publication date: 2015-02-11
Also published as: GB201314200D0

Abstract

A bulk feeder features a hopper (2,fig.1) and a tube 44 with a cut out portion 48 which leads to a rotatable spring (52,fig.4), which acts as a screw conveyor to push bulk material up the tube 44 and out of the hopper (2,fig.1). An end part of the tube 44 includes a locating feature, such as a slot (46,fig.4) and bolt 56 to secure it to an interior wall of the hopper (2.fig.1), against rotation as the spring (52,fig.4) rotates. The apparatus may further include an agitator.

Description

TITLE

Bulk feeders

DESCRIPTION

Technical Field

The present invention relates to bulk feeders (sometimes called screw conveyors), and in particular to bulk feeders for transporting powders. The bulk feeders may be particularly suitable for usc in food manufacturing plants for transporting powder (e.g. flavouring particles or other dry mixtures, flour etc.) to a mixing vessel or the like.

However, the bulk feeders can also be used in other processing plants such as those for manufacturing plastics, chemicals and pharmaceuticals, for example.

Background Art

A conventional bulk feeder includes a hopper into which powder can be deposited. A flexible tube extends from a lower, working end, of the hopper and a rotating spring (or screw) within the tube is used to transport the powder to another component of a food manufacturing plant. In a typical example the tube might have an outlet at its upper end through which the powder can fall into a processing hopper and then into a mixing vessel where it is mixed with wet ingredients, for example. A motor is mounted at the upper end of the tube, beyond the outlet, and is connected to the upper end of the spring to rotate it. At its lower end the spring passes through the working end of the bulk feeder so that powder from the hopper can enter the tube through an inlet. Once the powder enters the tube through the inlet it is transported along the flexible tube by the rotating spring until it falls through the outlet.

A rotating agitator is mounted in the working end of the hopper adjacent the tube.

The purpose of the agitator is to squeeze the powder in the working end into the tube and prevent voids developing in the tube. The agitator rotates about an axis that is parallel with the tube. The extcmal motor and gearbox for driving the agitator is mounted at the working end of the hopper.

Front and rear plates are connected by side plates to define a fixed structure or housing that encloses the working end of the hopper. One of the side plates (typically the one that faces downward) can be hinged and is secured in place by releasable fixings. When the hinged side plate is opened it provides only limited access into the interior of the working end for maintenance.

GB 2477973 discloses a bulk feeder and Figures 1, 5 and 6 are incorporated into the present application as Figures 1 to 3. The bulk feeder includes an open hoppcr 2 with a rcscrvoir part 4 that is defined by rectangular sidc walls and a fianncl part 6. The funnel part 6 channels powder down illto a lower working end 8 of the hopper.

The bulk feeder may be used in a food manufacturing plant for transporting powder (e.g., flavouring particles or other dry mixtures, flour etc.) to another component such as a processing hoper. The bulk feeder may be operated on demand -i.e. when the processing hopper requires powder to be delivered to it.

Thc hoppcr 2 is mountcd on a support frame 10 that includcs whccls 12. A lower part of the support frame 10 is U-shaped with an open side to allow a trolley (not shown) to be located underneath the working end 8. The support frame 10 includes a shelf 14 on which bags of powder can be restcd beforc they are emptied into the reservoir part 4, for examplc.

The working end 8 is defined by a rear plate 16. A front plate 20 is positioned opposite the rear plate 16. The front and rear plates arc connected by side plates 22, 24 to define a fixed enclosure or housing.

A fixed sensor 30 for monitoring the depth of powder within the working end 8 extends through an upper part of the rear plate 16.

A tubular shroud 32 is integrally formed with the front plate 20. The tubular shroud 32 is sized to receive a flexible powder tube 34 that contains a rotating spring or screw (not shown). A comprcssible seal (not shown) such as a silicone 0-ring may be provided in the shroud to provide a seal between the outer surface of the tube 34 and the shroud and to mechanically secure the tube in position.

As shown in Figure 2, the tube 34 extends part of the way into the interior of the working end. (It will be readily appreciated that in Figure 2 the side plates 22, 24 have been removed for clarity.) The rotating spring (not shown) extends beyond the lower end of the tube 34 and its lower end is received in the spring seat 36 that forms part of the rcar plate 16. The rotating spring can rotate freely within the spring seat 36 when the bulk feeder is in use. The spring seat 36 includes a drainage port for the free drainage of cleaning water.

A motor and gearbox 38 are mounted to the front plate 20 and are connected to the upper end of an agitator shaft (not shown). The lower end of the agitator shaft is received in a seat 40 that forms part of the rear plate 16. The lower end of the agitator shaft can rotate freely within the seat 40 when the motor is driven. The seat 40 also includes a drainage port for the free drainage of cleaning water.

It will be readily appreciated that both seats 36, 40 are located within the interior of the working end 8 of the hopper such that the rotating spring and agitator shaft do not pass through openings in the rear plate 16.

A gland-packed seal 42 where the packing is food-grade material is used to provide a powder-tight seal between the rotating agitator shaft (not shown) and the front plate 20.

When the bulk feeder is in use, a cover plate 26 is secured to the rear plate 16 to cover openings 18 and provide a powder-tight seal. Powder is added to the hopper by opening bags of powder and pouring it in to the hopper through the open end of the reservoir part 4. The weight of the powder in the hopper pushes powder into the lower working end 8. In other words, the interior of the housing defined by the rear plate 16, front plate 20 and side plates 22,24 is filled with powder. The agitator (not shown) is driven to rotate by the motor and gearbox 38 to prevent any voids from forming in the tube 34. The spring (not shown) is driven to rotate (typically by a motor and gearbox connected at its upper end) to transport the powder along the tube 34 until it reaches an outlet.

When the bulk feeder needs to be cleaned, a separate trolley (not shown) can be wheeled underneath the working end 8. The cover plate 26 is then released from the rear plate 16 to allow any remaining powder in the hopper to fall through the openings 1. and into the trolley. The cover plate 26 can be cleaned separately.

The reservoir part 4 of the hopper can be removed from the support frame 6 and the powder tube 34 can be removed from the tubular shroud 32. The reservoir part and tube can then be cleaned separately.

Cleaning water, typically supplied at pressure, is then used to flush out the working end 8 of the hopper. The internal seats 36, 40 for the rotating spring and the agitator shaft include drainage ports so that there is no gathering of waste water and they can undergo comprehensive or deep cleaning to remove the risk of any cross-contamination. The waste water flows out of the openings 18 in the rear plate 16.

Once the hopper 2 has been rinsed and properly dried the cover plate 26 can be re-secured to the rear plate 16.

Summary of the Invention

The bulk feeder of the present invention has an alternative design of transport tube that results in an improved powder transfer rate.

More particularly, the present invention provides a bulk feeder comprising: a tube containing a rotating spring (or screw); a hopper for receiving powder, the hopper having a working end through which powder can enter the tube defined by a housing having a front plate and a rear plate; wherein the tube extends through the front plate and an end part is located within the working end of the hopper, the end part of the tube including a locating feature that engages with a cooperating locating feature provided on the rear plate of the housing to prevent relative rotation therebetween, and a cut-out portion in the substantially cylindrical body of the end part of the tube that allows powder from the working end of the hopper to enter the tube.

Thc cooperating locating features provided on the end part of the tube and thc rcar plate of the housing can have any suitable shape and construction (e.g., a slot in the tube, optionally in its annular rim, and a protrusion on the rear plate or vice versa) and ensure that the tube remains stationary and does not rotate with the spring. In one arrangement the rear plate can include an annular collar which is upstanding from the remainder of the rear plate and is received within the open end of the tube (or the open end is received within the annular collar) when the tube is properly installed. A protrusion can extend radially from the outer (or inner) surface of the annular collar and can optionally be in the form of an anti-rotation locating bolt or similar fixing member. The locating bolt can be received in a threaded bore provided in the annular collar, the relative circumferential position of the locating bolt and the slot being selected to ensure the correct alignment of the tube within the working end of the hopper, i.e., the coopcrating locking features can be adapted to ensure that thc tube is properly oriented, typically so that the optional elongate slot (see below) in the substantially cylindrical body of the end part of the tube faces substantially upwards in use. When the tube is installed to the bulk feeder, the annular collar part of the rear plate is received within the open end of the tube (or the open end is received within the annular collar) and the bolt is received in the slot in the annular rim of the tube to prevent relative rotation between the tube and the rear plate. The tube is typically held axially by a clamp (see below) to prevent it from moving away from the locating bolt, i.e., to maintain the bolt in the slot in the annular rim of the tube during use.

An elongate slot may be provided in the substantially cylindrical body of the end part of the tube. The elongate slot may be used as a viewing window to check the relative axial position of thc spring. The elongate slot is preferably positioned between the cut-out portion and the locating feature, and preferably faces substantially upwards in use (i.e., towards the funnel part of the hopper).

The tube is preferably removably mounted to the bulk feeder. More particularly, the front plate may include an integral tubular shroud (or bulk feeder output tube) that surrounds and supports a portion of the tube. A compressible seal (e.g. a silicone o-ring) can be provided between the tubular shroud and the outer surface of the tube to provide both a powdcr-tight seal and the means by which the tube is mechanically removably sccurcd to the working end of the hoppcr. Duc to thc increased flow of powder through the tube, a clamp can be additionally or alternatively used to secure the tube to the tubular shroud. The clamp can include a first part that is mounted to the tubular shroud and a second part that can be selectively and removably secured to the first part. An annular bush (optionally made of rubber or a similar material) is positioned between the first and second parts and surrounds the tube. The clamp is adapted to apply a clamping force to the bush causing it to grip the outer surface of the tube. In one anangement, the bush can be provided with a tapered outer surface and a clamping force is applied to the bush by the second part of thc clamp when it is secured to the first part, i.e., when the bush is axially clamped between the first and second parts. The first and second parts of the clamp can have at least one wing part.

Each wing part of onc of the first and second parts can have a thrcaded borc for receiving a bolt or similar fixing membcr. Each wing part of the other one of the first and second parts can have a slot which is sized and shaped to receive the bolt shank.

To secure the first and second parts of the clamp together, they are positioned with the wing parts circumferentially offset and then rotated relative to each other so that the wing parts come into register and a bolt shank is received in a corresponding slot.

Each bolt or similar fixillg member can then be tightened until the bolt head is in contact with the adjacent wing part and the axial clamping force is applied to the bush by the first and second parts, the compressed bush in turn applying a radial clamping force to grip thc outer surface of thc tube. The combination of the clamp and the cooperating locating features prevent twisting of the tube during use.

A second clamp can also be provided at a lifting point of the tube.

The bulk feeder may include a rotating agitator mounted for rotation on a shaft within the working end.

A seat or bush for a lower end of the agitator shaft is preferably also formed on an internal surface of the rear plate. The agitator shaft seat preferably includes at least one drainage port so that waste water does not gather within the seat during the cleaning process.

The agitator may have any suitable construction.

An upper end of the agitator shaft can extend through an opening in the front plate to be connected to a motor and gearbox. In other words, the motor and gearbox for the agitator arc preferably mounted at an upper part of the working end. The upper end of the agitator shaft may be received within a tubular shaft or a support member that is integral with the front plate. The opening for the agitator shaft in the front plate is preferably sealed (e.g., by a gland-packed seal where the packing is food-grade material). The powder is not normally pushed against the front plate and there is a little risk of powder being spilt.

Thc hoppcr is preferably mounted on a moveable support frame that can havc wheels.

This allows the hopper to be moved from a use location to a different location where it can be cleaned. A shelf can be provided at one side of the support frame for supporting bags of powder, for example. It is generally preferred that part of the hopper and the shelf are removably mounted to the support frame so that they can be positioned in different orientations relative to the support frame. This also allows them to be removed for cleaning.

The hopper may have an upper reservoir part and a funnel part located between the reservoir part and the working end. A grid frame with openings may be positioned in the hopper to prevent any objects apart from powder falling into the working end.

The grid frame also prevents an operator from being accidentally hurt by the rotating agitator which is positioned below it inside the working end.

When the bulk feeder is in use, powder is added to the hopper (e.g., by opening bags of powder and pouring it in to the hopper through the open end of the reservoir part).

The weight of the powder in the hopper pushes powder into the lower working end.

The agitator is driven to rotate by the associated motor and gearbox to prevent any voids from forming in the tube. The spring is driven to rotate (typically by a motor and gearbox connected at its upper end) to transport the powder along the flexible tube. Powder enters the end part of the tubc through the cut-out portion.

To purge residue powder from the tube, a port can be provided in the tube wall that is adapted to be connected to an air supply. For example, the port can be provided with a suitable fitting that is connectable to a complementary fitting provided on an air supply hose. The air supply can be a filtered air supply. When purging is required, typically at the end of a transport phase, air at pressure is supplied into the tube through the port to push accumulated powder through and out of the tube to avoid compaction.

Drawings Figure 1 is a perspective view of a known bulk feeder; Figure 2 is a detail perspective view of the interior of the working end of the hopper of Figure 1 with side plates removed and without a spring and agitator; Figure 3 is a perspective view showing the front plate and the working end of the hopper of Figure 1 with the side plates in position; Figure 4 is a detail view of the end part of a tube for a bulk feeder according to the present invention; Figure 5 is a detail perspective view of the interior of the working end of a bulk feeder according to the present invention with the tube of Figure 4 in position; Figure 6 isa detail perspective view of the interior of the working end of a bulk feeder according to the present invention without the tubc of Figure 4; and Figure7isadetailviewoftheclamp thatis used tosecurethetubeto thebulkfeeder.

A bulk feeder according to the present invention will be described with reference to Figures 4 to 7. The bulk feeder is similar to the bulk feeder shown in Figures 1 to 3 and like components have been given the same reference numeral.

Figure 4 shows the end part of the improved transport tube 44 which in use is located within the working end 8 of the hopper. The tube 44 includes a locating slot 46 in its annular rim 44a. A cut-out portion 48 is provided in the substantially cylindrical body 44b and allows powder from thc working end 6 of the hopper to enter the tube. An elongate viewing slot 50 is also provided in the substantially cylindrical body 44b and is positioned axially between the cut-out portion 48 and the locating slot 46.

The rotating spring 52 (or screw) of the bulk feeder is shown in Figure 4 and extends beyond the cut-out portion 48 towards the annular rim 44a. Rotation of the spring 52 within the stationary tube 44 transports powder within the tube in a direction away from the annular rim 44a.

Figure 5 shows the interior of the working end 8 of the bulk feeder with the tube 44 in position. Figure 6 shows the interior of the working end 8 of bulk feeder without the tube 44 so that the mounting features provided on the rear plate are visible. (It will be readily appreciated that in Figures 5 and 6 the side plates that connect the front and rear plates have been removed for clarity.) The rear plate 16 includes an annular collar 54 which is received within the open end 44c of the tube 44 when it is installed to the bulk feeder. The annular collar 54 includes a threaded bore for receiving a locating bolt 56. When the tube 44 is installed, the locating bolt protrudes radially outwardly from the annular collar 54 and the bolt shank is received in the locating slot 46 as shown in Figure 5. The locating bolt 56 can be tightened to securely retain the end of the tube 44 in position on the annular collar 54.

The tube 44 extends through a tubular shroud 32 (or bulk feeder output tube) that is integrally formed with the front plate 20.

-10 -A clamp 58 is provided on the tubular shroud 32 to removably secure the tube 44 to the bulk feeder. The clamp 58 is shown in more detail in Figure 7 and includes a base that is mounted to the integral tubular shroud 32. The base 60 includes a pair of wings 60a each having a threaded bore for receiving a bolt 62. A housing 64 is removably secured to the base 60 and includes a pair of wings 64a having a slot 66 that is sized and shaped to receive the bolt shank.

An annular rubber bush (not shown) is located around the tube 44 and positioned between the base 60 and the housing 64, i.e., resting on the base and within the housing interior. The bush has a tapered outer surface and the housing 64 has a suitably shaped inner surface such that it applies an axial clamping force to the rubber bush when it is secured to the base 60. The compressed bush in turn applies a radial clamping force to the tube 44 to grip it securely. To secure the housing 64 to the base 60, the parts are positioned with the wings 60a, 64a circumferentially offset. The housing 64 is then rotated relative to the base 60 so that the wings 60a, 64a come into register (i.e., the wings on each side of the base and the housing are circumferentially aligned one on top of the other) and the bolt shanks are received in the corresponding slots 66 as shown in Figure 7. The bolts 62 can then be tightened until the bolt heads are in contact with the wings 64a of the housing 64 and the axial clamping forcc is applied to the bush.

To remove the tube 44 from the bulk feeder, the clamp bolts 62 are un-tightened so that the housing 64 can be unsecured from the base 60 by relative counter rotation.

The locating bolt 56 is also un-tightened to release the end part of the tube 44 from the annular collar 54. The tube 44 can then be removed through the tubular shroud 32.

Claims

CLAIMS1. A bulk feeder comprising: a tube containing a rotating spring; a hopper for receiving powder, the hopper having a working end through which powder can enter the tube defined by a housing having a front plate and a rear plate; wherein the tube extends through the front plate and an end part is located within the working cnd of the hopper, the end part of thc tube including a locating feature that engages with a cooperating locating feature provided on the rear plate of the housing to prevent relative rotation therebetween, and a cut-out portion in the substantially cylindrical body of the end part of the tube that allows powder from the working end of the hopper to enter the tube.
2. A bulk feeder according to claim I, ifirther comprising an elongate slot in the substantially cylindrical body of the end part of the tube.
3. A bulk feeder according to claim 2, wherein the elongate slot is positioned axially between the cut-out portion and the locating feature.
4. A bulk feeder according to claim 2 or claim 3, wherein the elongate slot faces substantially upwards in use.
5. A bulk feeder according to any preceding claim, wherein the tube is removably mounted to the bulk feeder.
6. A bulk feeder according to any preceding claim, wherein the tube is removably secured to the bulk feeder by at least one clamp.
7. A bulk feeder according to any preceding claim, wherein the tube includes a port adapted to be removably connected to an air supply. -12-
8. A bulk fccdcr substantially as herein described and with reference to Figures 4 to 7.