Abstract:
A pregrouted base plate and the method of its use and construction with rotating machinery such as pump and electric motor assemblies that are coupled together by a pair of shafts and require precise alignment of those shafts for a long and dependable service life is disclosed. The pregrouted base plate is formed as a generally rectangular parallelepiped structure with one side open. The novel method of its use includes pregrouting the baseplate before installation, curing the grout and machining the mounting surfaces for the rotating machinery before field installation to ensure precise alignment of the pump and motor shafts. A second embodiment is shown with an open frame having two sides open.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a pregrouted baseplate for supporting rotating machinery commonly used in industrial processing and the method of its use and manufacture. This rotating machinery usually takes the form of pumps, commonly referred to as driven equipment, that is powered by electric motors or steam turbines, commonly referred to as drivers. 
     Typically, industrial processing plants use large quantities of pumps for moving materials, usually in a liquid or gaseous form, through the processing procedures. These pumps are powered by electric motors or steam turbines as noted above that are mounted adjacent to the pump and coupled thereto by drive couplings. These drive couplings allow for a small amount of misalignment between the output or driving shaft of the drivers, i.e., electric motor or steam turbine, and the input or driven shaft of the driven equipment. Precise alignment between these shafts is critical for the pump and motor assemblies to have a reasonable service life. A critical aspect of maintaining this precise alignment is that the pump and motor are mounted to a mounting base or baseplate as they are commonly referred to in the industry. 
     These baseplates have mounting pads or surfaces that are precisely machined to help ensure proper alignment between the pump and motor shafts discussed above. The mounting surfaces include threaded holes machined to accept mounting bolts that secure the pump and electric motor to the baseplate. The baseplates are then prepared for installation on a foundation in the plant. It is this preparation process that causes problems with the baseplates. 
     The aforementioned baseplates typically have been a substantially rectangular parallelepiped configuration with one of the large sides missing to form an open box. The interior of this box forms a large cavity that has been the bottom side of the baseplate with the mounting surfaces previously described formed on the top side. In order to add stiffness to the baseplate and reduce vibration from the pump and motor operation, the cavity on the bottom of the baseplate was filled with a grout material such as epoxy or a cementitious material. The baseplate was then installed on a foundation in the plant and the motor and pump reattached. The problem with such a procedure is that the baseplate thus formed was distorted by the shrinkage of the grout material and the aforementioned precisely machined mounting surfaces were often out of tolerance. This resulted in increased vibration of the pump and motor assembly during operation and a shortened service life. The typical solution to date has been to try to remachine the mounting surfaces of the baseplate after the baseplate is installed on the foundation. This has produced less than desirable results as the machines used in the field cannot produce the desired tolerances and the cost of transporting and setting up these machines is prohibitive. 
     Therefore, there exists a need for a baseplate and the method of its use that will allow the use of epoxy or cementitious grouts while maintaining the required tolerances for the pump and motor mounting surfaces after installation. It is the construction and method of use of such a baseplate to which the present invention is directed. 
     2. Description of Related Art 
     U.S. Pat. No. 2,916,233 to M. F. Ecker discloses a pump base that is grouted in place. 
     A machinery base pad for vibrating machinery is disclosed in U.S. Pat. No. 5,149,050 to D. Smith et al. A plurality of channels and drains are provided to minimize environmental pollution from the lubricants vibrated out of the machine. 
     U. S. Pat. No. 5,277,395 to D. Smith et al. is a continuation of U.S. Pat. No. 5,149,050 and describes a machinery base pad with a plurality of I beams and tie down fastener subassemblies with a cementitious filler. 
     SUMMARY OF THE INVENTION 
     The pregrouted base plate of the present invention and the method of its use and construction is designed for use with rotating machinery such as pump and electric motor assemblies that are coupled together by a pair of shafts and require precise alignment of those shafts for a long and dependable service life. The pregrouted base plate is formed as a generally rectangular parallelepiped structure of suitably thick steel with one side open. The closed or top side of the pregrouted baseplate has a plurality of machined surfaces to which the pump and motor assemble will be bolted. This top surface may have a plurality of vent and grout holes formed therein also. The bottom or open side of the baseplate forms a large cavity into which the grouting material will be poured. This cavity may also have a number of stiffening members or ribs welded in place to minimize distortion of the baseplate. In a typical application of the novel method, the baseplate has the pump and motor assembly removed therefrom and the baseplate is inverted, i.e., the lower cavity is facing upward. If the baseplate has any vent or grout holes as mentioned previously, these are closed off. The surface of the baseplate that will be in contact with the grout material is prepared and cleaned by suitable means as sanding, sandblasting or solvent cleaning to ensure proper adhesion with the grout material. The grout material, either epoxy or cementitious, is prepared and poured into the cavity. The grout material is then allowed to cure. In the case of cementitious grout,. this can be up to five days. If epoxy grout is used and it is desired to accelerate the curing process, the baseplate with grout in place is postcured by maintaining an elevated temperature for a specified time period according to the grout manufacturer&#39;s instructions. 
     After the grouting material is completely cured, the baseplate is then placed on a table such as that of a horizontal boring mill and secured thereto. The mounting surfaces of the top of the baseplate are then checked for specified tolerances for levelness and flatness. The horizontal boring mill is then used to machine the mounting surfaces as required to bring the mounting surfaces into tolerance. Thus, a pregrouted baseplate is formed with the required grout material in position, properly cured and the mounting surfaces for the pump and motor assembly machined within tolerance. The pregrouted baseplate can then be installed on a foundation in the conventional manner. 
     One object of the present invention is to provide a method for producing a pregrouted baseplate that ensures the mounting surfaces for the pump and motor assembly are within tolerance after the grouting material is installed and cured. 
     Another object of the present invention is to provide a baseplate with a grouting material previously installed that is distortion free. 
     A further object of the present invention is to produce a baseplate free of air pockets or voids in the grout material. 
     Other objects and advantages of the present invention are pointed out in the claims annexed hereto and form a part of this disclosure. A full and complete understanding of the invention may be had by reference to the accompanying drawings and description of the preferred embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects and advantages of the present invention are set forth below and futher made clear by reference to the drawings, wherein: 
     FIG. 1 is an elevation view of a typical pump and motor assembly mounted on a pregrouted baseplate that is attached to a foundation. 
     FIG. 2 as a perspective view of a baseplate with the pump and motor assembly removed. 
     FIG. 3 is a perspective view of a baseplate showing the first step in producing the pregrouted,baseplate. 
     FIG. 4 perspective view of the pregrouted baseplate showing the grouting material in place and curing. 
     FlG.  5 . is a perspective view showing the pregrouted baseplate in place on a machining center and the mounting surfaces being machined to bring them into tolerance. 
     FIG.  6 . is a perspective view showing the pregrouted baseplate completed with the pump and motor assembly attached and ready for field installation. 
     FIG. 7 is a perspective view of an alternate embodiment of a pregrouted baseplate with the pump and motor assembly removed. 
     FIG. 8 is a perspective view of an alternate embodiment of a pregrouted baseplate showing the grouting material in place and curing. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to the drawings, and particularly to FIG. 1, an elevational view of a typical pump and motor assembly mounted on a baseplate that is attached to a foundation is shown. The pregrouted baseplate of the present invention is denoted generally by numeral  10 . Pregrouted baseplate  10  has rotating machinery such as typical pump and motor assembly  12  mounted thereon. Pump and motor assembly  12  includes electric motor  14  connected to pump  16  by coupling shaft  18 . Pregrouted baseplate  10  is secured to foundation or concrete slab  20  by suitable securing means such as anchor bolts  22  and nuts  24  cooperating with jack screws  25  in a manner to be described hereinafter. Foundation  20  is positioned on ground  26  at a suitable location within the customer&#39;s plant. Grouting material  28  is seen on the underside of pregrouted baseplate  10 . 
     Grouting material  28  may be inorganic, i.e., cementitious or organic, i.e., epoxy or a combination of both. Typically one or the other is used for a particular job. The novel method of creating pregrouted baseplate  10  will now be shown. As best seen in FIGS. 2 and 3, pregrouted baseplate  10  consists of frame  30  of a generally rectangular parallelepiped configuration. A plurality of mounting surfaces or pads  32  are shown on the top side of pregrouted baseplate  10 . Mounting surfaces  32  are adapted to receive rotating machinery such as pump and motor assembly  12  (not shown) with drilled and tapped holes  34  receiving bolts to secure pump and motor assembly  12  thereto. Frame  30  is shown to be of fabricated welded steel construction although other suitable materials such as fiberglass or high strength plastic could be used without departing from the scope of the current invention. Frame  30  also includes grout fill holes  35  and vent holes  36  for reasons to be discussed hereinafter. 
     Frame  30  also includes anchor bolt holes  37  and jack screw holes  38  positioned at each corner. These are used in leveling and securing pregrouted baseplate  10  to foundation  20 . Anchor bolts  22  are positioned in foundation  20  when it is poured to align with anchor bolt holes  37 . When it is desired to secure pregrouted baseplate  10  to foundation  20 , pregrouted baseplate  10  is placed over foundation  20  as shown in FIG.  1 . Anchor bolts  22  pass through anchor bolt holes  37  and then jack screws  25  are threaded through jack screw holes  38  until they contact foundation  20 . Jack screws  25  are then used to level pregrouted baseplate  10 . Once pregrouted baseplate  10  is leveled nuts  24  are tightened on anchor bolts  22 to secure pregrouted baseplate  10  and prevent any vertical movement. Wooden form  23  well known to those of ordinary skill in the art, is placed around foundation  20 . Low viscosity epoxy grout  21  is then poured into the space between pregrouted baseplate  10  and foundation  20 . Jack screws  25  will have been previously coated with a suitable material, such an grease, to ensure jack screws  25  do not stick to epoxy grout  21 . After epoxy grout  21  is cured, jack screws  25  are removed and pregrouted baseplate  10  is bonded to foundation  20 . 
     FIG. 3 is a perspective view of frame  30  in an inverted position showing the first step in producing pregrouted baseplate  10 . Frame  30  is open on the back or bottom side to form cavity  39  into which a grouting material will be poured. Support members or ribs  40  are welded into cavity  39  to aid in stiffening and supporting frame  30 . At this first step, frame  30  is supported on suitable supports  42  and inspected for levelness, and overall dimensional tolerances. After the dimensional tolerances are checked frame  30  is ready to be pregrouted. 
     As shown in FIG. 4, grouting material  44  has been prepared and poured into cavity  39  of frame  30 . Grouting material  44  is poured until it is approximately level with the top of frame  38  and the excess is then “screened” off as is done in cement finishing and well known to those of ordinary skill in the art. Vent holes  36  and grout holes  35  are covered as noted above to prevent grouting material  44  from escaping. Frame  30  is typical of the frames used today and vent holes  36  are usually provided because the frames  30  are typically grouted in the field with frame  30  in the position of FIG.  2 . Applicant&#39;s novel method does not require vent holes  36  as any entrapped air from the curing grouting material  44  is vented on the open side of frame  30 . Vent holes  36  and grout holes  35  are shown solely for the purpose of demonstrating that applicant&#39;s method is equally suitable for use with or without vent holes. Grouting material  44  may be an epoxy or cementitious composition as required. 
     If it is desired to accelerate the curing process and reduce the curing time, frame  30  with grouting material  44  in place, is maintained at an elevated temperature for a period of time as per the grouting material manufacturer&#39;s instructions. The elevated temperature at which the post curing will take place depends on the ambient conditions. If the ambient temperature is above 60° F., the elevated temperature typically will be 10° to 20° above the ambient temperature. When the ambient temperature is below 60° F., the elevated temperature will typically be in the range of 80° to 100° F. This step is important in applicant&#39;s novel method as it allows a faster, i.e. shorter, production time for pregrouted baseplate  10 . 
     The next step in applicant&#39;s novel method of producing a pregrouted baseplate is shown in FIG.  5 . After a complete curing of grouting material  44  is achieved, pregrouted baseplate  10  is mounted in a suitable fixture  46  on a suitable machining center such as horizontal boring mill  48 . Mounting surfaces  32  are then checked for dimensional tolerances such as flatness and parallelness. If required, cutting head  50  can then be used to “true” mounting surfaces  32  by machining the surfaces as required. The reason this is required is the stresses imposed by the shrinking of grouting material  44  during curing can cause frame  30  of pregrouted baseplate  10  to distort and move mounting surfaces  32  out of flatness. It is this checking and truing of mounting surfaces  32  after the grouting of cavity  39  that is essential to applicant&#39;s invention. 
     The final step in producing pregrouted baseplate  10  is shown in FIG.  6 . Pregrouted baseplate  10  is returned to its normal upright position and: pump and motor assembly  12  is reattached to mounting surfaces  32 . Thus a pregrouted baseplate is produced with the grout in place and cured and the mounting surfaces of the baseplate “trued” after the grouting material is in place. This ensures that pregrouted baseplate  10  will not require additional machining after installation and that pump and motor assembly  12  are precisely aligned. 
     An alternate embodiment of the present invention in shown in FIGS. 7 and 8 that allows the use of an open frame. Pregrouted baseplate  100  consists of outer frame  102  of a generally rectangular configuration that is open on the top and bottom to form an open cavity therein. Outer frame  102  is shown constructed of channel  104  welded together to form outer frame  102 . Although shown constructed of channel  104 , it will understood by those of ordinary skill in the art other suitable structural shapes such as I beam or wide flange beam could be used in the construction of outer frame without departing from the scope of the present invention. Support members or ribs  106  are welded into place to further stiffen and strengthen outer frame  102 . 
     A plurality of mounting surfaces or pads  108  are shown on the top side of pregrouted baseplate  100 . Mounting surfaces  108  are adapted to receive rotating machinery such as pump and motor assembly  110  (not shown) with drilled and tapped holes  112  receiving bolts to secure pump and motor assembly  110  thereto. Outer frame  102  is shown to be of fabricated welded steel construction although other suitable materials such as fiberglass or high strength plastic could be used without departing from the scope of the current invention. Outer frame  102  also includes anchor bolt holes  114  and jack screw holes  116  positioned along each side of outer frame  102 . Anchor bolt holes  114  and jack screw holes  116  function to level and secure pregrouted baseplate  100  to foundation  20  as in the first embodiment. As best seen in FIG. 8, when it is desired to pregrout pregrouted baseplate  100 , outer frame  102  is supported on suitable supports  118  and inspected for levelness, and overall dimensional tolerances. After the dimensional tolerances are checked outer frame  102  is ready to be pregrouted. A suitable grout retaining means secured as waxed plywood sheet  120  is secured to outer frame  102  by bolts  122  to form cavity  124 . Waxed plywood sheet  120  is used to ensure grouting material  126  does not stick to sheet  120  while curing. Grouting material  126  is prepared and poured into cavity  124  of outer frame  102 . Grouting material  126  is poured until it is approximately level with the top of outer frame  102  and the excess is then “screened” off as is in the previous embodiment. If it is desired to accelerate the curing process and reduce the curing time, outer frame  102  with grouting material  126  in place, is maintained at an elevated temperature for a period of time as per the grouting material manufacturer&#39;s instructions. Once a full cure of grouting material  126  is reached, waxed plywood sheet  120  is removed and pregrouted baseplate  100  can then be trued and machined as in the first embodiment. 
     The novel method of use and construction of my pregrouted baseplate will be readily understood from the foregoing description and, it will be seen that I have provided a novel method of producing a pregrouted baseplate that ensures the rotating machinery attached to the pregrouted baseplate will be properly aligned after installation and curing of the grouting material. Furthermore, while the invention has been shown and described with respect to certain preferred embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present invention includes all such equivalent alterations and modifications, and is limited only by the scope of the appended claims.