Abstract:
Abrading and cutting devices such as saws include waste containment systems and methods to improve removal of slurry or other contaminants from a work area during operations, and separation of slurry from a carrying medium such as air. A blade guard includes fluid channels, and may be removable from a blade guard carriage. The carriage may be used to minimize any need to readjust the blade guard position when the blade guard is returned to the carriage for further use. A vacuum bar may be included on the carriage. A vacuum pickup assembly may be used with a blade guard, and the vacuum assembly may include separate and/or different vacuum pickup configurations.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation-in-part of appilcation Ser. No. 09/661,957, filed Sep. 14,2000, now U.S. Pat. No. 6,626,166, issued Sep. 30, 2003, which is a division of Ser. No. 09/399,297, filed Sep. 17, 1999, now U.S. Pat. No. 6,318,351, issued Nov. 20, 2001. 

   BACKGROUND OF THE INVENTIONS 
   1. Field of the Invention 
   The present inventions relate to abrading and cutting devices and methods, and more specifically to waste containment systems and methods for such devices and methods, for example slurry containment systems and methods for saws, cutters and the like. 
   2. Related Art 
   Pavement treatment apparatus and methods are known for concrete and asphalt saws which may include a vacuum apparatus for removing water and particulate matter, commonly referred to as slurry, from a work site. See Bassols, U.S. Pat. No. 5,564,408, entitled Pavement Treatment Method and Apparatus, the specification and drawings of which are incorporated herein by reference. As discussed in that patent, concrete and asphalt saws are typically used to cut joints for expansion and contraction of such materials in freeway pavement, aircraft runways, and other pavement surfaces. Typical saws are marketed under different brand names and include a diamond blade of different diameters according to the thickness of the pavement to be cut, such as 12, 14, 16, or 24-inch blades, etc., driven by an internal combustion engine. The engine is also used to drive a traction mechanism at the rear of the saw for advancing the saw along the pavement. A belt takes power from a pulley driven by the internal combustion engine for powering a transmission box to step down the revolutions per minute (rpm) of the engine to a suitable rate for driving the traction wheels of the saw and for driving the saw blade. 
   The saw blade includes a blade guard for protecting the blade during operation and for preventing injury while the blade is rotating. The blade guard also contains cooling water sprayed onto the blade so that the cooling water drops onto the pavement. 
   The saw also includes a structural support frame for supporting all of the components and for mounting the wheels to the saw. The frame supports the engine, the shaft for driving the saw blade, the traction transmission and the pulleys for powering the traction transmission from the engine, among other elements. 
   In operation, the saw is started and positioned in alignment with the desired cutting path, and lowered into engagement with the pavement while at the same time turning on the coolant spray to the blade. An additional vehicle or other source is located nearby for supplying water for cooling the blade through a suitable hose. As cutting continues, the water and resulting slurry from the abraded pavement is picked up by a suction or vacuum bar to minimize filling previously cut joints. The slurry and any air picked up by the vacuum bar is taken back to a separator tank for removing the slurry. A disposal hose transports waste from the collection tank through a diaphragm pump to a truck or other container for disposal. 
   SUMMARY OF THE INVENTIONS 
   Waste containment systems and methods are described for abrading and cutting apparatus which provide improved removal of slurry and improved operating life of various components in the system. Such systems and methods may be used on saws, such as pavement and concrete saws, other cutting tools, such as wall saws, core drills and other boring equipment, and the like. The systems and methods may be implemented as original equipment or as accessories in kit form or individual components. 
   In one aspect of one of the inventions, a material pickup element is provided for picking up a fluid, which may include solid particles forming a slurry. The pickup element may be a vacuum bar, vacuum shoe or other suction device, for example. Element includes a number of openings comprising at least one and preferably a set of low vacuum apertures and at least one and preferably a second set of high vacuum apertures. In a preferred embodiment, the high vacuum apertures pickup most if not all of the slurry, and the low vacuum apertures focus, collect, concentrate or align the slurry so that it can be more easily picked up by the high vacuum apertures. For example, the low vacuum apertures can center or bring in fluid from both sides of the vacuum element so that an adjacent high vacuum aperture can pickup the slurry. Using both low and high vacuum apertures helps to conserve vacuum pressure, or minimize the loss of vacuum through larger openings, especially where the amount of vacuum available is limited or fixed. Conversely, using both low and high vacuum apertures permits placement of high vacuum areas where they may be most beneficial, and reduction of aperture size at other areas of the pickup element where high vacuum would not have significant incremental value over others already included. 
   In one preferred form of the pickup element, the low vacuum apertures are round or similar holes and the high vacuum apertures are extended slots in the pickup element. The round holes may be grouped in a series, and the round holes may be co-linear with a slot. Other configurations, arrangements and orientations for the openings can be used. 
   In one preferred aspect of one of the inventions, the pickup element is used on a concrete or similar saw which moves along the work surface. The openings are preferably distributed over the pickup element so as to take advantage of the forward or backward motion of the saw. In one preferred embodiment, the high vacuum apertures are placed in front of the low vacuum apertures, which in turn may be followed by one or more additional high vacuum apertures. Alternatively, high and low vacuum apertures may alternate along the pickup element, for example beginning and ending with high vacuum apertures. The pickup element can then bring in fluid from both sides of the element, minimize or limit flow over the work surface and tailor the location or flow of the slurry relative to the pickup element. 
   In a further preferred aspect of one of the inventions, one or more of the apertures or openings may extend along a surface of the pickup element in a direction at least partly perpendicular to the work surface. For example, in a vacuum bar that extends horizontally, most of the apertures can, open downwardly and extend horizontally over a horizontal surface of the vacuum bar and a high vacuum aperture can extend vertically or in a direction other than downwardly. A vertically extending high vacuum aperture can be advantageous directly behind the saw blade. 
   In a further aspect of one of the inventions, a system can be used for designing pickup elements. The system can include a processor or computer loaded with a computational fluid dynamics fluid flow optimizing program to optimize the flow of the slurry and maximize the suction created by the fan. Input parameters include maximum vacuum available, desired fluid flow rates through the pickup element, and the like. The system preferably identifies possible as well as optimum sizes and configurations for pickup elements, and potential and optimum sizes, configurations and distributions of vacuum openings. In one preferred embodiment, the system is used to identify the sizes, shapes and locations of openings to be used for picking up slurry, in addition to the sizes, shapes and locations of openings to be used for focusing, channeling or otherwise controlling flow of the slurry away from the pickup element. 
   In a further aspect of one of the inventions, the pickup element can include removable end caps having curved surfaces for more easily negotiating or riding over pebbles or other objects which may be in the line of travel. Having removable end caps makes for easier cleaning of the pickup element. 
   In another aspect of one of the inventions, a tool guard such as a blade guard includes a water supply conduit or tube for projecting or spraying fluid onto the tool. The fluid may be used as a lubricant and/or coolant for the tool. The fluid is directed toward the tool at an angle different than 90 degrees. For example, the fluid can be directed backward toward an on-coming surface of the tool. Directing the fluid backward relative to the motion of the tool reduces the amount of fluid thrown forward of the tool. Consequently, the amount of fluid to be picked up at the front of the tool is reduced. In one preferred embodiment, the fluid is directed backward about three degrees from a line perpendicular to the tool, such as a blade. 
   In a further aspect of one of the inventions, a separation system and method are provided for separating air and a second fluid. A receptacle is provided for receiving a combination of air and the second fluid, the receptacle including at least two vertically extending walls joining at a vertically extending angle. An inlet receives a combination of air and the second fluid and allows the combination to flow into the receptacle. A first outlet passes the second fluid from the receptacle and a second outlet passes air from the receptacle. This configuration contributes to providing a receptacle which more completely separates the air from the second fluid. This configuration makes the flow and disposition of the second material more controlled or organized, while promoting more uncontrolled or disorganized air flow. This type of receptacle configuration also reduces any tendency toward cyclone-type action in the fluid flow, for the air and for the second fluid. It also reduces the amount of symmetry in the surfaces in the receptacle, and in combination with other features, reduces residual splashing of the second fluid. 
   In another aspect of one of the present inventions, an inlet for a separation system discharges the air and fluid combination closer to the bottom of the receptacle than to the top. With this configuration, the fluid has a shorter distance to travel to the bottom of the receptacle, reducing the amount of splashing and reducing the amount of time the moving air from the inlet is around the moving fluid from the inlet. Additionally, when the outlet for the air is at the top of the receptacle, the air will have more time and area for shedding fluid before leaving the receptacle. Consequently, the air leaving the receptacle has a lower fluid content. Furthermore, where the fluid has abrasive, corrosive or other harmful material, the amount of harmful material leaving the receptacle through the air outlet and reaching other components is reduced. 
   In an additional aspect of one of the present inventions, an air outlet for a receptacle in a separation system is positioned off of a line, axis or plane of symmetry. Positioning of the air outlet in this way removes air that is less controlled or less organized earlier than air in other locations of the receptacle where the air may be more channeled. In one preferred embodiment, the only plane or line of symmetry for the air outlet is one between vertically extending walls of the receptacle. Locating the air outlet on this plane of symmetry reduces the possibility of exiting air pulling with it condensed fluid from either of the walls. 
   In a further aspect of one of the present inventions, an inlet for a separation system discharges an air and fluid combination into a receptacle between two vertically extending walls, and closer to one vertically extending wall than to the other. This asymmetry tends to reduce splashing of the second fluid and contributes to greater control, containment or organization of the second fluid. 
   In one aspect of the present inventions, a tool is provided for working a material, such as cutting concrete, where the tool is driven by a drive element, such as drive shaft. Vacuum is created by a vacuum generator driven by the same drive shaft that drives the tool. Such a design provides for a compact and self-contained combination of tool and waste containment system. The design also makes it easier to assemble the combination as a tool and kit for easy assembly and disassembly. 
   In another example of a tool guard, the tool guard has at least one wall with an edge portion extending adjacent a work piece to be operated on by the tool, and the at least one wall extends away from the edge portion, for example in the general direction in which the tool extends away from the work piece. A second wall portion contacts the at least one wall on the surface of the at least one wall which is on the same side as the tool is located, and extends from the wall in a direction away from the at least one wall, for example toward the tool. The second wall portion may start adjacent the edge portion and extend away from the edge portion, for example at an angle to that part of the edge portion where the second wall portion starts. In another example, the second wall portion may start further away from the edge portion and extend still further from the edge portion. In one example, the second wall portion is configured so the material can travel along the second wall portion in part through gravity and at least partly toward the edge portion. 
   In a further example of a tool guard, the tool guard has at least one relatively flat wall with a relatively straight edge portion extending adjacent a work piece to be operated on by the tool. The at least one wall extends away from the area of the work piece and extends generally adjacent the tool. A second wall portion fixed to the at least one wall includes a flange portion, which extends away from the at least one wall in the direction in which the tool is spaced from the at least one wall. Generally, the second wall portion extends along the at least one wall in a direction other than horizontal during normal operation of the tool. The second wall portion may have more than one segment, wherein one segment extends at an angle relative to the other segment. In one example, the tool is a saw blade and the tool guard is a blade guard wherein the second wall portion is on the same side of the at least one wall as the saw blade and extends away from the at least one wall. With many saw designs, the blade guard floats relative to the saw blade as the saw blade cuts into the work piece, with an edge portion of the at least one wall adjacent the work piece. The second wall portion generally includes a slope that allows material to flow along the second wall portion under the influence of gravity toward the edge portion. If the second wall portion has more than one segment, the segments can be oriented at angles relative to each other. 
   Another example of a tool guard has first and second oppositely facing walls extending on respective sides of a tool, for example a saw blade, and the first oppositely facing wall includes a third wall extending toward the second oppositely facing wall and the second oppositely facing wall includes a fourth wall extending toward the first wall. The first and second walls include respective edge portions adjacent a work surface and each of the third and fourth walls are preferably non-parallel with the edge portions. In one example, the third and fourth walls are positioned opposite each other. In a further example, the third and fourth walls each have first and second segments wherein the first segments are spaced apart from each other and wherein the second segments are joined by a joining wall. In another example, at least one of the third and fourth walls is configured to direct material flow to an outlet, opening or flow conduit, with the help of gravity or other forces. For example, where a fluid such as a liquid is used as the lubricant or coolant for the tool, the third and fourth walls may help flow material toward an outlet or disposal opening. The third and fourth walls, and any joining walls, can serve as water channels or water flow guides. The walls can also serve as baffles, vanes or other flow directors or flow preventers to help transmit fluid to a desired location or to limit flow in a given direction. For example, where the guard is used in conjunction with a vacuum assembly, the walls can be used to direct fluid toward a vacuum port. The walls may also limit the flow of fluid toward a back wall of the blade guard, for example. 
   In another example of a blade guard assembly, the assembly includes a blade guard support on a support surface, and a blade guard is configured to engage the support and be removable from the support. A blade guard support element on the blade guard support can be used to help support the blade guard. A rolling element on the blade guard support, such as a wheel, may be used to make easier the movement of the assembly, and permit the blade guard support to remain on the support surface when the blade guard has been removed. 
   In another example, a blade guard assembly includes a blade guard support and a blade guard, wherein the blade guard includes walls defining an opening for allowing fluid to flow from the blade guard to the support. In one example, the blade guard support includes a complementary opening for receiving the fluid, and where the blade guard support includes vacuum attachment means, vacuum can be used to remove fluid from the blade guard through the opening. One or more fasteners can be used to secure the blade guard to the blade guard support. 
   A tool guard and vacuum assembly has a tool guard extend adjacent the tool, and the vacuum assembly assembled with the tool guard has a plurality of walls defining openings. The vacuum assembly also includes two walls defining respective first and second passage ways communicating with two openings in the vacuum assembly. The first and second passage ways have different shapes. In one example, the passage ways have different cross-sectional areas. In another example, the passage ways follow different paths, and in a further example, the passage ways have different cross-sectional areas and follow different paths. 
   These and other aspects of the present inventions will be better understood after a consideration of the drawings, a brief description of which follows, and the detailed description of the preferred embodiments of the inventions. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a left front isometric view of a cutting device in the form of a saw incorporating a waste containment system in accordance with several aspects of the present inventions. 
       FIG. 2  is a top plan view of the saw of  FIG. 1 . 
       FIG. 3  is a right side elevation view of the saw of  FIG. 1 . 
       FIG. 4  is a left side elevation view of the saw of  FIG. 1 . 
       FIG. 5  is a schematic and flow diagram showing the flow of air and fluids through a waste containment system in accordance with several aspects of the present inventions. 
       FIG. 6  is a lower left front isometric view of a blade guard support in accordance with another aspect of the present inventions. 
       FIG. 7  is a bottom plan view of the blade guard support of  FIG. 6 . 
       FIG. 8  is a left front isometric view of a material pickup element such as a vacuum bar in the accordance with a further aspect of one of the present inventions. 
       FIG. 9  is a bottom plan view of the vacuum bar of  FIG. 8  showing high vacuum and low vacuum openings. 
       FIG. 10  is a left side elevation view of a container and pump for use with the containment system of  FIG. 1 . 
       FIG. 11  is a vertical cross-sectional view of the left side of the container and pump of  FIG. 10  showing an air and slurry input, a waste output and an air output. 
       FIG. 12  is a horizontal cross-sectional view of the top of the container and pump of  FIG. 10  showing the slurry input, the air output and a mounting assembly. 
       FIG. 13  is an upper right isometric view of the container and pump of  FIG. 10 . 
       FIG. 14  is a partial left elevation view of the saw of  FIG. 1  showing a vacuum generator and its drive mechanism. 
       FIG. 15  is a right side isometric view of the vacuum generator and its drive transmission assembly and mounting assembly. 
       FIG. 16  is a right side elevation view of the assemblies of  FIG. 15 . 
       FIG. 17  is a side elevation view and partial cut-away of a blade guard showing water tubes for wetting the saw blade. 
       FIG. 17A  is a detail of a water tube of  FIG. 17 . 
       FIG. 18  is a bottom plan view of a vacuum bar having a further arrangement of openings. 
       FIG. 19  is a bottom plan view of a vacuum bar having another arrangement of openings. 
       FIG. 20  is an upper isometric view of another example of a blade guard and another example of a material pickup assembly. 
       FIG. 21  is a side elevation view of the blade guard and material pickup assembly of  FIG. 20 . 
       FIG. 21A  is a transverse cross-section of the assembly of  FIG. 21  taken along line  21 A— 21 A. 
       FIG. 21B  is a longitudinal vertical cross-section of the assembly of  FIG. 21  taken along line  21 B— 21 B. 
       FIG. 21C  is a detail of  FIG. 21B . 
       FIG. 21D  is an isometric view of  FIG. 21C . 
       FIG. 22  is a side elevation view of the material pickup assembly of  FIG. 20 . 
       FIG. 23  is a lower isometric view of the material pickup element of  FIG. 20 . 
       FIG. 24  is a top plan view of the material pickup element of  FIG. 20 . 
       FIG. 25  is a lower isometric view of a manifold and associated mounting components for use with the material pickup assembly of  FIG. 20 . 
       FIG. 26  is a lower isometric view of the manifold of  FIG. 25 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The following specification taken in conjunction with the drawings sets forth the preferred embodiments of the present inventions in such a manner that any person skilled in the art can make and use the inventions. The embodiments of the inventions disclosed herein are the best modes contemplated by the inventor for carrying out the inventions in a commercial environment, although it should be understood that various modifications can be accomplished within the parameters of the present inventions. 
   In accordance with several aspects of the present inventions, a waste containment system and method are provided for abrading, cutting or coring machines. While the description herein will be directed primarily to cutting machines, and while the preferred embodiments will be described with respect to applications to concrete saws, it should be understood that the inventions can be applied to any number applications other than concrete saws and other cutting machines. The concepts are applicable to other machines in a manner similar to how they would be applied to concrete saws as described herein. For example, the high and low vacuum openings on a material pickup element can be applied to any number applications, while they are especially pertinent to those where the amount of vacuum is limited or fixed. As another example, the separation receptacle can take any number of configurations given the concepts described herein. Moreover, other aspects of the inventions described herein can be used in any number of applications. 
   A waste containment system and method on a concrete saw in accordance with various aspects of the present inventions provide an efficient and reliable apparatus and method for limiting or entirely removing any waste material created or generated while cutting concrete. The system and method removes a substantial amount of water or other coolant produced during the cutting process. The vacuum used to remove the slurry can be easily generated through the engine or other power plant on the saw without noticeably reducing its output. Waste material can be reliably removed from the vacuum system so as to reduce contamination or fouling of components, and to give an acceptable operating lifetime to the components. The system and methods can be implemented as a complete product or as individual components, such as in kit form. All parts can be made removable, and they can be used to retrofit many existing saws. 
   In accordance with one aspect of the present inventions, a concrete saw  300  ( FIG. 1 ) includes a frame or chassis  302  supporting an engine, shown schematically as  304 , for driving a saw blade  306  through a drive shaft  308 . The engine and the drive shaft, as well as other transmission components, also drive and power other components of the saw, as is known to those skilled in the art of concrete saws. The saw and saw blade can also be powered and driven by an electric motor, and all of the components on it can be driven or energized electrically. 
   The saw also includes a material pickup element in the form of a vacuum bar  310  to which is coupled a preferably 2 inch diameter vacuum hose  312  for removing a slurry of water and particulates created during cutting. Water is provided through a conduit (not shown) to the inside of the blade guard  314  to act as a coolant for the blade  306 . The particulates are typically bits of concrete both large and small produced during cutting. Other waste material will be produced using other equipment on different work surfaces, but many of the concepts described herein will be similarly applicable. The blade guard  314  is preferably similar or identical to a blade guard described in U.S. Pat. No. 5,564,408, and is supported by a blade guard mount  316 , shown in  FIG. 1  configured for mounting on a saw such as that manufactured by Cushion Cut. The blade guard includes a top mounted handle  318  for ease of access. 
   The vacuum hose  312  extends as short a distance as possible to a slurry recovery and separation assembly  320  ( FIG. 2 ) for transporting the slurry from the vacuum bar  310  to the assembly  320 . The vacuum hose  312  is preferably raised as little as possible above the level of the vacuum bar  310  so as to use as little vacuum as possible raising the slurry to the level of the assembly  320 . The assembly  320  is preferably located on a side or a surface of the saw  300  different from the right side where the blade is located so as not to obstruct the view that the operator has of the cutting area. 
   Vacuum is created in the assembly  320 , and therefore through the vacuum hose  312  and in the vacuum bar  310 , through a vacuum generator  322  coupled to the assembly  320  through a vacuum hose  324 . The vacuum generator  322  is driven by the drive shaft  308 , as discussed more fully below, and is controlled by the revolutions per minute (rpm) of the drive shaft. Alternatively, where the saw is electrically powered, the vacuum generator could be driven by current from the saw motor. 
   Waste is removed from the assembly  320  through a waste pipe  326  through a pump  328  ( FIG. 12 ) operated by a motor  330 . The pump  328  is similar to that described in U.S. Pat. No. 5,564,408 but includes metal reinforcing on several of the moving parts of the pump. The motor  330  is preferably an electric motor driven by current developed in an alternator or generator on the engine  304 . The pump also preferably includes conventional flap valves to control flow and prevent back flow on each side of the pump. 
   The vacuum bar  310 , modified blade guard  314 , vacuum hose  312 , assembly  320  and the vacuum generator  322  may be factory installed or produced as components for a kit or for retrofit on existing saws. The remaining components of the saw are typical, and do not require enhancements or extraordinary modifications. Some of the other typical components of the saw are illustrated for context such as the display panel  332  and handles  334 . While enhancements can be made to the basic saw to further optimize the operation, for example with larger saw blades, it is not believed that such modifications are necessary for proper operation. 
   The blade guard support  316  ( FIGS. 1 ,  6  and  7 ) is similar to that described in U.S. Pat. No. 5,564,408, and includes a spacer  336  having a width defining the spacing between the left plate  338  and right plate  340 , but also a depth  342  to provide more strength to withstand bending or buckling of the plates  338  and  340 . A mounting holster  344  accepts the support element of the saw for supporting the blade guard. 
   The vacuum bar  310  ( FIGS. 8 and 9 ) for picking up the slurry from around the saw blade and from grooves is similar to the vacuum bar described in U.S. Pat. No. 5,564,408 in the context of concrete saws. The vacuum bar is supported by the blade guard and held stationary relative to the blade guard by a mounting plate  346  through a mounting bolt (not shown). The position of the vacuum bar relative to the blade guard can be adjusted through the mounting bolt for adjusting the spacing between the bottom of the vacuum bar and the work surface. The preferred spacing for effective pickup of slurry from the work surface may depend on a number of factors such as the size of the vacuum bar and the number openings, as well as the vacuum developed at the vacuum bar and the surface makeup. The spacing will also depend on the uniformity of the work surface and how much large debris is created during cutting. For concrete, the spacing may be about 1/16 th  (one-sixteenth) of an inch, and greater for asphalt. 
   The vacuum bar is also supported or stabilized by a left side wall  348  and a U-shaped internal blade guard wall  350 . The left side wall  348  is welded or otherwise mounted to the mounting plate  346  and to the top of the vacuum bar manifold  352 , as well as to the left vacuum tube  354  adjacent an inner side surface  356 . The right side and rear of the wall  350  are mounted to the top surfaces of the right vacuum tube  358  and manifold  352 , respectively. Part of the left side of the wall  350  is welded to the top of the left vacuum tube  354 , and a remainder extends between the right vacuum tube  358  and the left vacuum tube  354  ( FIG. 9 ). Various reinforcing walls can also be included. The vacuum coupling  360  is mounted to the top of the manifold  352  for accepting the vacuum hose  312 . The tail  362  of the vacuum bar extends rearwardly from the center of the manifold  352 . The left side vacuum tube  364  extends at an angle from the left vacuum tube  354  to the left side and toward the front, and the right side vacuum tube  366  extends to the right side from the right vacuum tube  358  and toward the front. The left side vacuum tube  364  joins the left vacuum tube  354  at a point forward of the manifold  352  in order to make room for other hardware on the saw. 
   As shown in  FIGS. 8 and 9 , the vacuum bar  310  defines a housing beginning with the manifold  352  and having a plurality of housing walls such as the top  368  of the manifold, the bottom wall  370  of the manifold, and a front manifold wall  372 . The housing of the vacuum bar also includes a first housing wall  374  defining the right vacuum tube  358  and comprising a top wall  376 , a left side wall  378 , a right side wall  388 , and a bottom wall  382 , and closed off by a preferably removable end cap ( FIG. 8A ). The first housing wall  374  is shown having a square, longitudinally extending configuration or cross-section defining a channel  390  closed by the end cap on one end and joining the manifold at the other end adjacent the forward wall  372 . Other configurations are possible, but a square cross-section is preferred to enhance pickup and transport of the slurry. The other vacuum tubes are also preferably square in cross-section. 
   The bottom wall  382  includes a plurality of opening walls defining a plurality of apertures passing through the bottom wall  382  to permit a pressure differential across the bottom wall between the channel  390  and the outside of the tube  358  when vacuum is applied to the vacuum coupling  360 . The plurality of apertures includes at least one low vacuum aperture  392  and at least one high vacuum aperture  394 . The high vacuum aperture picks up most if not all of the slurry in its region and the low vacuum aperture focuses, collects concentrates or aligns the slurry so that it can be more easily picked up by a high vacuum aperture, typically a different high vacuum aperture. Some pickup may occur with the low vacuum apertures. It is believed that the low vacuum apertures center or bring in fluid from both sides of the vacuum bar so that it can be picked up by a high vacuum aperture following behind. For example, a trailing high vacuum aperture  396  generally aligned with the preceding low vacuum apertures  392  will pickup the slurry gathered by the apertures  392 . The trailing high vacuum aperture  396  is formed in the bottom wall  370  of the manifold. Additionally, though not necessarily, a side high vacuum aperture  398  formed in the bottom surface or wall  400  of the right side vacuum bar  366  may also pickup slurry gathered by the low vacuum apertures  392 . It should be noted that aperture  398  will also pickup water splashed away from the saw blade, which would not typically include any particulates generated during cutting. 
   Using high vacuum and low vacuum apertures helps to conserve vacuum pressure or minimize the loss of vacuum through larger openings, especially where the amount of vacuum available may be limited by the size of the saw, available horsepower, and the like. They are also helpful, for a given size of saw, where larger blades are used in place of smaller blades. With a larger blade, the vacuum bar  310  is longer in overall dimension, preferably extending at least to the front of the blade guard if not further forward. For a given saw, a 30 inch blade would preferably include a vacuum bar  310 A ( FIG. 18 ) that was about 44 or 45 inches long, whereas the suction bar shown in  FIGS. 8 and 9  was designed for a 16 inch blade and is about 27 or 28 inches long. A 26 inch blade would preferably include a vacuum bar  310 B ( FIG. 19 ) that was about 38 or 40 inches long. Additionally, having both low and high vacuum apertures allows positioning of the high vacuum apertures at locations of high slurry and/or water production, and positioning of low vacuum apertures elsewhere where high vacuum is not as important. Nonetheless, the low vacuum apertures still help to collect the slurry to be picked up by a following or trailing high vacuum aperture. 
   In one preferred aspect of the present inventions, the low vacuum apertures are round or similarly shaped holes having walls  402 ,  404  and  406 . The holes are preferably formed straight through the bottom wall  382  of the housing  374  perpendicular to the surface of the housing. However, the configurations of the holes can be different, as well as different from each other, in size, shape, positioning and orientation. For example, the low vacuum holes can be arranged in a series such as those shown in  FIG. 9 , aligned with one another, and also aligned with the end of the high vacuum aperture  394 . The first one or several low vacuum holes, for example, can be the same size while following holes toward the rear of the vacuum bar can be larger in size, and therefore higher in vacuum. Conversely, they can decrease in size in the same direction. Additionally, the apertures can be placed other than in the center of the bottom wall  382 . 
   In another preferred aspect of the present inventions, the high vacuum apertures are extended slots defined by substantially straight walls  408  joined by substantially circular end walls  410 . The high vacuum apertures are also preferably formed straight through the bottom wall  382  of the housing  374  perpendicular to the surface. As with the low vacuum apertures, the high vacuum apertures can be different as well as different from each other in size, shape, position and orientation, and may vary in size from one end to the other of an individual slot. 
   The apertures, such as the high vacuum apertures, can be curved such as the high vacuum apertures  396  in the manifold  352 . They also can have other shapes. The aperture  396  extends almost the entire length of the manifold and curves toward longitudinal center line of the manifold. Additionally, as can be seen in  FIG. 9 , a high vacuum aperture such as  396  can be formed from two or more openings, including  398 . A second high vacuum aperture  412  may be formed from a long slot and two oppositely extending short slots. Additional high vacuum apertures  414  and  416  are preferably formed in the bottom wall  370  of the manifold and the bottom wall of the tail  362  of the vacuum bar, respectively, preferably aligned with the plane of the saw blade to remove slurry not only from the work surface but also the groove just cut. 
   The high vacuum aperture  414  is formed from a slot in the bottom  370  in the manifold and from a slot  418  ( FIG. 8 ) formed in a vertical forward wall  372  of the manifold. As can be seen, a high vacuum aperture can be formed in two different surfaces of the vacuum bar. The slot  418  can be formed as its own high vacuum aperture positioned directly behind saw blade to pickup material thrown up by the saw blade. However, it is believed that a continuous high vacuum aperture formed by the slot  418  and the slot  414  is more effective at picking up slurry immediately behind the saw blade. The slot  418  can be wider than the other high vacuum slots, as can other high vacuum slots immediately behind the blade, or they can be the same width. 
   The first housing wall  374  may also include an additional high vacuum aperture  418  at a forward portion  420  of the first housing  374 . The aperture  418  would be the forward-most aperture on the right side of the vacuum bar to be able to pickup water or slurry from the work surface. In the preferred embodiment, three low vacuum apertures  422  are positioned close behind and aligned with the high vacuum aperture  418 . 
   In the preferred embodiment, the left vacuum bar  354  forms a second housing element  424  in fluid communication with the manifold and the first housing wall  374 , extending forward of the manifold and slightly divergent from the first housing wall  374 . The second housing element  424  also preferably includes a forward high vacuum aperture  426  to be the forward-most high vacuum aperture on the left side of the vacuum bar. It also includes a set or series of low vacuum apertures  428  preferably aligned with and rearward of the high vacuum aperture  426 . An additional high vacuum aperture  430  may be formed between the low vacuum apertures  428  and the manifold  352 . 
   As can be seen in  FIG. 9 , the high vacuum and low vacuum apertures can alternate and can be aligned with respect each other, preferably in the general direction of travel of the vacuum bar. The openings are preferably distributed over the vacuum bar so as to take advantage of the forward or backward motion of the saw. The different openings promote more even flow of the slurry relative to the vacuum bar and conserve vacuum pressure. The high vacuum and low vacuum apertures may alternate between a single large opening and a series of small openings, again followed by a large opening. The actual distribution, configuration and arrangement of the different apertures may be determined by a fluid dynamics computer program based on various input parameters, including available vacuum or suction, viscosity, desired flow rates, and the like. The openings are also given, typically, and the system works iteratively to develop possible solutions. While most of the apertures open downwardly from the bottom of the vacuum bar toward the work surface, at least one aperture  414  includes a portion (slot  418 ) that extends vertically, opening or facing other than downwardly. In one preferred embodiment, the low vacuum apertures are 0.125 in. in diameter (less a few thousandths of an inch for a powder coating on the vacuum bar) and separated from each other by about 0.750 in. They are preferably arranged in series of three. The width of the high vacuum apertures is preferably 0.125 in., and their length may range from less than an inch to several inches, depending on the length of the vacuum bar. The vacuum bar for a 16 in. saw blade can have high vacuum aperture lengths up to four or five inches or more for vacuum developed with a conventional saw with the system described herein. 
     FIG. 8A  shows a bull-nosed end cap  432  for closing off the forward ends of the left and the right vacuum tubes and the rearward end of tube  362 . The bull nose shape includes curved surfaces  434  for more easily negotiating or riding over pebbles or other objects which may be in the line of travel, such as created during cutting. The end caps are removable for easier cleaning of the vacuum bar. 
   The slurry recovery and separation assembly  320  ( FIGS. 10–13 ) separates the air from the water coming from the vacuum hose  312 , and therefore removes abrasive material from the air. Other damaging materials may also be present in the slurry, which are preferably removed from the air. The assembly  320  preferably includes a fluid-tight receptacle, container, canister or tank  436  for receiving a combination of the air and slurry, and including at least two vertically extending walls, such as right side wall  438  and front exit wall  440 . The two walls meet and join at a vertically extending 90 degree angle  442  so that the potential for the air and slurry within the tank  436  to rotate or create a cyclone-type motion is reduced. The left side wall  444 , similar in shape to the right side wall  438 , also extends vertically and joins the front exit wall  440  at a vertically extending angle  446 . Both of the left and right side walls meet and join a back inlet wall  448  at respective vertically extending angles or corners  450  and  452 , respectively. The tank  436  is closed by a top or cover  454  which joins the respective side walls at 90 degree angles at a support flange  456  extending around the perimeter of the tank. It is removable for easy cleaning of the tank. The tank  436  preferably does not have a flat, horizontal bottom, to reduce splashing. The remaining walls between the left and right side walls are generally square or rectangular, join the respective side walls at 90 degree angles, preferably, but are arranged more or less horizontally or vertically as a function of location relative to an inlet or an outlet. 
   The back inlet wall  448  extends vertically a substantial portion of the height of the tank  436 . The bottom joins a first shelf plate  458  at an angle  460  of approximately 100 degrees for allowing liquid to flow down the first shelf plate  458 . The first shelf plate  458  slopes to a lower shelf plate  462 . The first shelf plate  458  and the lower shelf plate  462  join at an angle  464  of approximately 200 degrees to minimize upward splashing of slurry, and to move slurry down to the bottom of the lower shelf plate  462  where it collects. The lower shelf plate  462  ends at and is supported by a pump support plate  464  and joins a slurry outlet plate  466  at an angle  468  of approximately 30 degrees, a small acute angle. This angle is relatively small so as to effectively retain the slurry in the relatively narrow bottom until it is pumped out by the pump  328  through a slurry outlet  470  located close to and connected to the pump by a short tube of about several inches. The slurry outlet plate  466  extends upwardly and rearwardly to approximately the same level as angle  464 , where it joins a riser plate  472  at an angle  474  of approximately 223 degrees. The angle  474  is preferably greater than 180 degrees so as to increase the volume of the mid-level portion of the tank, or that portion of the volume of the tank between angle  474  and the top of the riser plate  472  and the back inlet wall  448 , while still presenting a splash plate or wall tending to keep the slurry and any excess water between plates  462  and  466 . The riser plate  472  is preferably at about a 15 degree angle from the vertical to provide a vertically extending wall for minimizing splashing while still providing an increasing volume in the upward direction and interrupting any direct line of air flow from the inlet to the air outlet. The riser plate  472  extends away from the back inlet wall  448  to allow air to travel more easily upward and away from the slurry. 
   The riser plate  472  joins an upper shelf plate  476  at an angle  478  of approximately 249 degrees. The upper shelf plate  476  extends forward to vertical front exit wall  440  where they join at an angle  480 . The upper shelf plate  476  provides the base portion of the upper approximate one-third of the tank, measured vertically. The upper third of the tank preferably contains almost all air and very little moisture or slurry. The intermediate approximate one-third of the tank, measured vertically, will have a substantial portion of air and some water or slurry. The lower one-third, measured vertically, preferably has almost exclusively slurry. The depth of the slurry is preferably about 3 to  3½ inches.    
   The tank includes an inlet  482  for receiving a combination of air and slurry from the vacuum hose  312  and allowing the combination of air and slurry to flow into the tank. The inlet passes through the back inlet wall  448 . The inlet  482  is preferably a relatively rigid tube or pipe  484  and extends a substantial distance from the wall  448  toward the riser plate  472  to a 90 degree elbow  486 . The elbow  486  terminates in a wall  488  defining an opening  490  preferably facing directly downward toward lower shelf plate  462  for allowing the slurry to drop straight down. The opening  490  is preferably positioned below the upper shelf plate  476  so that there is no direct line of air flow between the opening  490  and the air outlet. The opening  490  as well as the rest of the inlet  482  are preferably two inches in diameter and may pass an approximately 3:1 ratio of air to slurry by cross-sectional area at about 200 cubic feet per minute. The opening  490  is positioned significantly below the upper shelf plate  476  so that the water and slurry are input well below the upper third of the tank. The inlet  482  is preferably centered between the left and right side walls. Additionally, the slurry is preferably input closer to the riser plate  472  than to the inlet plate  448  so that the slurry travels as little as possible before reaching the bottom of the tank and the slurry outlet  470 . The opening  490  is preferably high enough above the slurry level that vacuum is still created in the vacuum line  312  without creating turbulence on the surface of the slurry at the bottom of the tank, while at the same time minimizing the height that the slurry must be raised from the suction bar to the inlet  482 . 
   A second, air outlet  492  removes air from the tank  436  thereby creating a vacuum within the tank, which creates a vacuum within the vacuum hose  312  for producing suction in the suction bar  310 . The air outlet  492  is preferably centered between the side walls and located close to the air outlet wall  440  and a significant distance from the slurry in the bottom of the tank. The air outlet is not located on any line or plane of symmetry other than between the two side walls thereby reducing the possibility that air being removed from the tank is part of a channel of air flow. The air travels a significant distance through the tank to reach the outlet, and does not have a direct line of travel between the opening  490  and the outlet  492 . The outlet  492  includes a wall  494  for defining an opening  496  which is preferably flush with the top  454  of the tank. 
   The separation tank promotes organized control of the slurry and disorganized or uncontrolled flow of air within the tank. The irregular surfaces and discontinuous walls in the tank reduces cyclone-type fluid flow within the tank which would tend to keep moisture and particulates carried in the air. The inlet is placed close to the slurry or other material outlet and close to a wall to help contain the material flow. Residual splashing is minimized as much as possible by interrupting any straight or parabolic air path and any air flow channels, and reducing symmetries of surfaces within the tank, while encouraging a gentle gradient of air flow from the area of the inlet portion of the tank to the outlet portion of the tank. Additionally, it is preferred to minimize the amount of directional change of the air and slurry coming out of the opening  490 . It is also preferred to place the inlet opening far enough away from any given surface to minimize funneling or channeling of air upward past the opening  490 . One measure of one preferred inlet position is to have a relatively large change in cross-sectional area going from the opening  490  into the open tank and reducing the velocity of the air and slurry mixtures. Additionally, a large total volume for the tank is preferred. 
   Some exemplary approximate dimensions for the separation tank have the width equal to about 9 and ½ in. and the overall length about 27 inches. The inlet wall is about 12 inches high and height from the pump support plate  464  to the top of the tank is about 18 inches. The plate  440  is about five inches high, the plate  476  about 13 inches long and the plate  472  about eight inches long. The plate  466  is about four inches long and the plate  462  about eight inches long. The plate  458  is about seven inches long. The length of the inlet  482  from the center of the opening  490  to the outer most point of the pipe outside the tank is about 13 and ½ inches. These dimensions give a tank having a low height, large volume and a relatively large transition from the inlet pipe to the tank. 
   A level indicator or overflow alarm (not shown) can be included to indicate when the level of slurry reaches a selected level. Other indicators and safety features can be included as desired to make easier becoming familiar with a machine and for using the machine. 
   Power to the pump  328  is provided by a sealed conductor  498  extending from a fast hook-up and disconnect junction and switch box  500 , mounted at the inlet panel.  448 , to the pump  328 . The conductor extends through a sealed opening in the panel  466 . A shut-off switch  502  can be used to start or stop the pump. 
   A mounting plate  504  ( FIGS. 13 and 14 ) can be fastened to the side of the saw so that the separation tank and pump assembly can be removably mounted to the saw through hooks or other brackets  506 . The plate and hooks are preferably configured to insure that the separation tank and pump assembly maintain a center of gravity for the tank. 
   The vacuum generator  322  includes a housing  508  ( FIG. 1 ) for containing an impeller or fan  510  ( FIGS. 15–17 ) for creating a vacuum in the tank. The fan may be a Breuer Electric Mfg. Tornado with a number 12692 impeller capable of generating at least 180 to 184 cubic feet per minute of flow, or more, at 16,500 rpm through a two inch diameter orifice. The fan is preferably rated for fifty-one inches of static water lift. The fan chamber part number 12642 and the fan chamber plate part number 11237 are also included. The fan is driven off of the saw blade drive shaft  308  through a pulley  512  which drives a second pulley  514 , which in turn drives the shaft  516  of the fan. The fan exhaust  518  is directed into the housing  508  for cooling the high speed bearings and/or components of the saw. 
   The fan and two idlers (one for each drive belt, not shown) are each supported by two high speed, long life and lifetime lubricated bearings mounted, supported and protected on the saw frame by suitable supports. The bearings are preferably rated for at least the 16,500 rpm operating conditions, and preferably higher. The preferred bearings are SKF Mfg. number 6202-2Z/C3HT bearings rated for 29,000 rpm. 
   The tool guard such as the blade guard  314  includes a water supply conduit or tube  520  for projecting or spraying fluid onto the saw blade ( FIG. 17 ). The water is directed toward the tool at an angle different than 90 degrees. For example, the water can be directed backward toward the rotationally-advancing side of the blade. Directing the water backward relative to the rotation of the blade reduces the amount of water thrown forward of the blade. Consequently, the amount of water to be picked up at the front of the blade is reduced. In one preferred embodiment, the water is directed backward at an angle  522  of about three degrees from a line  524  perpendicular to the blade. 
   By including a vacuum generator on the saw driven by the saw engine or other power supply, the components of the saw can still be part of a self-contained unit. The vacuum generator can operate and produce the desired vacuum under a number of different conditions, such as different saw blade sizes, cutting speeds and the like. The vacuum generator can also be easily mounted on and removed from the saw along with the other slurry containment components. The separation tank, the suction bar, the pump assembly, blade guard and vacuum hose can be easily installed on existing saws and removed if desired. The components can be made available in kit form or installed at the factory. 
   The waste containment and separation system can be used in other applications beyond concrete saws. Wall saws, grinding heads and core drills also produce particulates that can be contained through application of one or more of the concepts described herein. For example, using high and low vacuum apertures in a pickup element conserves vacuum pressure and permits a selective arrangement of high vacuum pickup locations. Vacuum generators can also be driven off of the drive elements of the tools, if desired. Additionally, the concepts developed for separating air from a slurry for maintaining the integrity of the vacuum generator can be applied, to other applications. The amount of feedback of damaging particulates or other contaminants can be reduced, thereby extending the life of many components. Filters may not be necessary, as they reduce the vacuum and produce drag. 
   An example of a tool guard and material pickup assembly  600  ( FIGS. 20–21 ) includes a tool guard  602 , which in the present example is a blade guard for a saw blade, such as that used in concrete saws, flat saws and other cutting or processing equipment. The assembly also includes a material pickup assembly  604 . The material pickup assembly  604  in the present example serves not only to pickup material produced during the cutting operation, but also to support the blade guard  602 . 
   The blade guard extends partly about the saw blade  606  as the saw blade cuts concrete or other work material. The blade guard  602  defines a volume within which the saw blade operates as the saw blade cuts into the concrete. The blade guard includes at least a first wall  608  and a second wall  610  ( FIG. 21 ) extending on opposite sides of the saw blade and having respective inside surfaces  612  and  614  facing each other and extending on respective sides of the saw blade. The first wall  608 , and preferably the second wall  610 , include respective edge portions  616  to substantially defining the lower-most portions of the blade guard, and which are adjacent but spaced apart from the concrete during operation. The blade guard also preferably includes one or more transverse extending rim or spacer walls  618  spanning and separating the first and second walls  608  and  610 , respectively, and for completing the enclosure defined by the blade guard. The blade guard may include a handle  620  for lifting the blade guard from the material pickup assembly  604 . The blade guard has one or more fluid supply tubes  622 , for supplying fluid such as water to lubricate and cool the saw blade. The tubes  622  receive fluid through appropriate supply lines, as would be known to those skilled in the art. The saw blade is driven by the saw in a manner similar to that described previously, and the assembly  600  moves with the saw in a similar manner, as known to those skilled in the art. 
   Considering the blade guard in this example in more detail with respect to  FIG. 21 , the inside surface of the first wall  608  includes at least one second wall, such as the water channel  624 , contacting the inside surface of the first wall  608  and extending laterally from the inside surface in the same direction that the saw blade is spaced from the first wall, and extending longitudinally in a direction away from the edge portion  616 . In the example shown in  FIG. 21 , the work surface is relatively horizontal and the first wall  608  extends substantially vertically upward from the edge portion  616 , and the second wall portion slopes downwardly from a point  626  closer to the saw blade to a point  628  further away from the saw blade. The second wall portion in the example shown in  FIG. 21  is fixed, bonded, riveted and/or welded to the inside surface of the first wall  608  and includes a rectangular flange portion extending to the interior of the blade guard from the inside surface of the first wall  608 . The rectangular flange portion promotes water flow, with the assistance of gravity, downwardly and closer to the lower edge  616 , and preferably it channels the fluid to a second water channel  630  having a steeper slope than the first water channel  624 . The rectangular flange portion of the first water channel  624  also limits fluid flow along the inside surface of the first wall  608  and channels that fluid to the second water channel  630 . In the example shown in  FIG. 21 , the water channel  624  is L-shaped and has the vertical leg mounted to the first wall and the second leg extending into the interior of the blade guard. It is positioned at an approximate vertical midpoint in the blade guard. The second water channel extends from the second point  628  to a point  632  adjacent the lower edge  616 , where the second water channel terminates at a line spaced apart from the adjacent vertical wall  634  to form an opening  636  feeding into the material pickup assembly, as described more fully below. 
   In the example shown in  FIG. 21 , the first water channel  624  joins near the point  628  with a preferably mirror image water channel  638  contacting and fixed to the second wall  610 , preferably having the same shape, size and slope as the first water channel  624 , joining the first water channel through a joining wall  640 . The joining wall  640  preferably begins approximately 1 in. outboard of the perimeter of the saw blade and extends to the outer point  628 . The first and second water channels are preferably joined to or continuous between each other at the point  628 , and the second water channel preferably spans the space between the first and second walls  608  and  610 , respectively. The first and second water channels also reduce the spray of fluid and material upward and toward the walls  618 , and thereby channel the fluid downward. 
   A third water channel  642  has a smaller slope than the first channel  624  and extends from a point adjacent the opening  636  slightly upwardly and in the direction of the blade to a point  644 . The third water channel shown has a U-shaped cross section (as seen in  FIGS. 21C &amp; 21D ) and also channels fluid to the opening  636  and reduces the amount of fluid reaching the lower edge  616 . The first, second and third water channels are positioned on that part of the blade guard which receives the spray of material and fluid from the saw blade. The blade guard and material pickup are reversible to accommodate a down cut saw and an up cut saw. The opening  645  in the first side of the blade guard permits viewing of the blade when positioned on the outside of the saw and accommodates the blade shaft when positioned adjacent the saw. A substantially similar opening is formed in the second side  610 . The structure on the first side of the blade guard is preferably symmetrical with that on the opposite side. The water channels can take any number of shapes, sizes and configurations. 
   A fourth water channel  646 , and a mirror image water channel on the opposite side of the blade, channel water to a fifth water channel  648  extending downwardly and away from the blade to an opening  650 , which receives fluid for transfer to the material pickup assembly. A sixth water channel  652  has a greater slope than water channel  642 , as it is closer to the blade. The sixth water channel  652  also channels fluid to the opening  650 . The water channels have similar structures and functions. The blade guard also preferably includes deflector plates  654 ,  656  and  658  having a structure and function similar to that of the diagonal plate in Bassols, U.S. Pat. No. 5,564,408. 
   The example of  FIGS. 20 and 21  also includes a blade guard support, which in this example also serves as the vacuum assembly  604 . The blade guard support includes at least one and preferably three rolling elements, casters or wheels  660  for supporting the blade guard support on the work surface. The wheels are adjustable vertically to adjust the relative spacing of the blade guard support, and in the present example the vacuum assembly, from the work surface. The wheels  660  support the blade guard support at the desired spacing from the work surface even when the blade guard is removed and then replaced. Re-adjustment of the blade guard upon replacement is not necessary. The blade guard support includes one or more walls  662  extending upward from the area where the lower edges  616  of the blade guard rest. The walls  662  help to support the blade guard. Mounting plates  664  include slots  666  for receiving fasteners, bolts  668  or other means ( FIG. 21 ) for fixing the blade guard to the blade guard support. The blade guard fits within the enclosure defined by walls  662  and mounting plates  664 . 
   In the present example shown in  FIGS. 20 and 21 , the assembly includes a material pickup assembly in the form of a vacuum assembly  604  having, in this example, first and second vacuum ports  670  and  672  at the two ends of the assembly coupled to vacuum manifolds  674  and  676 , respectively. First and second vacuum tubes  678  and  680 , respectively, extend almost the entire length of the vacuum assembly, and the ends of the vacuum tubes extend over and engage respective vacuum ports  682  on the manifolds ( FIG. 26 ). Each vacuum tube is preferably a square aluminum tube having a three quarter inch internal dimension, and a plurality of vacuum holes  684  extend through the bottom walls of the tubes. Each vacuum tube includes a closure at approximately the center point thereof so the fluid does not flow from one half of the tube to the other half. The vacuum assembly also includes an aluminum wear plate  686  forming the bottom surface of the vacuum bar and having a plurality of vacuum holes  688  coaxial with and having the same diameter as the vacuum holes  684 . 
   Each manifold  674  and  676  preferably includes a substantially identical aluminum manifold plate  690  ( FIGS. 25 &amp; 26 ). Each manifold plate is covered on the bottom by the wear plate  686 . The three transverse vacuum ports  692  open into a transverse channel  694 . The channel  694  flows into a longitudinal channel  696  and out through a first opening through a coupling plate  698  which flows into the vacuum port  670 . The first opening is preferably curved and is formed by walls which are preferably smooth and continuous, so as to minimize flow eddies and accumulation of debris. 
   Each vacuum tube is coupled to its port  682 , which flows into respective second and third channels  700  and  702 , which are preferably substantially identical to each other. Each channel extends away from the respective tube and inward toward the center of the manifold, and then flows upwardly through the coupling plate  698  and into the vacuum port  670 . The flow from the channels combine in the coupling plate  698 . 
   The material flow from the water channels inside the blade guard flow downward to the wear plate and through an opening in the mounting plate  664  and through a fourth opening  704  in the manifold. The fourth opening flows into a fourth channel in the manifold. The fourth channel extends outwardly away from the blade and upwardly toward the coupling plate  698 , after which the flow joins the material flow from the other channels in the vacuum port  670 . 
   Having thus described several exemplary implementations of the invention, it will be apparent that various alterations and modifications can be made without departing from the inventions or the concepts discussed herein. Such operations and modifications, though not expressly described above, are nonetheless intended and implied to be within the spirit and scope of the inventions. Accordingly, the foregoing description is intended to be illustrative only.