Patent Description:
Carbon dioxide systems, including apparatuses for creating solid carbon dioxide particles, for entraining particles in a transport gas and for directing entrained particles toward objects are well known, as are the various component parts associated therewith, such as nozzles, are shown in <CIT>, <CIT>, <CIT>,<CIT>, <CIT>, <CIT>,<CIT>,<CIT>, <CIT>, <CIT>, <CIT>,<CIT>,<CIT> <CIT>, <CIT>, <CIT>, <CIT>, <CIT>,<CIT>, <CIT>, <CIT>,<CIT>, <CIT>,<CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

Additionally, <CIT>, for Particle Blast System With Synchronized Feeder and Particle Generator; <CIT>, for Method And Apparatus For Sizing Carbon Dioxide Particles; <CIT>, for Method And Apparatus For Dispensing Carbon Dioxide Particles; <CIT>, for Method And Apparatus For Forming Carbon Dioxide Pellets; <CIT> for Apparatus Including At Least An Impeller Or Diverter And For Dispensing Carbon Dioxide Particles And Method Of Use; <CIT>, for Method And Apparatus For Forming Solid Carbon Dioxide; <CIT>, for Particle Feeder; <CIT>, for Apparatus And Method For High Flow Particle Blasting Without Particle Storage; and <CIT>, for Blast Media Comminutor, represent additional prior art documents in the field.

<CIT> illustrates a particle blast apparatus that includes a particle generator that produces small particles by shaving them from a carbon dioxide block and entrains the carbon dioxide granules in a transport gas flow without storage of the granules. <CIT>,<CIT> and <CIT> disclose particle blast apparatuses that include a particle generator that produces small particles by shaving them from a carbon dioxide block, a particle feeder which receives the particles from the particle generator and entrains them which are then delivered to a particle feeder which causes the particles to be entrained in a moving flow of transport gas. The entrained flow of particles flows through a delivery hose to a blast nozzle for an ultimate use, such as being directed against a workpiece or other target.

<CIT> illustrates an apparatus for preparing, classifying, and metering particle media useful for various purposes including blast cleaning and treating systems includes transferring a media having a working particle size range and sending the media particles through a classifier. The heavier portions of the particles are taken from the classifier in a controlled manner and providing along with a pressurized air input, a fluidized air/particle output in a controlled manner such that the air/particle ratios are controlled and the particles are in a steady or pulsed flow as desired.

For some blasting applications, it may be desirable to have a range of small particles, such as in the size range of <NUM> diameter to. <NUM> diameter. <CIT> (corresponding to <CIT>) discloses a comminutor which reduces the size of particles of frangible blast media from each particle's respective initial size to a second size which is small than a desired maximum size.

The accompanying drawings illustrate embodiments which serve to explain the principles of the present innovation.

In the following description, like reference characters designate like or corresponding parts throughout the several views. Also, in the following description, it is to be understood that terms such as front, back, inside, outside, and the like are words of convenience and are not to be construed as limiting terms. Terminology used in this patent is not meant to be limiting insofar as devices described herein, or portions thereof, may be attached or utilized in other orientations. Referring in more detail to the drawings, one or more embodiments constructed according to the teachings of the present innovation are described.

According to the present patent, there is provided a feeder assembly configured to transport cryogenic blast media from a source of cryogenic blast media into a flow of transport gas according to claim <NUM>, a method of entraining a plurality of particles of cryogenic blast media in a flow of transport gas according to claim <NUM> and the use, according to claim <NUM>, of a feeder assembly according to any of the claims <NUM> to <NUM> for performing a method of entraining a plurality of particles of cryogenic blast media in a flow of transport gas according to any of claims <NUM> to <NUM>.

Although this patent refers specifically to carbon dioxide, the invention is not limited to carbon dioxide but rather may be utilized with any suitable frangible material as well as any suitable cryogenic material or other type of particle such as water ice pellets or abrasive media. References herein to carbon dioxide, at least when describing embodiments which serve to explain the principles of the present innovation are necessarily limited to carbon dioxide but are to be read to include any suitable frangible or cryogenic material.

Referring to <FIG>, there is shown a representation of a particle blast apparatus, generally indicated at <NUM>, which includes cart <NUM>, delivery hose <NUM>, hand control <NUM>, and discharge nozzle <NUM>. Internal to cart <NUM> is a blast media delivery assembly (not shown in <FIG>) which includes a hopper and a feeder assembly disposed to receive particles from the hopper and to entrain particles into a flow of transport gas. Particle blast apparatus <NUM> is connectible to a source of transport gas, which may be delivered in the embodiment depicted by hose <NUM> which delivers a flow of air at a suitable pressure, such as but not limited to <NUM> PSIG. Blast media, such as but not limited to carbon dioxide particles, indicated at <NUM>, may be deposited into the hopper through top <NUM> of the hopper. The carbon dioxide particles may be of any suitable size, such as but not limited to a diameter of <NUM> and a length of about <NUM>. The feeder assembly entrains the particles into the transport gas, which thereafter flow at a subsonic speed through the internal flow passageway defined by delivery hose <NUM>. Delivery hose <NUM> is depicted as a flexible hose, but any suitable structure may be used to convey the particles entrained in the transport gas. Hand control <NUM> allows the operator to control the operation of particle blast apparatus <NUM> and the flow of entrained particles. Downstream of control <NUM>, the entrained particles flow into entrance 10a of discharge nozzle <NUM>. The particles flow from exit 10b of discharge nozzle <NUM> and may be directed in the desired direction and/or at a desired target, such as a work piece (not shown).

Discharge nozzle <NUM> may be of any suitable configuration, for example, discharge nozzle <NUM> may be a supersonic nozzle, a subsonic nozzle, or any other suitable structure configured to advance or deliver the blast media to the desired point of use.

Control <NUM> may be omitted and the operation of the system controlled through controls on cart <NUM> or other suitable location. For example, the discharge nozzle <NUM> may be mounted to a robotic arm and control of the nozzle orientation and flow accomplished through controls located remote to cart <NUM>.

Referring to <FIG> and <FIG>, there is shown hopper <NUM> and feeder assembly <NUM> of particle blast apparatus <NUM>. Hopper <NUM> may include a device (not shown) for imparting energy to hopper <NUM> to aid in the flow of particles therethrough. Hopper <NUM> is a source of blast media, such as cryogenic particles, for example but not limited to carbon dioxide particles. Hopper exit 18a is aligned with guide <NUM> (see <FIG>), at hopper seal <NUM>. Any suitable source of blast media may be used, such as without limitation, a pelletizer.

Feeder assembly <NUM> is configured to transport blast media from a source of blast media into a flow of transport gas, with the blast media particle being entrained in the transport gas as the flow leaves feeder assembly <NUM> and enters delivery hose <NUM>. In the embodiment depicted, feeder assembly <NUM> includes metering portion <NUM>, comminutor <NUM> and feeding portion <NUM>. As discussed below, comminutor <NUM> may be omitted from feeder assembly <NUM> (with metering portion <NUM> discharging directly to feeding portion <NUM>), metering portion <NUM> may be omitted from feeder assembly <NUM> (with comminutor receiving particles directly from a source of blast media such as hopper <NUM>), and feeding portion <NUM> may be of any construction which entrains particles into the transport gas whether a single hose, multiple hose and/or venturi type system. The pressure and flow of transport gas delivered to feeding portion <NUM> is controlled by pressure regulator assembly <NUM>.

Feeder assembly <NUM> includes a plurality of motors to drive its different portions. These motors may be of any suitable configuration, such as pneumatic motors and electric motors, including without limited to, DC motors and VFD. Metering portion <NUM> includes drive 26a, which, in the embodiment depicted, provides rotary power. In the embodiment depicted, comminutor <NUM> includes three drives, 28a and 28b, which provide rotary power, and 28c, which provides rotary power through right angle drive 28d. In the embodiment depicted, feeding portion <NUM> includes drive 30a, which provides rotary power through right angle drive 30b. Any suitable quantity, configuration and orientation of drives, with or without the presence of right angle drives, may be used. For example, fewer motors may be used with appropriate mechanisms to transmit power to the components at the appropriate speeds (such as chains, belts, gears, etc.). As can be seen in <FIG>, with the drives and right angle drives removed, locating pins may be used to locate the drives.

Feeder assembly <NUM> may include one or more actuators <NUM>, each having at least one extendable member (not illustrated), disposed to be selectively extended into the particle flow from hopper <NUM> to feeder assembly <NUM> at guide <NUM>, capable of mechanically breaking up clumps of particles, as such is described in <CIT>.

Referring also to <FIG> and <FIG>, metering portion <NUM> includes guide <NUM> and metering element <NUM>. Metering element <NUM> is configured to receive blast media from hopper <NUM>, a source of blast media (in the embodiment depicted, cryogenic particles) from first region <NUM> and to discharge blast media at second region <NUM>. Guide <NUM> may be made of any suitable material, such as aluminum, stainless steel, or plastic. Guide <NUM> is configured to guide blast media from hopper <NUM> to first region <NUM>. Guide <NUM> may have any configuration suitable to guide blast media from hopper <NUM> to first region <NUM>, such as without limitation converging walls. Metering element <NUM> is configured to control the flow rate of blast media for particle blast apparatus <NUM>. The rate may be expressed using any nomenclature, such as mass (or weight) or volume per unit time, such as SI unit kg/s [pounds per minute]. Metering element <NUM> may be configured in any way suitable to control the blast media flow rate. In the embodiment depicted, metering element <NUM> is configured as a rotor - a structure which is rotatable about an axis, such as axis 36a. In the embodiment depicted, metering element <NUM> is supported by shaft 36b, with a key/keyway arrangement preventing rotation between metering element <NUM> and shaft 36b. Drive 26a is coupled to shaft 36b and may be controlled to rotate shaft 36b about axis 36a, thereby rotating metering element <NUM> about axis 36a. Metering element <NUM> will also be referred to herein as rotor <NUM>, metering rotor <NUM> or even doser <NUM>, it being understood that references to metering element <NUM> as a rotor or a doser shall not be interpreted in a manner which limits metering element to the rotor structure illustrated. As a non-limiting example, metering element <NUM> may be a reciprocating structure. Metering rotor <NUM>, as depicted, includes a plurality of cavities <NUM>, which are also referred to herein as pockets <NUM>. Pockets <NUM> may be of any size, shape, number or configuration. In the embodiment depicted, pockets <NUM> open radially outwardly and extend between the ends of metering rotor <NUM>, as described below. Rotation of metering rotor <NUM> cyclically disposes each pocket <NUM> at a first position adjacent first region <NUM> to receive particles and a second position adjacent second region <NUM> to discharge particles.

Comminutor <NUM> includes roller <NUM> which is rotatable about an axis, such as axis 44a and roller <NUM> which is rotatable about an axis, such as axis 46a. In the embodiment depicted, roller <NUM> is supported by shaft 44b, with a key/keyway arrangement preventing rotation between roller <NUM> and shaft 44b. Drive 28a is coupled to shaft 44b and may be controlled to rotate shaft 44b about axis 44a, thereby rotating roller <NUM> about axis 44a. In the embodiment depicted, roller <NUM> is supported by shaft 46b, with a key/keyway arrangement preventing rotation between roller <NUM> and shaft 46b. Drive 28b is coupled to shaft 46b and may be controlled to rotate shaft 46b about axis 46a, thereby rotating roller <NUM> about axis 46a. Rollers <NUM>, <NUM> may be made of any suitable material, such as aluminum.

Rollers <NUM> and <NUM> have respective peripheral surfaces 44c, 46c. Gap <NUM> is defined between each respective peripheral surface 44c, 46c. Converging region <NUM> is defined upstream of gap <NUM> by gap <NUM> and rollers <NUM>, <NUM>. (Downstream is the direction of flow of blast media through feeder assembly <NUM>, and upstream is the opposite direction. ) Converging region <NUM> is disposed to receive blast media from second region <NUM> which has been discharged by rotor <NUM>. Diverging region <NUM> is defined downstream of gap <NUM> by gap <NUM> and rollers <NUM>, <NUM>.

Comminutor <NUM> is configured to receive blast media, which comprises a plurality of particles (carbon dioxide particles in the embodiment depicted) from metering element <NUM> and to selectively reduce the size of the particles from the particles' respective initial sizes to a second size which is smaller than a predetermined size. In the embodiment depicted, comminutor <NUM> receives blast media from metering portion <NUM>/metering element <NUM>. In an alternative embodiment, metering portion <NUM>/metering element <NUM> may be omitted and comminutor <NUM> may receive blast media from any structure, including directly from a source of blast media. As is known, rollers <NUM>, <NUM> are rotated to move peripheral surfaces 44c, 46c in the downstream direction at gap <NUM>, the terminus of converging region <NUM>. As blast media particles travel in the downstream direction through gap <NUM>, the sizes of particles which are initially larger than the width of gap <NUM> between peripheral surfaces 44c, 46c will be reduced to a size based on the gap size.

The size of gap <NUM> may be varied between a minimum gap and a maximum gap. The maximum gap and minimum gap may be any suitable size. The maximum gap may be large enough that none of the particles traveling through gap <NUM> undergo a size change. The minimum gap may be small enough that all of the particles traveling through gap <NUM> undergo a size change. Depending on the maximum gap size, there may be a gap size, which is less than the maximum gap size, at which comminution of particles first begins. At gap sizes at which less than all of the particles traveling through gap <NUM> are comminuted, comminutor <NUM> reduces the size of a plurality of the plurality of particles. In the embodiment depicted, the minimum gap is configured to comminute particles to a very fine size, such as <NUM>,<NUM> [<NUM> inches], which may be referred to in the standard industry as microparticles, with the minimum gap being <NUM>,<NUM> [<NUM> inches]. In the embodiment depicted, the maximum gap is configured to not comminute any particles, with the maximum gap being <NUM>,<NUM> [<NUM> inches]. Any suitable minimum and maximum gap may be used.

Feeding portion <NUM> may be of any design which is configured to receive blast media particles and introduce the particles into the flow of transport gas, entraining them in the flow. In the embodiment depicted, feeding portion <NUM> includes feeding rotor <NUM>, guide <NUM> disposed between gap <NUM> and feeding rotor <NUM>, and lower seal <NUM>. Feeding rotor <NUM> is rotatable about an axis, such as axis 54a. In the embodiment depicted, shaft 54b (see <FIG>) is integral with feeding rotor <NUM>, and may be of unitary construction. Alternately, shaft 54b may be a separate shaft which carries feeding rotor <NUM> so that feeding rotor <NUM> does not rotate with respect to shaft 54b. Feeding rotor <NUM> may be made of any suitable material, such as stainless steel.

As illustrated, drive 30a is coupled to shaft 54b, through right angle drive 30b, and may be controlled to rotate shaft 54b and, concomitantly, feeding rotor <NUM> about axis 54a.

Feeding rotor <NUM> comprises peripheral surface 54c (see <FIG>), also referred to herein as circumferential surface 54c, which has a plurality of pockets <NUM> disposed therein. Each pocket <NUM> has a respective circumferential width. Guide <NUM> is configured to receive particles from comminutor <NUM> and guide the particles into pockets <NUM> as feeding rotor <NUM> is rotated about axis 54a. As mentioned above, in one embodiment, comminutor <NUM> may be omitted from feeder assembly <NUM> with guide <NUM> receiving particles directly from metering element <NUM>. Guide <NUM> includes wiping edge 56a adjacent peripheral surface 54c and extending longitudinally, generally parallel to axis 54a. Feeding rotor <NUM> rotates in the direction indicated by the arrow such that wiping edge 56a defines a nip line for feeding rotor <NUM> and functions, with the rotation of feeding rotor <NUM>, to force particles into pockets <NUM>.

Lower seal <NUM> seals against peripheral surface 54c. Lower seal <NUM> may be of any suitable configuration.

Feeding portion <NUM> defines transport gas flow path <NUM> indicated by flow lines 62a and 62b through which transport gas flows during operation of particle blast apparatus <NUM>. Transport gas flow path <NUM> is connectable to a source of transport gas, either directly or through pressure regulator assembly <NUM> (described below), with the appropriate fittings external to feeding portion <NUM>. Transport gas flow path <NUM> may be defined by any suitable structure and configured in any suitable way which allows the entrainment of particles discharged from pockets <NUM> into the transport gas. In the embodiment depicted, lower seal <NUM> and piston <NUM> define at least a portion of transport gas flow path <NUM>, with part of flow path <NUM> being through pockets <NUM>, as described in <CIT>.

Rotation of feeding rotor <NUM> introduces particles into the flow of transport gas, entraining them in the flow. The entrained flow (particles and transport gas) flow through delivery hose <NUM> and out discharge nozzle <NUM>. Thus, there is a particle flow path extending between the source of blast media to the discharge nozzle, which, in the embodiment depicted, extends through metering portion <NUM>, comminutor <NUM> and feeding portion <NUM>.

Referring to <FIG>, there is shown an enlarged fragmentary cross-sectional view of metering rotor <NUM> and guide <NUM>. Guide <NUM> includes wiping edge 22a disposed adjacent outer peripheral surfaces 36c of metering rotor <NUM>. Outer peripheral surfaces 36c travel past wiping edge 22a as metering rotor <NUM> is rotated. Wiping edge 22a is configured to wipe across opening 42a of each pocket <NUM> as metering rotor <NUM> is rotated. Wiping edge 22a is disposed at wiping angle α relative to a tangent to metering rotor <NUM>, with an arcuate section transitioning from the sloped sides of guide <NUM> to wiping edge 22a. In the embodiment depicted, this arcuate transition section has a radius of. <NUM> inches, although any suitable radius or transition shape may be used. As used herein, wiping angle is the angle formed between the wiping edge and a tangent to metering rotor as illustrated measured in <FIG>. Wiping angle α is configured to not result in a nip line between wiping edge 22a and outer peripheral surfaces 36c as metering rotor <NUM> is rotated in the direction indicated. If a nip line is present at this location, particles could be forced and/or crushed into pockets <NUM>, which for carbon dioxide particles, results in the particles tending not to fall out of the pocket at discharge. In the embodiment depicted, wiping angle α is greater than <NUM>°.

<FIG> illustrates the overhang of entrance <NUM> relative to metering rotor <NUM>, the overhang of housing <NUM> relative to roller <NUM>, and that roller <NUM> (and correspondingly roller <NUM>) is wider than metering rotor <NUM>. As shown, surface 22c of entrance <NUM> axially overhangs first end 36d of metering rotor <NUM> and surface 22d of entrance <NUM> axially overhangs second end 36e. The upper portions of both ends 36d, 36e are disposed in recesses, defined by surfaces 22c, 22d in housings 94f, 94e respectively. With this construction, particles traveling through guide <NUM> are blocked from reaching ends 36d, 36e. Similarly, surfaces 94a' and 94b' overhang the ends of roller <NUM> (and concomitantly the ends of roller <NUM>, not seen in <FIG>). The upper portions of both ends of rollers <NUM>, <NUM> are disposed in recesses. As can be seen in <FIG>, roller <NUM> (and concomitantly roller <NUM>) is wider than metering rotor <NUM>. This construction avoids ledges where ice could build up.

Referring to <FIG>, an exploded perspective view of feeding portion <NUM> is depicted. In addition to the above description, in the embodiment depicted, feeding portion <NUM> includes housing <NUM> and base <NUM>. Base includes centrally disposed raised portion <NUM>. Similar to as described in <CIT>, an internal cavity of piston <NUM> sealingly engages raised portion <NUM>, forming a chamber which is in fluid communication with the transport gas. Spring <NUM> is disposed to urge piston upwardly, with pilot <NUM> engaging piston <NUM> as seen in <FIG>. In the embodiment depicted, lower seal <NUM> is secured to piston <NUM> by fasteners <NUM> with appropriate seals.

Housing <NUM> includes bores 66a, 66b which receive bearings 78a, 78b. Bearings 78a, 78b rotatably support feeding rotor <NUM>. Bearing 78a is retained in bore 66a by retainer <NUM> which is secured to housing <NUM>. Bearing 78b is retained in bore 66b by retainer/support <NUM>, which is secured to housing by fasteners <NUM>. Right angle drive 30b may be attached to retainer/support <NUM>. Housing <NUM> may be made of any suitable material, such as aluminum.

Inlet <NUM> and outlet <NUM> (see <FIG>) of transport gas flow path <NUM> are formed in housing <NUM> as shown. Fittings <NUM>, <NUM> sealing engage housing <NUM> at inlet <NUM> and outlet <NUM>, respectively, with retainers 90a, 92a securing them thereto.

Referring to <FIG> and <FIG>, there are illustrated exploded perspective views of metering portion <NUM> and comminutor <NUM>. In the depicted embodiment, housing <NUM> houses metering rotor <NUM> and rollers <NUM>, <NUM>. Shaft 36b may be rotationally supported by bearings 36f. Housing <NUM> may be made of any suitable material, such as aluminum, and of any suitable configuration. In the embodiment depicted, housing <NUM> comprises six parts. As illustrated, housings 94a and 94b carry roller <NUM>, while housing 94c and 94d carry roller <NUM>. Housings 94e and 94f carry metering rotor <NUM>.

Housings 94c and 94d are moveable relative to housings 94a and 94b so as to vary the width of gap <NUM>. Housings 94a, 94b, 94c and 94d have corresponding supports 96a, 96b, 96c and 96d. Supports 96a, 96b rotatably support shafts 36b and 44b, and supports 96c, 96d rotatably support shaft 46b. Supports 96a, 96b, 96c and 96d may be made of any suitable material, such as aluminum. Housings 94a, 94b and supports 96a, 96b are depicted as not being moveable relative to feeding portion <NUM> and hopper <NUM>.

Referring also to <FIG> and <FIG>, feeder assembly <NUM> includes gap adjustment mechanism <NUM> which is connected to supports 96c, 96d to move and dispose them at a plurality of positions, including a first position at which gap <NUM> is at its minimum and a second position at which gap <NUM> is at its maximum. Gap adjustment mechanism <NUM> comprises shaft <NUM> which is rotatable about an axis, such as axis 100a, and external teeth or threads 100b disposed extending longitudinally as illustrated. Drive 28c is coupled to shaft <NUM> through right angle drive 28d and may be controlled to rotate shaft <NUM>. Gap adjustment mechanism <NUM> comprises member <NUM> gear with internal teeth or threads 102a disposed about axis 100a, which are shaped complementarily with external teeth or threads 100b, engaging therewith. Rotation of shaft <NUM> causes relative longitudinal motion between shaft <NUM> and member <NUM>.

Member <NUM> is secured to plate <NUM> by a plurality of fasteners <NUM>. Plate <NUM> is secured to support 96c by fastener 108a and to support 96d by fastener 108b.

Shaft <NUM> includes flange <NUM> which is captured between support <NUM> and retainer <NUM>, allowing rotational motion about axis 100a with little or no axial motion. A plurality of rods <NUM> secure support <NUM> to supports 96a, 96b, with no movement therebetween. Rods <NUM> support plate <NUM> so that it can move axially along rods <NUM>. Plate <NUM> includes a plurality of guides 104a which are disposed in complementarily shaped bores 118c, 118d. Since plate <NUM> is secured to supports 96c, 96d by fasteners 108a, 108b, there is no relative movement between guides 104a and supports 96c, 96d. Guides 104a are sized to allow rods <NUM> to slide axially therein.

Supports 96a, 96b include guides 120a, 120b respectively which are disposed in complementarily shaped bores (not seen) in supports 96c, 96d. These bores are sized to allow guides 120a, 120b to slide axially therein. Guides 120a, 120b support and guide supports 96c, 96d at and between the first and second positions of their travel. Rods <NUM> extend through guides 104a, bores 118c, 118d, and guides 120a, 120b, being fastened to supports 96a, 96b such that support <NUM> is supported and does not move relative to supports 96a, 96b.

Rotation of shaft <NUM> moves plate <NUM> along axis 100a and concomitantly moves supports 96c, 96d and roller <NUM> relative to supports 96a, 96b and roller <NUM>, thereby varying the width of gap <NUM>.

Rollers <NUM> and <NUM> may comprise a plurality of rollers. As seen in <FIG>, roller <NUM> may comprise sub-rollers A and B non-rotatably carried by shaft 44b and roller <NUM> may comprise sub-rollers C and D non-rotatably carried by shaft 46b. Each individual sub-roller A, B, C, D has a respective peripheral surface A', B', C' and D'.

Rollers <NUM>, <NUM>, regardless whether comprised of single rollers or a plurality of rollers, may include a plurality of bores <NUM> therethrough. If rollers <NUM>, <NUM> comprise a plurality of rollers, bores <NUM> within each roller may be aligned axially. Bores <NUM> reduce the overall mass of rollers <NUM>, <NUM>. Such reduced mass reduces the time required for a temperature change in rollers <NUM>, <NUM>, such as a reduction in the time required for any ice built up on rollers <NUM>, <NUM> during operation to melt during periods that particle blast apparatus <NUM> is not being operated. In another embodiment, air or other gas may be directed to flow through bores <NUM> to promote a faster temperature change.

For additional clarity, <FIG> provides a cross-sectional perspective view of feeder assembly <NUM>.

Referring to <FIG> and <FIG>, supports 96c, 96d (not visible in <FIG> and <FIG>) are disposed at the second position at which gap <NUM> is at its maximum. Roller <NUM> is spaced apart from roller <NUM> at a maximum distance. Regardless of the position of roller <NUM> and the concomitant size of gap <NUM>, roller <NUM> remains in the same position. Roller <NUM> defines first edge 48a of gap <NUM>, which also remains in the same position regardless of the position of roller <NUM>.

First edge 48a is always disposed at a location disposed intermediate axis 54a and wiping edge 56a. Wiping edge 56a defines a boundary of wiping region 56b. Generally wiping region 56b extends about the width of one pocket <NUM> when the leading edge of such pocket <NUM> is disposed at wiping edge 56a. Wiping region 56b is in alignment with first edge 48a. When supports 96c, 96d are disposed at the first location at which the size of gap <NUM> is at a minimum, the entire gap is aligned with wiping region 56b, such that the comminuted particles may fall or be directed into pockets <NUM> proximal wiping edge 56a.

<FIG> is similar to <FIG>, depicting gap <NUM> at a size in between the maximum gap and minimum gap. Feeder assembly <NUM> is configured such that gap adjustment mechanism <NUM> may dispose supports 96c, 96d at a plurality of positions in-between the first and second positions such that gap <NUM> may be set at a plurality of sizes in-between the maximum gap and the minimum gap. In the depicted embodiment, the configuration of gap adjustment mechanism <NUM> essentially allows the size to be set at the maximum, minimum and any size in-between.

Peripheral surfaces 44c, 46c may be of any suitable configuration. In the embodiment depicted, peripheral surfaces 44c, 46c have a surface texture, which may be of any configuration. It is noted that for clarity, surface texture has been omitted from the figures except in <FIG> and <FIG>. <FIG> and <FIG> illustrate rollers <NUM>, <NUM> having a surface texture comprising a plurality of raised ridges <NUM>. <FIG> illustrates rollers <NUM>, <NUM> comprised of sub-rollers A, B, C and D, viewed from the top into converging region <NUM>. Each sub-roller peripheral surface A', B', C', D' comprises a plurality of raised ridges <NUM> disposed at an angle relative to either edge. The angle may be any suitable angle, such as <NUM>° relative to the axial direction. In the embodiment depicted, the angles of each sub-roller peripheral surface A', B', C', D' ridge are the same, although any suitable combination of angles may be used.

The surface texture in the depicted embodiment is configured to provide uniformity across the axial width of rollers <NUM>, <NUM> of the comminuted particles discharged by comminutor <NUM> to feeding portion <NUM>. Such uniformity is achieved in the depicted embodiment by the surface texture being configured to move particles entering comminutor <NUM> at converging region <NUM> toward the axial middle of rollers <NUM>, <NUM>. As seen in <FIG>, the plurality of ridges <NUM> of roller <NUM> (sub-rollers A, B) and the plurality of ridges <NUM> of roller <NUM> (sub-rollers C, D) form a diamond pattern in converging region <NUM>. At the interface between sub-rollers A and B and sub-rollers C and D, individual raised ridges <NUM> may or not precisely align.

When viewed from the bottom, the plurality of ridges <NUM> of roller <NUM> (sub-rollers A, B) and the plurality of ridges <NUM> of roller <NUM> (sub-rollers C, D) form an X pattern in the diverging region.

<FIG> shows a top view of metering rotor <NUM> through guide <NUM>. Arrow <NUM> indicates the direction of rotation of metering rotor <NUM>. Referring also to <FIG>, in the depicted embodiment, metering rotor <NUM> is configured to provide uniformity across the axial width of metering rotor <NUM> of the blast media particles discharged by metering rotor <NUM> at second region <NUM> to comminutor <NUM> and uniformity in the rate of discharge at second region <NUM>. Such uniformity may be achieved in the depicted embodiment by the configuration of pockets <NUM>. Metering rotor <NUM> may be made of any suitable material, such as UHMW or other polymers.

As seen in <FIG>, metering rotor <NUM> comprises first end 36d and second end 36e which are spaced apart from each other along axis 36a. Pockets <NUM> extend from first end 36d to second end 36e. Pockets <NUM> when viewed radially toward axis 36a have a general V shape, also referred to herein as a chevron shape, with apex 42b pointed in the opposite direction of rotation. Pockets <NUM> when viewed axially have a general U shape. Any suitable axial shape may be used. Any suitable radial shape may be used, including pockets that extend straight from first end 36d to second end 36e.

In the depicted embodiment, pockets <NUM> are configured to promote movement of particles toward the axial center of pockets <NUM>. As metering rotor <NUM> rotates in the direction of arrow <NUM>, the axial inclination of the chevron shape may cause particles to move toward the axial center, resulting in more even distribution across the axial width of metering rotor <NUM>.

<FIG> illustrate the axial profile of pockets <NUM> at the corresponding locations indicated in <FIG> illustrates the profile of pockets <NUM> at apex 42b, the midpoint. At apex 42b, the angle of pockets <NUM> transition to the opposite, mirror angle, without a sharp intersection. A radius may be formed at this intersection to create a non-sharp transition 42c.

<FIG> is a view of metering rotor <NUM> looking upstream from the bottom, through second region <NUM>. Discharge edge 22b is illustrated extending generally axially relative to axis 36a. As can be seen, the V or chevron shape of pockets <NUM> results in the outermost portions 42d of pockets <NUM> passing discharge edge 22b first, prior to apex 42b. With this configuration, only a small section of one of the lands of peripheral surface 36c arrives at discharge edge 22b, providing less pulsing than if each land forming peripheral surface 36c were axially straight.

As mentioned above, metering element <NUM> is configured to control the flow rate of blast media for particle blast apparatus <NUM>. By separating the flow rate control from the feeding rotor, the delivery speed, pulsing at lower flow rates may be avoided. When the feeding rotor also controls the particle flow rate, to deliver lower flow rates, the rotational speed of the feeding rotor must be reduced. At lower speeds, due to the relative alignment of the pockets of the feeding rotor, pulsing occurs. Even with the pockets of the feeding rotor full, at lower rotational speeds of the feeding rotor, the time between the presentation of each opening for discharge is increased resulting in the pulsing.

In embodiments in which metering element <NUM> is present, feeding rotor <NUM> may be rotated at a constant, typically high, speed, independent of the feed rate. At a constant high speed, the time between the presentation of each opening for discharge is constant for all feed rates. At low feed rates with feeding rotor <NUM> rotating at a constant high speed, the percentage fill of each pocket will be smaller than at high feed rates, but pulsing will be reduced.

By separating the flow rate control from the feeding rotor, the feeding rotor may be operated closer to its optimal speed (based, for example, on component designs and characteristics, such as the motor profile, wear rate, etc.).

In the embodiment depicted, feeding rotor <NUM> may be operated at a constant rotation speed for all feed rates, such as <NUM> RPM to <NUM> RPM. In the embodiment depicted, comminutor <NUM> may be operated at a constant rotation speed for all speed rates, such as <NUM> RPM for each roller <NUM>, <NUM>. In the embodiment depicted, metering rotor <NUM> may be operated at a rotation speed that varies so as to control the flow rate of particles.

For best operation, the flow of transport gas needs to be adequate and consistent providing the desired controllable flow and pressure. Although an outside source of gas, such as air, may be able to provide the desired flow and pressure in a controllable manner, outside sources are generally unreliable in this regard. Thus, for such consistency and control, prior art particle blast systems have included on board pressure regulation connected to an outside source of gas, such as air. Prior art particle blast systems have used a valve, such as a ball valve, as an on-off control of the incoming gas and regulated the pressure downstream thereof. Prior art pressure regulation has been accomplished by use of an inline pressure regulator disposed in the flow line with the desired pressure controlled by a fluid control signal, such as an air pressure signal from a pilot control pressure regulator. At higher transport gas flow rates, the inline pressure regulator produced high pressure losses. In the prior art, to make up for such pressure loss at higher flows, oversized inline pressure regulators or alternate non-regulated transport gas flow paths can be utilized, adding cost, complexity and undesirable increase in overall weight and size of design.

Referring to <FIG>, pressure regulator assembly <NUM> of the embodiment depicted is shown. Pressure regulator <NUM> includes flow control valve, generally indicated at <NUM>. Flow control valve <NUM> comprises actuator <NUM> and ball valve <NUM>. Ball valve <NUM> includes inlet <NUM>, which is connected to a source of transport gas, and outlet <NUM>, which is connected through appropriate fitting <NUM> to inlet <NUM> and which may itself be considered a source of transport gas. In the embodiment depicted, T fitting <NUM> is connected to inlet <NUM>. T fitting <NUM> includes inlet 212a which is connected to a source (not shown) of transport gas which, in the embodiment depicted, is not pressure regulated. T fitting includes outlet 212b which is connected to another T fitting <NUM>, to which pressure sensor <NUM> is connected and senses the pressure within T fitting <NUM>. Outlet 214a is configured to provide pressure and flow to other components of particle blast system <NUM>.

Referring to <FIG>, a cross-sectional top view of actuator <NUM> is illustrated, with ball valve <NUM> illustrated diagrammatically. Actuator <NUM> is configured to be coupled with a controlled member, in the embodiment depicted, ball <NUM> (see <FIG>) to move the controlled member between and including a first controlled position and a second controlled position. In the embodiment depicted, when ball <NUM> is at the second controlled position, ball valve <NUM> is closed. Actuator <NUM> comprises body <NUM> which defines first internal chamber <NUM>, which is generally cylindrical, but which can be any suitable shape. At one end, end cap <NUM> is connected to body <NUM>, sealing first internal chamber <NUM>. At the other end, body <NUM> is connected to body <NUM>, sealing internal chamber <NUM>. Body <NUM> may be of unitary construction or of assembled pieces. Body <NUM> and body <NUM> may be of unitary construction. Body <NUM> defines second internal chamber <NUM>.

Piston <NUM> is disposed in first internal chamber <NUM>, sealingly engaging sidewall 222a. Within first internal chamber <NUM>, piston <NUM> forms chamber <NUM> on first side 230a, and chamber <NUM> on second side 230b. Piston <NUM> is disposed in first internal chamber <NUM>, sealingly engaging sidewall 222a. Within first internal chamber <NUM>, piston <NUM> forms chamber <NUM> on first side 236a, with second chamber <NUM> disposed on second side 236b.

Piston <NUM> is shaped complementarily to sidewall 222a and includes extension 230c with teeth 230d. Piston <NUM> is shaped complementarily to sidewall 222a and includes extension 236c with teeth 236d. Teeth 230d and teeth 236d engage pinion <NUM> which is rotatable about axis 240a, which in the embodiment depicted, is aligned with axis 218b of stem 218a. Pinion <NUM> is coupled, directly or indirectly to stem 218a which in turn is connected to ball <NUM>. Rotation of pinion <NUM> causes concomitant rotation of stem 281a and ball <NUM>. Pinion <NUM> may be rotated between and including a first position and a second position, which correspond to the first and second positions of ball <NUM> - when pinion <NUM> is at its first position, ball <NUM> is at its first position; when pinion <NUM> is at its second position, ball <NUM> is at its second position.

Pistons <NUM> and <NUM> also move between and including first and second positions, concomitantly due to their engagement with pinion <NUM>. As pistons <NUM> and <NUM> move, they cause pinion <NUM> to rotate correspondingly. At their respective second positions, pistons <NUM> and <NUM> are at their minimum spaced apart distance relative to each other, causing pinion <NUM> and ball <NUM> to be at their respective second positions, making ball valve <NUM> closed. At their respective first positions, pistons <NUM> and <NUM> are at their maximum spaced apart distance relative to each other, causing pinion <NUM> and ball <NUM> to be at their respective first positions. In the embodiment depicted, ball valve <NUM> is a quarter turn valve and when ball <NUM> is at its first position, ball valve <NUM> is completely open. Although two pistons <NUM>, <NUM> are illustrated, piston <NUM> could be omitted with piston <NUM> being appropriately sized.

Ball valve <NUM> regulates the pressure of the flow of transport gas into inlet <NUM>. With reference to the pneumatic circuit schematic of <FIG>, chambers <NUM> and <NUM> are in fluid communication with the flow passageway downstream of ball <NUM> so that the pressure within chambers <NUM> and <NUM> is the same as the actual static pressure in downstream passageway <NUM>. In <FIG>, this is diagrammatically illustrated by line <NUM>, bypass valve <NUM> and line <NUM>. Activation of bypass valve <NUM> allows the user to set ball valve <NUM> to completely open, bypassing/disabling the regulating function of ball valve <NUM>. Lines <NUM>, <NUM> may be of any suitable configuration.

Chamber <NUM> is placed in fluid communication with a pressure control signal, which either is or is proportional to the desired downstream pressure. As shown diagrammatically in <FIG>, actuator <NUM> includes port <NUM> in fluid communication with chamber <NUM> which is configured to be connected to a pressure control signal by line <NUM>. As illustrated, quick exhaust valve <NUM> may be interposed between port <NUM> and line <NUM>, which may allow quick exhaust of the pressure within chamber <NUM> when desired, such as when ball valve <NUM> is being closed. The pressure of pressure control signal may be set by the operator. As seen in <FIG>, pressure regulator <NUM> controls the pressure delivered to line <NUM> when control valve <NUM> is in the appropriate position. The position of control valve <NUM> is controlled by blast valve <NUM>, which may be disposed in hand control <NUM>. Actuation of blast valve <NUM> delivers regulated pressure flow from regulator <NUM> to control valve <NUM> causing it to move to the appropriate position for controlled pressure flow from pressure regulator <NUM> to flow to line <NUM>. The pressure of the input to pressure regulator <NUM> may be unregulated as indicated in <FIG>, it being noted that that input is regulated upstream thereof by regulator <NUM>.

During operation, pressure within chamber <NUM>, controlled by the pressure control signal delivered through line <NUM>, will move pistons <NUM> and <NUM> outwardly, causing ball valve <NUM> to open, increasing the pressure in downstream flow passageway <NUM>. As this pressure increases, the pressure within chamber <NUM> and <NUM> will increase and act on pistons <NUM> and <NUM> against the pressure in chamber <NUM>, moving pistons <NUM> and <NUM> inwardly causing ball valve <NUM> to close, reducing the flow and the pressure in downstream flow passageway <NUM>, which is the portion of the flow passageway downstream of ball <NUM>, including the portion thereof within ball valve <NUM>. Ball valve <NUM> will move to an equilibrium position at which the force on pistons <NUM> and <NUM> from chambers <NUM> and <NUM> equals the force on pistons <NUM> and <NUM> from chamber <NUM>. Changes in pressure in chambers <NUM> and <NUM>, such as due to changes in the upstream source pressure, or in chamber <NUM>, such as due to a change by the operator, will result in ball valve <NUM> moving to a new equilibrium position.

As seen in <FIG>, piston <NUM> is disposed in second internal chamber <NUM>, sealingly engaging sidewall 228a. Within second internal chamber <NUM>, piston <NUM> forms chamber <NUM> on first side 266a and chamber <NUM> (see <FIG>) on second side 266b. Piston <NUM> is shaped complementarily to sidewall 228a and includes extension 266c which extends through bore 226a of end wall 226b, into chamber <NUM>. A pair of spaced apart seals <NUM> disposed in annular grooves in bore 226a seal between chamber <NUM> and <NUM> against extension 266c. Vent <NUM> vents the area between seals <NUM> so that there will be a difference in pressure across the seals for all the seals to effectively be compression loaded in the seal grooves and prevent leakage.

End cap <NUM> is connected to body <NUM>, and includes annular groove <NUM>, which is shaped complementarily to and aligned with annular groove <NUM>. Piston <NUM> is moveable between and including a first position at which the internal volume of chamber <NUM> is at its maximum and a second position at which the internal volume of chamber <NUM> is at its minimum, whereat extension 266c extends its maximum distance into chamber <NUM>.

The ends of springs <NUM> and <NUM> are disposed in annular grooves <NUM> and <NUM> and configured to resiliently bias piston <NUM> toward the second position. In <FIG>, with piston <NUM> in its first position, springs <NUM> and <NUM> are in their most compressed state, urging piston to the right to move to its second position. Although two springs are shown, there need be only at least one resilient member to resiliently urge piston <NUM> toward its second position.

To hold piston <NUM> in its first position, chamber <NUM> may be selectively pressurized with sufficient pressure to overcome the force exerted by springs <NUM> and <NUM>. Body <NUM> includes port <NUM> in fluid communication with chamber <NUM>. Fitting <NUM> is illustrated disposed in port <NUM>, with line <NUM> in fluid communication with chamber <NUM> through fitting <NUM>. Line <NUM> is connected to a source of pressurized fluid, such as air, so that chamber <NUM> can be pressurized. As seen in <FIG>, pressure in line <NUM> is controlled by blast valve <NUM>. Actuation of blast valve <NUM> delivers pressure to line <NUM> and ultimately chamber <NUM> such that piston <NUM> is held in its first position, overcoming the force exerted by springs <NUM> and <NUM>. At this position, piston <NUM> has its full range of motion from its first position to its second position.

Referring to <FIG>, <FIG> and <FIG>, when blast valve <NUM> is released, pressure within chamber <NUM> is vented through blast valve <NUM> via line <NUM>, allowing springs <NUM> and <NUM> to immediately move piston <NUM> from its first position (<FIG>) to its second position (<FIG>). As piston <NUM> moves from its first position to its second position, part of piston <NUM>, extension 266c, engages piston <NUM> and moves piston <NUM> to its second position, at which ball valve <NUM> is closed. Concomitantly with the release of blast valve <NUM>, pressure to line <NUM> is interrupted resulting in control valve <NUM> to interrupt the pressurization of chamber <NUM>. With the drop in pressure of chamber <NUM>, quick exhaust valve <NUM> allows venting of chamber <NUM> as piston <NUM> is moved by extension 266c.

Claim 1:
A feeder assembly (<NUM>) configured to transport cryogenic blast media from a source of cryogenic blast media into a flow of transport gas, the cryogenic blast media comprising a plurality of particles, each particle of the plurality of particles having a respective initial size, the feeder assembly (<NUM>) comprising:
a. a metering element (<NUM>);
b. a feeding rotor (<NUM>) rotatable about a feeding rotor axis, wherein the feeding rotor (<NUM>) comprises
i. a circumferential surface (54c), and
ii. a plurality of pockets (<NUM>) disposed in the circumferential surface (54c), each of the plurality of pockets (<NUM>) having a respective circumferential pocket width;
c. a comminutor (<NUM>) disposed between the metering element (<NUM>) and the feeding rotor (<NUM>);
d. a guide (<NUM>) disposed between the comminutor (<NUM>) and the feeding rotor (<NUM>), the guide (<NUM>) configured to receive particles from the comminutor (<NUM>) and guide the particles into the plurality of pockets (<NUM>) as the feeding rotor (<NUM>) rotates, the guide comprising a wiping edge (56a) disposed adjacent the circumferential surface (54c), wherein the wiping edge (56a) is oriented generally parallel to the feeding rotor axis, wherein the wiping edge (56a) is configured to force particles into the plurality of pockets (<NUM>) as the feeding rotor (<NUM>) rotates; and
d. a transport gas flow path (<NUM>) through which the transport gas flows during operation of the feeder assembly (<NUM>),
wherein the metering element (<NUM>) is configured to:
i. receive from a first region (<NUM>) the cryogenic blast media from the source of cryogenic blast media;
ii. control the rate of flow of the cryogenic blast media through the feeder assembly (<NUM>); and
iii. discharge the cryogenic blast media to the comminutor (<NUM>); and
wherein the comminutor is:
i. configured to receive cryogenic blast media from the metering element;
ii. configured to reduce the size of a plurality of the plurality of particles from each particle's respective initial size to a second size which is smaller than a predetermined size; and
iii. disposed to discharge the cryogenic blast media directly to the feeding rotor through the guide (<NUM>), and
wherein the feeding rotor (<NUM>) is:
i. disposed to receive the cryogenic blast media directly from the comminutor (<NUM>) through the guide (<NUM>); and
ii. configured to introduce the cryogenic blast media into the flow of transport gas in the transport gas flow path (<NUM>).