Patent Publication Number: US-2007102360-A1

Title: Polymer blending system

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims priority to U.S. Provisional Patent Application No. 60/731,031 filed on Oct. 28, 2005 entitled POLYMER BLENDING SYSTEM. 
    
    
     FIELD OF THE INVENTION  
      The present invention concerns blending of two or more liquids into one homogenously liquid stream, and more particularly relates to a polymer blending and surfactant washing system, particularly in use for adding flocculants and coagulants in a liquid/solid extraction system prior to filtration.  
     BACKGROUND OF THE INVENTION  
      Apparatus for filtering, compressing, liquid extraction, washing and chemical treatment of sludge, slurries or other wet materials are well known. Such equipment finds particular application in the pulp and paper industry, waste water treatment, mineral processing, agriculture, food processing, pharmaceutical manufacturing, fisheries, breweries, wineries, chemical processing, oil and tar sands industry, etc. The systems typically use a chemical (e.g., polymer) blending system for adding a mixture of polymer, coagulant and dilution water to the sludge, slurries or other liquid/solid materials. The systems typically employ several components (e.g., aging tanks) to accomplish a desired blending of the chemicals (e.g., polymers and coagulants used in filtration and liquid/solid separation systems).  
      An improved and more compact apparatus is desired for filtration, compressing, liquid extracting, washing and chemical treating of the sludge, slurries or other wet materials.  
     SUMMARY OF THE PRESENT INVENTION  
      An aspect of the present invention is to provide a system for extracting liquid from a mass comprising a system mass input, a blending system connected to the system mass input, with the blending system being configured to mix a chemical with a fluid to form a mixed solution, a liquid extraction assembly connected to the blending system, and piping having a first section between the system mass input and the blending system and a second section between the blending system and the liquid extraction assembly. The system is configured to have mass inputted into the system mass input, transport the mass to the blending system through the first section of the piping, inject the mixed solution into the mass in the blending system, and transport the mass from the blending system to the liquid extraction assembly. The blending system comprises a mechanically movable assembly for mixing the chemical with the fluid.  
      Another aspect of the present invention is to provide a method of extracting liquid from a mass comprising inputting the mass into a system mass input, connecting a blending system connected to the system mass input, mixing a chemical and a fluid with the blending system to form a mixed solution, connecting a liquid extraction assembly to the blending system, providing piping having a first section between the system mass input and the blending system and a second section between the blending system and the liquid extraction assembly, transporting the mass to the blending system through the first section of the piping, injecting the mixed solution into the mass in the blending system, transporting the mass from the blending system to the liquid extraction assembly, and extracting the liquid from the mass using the liquid extraction assembly. The blending system comprises a mechanically movable assembly for mixing the chemical with the fluid.  
      Yet another aspect of the present invention is to provide a chemical and fluid mixing system for use with a system for extracting liquid from a mass comprising a mix housing defining a mixing area, a mix blade within the mixing area, a mix ring surrounding the mix blade, a motor housing having a motor therein, and a seal plate engaged with the mix ring and the motor housing. The mix housing is connected to the motor housing. The motor includes an output shaft extending through a wall of the motor housing and into the mix area, with the output shaft being connected to the mix blade for rotating the mix blade. The housing has an inlet allowing a chemical and a fluid to enter the mixing area along an inlet line and an outlet allowing the chemical and the fluid to exit the mixing area along an outlet line.  
      These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       FIG. 1  is a top view of a system for extracting liquid from a mass using a polymer blending system of the present invention.  
       FIG. 2  is a front view of the system for extracting liquid from a mass using a polymer blending system of the present invention.  
       FIG. 3  is a side view of the system for extracting liquid from a mass using a polymer blending system of the present invention.  
       FIG. 4  is a schematic of the system for extracting liquid from a mass using a polymer blending system of the present invention.  
       FIG. 5  is an exploded side view of a first embodiment of the polymer blending system of the present invention.  
       FIG. 6  is an exploded side view of a second embodiment of the polymer blending system of the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
      For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as orientated in  FIG. 6 . However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.  
      The present invention relates to an apparatus and method for blending two or more liquids into one homogenous liquid stream. For example, the present invention can be used in a polymer blending and surfactant washing system for addition of flocculants and coagulants prior to filtration in liquid/solid extraction systems, thereby enhancing extraction of the liquid from a humid mass (e.g., sludges and slurries), as those used or produced in the pulp and paper industry, waste water treatment plants, pharmaceutical manufacturing, agricultural, food and beverage industries, etc. The present invention is used to assist in removing a portion of liquid from the humid mass.  
      The reference number  10  ( FIGS. 1-4 ) generally designates a system for extracting liquid from a mass using a blending system  18  of the present invention. Such systems  10  for extracting liquid from a mass are well known to those skilled in the art and the system  10  as described herein is only for illustrative purposes. For example, the blending system  10  of the present invention can be used in the system disclosed in PCT Application No. PCT/US2005/028041 entitled ROTARY FAN PRESS, the entire contents of which are hereby incorporated herein by reference.  
      The illustrated system  10  for extracting liquid from a mass comprises a platform  12  having an upper surface  14 , a system mass input  16 , the blending system  18  on the upper surface  14 , a liquid extraction assembly  40  on the upper surface  14 , and piping  22  having a first section  24  between the system mass input  16  and the polymer feeding and blending system  18 , and a second section  26  between the polymer feeding and blending system  18  and the liquid extraction assembly  40 . The system  10  is configured to have mass inputted into the system mass input  16 , transport the mass to the blending system  18  through the first section  24  of the piping  22 , inject polymer into the mass in the blending system  18 , and transport the mass from the blending system  18  to the liquid extraction assembly  40 . Pressure from mass forced into the liquid extraction assembly  40  forces liquid in the mass to exit the mass. In the illustrated embodiment, the liquid extraction assembly  40  comprises a pair of liquid extraction presses  11 . However, it is contemplated that the liquid extraction assembly  40  of the present invention could use any number (including only one) of the liquid extraction presses  11  as described in more detail below.  
      In the illustrated embodiment, the system  10  can either include a source of mass (as shown schematically in  FIG. 4 ) or be configured to be connected to a source of mass (as illustrated in  FIG. 1 ). The mass is preferably a humid mass (e.g., sludges and slurries). As stated above, the mass can be that used or produced in the pulp and paper industry, waste water treatment plants, agricultural industries, food and beverages industries, etc. The system  10  of the present invention removes at least a portion of the liquid in the mass. In the illustrated embodiment, the system  10  is portable and can be directly brought to the pulp and paper industry, waste water treatment plants, agricultural industry, food and beverages industries, etc. for use at those locations. The system mass input  16  is configured to be connected to a hose that transports the mass to the system  10  from the source of mass. Preferably, the system  10  is located on the platform  12  that has an upper surface  14  smaller than 72 square feet to provide a compact and easily movable system. However, several of the inventive features disclosed herein can be used in a stationary and fixed system. In a stationary and fixed system, the source of mass can comprise a tank  21  (see  FIG. 4 ) having the mass therein, with the tank  21  communicating with the system mass input  16 .  
      The illustrated system  10  preferably includes a mass feed pump  27  for assisting in drawing the mass from the source of mass through the hose or from the tank  21 . The mass feed pump  27  also provides pressure to the mass to assist in moving the mass through the piping  22  and into and through the liquid extraction assembly  40 . Mass feed pumps  27  are well known to those skilled in the art. After passing through the mass feed pump  27 , the mass is fed into the blending system  18 . The blending system  18  is configured to be connected to a water supply  29  for mixing water with polymer in the blending system  18 . In the illustrated example, the system  10  includes a fitting  31  for connecting to a water supply for supplying the blending system  18  with the water. The blending system  18  includes an injection area  28  connected to the first section  24  and the second section  26  of the piping  22  and defines a transition from the first section  24  to the second section  26 . After the water is mixed with the polymer, a combination of the water and polymer is injected into the injection area  28  for mixing with the mass from the first section  24  before the mass is moved to the second section  26  of the piping  22 . The blending system  18 , as discussed in more detail below, preferably uses a polymer that is preferably a conventional known polymer flocculent, such as a polyacrylamide.  
      In the illustrated example, once the mass is moved to the second section  26  of the piping  22 , the mass is thoroughly mixed with the combination of polymer and water in an adjustable mix valve  30  in the second section  26  of the piping  22 . The second section  26  of piping  22  preferably includes a first portion  32  extending vertically upwards from the mix valve  30  to a top of the second section  26  of the piping  22 . The second section  26  of the piping  22  also includes a second portion  34  comprising a plurality of horizontal rows  36  of pipes, with each row  36  connected at one end to the row  36  above and at another end at the row  36  below. The second portion  34  of the second section  26  of the piping  22  is connected to the liquid extraction assembly  40 , wherein the mass is fed into the liquid extraction assembly  40 . In the illustrated embodiment, the second section  26  of the piping  22  includes a mass bypass tube  38  having a selectively opening valve for allowing the mass in the second section  26  of the piping  22  to bypass the liquid extraction assembly  40 . It is contemplated that the mass taken out of the second section  26  of the piping  22  could be reinserted into the system  10  by placing the mass taken out of the second section  26  into the source of mass or directly or indirectly into the system mass input  16 . Likewise, the second section  26  of the piping  22  can include an extraction valve for each liquid extraction press  11  of the liquid extraction assembly  40  for selectively allowing the mass in the second section  26  to be fed into one or more of the liquid extraction presses  11 .  FIG. 4  illustrates a schematic representation of the system  10 . As shown schematically in  FIG. 4 , the system  10  can include at least one conveyor  35  for accepting the solid portion of the mass exiting one or more of the liquid extraction assemblies  40  to move the mass to a disposal or collecting device (not shown).  
      In the illustrated example, the liquid extraction assembly  40  accepts the mass from the piping  22  and outputs a solid and the at least a portion of the liquid. The liquid extraction assembly  40  of the present invention includes a pair of liquid extraction presses  11  connected to a motor assembly  44 . In the illustrated example, the system  10  of the present invention comprises a pair of liquid extraction presses  11  that share the motor assembly  44 . However, it is contemplated that only one liquid extraction press  11  could be used or that each liquid extraction press  11  could have its own motor assembly  44 . Furthermore, the system  10  can include any number of liquid extraction presses  11 .  
      The blending system  18  of the present invention is configured to be connected to the water supply  29  for mixing water with a chemical (e.g., polymer) in the blending system  18 . The blending system  18  includes an outlet  50  configured to be connected to the piping of the liquid extraction system. The chemical is preferably a polymer, and is more preferably a conventional known polymer flocculent, such as a polyacrylamide. The polymer and water mixture flocculates the mass to assist in removing the liquid from the mass.  
      In the illustrated example, the blending system  18  includes an inlet  52  for accepting the water from the water supply  29  and the chemical from a chemical supply  54 . Although the water and the chemical are shown as coming into the blending system  18  together, it is contemplated that the chemical and the water can be separately introduced into the blending system  18 . Furthermore, it is contemplated that the chemical can originate as an emulsion (liquid) or dry powder in the present invention. Preferably, the chemical from the chemical supply is an emulsion. The emulsion is in a concentrated form with different viscosities, etc. and percent active (typically 30-40% active) product. However, it is contemplated that a dry powder could be used, with the powder blended to end with an emulsion equivalent. The blending system  18  of the present invention also includes the outlet  50  for outputting the homogenously mixed water and chemical.  
      The illustrated blending system  18  includes a drive motor  56  with a motor housing  59  having an output shaft  58 , a back seal plate  60 , a tapered mix ring  62 , a mixer blade  64  and a mix housing  66  having the inlet  52  and the outlet  50 . The back seal plate  60  includes a centrally located opening for accepting the output shaft  58  of the drive motor  56  therethrough. Preferably, the back seal plate  60  is affixed to the motor housing  59 . The tapered mix ring  62  is connected to the mix housing  66 , and/or the back seal plate  60 , preferably by screws, bolts or other type of fasteners (although other connection means could be used (e.g., welding)). The mixer blade  64  is connected to the output shaft  58  of the drive motor  56  and rotates therewith. The mixer blade  64  comprises two fixed, tapered blade portions from a center of the mixer blade  64  (i.e., the portion connected to the output shaft  58 ). The angle of the blade portions and an edge blade taper of the blade portions causes a back and forth motion within the mixing area. The mix housing  66  is sealed to the back seal plate  60  thereby defining a mixing area between an inside of the mix housing  66  and the back seal plate  60 .  
      In use, the water and the chemical enter the mixing area of the blending system  18  through the inlet  52 . The water and the chemical are then thoroughly mixed using the mixer blade  64 . The tapered mix ring  62  also assists in mixing as the mixture will abut against an inside of the tapered mix ring  62  to flow the mixture back towards the mixer blade  64  to further mix the mixture and to preferably wash the surfactants from the chemical chains (e.g., polymer chemical chains). The tapered mix ring  62  also includes a plurality of oval shaped discharge openings  70 , with the mixture preferably exiting through the openings  70  before the mixture exits the mix housing  66  through the outlet  50 . Preferably, the emulsion polymer is diluted in the water at an ending dilution of about 0.5-0.2% polymer in the mixture. In order to get the most activation out of the polymer, the water has to come in contact with the active polymer. In order to do this, the water has to wash away the surfactants first and then blend into the active polymer, which will then uncoil (expand). Thereafter, the mixture is injected into the sludge/slurry to flocculate the solids. The blending system  18  of the present invention uses approximately 50-70% less polymer than prior art mixers and also helps achieve a better dewatered cake (solids) after the sludge goes through the liquid extraction system.  
      The reference numeral  18   a  ( FIG. 6 ) generally designates another embodiment of the present invention, having a second embodiment for the blending system. Since blending system  18   a  is similar to the previously described blending system  18 , similar parts appearing in  FIG. 5  and  FIG. 6 , respectively, are represented by the same, corresponding reference number, except for the suffix “a” in the numerals of the latter. The second embodiment of the blending system  18   a  is identical to the first embodiment of the blending system  18 , except that the mix ring  62   a  is not tapered.  
      It is to be understood that variations and modifications can be made on the aforementioned structure without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.