Abstract:
This mixed liquid separation apparatus separates and extracts an oil and fat component, which has a lower specific gravity and higher viscosity than a coolant, from a mixed liquid in which the oil and fat component forms a surface layer as a result of floating to the surface of the coolant. The mixed liquid separation apparatus has a liquid separation and transfer part that is composed of a helical body, a shaft and rotary drive part. The liquid separation and transfer part is disposed in a vertical orientation such that the bottom of liquid separation and transfer part is inserted in a storage tank, which stores the mixed liquid, and separates the oil and fat component from the coolant and transfers said oil and fat component upward. The helical body has an inner end surface that is disposed so as to allow a band member, which is in sliding contact with the outer circumferential surface of the shaft, to orbit in a helical manner in a plurality of stages along the outer peripheral surface of the cylindrical rod-like shaft. The oil and fat component, which adheres to the band member, is pushed up along the outer circumferential surface of the shaft due to the relative rotation of the helical body and the shaft.

Description:
TECHNICAL FIELD 
     The present invention relates to a mixed liquid separation apparatus which separates predetermined substances from a mixed liquid with different types of components after washing, lubrication, etc. in machine tools and other factory facilities. 
     BACKGROUND ART 
     In the machining and other manufacturing fields, a coolant, which is mostly comprised of industrial use water, has been used for various purposes, such as lubrication and cooling at the time of machining, and washing and degreasing after machining. These coolants have cutting fluid, cleaning solution, and other various components added in accordance with the purpose of use. After use, they are recovered in the state of a waste liquor in which swarf and the oil for lubrication use are mixed. The recovered waste liquor is recirculated for use after removing the foreign matter. As the apparatus for such waste liquid treatment, in the past, various types of apparatuses have been used (for example, see PLT 1). 
     The prior art which is shown in this PLT 1 employs the following screw pipe type of liquid separation mechanism. At the inside of a cylindrical outside member, a rod-shaped inside member which rotates relative to the outside member is coaxially arranged. A spiral-shaped guide partition, which is provided at the outer circumference of the inside member, is made to slidingly contact the inner circumferential surface of the outside member. At the time of operation, the bottom part of the screw pipe is immersed in the mixed liquid to be separated. In that state, the outside member and the inside member are made to rotate relative to each other. Due to this, the guide partition slidingly contacts the inner circumferential surface of the outside member while rotating. The oil which floats on the surface of the mixed liquid and other substances for separation are transported upward along the spiral surface of the guide partition to be separated and recovered. 
     CITATIONS LIST 
     Patent Literature 
     PLT 1: WO2005/038408A2 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, the above prior art suffered from the following problems, when used for a cutting machine or other mechanical apparatus which produces swarf, sludge, or other solid foreign matter. In such a mechanical apparatus, the mixed liquid to be treated contains not only the floating oil to inherently be separated, but also swarf, sludge, and other solid foreign matter. For this reason, if making the above-mentioned liquid separation mechanism operate, such solid foreign matter deposits on the spiral-shaped guide partition together with the oil. If operating the screw pipe in a state with such solid foreign matter deposited, in the process of making the solid foreign matter move upward along the guide partition, the solid foreign matter is caught between the sliding contact parts of the guide partition and outside member, resulting in the problem of clogging. Such clogging not only obstructs recovery of oil and lowers the efficiency of the apparatus, but also causes poor operation of the screw pipe and abnormal wear due to the caught foreign matter and results in shorter part lifetime and higher cost of the apparatus. As explained above, in the prior art, there was the problem that it was difficult to realize low cost, high liquid separation efficiency for a mixed liquid containing swarf, sludge, and other solid foreign matter. 
     The present invention was made in consideration of these problems and has as its object the provision of a mixed liquid separation apparatus which treats a mixed liquid which contains swarf, sludge, and other solid foreign matter and realizes low cost, high liquid separation efficiency. 
     Solution to Problem 
     The mixed liquid separation apparatus of the present invention is a mixed liquid separation apparatus for separating and taking out a second substance from a mixed liquid containing at least two types of liquid substances with different viscosities and specific gravities, wherein said second substance floats on a surface of a first substance among said liquid substances and forms a surface layer of said second substance with a specific gravity smaller than said first substance and a viscosity higher than said first substance, comprising a liquid separation and transport part, which is arranged in a vertical posture with a bottom part inserted into a storage tank which stores said mixed liquid, separates said second substance from said first substance and transports said second substance upward, and a liquid recovery part which recovers said transported second substance in a receptacle, wherein said liquid separation and transport part comprises a columnar rod-shaped shaft part, a spiral member which is provided with a band member with an inside end face, wherein said inside end face slidingly contacts an outer circumferential surface of said shaft part and said spiral member circles around said outer circumferential surface in a spiral shape in several turns, and a rotation drive part which makes said spiral member and said shaft part rotate relative to each other, and wherein said second substance deposited on said band member is pushed up by said relative rotation along said outer circumferential surface of said shaft part. 
     Advantageous Effects of Invention 
     According to the present invention, the mixed liquid separation apparatus, wherein the second substance is separated and taken out from the mixed liquid in a state where the second substance floats on a surface of the first substance and the second substance forms a surface layer of the second substance with a specific gravity smaller than the first substance and a viscosity higher than it, has the following. That is, the liquid separation and transport part is arranged in a vertical posture with a bottom part inserted into a storage tank which stores the mixed liquid, and separates the second substance from the first substance and transports it upward. This liquid separation and transport part is comprised of a columnar rod-shaped shaft part, a spiral member which is provided with a band member with an inside end face which slidingly contacts the outer circumferential surface of the shaft part and circling around the outer circumferential surface in a spiral shape in several turns, and a rotation drive part which makes these rotate relative to each other. Due to this, it is possible to push up the second substance, which is deposited on the band member by relative rotation along the outer circumferential surface of the shaft part, and possible to realize low cost, high liquid separation efficiency for a mixed liquid which contains swarf, sludge, and other solid foreign matter. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an explanatory view for explaining a liquid treatment system of a mixed liquid separation apparatus of one embodiment of the present invention. 
         FIG. 2  is a view of the overall configuration of a mixed liquid separation apparatus of one embodiment of the present invention. 
         FIG. 3  is a partial cross-sectional view of a mixed liquid separation apparatus of one embodiment of the present invention (first embodiment). 
         FIGS. 4( a ) and ( b )  are explanatory views for explaining the functions of a liquid separation and transport part in the mixed liquid separation apparatus of one embodiment of the present invention. 
         FIG. 5  is an explanatory view for explaining the functions of a liquid recovery part in the mixed liquid separation apparatus of one embodiment of the present invention. 
         FIGS. 6( a ) to ( c )  are explanatory views for explaining the configuration and functions of a foreign matter ejection part in a mixed liquid separation apparatus of one embodiment of the present invention, wherein (b) is a partial view seen from the arrow mark of line A-A of (a). 
         FIG. 7  is a partial cross-sectional view of a mixed liquid separation apparatus of one embodiment of the present invention (second embodiment). 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present invention will be explained with reference to the drawings. Note that the reference notations are examples which show correspondence with specific means which are described in the embodiments. First, referring to  FIG. 1 , the configuration of a liquid treatment system, in which a mixed liquid separation apparatus of the present invention is used, will be explained as one example. As shown in  FIG. 1 , a liquid treatment apparatus  1  is provided with a storage tank  3  which stores a coolant  2  to be treated. The coolant  2  is sucked in through a suction pipe  4  by a liquid transport pump  5  and is sent through liquid transport piping  7  to a machine tool  8  to be fed with the coolant (arrow mark “a”). The machine tool  8  is provided with a processing machine  9  which cuts a workpiece  10 . The coolant  2  which is fed to the machine tool  8  is fed through the processing machine  9  for the purpose of cooling or lubricating the cutting location of the workpiece  10  and drops down as liquid drops  2   a  (arrow mark “b”) to be recovered inside a coolant receiver  11 . 
     The recovered coolant  2  is contaminated with the lubricant and other oil  12  which is used for the mechanical parts of the processing machine  9  and the swarf which is produced during the cutting and other solid foreign matter  13 . The mixed liquid which contains the contaminants is recovered through return piping  14  in the storage tank  3  (arrow marks “c” and “d”). Inside the storage tank  3 , the oil  12 , which has a smaller specific gravity and higher viscosity than the coolant  2 , floats up and forms a surface layer. The oil  12  is organic matter and spoils along with the elapse of time to thereby cause degradation of the coolant  2 . For this reason, the liquid treatment apparatus  1  is provided with a mixed liquid separation apparatus  6  which has the function of separating the oil  12  from the mixed liquid which contains the contaminants and prevents the oil  12  from stagnating in the storage tank  3 . 
     The mixed liquid contains at least two types of liquid substances which differ in viscosities and specific gravities. Among these substances, the first substance constituted by the coolant  2  has on its surface a surface layer of a second substance constituted by the oil  12  with a specific gravity smaller than the first substance and a viscosity higher than it, the second substance floating on the first substance. The mixed liquid separation apparatus  6  has the function of separating and taking out the oil  12  from the mixed liquid in such a state. 
     Next, referring to  FIG. 2  and  FIG. 3 , the configuration of the mixed liquid separation apparatus  6  will be explained. As shown in  FIG. 2 , the mixed liquid separation apparatus  6  is configured with a vertically long liquid separation and transport part  20  which is arranged in the storage tank  3  in a vertical posture. The liquid separation and transport part  20  is provided with a bottom part  20   a , intermediate part  20   b , and rotation drive part  20   c . The bottom part  20   a  is passed through an opening which is provided at the upper cover  3   a  of the top surface of the storage tank  3  and is immersed in the coolant  2  which is stored in the storage tank  3 . A mounting member  27  which is provided at the top part of the bottom part  20   a  is fastened to the top surface of the upper cover  3   a , whereby the mixed liquid separation apparatus  6  as a whole is attached to the storage tank  3 . The coolant  2  in the storage tank  3  contains contaminants of oil  12  and solid foreign matter  13 . The oil  12  is in a state floating at the surface of the coolant  2 . 
     At the bottom part  20   a  and the intermediate part  20   b , the liquid separation and transport part  20  is comprised of mainly a columnar rod-shaped shaft part  23  and a spiral member  24 . The spiral member  24  is provided with a band member  24   a  with an inside end face which slidingly contacts the outer circumferential surface  23   a  of the shaft part  23  and circles around the outer circumferential surface in a spiral shape in several turns. Here, “in a spiral shape in several turns” indicates the band member  24   a  being arranged in a plurality of turns in the axial center direction of the shaft part  23 . Not only the case of a single-start spiral, but also multiple-start spirals is included for the expression. At the bottom part  20   a , a plurality of support rods  26  which extend downward from the mounting member  27  are used to fasten and support the bottom end part of the shaft part  23  through a coupling plate  25 . The spiral member  24  is rotated relatively by the rotation drive part  20   c  about the fixed shaft part  23 . At the bottom part  20   a , the spiral member  24  is formed with an exposed region where the spaces between the turns of the band member are open to the outer circumferential side direction. At the intermediate part  20   b , the spiral member  24  is surrounded in a closed manner in the outer circumferential side direction by a tubular cover member  28 . 
     The rotation drive part  20   c  arranges a motor  30  in a vertical posture on the top surface of the top plate  29  and transmits rotational drive force to the spiral member  24 . The bottom part  20   a  is immersed in the coolant  2 . In that state, the rotation drive part  20   c  is driven to make the spiral member  24  rotate relative to the shaft part  23 . Due to this, the oil  12  which floats and forms a surface layer in the coolant  2  is separated from the coolant  2  in the mixed liquid state and transported upward. 
     At the top end part of the intermediate part  20   b , a disk-shaped receptacle  21  is attached. At the top surface of the disk-shaped receptacle  21 , there is a recessed part which receives the separated and transported oil  12 . At the top surface of the receptacle  21 , the liquid recovery part  22  is formed and arranged in a shape so that the shaft part  23  and spiral member  24  pass through it in the vertical direction. The oil  12  which is separated by the liquid separation and transport part  20  from the coolant  2  and transported upward is recovered by the liquid recovery part  22  in the receptacle  21 . 
     Here, referring to  FIG. 3  (first embodiment), the detailed structures of the rotation drive part  20   c  and liquid recovery part  22  will be explained. The output shaft  30   a  of the motor  30  extends downward from the top plate  29  and is coupled to a vertical power transmission shaft  36  which is supported by a bearing member  34  through a coupling part  35 . The bearing member  34  is held at a horizontal intermediate plate  33  which is arranged below the top plate  29 . The intermediate plate  33  and the top plate  29  are supported by a plurality of connecting bolts  32  which are fixed and fastened to the peripheral edge part of the receptacle  21  (see  FIG. 6( a ) ). Furthermore, between the top plate  29  and the receptacle  21 , a cover member  31  which covers the inside in a closed manner is attached. 
     Below the intermediate plate  33 , a coupling plate  37  which extends in the horizontal direction from a power transmission shaft  36  and rotates together with the power transmission shaft  36 , is provided. The top end part of the spiral member  24  is fastened to the coupling plate  37  by bolts  38 . The motor  30  is driven to make the power transmission shaft  36  rotate to thereby drive the spiral member  24  to rotate through the power transmission shaft  36 . At this time, since the shaft part  23  is fixed and supported at the bottom end part by the coupling plate  25 , the spiral member  24  rotates relative to the shaft part  23 . Further, due to this relative rotation, the oil  12  which deposits on the band member  24   a  is pushed up along the outer circumferential surface  23   a  of the shaft part  23  and transported in the upward direction. 
     The liquid recovery part  22  which is arranged at the top end part of the shaft part  23  is configured provided with a closed surrounding member  40  which surrounds several turns (here, three turns) of the band member  24   a  in a closed manner from the outside at the top part of the spiral member  24 . The closed surrounding member  40  is joined with the coupling plate  3  by a coupling rod  39  and rotates together with the power transmission shaft  36 . The closed surrounding member  40  is an approximately cylindrical member which has an inner circumferential surface which slidingly contacts the outside end face of the band member  24   a . At the surrounding range of the closed surrounding member  40 , the spaces  41  between the turns of the band member  24   a  are surrounded in a closed manner from the outside. Further, the bottom part of the inner circumferential surface of the closed surrounding member  40  is taper cut wherein the end part of the outer circumferential surface becomes a bottom end part  40   a  with an acute angle cross-section. Between the bottom end part  40   a  and the bottom part  21   a  of the receptacle  21  (see  FIG. 3 ), a clearance is secured for the oil  12  to flow out. The oil  12  which moves upward by the liquid separation and transport part  20  and reaches the liquid recovery part  22  enters the closed surrounding member  40 . Due to the push-up action of the band member  24   a , the oil  12  is discharged from the top surface side of the closed surrounding member  40  and from the clearance between the bottom end part  40   a  and the bottom surface  21   a , and the oil  12  is recovered at the receptacle  21 . 
     Referring to  FIG. 4 , the operation of moving the oil  12  by the combination of the shaft part  23  and spiral member  24  at “the liquid separation and the transport part  20 ”, will be explained.  FIG. 4( a )  shows the state where the bottom part of the bottom part  20   a  is immersed in the coolant  2 . At the surface layer of the coolant  2 , the oil  12  is present in a floating state. Further, the solid foreign matter  13  floats in the coolant  2 . Further, the oil  12  is high in viscosity and easily deposits, so deposits on the top surface  24   b  of the band member  24   a  or the outer circumferential surface  23   a  of the shaft part  23  positioned near the surface of the coolant  2  along with the surrounding solid foreign matter  13 . 
     In this state, the rotation drive part  20   c  is used to make the spiral member  24  rotate in a predetermined rotation direction (arrow mark “e”) whereby the oil  12  which deposits on the top surface  24   b  and outer circumferential surface  23   a  is acted on by a push-up action making it move upward along the outer circumferential surface  23   a . That is, as shown in  FIG. 4( b ) , the band member  24   a  turns around the outer circumferential surface  23   a  in the horizontal circumferential direction (arrow mark “f”) whereby a force acts on the oil  12  making it move upward by the top surface  24   b . Due to this, the oil  12  is pushed upward along the outer circumferential surface  23   a.    
     At this time, at the bottom part  20   a , the spiral member  24  forms an exposed range, where the spaces  41  between the turns of the band member  24   a  are opened to the outer circumferential side direction (see  FIG. 3 ). Due to the above-mentioned push-up operation, the solid foreign matter  13 , which deposits on the top surface  24   b  and is present in the spaces  41 , separates from the spaces  41  which are opened at the outer circumferential side and drops down (arrow mark “g”) in the process of upward movement. In other words, in this exposed range, it is not obstructed to eject the solid foreign matter  13 , which is transported upward together with the oil  12 , from the spaces  41  to the outside. Due to this, it is possible to suppress the inconvenience which the solid foreign matter  13  caused in the prior art, that is, the inconvenience where solid foreign matter  13  is caught in the sliding contact parts with the guide partition and clogs them. 
     Further, the present embodiment employs a configuration to drive rotation of the spiral member  24  on the outer circumferential side of the fixed shaft part  23 , so a ring-shaped fluid motion is caused by a trail-along effect at the nearby coolant  2  along with rotation of the spiral member  24 . Further, due to this ring-shaped fluid motion, there is increased probability that the oil  12 , which floats at the surface layer of the coolant  2 , approaches the band member  24   a  or outer circumferential surface  23   a  and is deposited to them or trapped by them. It becomes possible to improve the separation efficiency of the oil  12 . 
     Next, referring to  FIG. 5 , details of the function of the liquid recovery part  22  will be explained. The oil  12 , which is trapped at the bottom part  20   a  by the band member  24   a  and moves upward by the intermediate part  20   b , moves upward through the inside of the closed surrounding member  40  when reaching the liquid recovery part  22 . At this time, the spaces  41  between the turns of the band member  24   a  are surrounded in a closed manner by the closed surrounding member  40 , so free fluid motion to the outside is obstructed. 
     For this reason, the upward moving oil  12  is recovered in the receptacle  21  through the clearances between the bottom end part  40   a  of the closed surrounding member  40  and the bottom surface  21   a  of the receptacle  21 , by the two paths (discharge parts) of the downward discharge path (arrow mark “h”) where it is discharged to the bottom surface  21   a , or, of the overflow path (arrow mark “i”) where it is lifted up to the top surface of the closed surrounding member  40  by the band member  24   a  and overflows. Near the outer circumference of the receptacle  21 , a guide pipe  21   c  which extends downward and a communicated ejection port  21   b , are provided. The oil  12  which is recovered in the receptacle  21  is guided through the ejection port  21   b  to the guide pipe  21   c  where it drops down into the recovery box  43  arranged below it and is recovered. 
     Next, referring to  FIG. 6 , the configuration and function that the foreign matter ejection part ejects the solid foreign matter  13  which is contained in the oil  12  recovered in the receptacle  21 , will be explained. The ejection port  21   b , which is provided at the bottom surface  21   a  of the receptacle  21 , serves also as an ejection port for ejecting downward the solid foreign matter  13  which is discharged from the liquid recovery part  22  together with the oil  12 . That is, as shown in  FIGS. 6( a ) and ( b ) , a plate-shaped scraping member  42  with a sliding contact part  42   a  provided at the end part, is fastened by bolts  44  to a mounting surface  40   b  which is formed by partially cutting the side face of the closed surrounding member  40 . The scraping member  42  is arranged inside the receptacle  21  with the sliding contact part  42   a  in sliding contact with the flat bottom surface  21   a . The closed surrounding member  40  is coupled to the coupling plate  37  (see  FIG. 3 ) through a connecting rod  39 . Due to the relative rotation of the rotation drive part  20   c , the closed surrounding member  40  rotates. Due to this, the scraping member  42  slidingly contacts the bottom surface  21   a  by the sliding contact part  42   a  to slide in the rotation direction. 
     As shown in  FIG. 6( c ) , if the closed surrounding member  40  rotates (arrow mark “k”), the scraping member  42  which slidingly contacts the bottom surface  21   a  is used to scrape together the solid foreign matter  13  and the oil  12  on the bottom surface  21   a , and to eject them downward through the ejection port  21   b . A foreign matter ejection part has the closed surrounding member  40  which is driven to rotate by the rotation drive part  20   c , and the scraping member  42  which is attached to the closed surrounding member  40 , and the foreign matter ejection part transports and ejects the solid foreign matter  13  to the ejection port  21   b  in the receptacle  21 . That is, this foreign matter ejection part has the scraping member  42  which slidingly contacts the flat bottom surface  21   a  of the receptacle  21  and slides over the bottom surface  21   a  by relative rotation of the rotation drive part  20   c . Due to this scraping member  42 , the solid foreign matter  13  on the bottom surface  21   a  is scraped together at the ejection port  21   b.    
     In the first embodiment in the above embodiments, as the rotation drive part  20   c  which makes the spiral member  24  and the shaft part  23  rotate relative to each other, a configuration making the spiral member  24  rotate with respect to a fixed shaft part  23 , is employed, but it is also possible to make the shaft part  23  rotate with respect to a fixed spiral member  24 . For example, as shown in  FIG. 7 , the shaft part  23  is directly coupled with the output shaft  30   a  of the motor  30  through the coupling part  35 , while the spiral member  24  is fastened and joined by bolts  138  and the fixed plate  137  to the intermediate plate  33 . Due to this configuration as well, the spiral member  24  and the shaft part  123  can be made to rotate relative to each other. In the same way as the first embodiment, the spiral member  24  can be used to push up the oil  12  along the outer circumferential surface of the shaft part  123 . 
     As explained above, the mixed liquid separation apparatus  6  in the present embodiment is an apparatus for separating and taking out oil  12  from a mixed liquid, wherein the oil  12 , i.e. the second substance, floats on a surface of the coolant  2 , i.e. the first substance and forms a surface layer of the oil  12  with a smaller specific gravity than the first substance and a higher viscosity than it. The liquid separation and transport part  20  is arranged in a vertical posture with its bottom part  20   a  inserted into the storage tank  3  which stores the mixed liquid, separates the oil  12  from the coolant  2  and transports it upward. The liquid separation and transport part  20  comprises a columnar rod-shaped shaft part; a spiral member which is provided with a band member with an inside end face which slidingly contacts the outer circumferential surface of the shaft part and circles around the outer circumferential surface in a spiral shape in several turns; and a rotation drive part which makes the spiral member and the shaft part rotate relative to each other. Due to this, it is made possible to push up the second substance which is deposited on the band member by relative rotation along the outer circumferential surface of the shaft part. 
     Due to this, it is possible to suppress the issue of solid foreign matter  13  being caught in and clogging the mechanism. Furthermore, it becomes possible to improve the system efficiency due to the mixed liquid separation apparatus  6  and possible to prevent poor operation or abnormal wear due to foreign matter being caught. That is, it is possible to realize low cost, high liquid separation efficiency for a mixed liquid which contains swarf, sludge, or other solid foreign matter  13 . 
     Note that, in the above embodiments, the example is shown where the first substance is the coolant  2  and the second substance is the oil  12  which float at the surface of the coolant  2 , but the present invention is not limited to these. If configured to separate and take out a second substance from a mixed liquid in a state where the first substance is formed on its surface with a surface layer of a second substance with a specific gravity smaller than the first substance and a viscosity higher than it, the second substance floating on it, the present invention can also be applied to combinations of other types of substances. For example, the present invention can also be applied to a combination of a first substance of a washing solution and a second substance of a washed substance which floats on the surface of the washing solution. 
     INDUSTRIAL APPLICABILITY 
     The mixed liquid separation apparatus of the present invention covers a mixed liquid which contains swarf, sludge, or other solid foreign matter and has the effect that it can realize a low cost, high liquid separation efficiency. It is useful in the liquid treatment field of recovering and reusing a coolant which is used in a machine tool or a washing liquid which is used in a washing apparatus. The present invention was explained with reference to specific embodiments selected for the purpose of illustration, but to a person skilled in the art, it is clear that numerous modifications can be made without departing from the basic concept of the present invention and its scope of disclosure. 
     REFERENCE SIGNS LIST 
     
         
           1 . liquid treatment apparatus 
           2  coolant 
           3  storage tank 
           6  mixed liquid separation apparatus 
           12  oil 
           13  solid foreign matter 
           20  liquid separation and transport part 
           20   a  bottom part 
           20   c  rotation drive part 
           21  receptacle 
           21   a  bottom surface 
           21   b  ejection port 
           22  liquid recovery part 
           23  shaft part 
           23   a  outer circumferential surface 
           24  spiral member 
           24   a  band member 
           40  closed surrounding member 
           41  space 
           42  scraping member