Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
JIG CONCENTRATOR
Document Type and Number:
WIPO Patent Application WO/2020/198709
Kind Code:
A1
Abstract:
A jig concentrator apparatus has a jigging bed having a plurality of holes, a flow control valve associated with the jigging bed to control a flow of fluid, a pulsion valve connected to the flow control valve for controlling a pulsation of water or media, wherein the valve is housed under the bed, a water or fluid inlet attached to the water pulsion valve for input of water in the apparatus, and a pressured air buffer mounted on the water inlet to buffer and store air in the jig concentrator

Inventors:
SNOBY RICHARD (US)
SNOBY ANDREW (US)
Application Number:
PCT/US2020/025538
Publication Date:
October 01, 2020
Filing Date:
March 27, 2020
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
SNOBY RICHARD (US)
SNOBY ANDREW (US)
International Classes:
B03B4/06; B03B4/00; B03B5/18; B03B5/24; B03B11/00; B07B4/00
Foreign References:
US20080190823A12008-08-14
US5740920A1998-04-21
US2978397A1961-04-04
EP0499769A11992-08-26
CN1418733A2003-05-21
Attorney, Agent or Firm:
ACHARYA, Nigamnarayan (US)
Download PDF:
Claims:
Claims

1. A jig concentrator, comprising;

a jigging bed having a plurality of holes;

a flow control valve associated with the jigging bed to control a flow of fluid; a pulsion valve connected to the flow control valve for controlling a pulsation of water or media, wherein the valve is housed under the bed;

a water or fluid inlet attached to the water pulsion valve for input of water in the jig concentrator; and

a pressured air buffer mounted on the water inlet to buffer and store air in the jig concentrator.

2. The jig concentrator of claim 1, wherein the jigging bed supports allows the water to flow through the holes in the jig bed to create pulsion and suction stroke motion, a flow control valve associated with the jigging bed to control a flow of fluid, wherein the flow control valve restricts the flow per unit of time to establish the amplitude of the jigging stroke; a water pulsion valve connected to the flow control valve for controlling a pulsation of water and for determining the frequency of the jigging stroke, and a water inlet attached to the water pulsion valve for input of water in the apparatus.

3. The jig concentrator of claim 1, wherein a pulsion valve is housed under the fluid inlet to independently control by-pass of the fluid. 4. The jig concentrator of claim 1, further comprising pipes with holes to create even distribution of fluid through jigging bed in the jig concentrator.

5. The jig concentrator of claim 1, wherein a punched screen plate is connected to the jigging bed for supporting a ragging material.

6. The jig concentrator of claim 2, wherein a plurality of delivery pipes are attached to the hutch for input of the fluid in the jig.

7. The jig concentrator of claim 2, wherein multiple chambers are connected to the hutch for collecting any heavy and light particles.

8. The jig concentrator of claim 2, wherein plurality of slots associated with delivery pipes for the even delivery of jigging fluid for optimizing the stratification of the material the in layers based on density.

9. A method of sizing and separating particles of a generally low-density material, using a jig concentrator comprising a stand, a frame, a jigging bed in the frame on the stand, wherein the jigging bed supports allows the water to flow through the holes in the jig bed to create pulsion and suction stroke motion, a flow control valve associated with the jigging bed to control a flow of fluid, wherein the flow control valve restricts the flow per unit of time to establish the amplitude of the jigging stroke; a water pulsion valve connected to the flow control valve for controlling a pulsation of water and for determining the frequency of the jigging stroke, and a water inlet attached to the water pulsion valve for input of water in the apparatus; and a pressured air buffer mounted on the water inlet to buffer and store air in the apparatus, comprising:

a) actuating a motor for imparting the pulsion and suction motion; and b) supplying material onto the jigging bed. 10. The method of claim 9, wherein the pulsion valve is housed under the bed to control by-pass of the fluid.

11. The method of claim 9, wherein the fluid is media or water.

12. The method of claim 9, wherein the fluid is air free.

Description:
JIG CONCENTRATOR

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 62/824,435, entitled“JIG CONCENTRATOR” filed March 27, 2019, the contents of which are incorporated herein by reference in its entirety and for all purposes.

TECHNICAL FIELD

[0002] This application relates to jigs. This application relates to jigs which separate materials in a feed mixture on the basis of differing specific gravities.

BACKGROUND

[0003] Jigging and wet jigging has been used for hundreds of years to separate materials. Typical jigs use a jig tank which is open at its top and bottom ends. The material being delivered to the jig may be sized to prevent oversized or undersized particles from entering the jig tank by perforated screens, and can be caused to flow down a portion of the chute to be discharged from the jig. In the upper portion of the jig tank a material support device, such as perforated screen plate or other supports with a plurality of holes, can support the material to be jigged and allow fluid to be pulsed through the material support device. The material (e.g., ore) containing light and heavy particles (e.g., by specific gravity) are transported in the jig from feed end to discharge end by water pulsions or pulsation and additional material being delivered to the jig.

[0004] The material support may have a grate on top of it which acts as a containment grid for ragging material. Water pulsions or pulsations within the jig lift the ragging up and off the screen and create a dilation of the bed of material above the screen. This puts particles in the bed in a state of suspension. Heavier particles within the bed progress downwardly into the ragging until they are finally able to pass through the screen. The particles settle within the tank until they are able to exit at the bottom through a valve.

[0005] A jig is an apparatus that accomplishes two primary functions. It stratifies material according to density and then makes a separation. The act of jigging to stratify particles according to their density generally occurs through four (4) fundamental actions or phases. First, the differential acceleration phase occurs from the initial upward pulsation of the jigging fluid and the smaller, lighter particles are accelerated faster and higher than coarser, more dense particles. Second, the free settling velocity phase allows the larger, higher density particles to begin falling sooner and faster. Hindered settling is the third phase and occurs when the jigging bed of material becomes smaller and the particles bump into each other and prevents larger, low density particles from falling through the stratified bed of particles. The final phase is consolidated trickling in which the very small, high density particles are drawn to the lower levels of the stratified bed during the suction stroke. The light and heavy particles may be separated by using their abilities to penetrate an oscillating fluid bed supported on a screen. Separation of light and heavy articles may also be achieved by measuring the interface between a selected layer of light and heavy particles and withdraw heavy particles from the lower layer of the jigged bed of material with a mechanical device such as a valve, star gate, vibrating feeder and other devices known to people familiar with the art.

[0006] People familiar with the art of jigging will recognize that a pulsating current of fluid, including water may be generated by a plunger, mechanical lever, air injection, flexible diaphragm etc. to dilate and collapse a mixture of particles. Each system has benefits and limitations. Mechanical systems wear and ultimately fail. In systems that use air to set the water into motion, there is always the need for additional space to contain the air by achieving optimized stratification of particles according to specific density. By optimizing the stratification of particles according to their respective densities, it allows the second primary function of a jig, separation, to be accomplished more efficiently, it allows the second primary function of a jig, separation, to be accomplished more efficiently.

[0007] Accordingly, there is always a need for an improved jig or jig concentrator. This application is directed to these needs among others.

SUMMARY

[0008] This application discloses a jig or a jig concentrator for separating heavy and light particles from materials having varying specific gravity. In one example, the jig can separate heavies and lights from ores and minerals from ores. The jig can be used on material that traditionally is separated with a jig or density separator.

[0009] One embodiment includes a jig or jig concentrator apparatus having a bed or jigging bed for stratifying and separating heavy and light particles, which can be effective over a wider distance than current technology and thus offer increased capacity. The jig bed can support the material and can allow the water to flow through the holes in the jig bed, which creates pulsion (e.g., pushing and driving) and suction strokes. The jig can be wider because the water can be introduced directly under the jigging bed. The jig can have a flow control valve associated with the jigging bed to control a flow of fluid. The flow control valve can restrict the flow per unit of time (the complete stroke cycle) to establish the amplitude of the jigging stroke. The jig can have a water pulsion valve connected to the flow control valve for controlling a pulsation of water and for determining the frequency of the jigging stroke. The jig can also have a water inlet attached to the water pulsion valve for input of water in the apparatus. A pressured air buffer can be mounted on the water inlet to buffer and store air. The air buffer can be used to avoid water pressure or hammering to the pump supplying water to the jig.

[0010] One embodiment can provide a jig concentrator that achieves optimized layering of the light and heavy particles with lower cost and allows jigs to be wider while maintaining optimum stratification of light and heavy particles.

[0011] According to an embodiment of this application, a jig concentrator has ajigging bed installed in the apparatus for supporting heavy and light particles, through which a fluid, usually water, may flow, a flow control valve associated with the jigging bed to control a flow of fluid, a water pulsion valve connected to the flow control valve for controlling a pulsation of water, a water inlet attached to the water pulsion valve for input of water in the apparatus and a pressured air buffer mounted on the water inlet to buffer and store air in the apparatus.

[0012] Another specific embodiment is a jig concentrator having ajigging bed having one or more holes, a flow control valve associated with the jigging bed to control a flow of fluid, a pulsion valve connected to the flow control valve for controlling a pulsation of water or media, wherein the valve is housed under the bed, a water inlet attached to the water pulsion valve for input of water in the apparatus; and a pressured air buffer mounted on the water inlet to buffer and store air in the apparatus. There can be a plurality of hutches forms the longer jigging bed for storing of the fluid and sorting the material. The pulsion valve can be housed under the fluid inlet to independently control by-pass of the fluid. The jig can have pipes, under the jig bed, with holes to create even distribution of fluid through jigging bed in the jig concentrator. There can be a punched screen plate connected to the jigging bed for supporting a ragging material. Further, a plurality of delivery pipes is attached to the hutch for input of the fluid in the jig. The concentrator can have multiple chambers that are connected to the hutch for collecting any heavy and light particles. A plurality of slots associated with delivery pipes for the even delivery of jigging fluid can optimize the stratification of the material the in layers based on density.

[0013] Another embodiment includes a method of sizing and separating particles of a generally low-density material, using a jig concentrator comprising a stand, a frame, a jigging bed in the frame on the stand, wherein the jigging bed supports allows the water to flow through the holes in the jig bed to create pulsion and suction stroke motion, a flow control valve associated with the jigging bed to control a flow of fluid, wherein the flow control valve restricts the flow per unit of time to establish the amplitude of the jigging stroke; a water pulsion valve connected to the flow control valve for controlling a pulsation of water and for determining the frequency of the jigging stroke, and a water inlet attached to the water pulsion valve for input of water in the apparatus; and a pressured air buffer mounted on the water inlet to buffer and store air in the apparatus. This method includes actuating a motor for imparting the pulsion and suction motion; and supplying material onto the jigging bed.

[0014] In another embodiment, the fluid can be media or water. In yet another embodiment, the fluid can be air-free.

[0015] While the invention has been described and shown with particular reference to the preferred embodiment, it will be apparent that variations might be possible that would fall within the scope of this application.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 illustrates a schematic view of one embodiment of the jig concentrator;

[0017] FIG. 2A illustrates a perspective view of an exemplary pulsion valve used with the embodiment in FIG 1 ;

[0018] FIG. 2B illustrates a perspective view of another exemplary pulsion valve used with the embodiment in FIG 1 ;

[0019] FIG. 3 illustrates a schematic view of the jigging bed and water assembly;

[0020] FIG. 4 illustrates is a bottom view of the jig showing the slots and pipes on the under-bed, e.g., the fluid delivery via pipes system or assembly

[0021] FIG. 5 illustrates a schematic view of the jig hutch; and [0022] FIG 6 shows illustrative examples of pulsion values.

DETAILED DESCRIPTION

[0023] FIG. 1 shows one embodiment of the jig or jig concentrator 100 in which the jig concentrator 100 includes a jigging bed 110 having one or more holes, a flow control valve 120 associated with the jigging bed 110 to control a flow of fluid into the jigging bed 110, a pulsion or pulsation valve 120 connected to the flow control valve for controlling a pulsation of fluid inlet 133 operatively connected to the water pulsion valve 150 for input of water jig concentrator 100; and a pressured air buffer 200 mounted on the water inlet to buffer and store air in the apparatus. The jigging bed 110 can be a typical jigging bed for known in the art, e.g., for density separation.

[0024] Beneath of jigging bed 110 may be a single or multiple fluid or liquid distribution assembly (shown later), each containing a single or multiple opening/slots for the release of a fluid. These fluids can be water or media with a specific gravity. A jigging bed 110 of the jig concentrator 100 holds the materials, which can be stratified and layered into heavy and light particles. The jigging bed 110 used to support the layered heavy and light particles identified by differences in specific gravity. The jigging bed 110 anticipates a material support that allows the fluid to be pulsed through it from the water or media pulsed from the pipes (shown later). The jigging bed 110 can use a screen media, e.g., a punched screen plate to support the light and heavy particles, which are known in the art.

[0025] As can be seen, the jig concentrator 100 has a hutch 130, a jigging bed 110 in the hutch 130. The jigging bed 110 or supports allows the water to flow through the holes (shown later) in the jigging bed 110 to create pulsion and suction stroke motion and a flow control valve 120 associated with the jigging bed to control a flow of fluid. The flow control valve 120 restricts the flow per unit of time to establish the amplitude of the jigging stroke. The water pulsion valve 120 connected to the flow control valve 120 120 controls the pulsation of water and for determining the frequency and (amplitude) of the jigging stroke. The water inlet 133 attached to the water pulsion valve 120 or 150 for input of water or media in the jig concentrator. A pressured air buffer 200 mounted on the water inlet to buffer and store air can be used to allow for adequate pulsation. In this embodiment, the pulsing is created with water flow or media flow without the need for air.

[0026] The jigging bed 110 may be used for supporting a ragging material. The punched screen plate is a standard that may offer sufficient open area, to support an accurately sized material used as ragging material or material. The ragging material, that attempts to pass the openings of the jigging bed may not, is retained on the jigging bed.

[0027] The jigging bed 110 supports material to react to the principle of jigging. The jigging is actuated by alternate strokes of pulsation and suction. The material supported by the jigging bed 110 begins to dilate at start of a pulsation stroke, and separation of particles through differential acceleration followed by free settling and hindered settling principles. A suction stroke can help stratification of the material bed according to the specific gravity and consolidation trickling of fine particles.

[0028] One or more flow control valves 120 is associated with the jigging bed 110. The flow control valve 120 regulates the flow of the fluid to influence the amplitude of the jigging stroke. The flow control valves 120 may be fitted with actuators and position holders. Pneumatically-actuated globe valves and diaphragm valves are widely used for control purposes in many industries, although quarter-turn types like ball and butterfly valves are also used. The flow control valves 120 can also work with hydraulic actuators and may be known as hydraulic pilots. These types of valves are also known as automatic control valves. The flow control valves may also be manual. The hydraulic actuators respond to changes of pressure or flow and will open/close the valve. Automatic control valves do not require an external power source, meaning that the fluid pressure is enough to open and close them.

[0029] Referring to FIG. 5, multiple hutches 130 can be connected to form a jigging bed 110 for storing of the fluid and may be a conduit for the discharge of material. The hutch 130 openings may or may not be fitted with valves. The frames can be connected through, e.g., bolt holes 117, to elongate the frame or bed. The jig concentrator apparatus 100 and the fluid reservoir are all contained within a vessel and the hutch 130 is filled with fluid. The hutch 130 can be a single unit or chambers or be multiple units or chambers. Chamber 160/160is included to collect any material that finds its way below the hutch 130. Integrated into the jig concentrator apparatus 100, there may be a mechanism for separating feed material that has experienced jigging action and rising current action. The jigging bed 110 has holes like those in the art.

[0030] A water pulsion valve 130 can be connected to the flow control valve 120 for controlling a pulsation of water. The water pulsion valve 130 regulates the frequency of the flow of fluid, generally water or media, to create the jigging stroke from a reservoir of pressured fluid generated by a centrifugal, reciprocating or peristaltic positive displacement pump, and regulates the acceleration and decelerations of the fluid that is pumped. This uncontrolled energy appears as pressure spikes and usually leads to damaged seals, gauges, diaphragms, valves and piping joints. To avoid such damage an air reservoir 110 can be included in the piping of the jig concentrator apparatus 100.

[0031] FIG. 2A and FIG. 2B show an exemplary pulsion valve 120 is housed under the water reservoir 110 to control, and if needed, by-pass a portion of the fluid. Water inlet 133 allows water to flow therein, and water exits through exit opening 135. FIG. 2B show half of the valve and its mirror image is opposite to the adjustable housing 152. The pulsion valve 150 may also be referred to as a dynamic, severe flow control valve 120

[0032] As can be seen from FIG. 2A and FIG. 2B, the pulsion valve 150 can have an adjustable housing 152 to allow for controlled by-pass of the fluid and the fluid inlet (not shown) is on the top portion to let water or media therein. In one example the adjustable housing can slide along slide 153. As shown in A(n) propeller 151 is attached to the adjustable housing for generating a disturbance in fluid flow, from (that) the severe disturbance of flow from minimal to full flow a jigging stroke is created within the jig hutch, which causes the particles moves in a jigging motion. The adjustable housing 152 may move in the horizontal direction from the flow of fluid to allow more or less fluid to by-pass the pulsion valve. The pulsion valve 120 can control the flow of water through a flexible hose by clearance with the housing to allow for flows containing solid particulate matter such as slurries. The valve body or housing 152 may be constructed from plastic, metal, wood or other materials depending on the intended use.

[0033] The jig concentrator pulses the water upwards from the lower portion of the hutch 130. The water from beneath creates a vertical pulsation of water or rising current, that is evenly distributed throughout the hutch 130 of the jig concentrator. This type of water motion provides advantages in particle stratification and economics. The water is controlled through the flow control valve 120 and flow in direction of the hutch 130. A jigging stoke maintained by a reservoir of relatively high pressure fluid from that pulsating delivery allows a release of a predetermined volume of fluid. The stroke may be a sinusoidal wave or a skewed sinusoidal wave.

[0034] The fluid reservoirs and pipes under the jigging bed 120. In this arrangement, there is delivery of relatively equal amounts of fluid (water or media) from each outlet on the fluid reservoir. In this arrangement, the widths of jigging concentrators are no longer limited by the projection of a pressure wave such as is created by pulsed air forcing the movement of water. The intermittent and timed delivery of water under pressure into the jig hutch 130 occurs independent of air pulsations or mechanical devices that constrict the volume of fluid inside the jig hutch 130.

[0035] A water inlet 133 attached to the water pulsion 130 valve for input of water in the apparatus 100. The water inlet 133 may fill the apparatus with water at a predetermined pressure. The width of jigging bed 110 may much wider. The water is flowing from inlet.

[0036] FIG. 4 shows a bottom view of the jigging bed 110 of jig concentrator 110 on frame 170, which can have multiple slots 180 associated with delivery pipes 185 for separating the material from the material. The slots 180 keep the original strength of the delivery pipe 185 and provide more uniform distribution of fluid. The slots on the bottom can be used to avoid buildup of particles where the water is dirty or the media is thicker. The slots 180 also separate the heavy particles that may be entrained with the jigging fluid (e.g., media or water).

[0037] Referring to FIG. 4, multiple fluid inlet 170 to conserve the fluid in the apparatus 100. The pulsating action of the fluid may projected without reasonable geometric limitations. The pulsating source may be limited by the volume of the reservoir multiple fluid inlet 170 to conserve the fluid in the apparatus 100. The pulsating action of the fluid may project without reasonable geometric limitations. The pulsating source may be limited by the volume of the reservoir.

[0038] The jigging concentrator may have a 40’ wide jigging bed with an even jigging stroke across the full width. Specifically, the jig of increased effectiveness by reason of the use of more efficient jigging stroke made so by the fluid introduction into the hutch 109/910 with relatively independent control of the amplitude, frequency and acceleration of the stroke.

[0039] A pressured air buffer 110 mounted on the water inlet 104 to buffer and store air in the apparatus 100. The pressured air buffer 110 is essential to act as a buffer and a variable storage medium for the water reservoir apparatus 104. The pressured air buffer 110 will must modulate its capacity during normal work, as water is consumed and replenished in the water reservoir.

[0040] As shown herein and for example FIG. 6, a base fluid (water) delivery system or assembly can be connected to the fluid inlet 170. The base fluid delivery system or assembly is used to fill the water in the fluid inlet 170. The base fluid delivery system or assembly 220 consists two relief valves to control the flow of fluid in the fluid inlet. The base fluid delivery system or assembly 220 is attached with the pump also, for supplying of water in the fluid inlet.

[0041] Referring to FIG.3, a schematic drawing, the jigging concentrator 111 provides an optimal jigging stroke with a pulsating rising current. The ideal jigging stroke is based on the specific gravity. The specific gravity also known as gravity separation. The gravity separation uses density of particles in fluid. Pulsating water with controlled alternating pressure enters in the apparatus, through the water inlet 121 the water enters in the jig. The water that entered in jig is slurry. The slurry may separate the heavy and light particles from the gravity separation. The water rises on the jig bed through a screen called perforated plates that made from a urethane. Material M can be separated.

[0042] Multiple hoppers can be connected to the hutch 130 for collecting any heavy and light particles discharged below the material support device. The hopper is a large, pyramidal shaped container used in processes to hold particulate material that has collected from expelled fluid, discharged through the material support device or discharged by mechanisms installed to separate high density particles from lower density particles. The hoppers are usually installed in groups to allow for a greater collection quantity. The hopper walls are insulated to protect the outside environment and personnel from the discarded contents.

[0043] In operation and use or as schematically shown in FIG 3, water or media to the jig concentrator 111 pulses upwards from beneath the hutch or jigging bed through one or more pipes with holes or slots 121. The water from beneath creates a vertical pulsation of water or rising current, which is releases along the walls of the hutch of the jig concentrator. This type of water motion provides advantages in particle stratification and economics of material M. Water or media can be controlled through a typically flow valve and can flow along the direction of the arrowed line in the hutch or bed. This embodiment can achieve a jigging stoke by maintaining a reservoir of relatively high-pressure fluid, primarily water, from which a pulsating delivery system allows the release of a predetermined volume of fluid or through the use of a pulsating pump. The resulting action on particles located on a jigging bed is the same. The pulsion or pulsation can be created by media, water, or air free fluid.

[0044] FIG. 4 shows a bottom view of the jigging bed 110 of jig concentrator 110 on frame 170, which can have multiple slots 180 associated with delivery pipes 185 for separating the material from the material. The slots 180 keep the original strength of the delivery pipe 185 and provide more uniform distribution of fluid. The slots on the bottom can be used to avoid buildup of particles where the water is dirty or the media is thicker. The slots 180 also separate the heavy particles that may be entrained with the jigging fluid (e.g., media or water).

[0045] Another embodiment includes a method of sizing and separating particles of a generally low-density material, using a jig concentrator comprising a stand, a frame, a jigging bed in the frame on the stand. The jigging bed supports allows the water to flow through the holes in the jig bed to create pulsion and suction stroke motion, a flow control valve 120 associated with the jigging bed to control a flow of fluid, wherein the flow control valve 120 restricts the flow per unit of time to establish the amplitude of the jigging stroke; a water pulsion valve connected to the flow control valve 120 for controlling a pulsation of water and for determining the frequency of the jigging stroke, and a water inlet attached to the water pulsion valve for input of water in the apparatus; and a pressured air buffer mounted on the water inlet to buffer and store air in the apparatus. The steps include actuating a motor for imparting the pulsion and suction motion; and supplying material onto the jigging bed.

[0046] Another embodiment includes a jig that powered by a motion and gears like other jigs on the market and known to those with skill in the art. Methods and systems can include actuating a motor for imparting the pulsion and suction motion; and supplying material onto the jigging bed.

[0047] One embodiment includes a jig that is not a baum Jig in that certain embodiments do not use air to set water into a jigging stroke motion. It such embodiments, certain do not include diaphragms or mechanical levers or plungers to set water into a jigging stroke motion. These embodiments allow a pulsion valve to control the flow of only water to create a jigging stroke motion. In so doing the design can create an even jigging stroke over a width of jigging machine that can result in a wider jigging bed than those of typical baum or mechanical jigs.

[0048] The light and heavy particles are separated by the jig concentrator 100 without consuming long hours. Moreover, the metal is separated from material stream. The effectiveness of the jigging in the bed of liquid can be varied accordingly. The valves and liquid flow so that the forces in the jigging bed 110 are effective.

[0049] As can be seen, the terms "heavier" and "lighter" refer to relatively greater and lesser specific gravity, respectively. Within the separation, absolute weight can be less important than buoyancy in the fluid.

[0050] Although the field of the invention has been described herein with limited reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention.