Abstract:
A solid-liquid separating apparatus comprising a cylindrical strainer formed by circular ring members with gaps in between, a casing having the strainer therein, and scrapers disposed in the respective gaps between the circular ring members for removing solid matter adhering to the end (flat) surfaces of the circular ring members. Each of the scrapers comprises a flat auxiliary circular ring member and a flat protruding element. The external diameter of the auxiliary circular ring member is smaller than the external diameter of the circular ring members and is larger than the internal diameter of the circular ring members, and the protruding element extends from the outer circumferential surface of the auxiliary circular ring member. The auxiliary circular ring members are disposed coaxially with the circular ring members, and the tip ends of protruding elements reach the outer circumferences of the circular ring members.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a solid-liquid separating apparatus for separating solid matter, raw contaminants, etc. from liquid of a solid-liquid mix. 
     2. Prior Art 
     Solid-liquid separating apparatus are used in, for example, raw contaminant dehydration treatment devices, etc. installed in kitchen sinks. Such solid-liquid separating apparatus separates the solid matter and liquid from water-containing raw contaminants produced as a mixture of solid matter and liquid by mixing raw contaminants discharged from the kitchen with water and pulverizing this mixture. 
     One of such solid-liquid separating apparatuses is described in Japanese Patent Application No. H11-133089 (Laid-Open (Kokai) No. 2000-317693) filed by the applicant of the present application. 
     This prior art solid-liquid separating apparatus will be described with reference to FIGS. 6 and 7. 
     The solid-liquid separating apparatus  10  is comprised substantially of a strainer  12  and a casing  24 . 
     The strainer  12  is in a cylindrical shape by way of arranging a plurality of flat-plate-form circular ring members  14  adjacent each other with specified gaps in between. The casing  24  has an accommodating section  26  that accommodates the strainer  12 . 
     The accommodating section  26  is divided by the strainer  12  into two regions: an internal region B that is inside the strainer  12  and an external region C that is outside the strainer  12 . An intake port  28  that introduces a mixture of solid matter and a liquid is formed in the external region C, and an outlet port  30  that discharges to the outside the liquid that passes between the circular ring members  14  and advances into the internal region B is formed in the internal region B. 
     The solid-liquid separating apparatus  10  further includes a scraper  20 . The scraper  20  is comprised of a plurality of flat-plate-form (fin-form) protruding elements  22  so that the tip ends thereof enter the respective gaps between the circular ring members  14 . The scraper  20  is moved relative to the strainer  12  and the protruding elements  22  thereof scrape away solid matter adhering to the end surfaces (or the flat, side surfaces) of the circular ring members  14  that form the strainer  12 . The flat-plate-form protruding elements  22  enter from the outer circumferential sides of the circular ring members  14  into the gaps. The tip ends of the protruding elements  22  reach the inner circumferential surfaces of the circular ring members  14  and advance into the internal region B of the strainer  12 . 
     Both end surfaces (flat surfaces) of the respective flat-plate-form protruding elements  22  that enter the respective gaps between the circular ring members  14 , i.e., the spaces between the end surfaces (flat surfaces) of the circular ring members  14 , make rubbing contact with the end surfaces (flat surfaces) of the circular ring members  14  that are positioned on both sides of each flat-plate-form protruding element  22 . 
     The plurality of flat-plate-form protruding elements  22  are provided on, for instance, a supporting member  32  (see FIG.  7 ). The protruding elements  22  protrude from the supporting member  32  toward the strainer  12 . The supporting member  12  is installed parallel to the axis of the strainer  12  and forms a part of the scraper  20  together with the flat-plate-form protruding elements  22 . The flat-plate-form protruding elements  22  are arranged so as to have gaps in between that are substantially equal in size to the thickness of the circular ring members  14  and also have a fixed spacing between adjacent flat-plate-form protruding elements  22 . As one example, the flat-plate-form protruding elements  22  are in a wedge shape (see FIG.  6 ). The end surfaces of the protruding elements  22  on the upstream side with respect to the direction of rotation D of the strainer  12  are formed as inclined surfaces with respect to the radial direction of the circular ring members  14 . As a result, the solid matter that has been scraped away from the end surfaces of the circular ring members  14  is gradually moved toward the outer circumferences of the circular ring members  14  as the strainer  12  rotates. 
     Furthermore, the edge of the end surface of the supporting member  32  on the upstream side with respect to the direction of rotation D (see FIG. 6) of the strainer  12  is in contact with the outer circumferential surfaces of the circular ring members  14  so as to function as a scraper that scrapes away the solid matter  16  deposited on the outer circumferential surfaces of the circular ring members  14 . Accordingly, the end surface of the supporting member  32  on the upstream side with respect to the direction of rotation D of the strainer  12  is formed as an inclined surface with respect to the radial direction of the circular ring members  14 . Thus, the solid matter  16  that has been scraped from the outer circumferential surfaces of the circular ring members  14  is gradually moved away from the circular ring members  14  as the strainer  12  rotates. 
     With the structure above, the scraper  20  scrapes away the solid matter  16  adhering to the end surfaces of the circular ring members  14  by the flat-plate-form protruding elements  22 , and solid matter  16  adhering to the outer circumferential surfaces of the circular ring members  14  is scraped away by the end surface of the supporting member  32  that is located on the upstream side with respect to the direction of rotation D of the strainer  12 . The solid matter  16  that has been scraped away is moved by the flat-plate-form protruding elements  22 , which are formed with inclined surfaces that incline with respect to the radial direction of the scraper  20 , and by the end surface of the supporting member  32  that is located on the upstream side with respect to the direction of rotation D of the strainer  12 . As a result, the solid matter  16  is extracted through a discharge opening  34  disposed in the casing  24  and on the upstream side of the scraper  20 . 
     The driving device  36 , that is a motor and the like, rotates the strainer  12 . The strainer  12  is rotated continuously during the solid-liquid separation process. 
     In operation, the strainer  12  acts as a filter. In other words, the liquid  18  passes through the gaps between the stacked circular ring members  14  and advances into the internal region B, and the solid matter  16  that is larger than the gaps is deposited on the outer circumferential surfaces of the circular ring members  14 . Some of the solid matter  16  that can advance into the gaps adhere to the end surfaces of the circular ring members  14  and cannot advance into the internal region B. As a result, the solid matter and liquid are separated. 
     The liquid  18  that has advanced into the internal region B is discharged to the outside of the casing  24  via the outlet port  30 . The solid matter  16  adhering to or deposited on the circular ring members  14  is scraped away by the scraper  20  and discharged to the outside of the casing  24  via the discharge opening  34  that is opened in the casing  24 . Since the solid matter  16  deposited or adhering on the outer circumferential surfaces and end surfaces of the circular ring members  14  is scraped away by the scraper  20  each revolution of the strainer  12 , no clogging would occur; and solid-liquid separation is continuously performed. 
     The space of each one of the gaps between the end surfaces of the respective circular ring members  14  that make up the strainer  12  is determined based upon the size of the solid matter that is to be separated from the liquid. More specifically, if it is desired to separate even solid matter  16  of a small size so that the proportion of solid matter contained in the liquid  18  following the separation is reduced and the quantity of contaminants in the liquid  18  is thus reduced, then the spacing of the gaps between the circular ring members  14  is narrowed. For the opposite case, the spacing of the gaps between the circular ring members  14  is widened to some extent. 
     FIGS. 8 through 10 show the solid-liquid separating apparatus  10  in a concrete manner. The solid-liquid separating apparatus  10  comprises the strainer  12 , the casing  24 , the scraper  20  and a driving device  36  that rotationally drives the strainer  12 . 
     The strainer  12  is formed into a cylindrical body by stacking sideways a plurality of circular ring members  14  with gaps in between. The circular ring members  14  consist of two types of ring members: flat-plate-form first circular ring members  14   a  and flat-plate-form second circular ring members  14   b . The second circular ring members  14   b  have the same external diameter as the first circular ring members  14   a , and a plurality of outer projections  38  (in FIG. 8, three outer projections  38 ) are formed at specified angular intervals on the outer circumferential surface of the second circular ring members  14   b.    
     More specifically, the strainer  12  is formed in a cylindrical body. This cylindrical strainer  12  is obtained by stacking a plurality of the respective circular ring members  14   a  and  14   b  side by side with specified gaps between the respective circular ring members  14   a  and  14   b . A specified number of first circular ring members  14   a  (for instance, a single first circular ring member  14   a  in FIGS. 9 and 10) are interposed between two second circular ring members  14   b.    
     Furthermore, spacers  44  are fitted over first stays  42  that pass through through-holes  40  formed in the respective circular ring members  14   a  and  14   b  and integrally connect all of the circular ring members  14   a  and  14   b . Thus, the spacers  44  are used as a means for setting the spacing of the circular ring members  14   a  and  14   b . The thickness of the spacers  44  constitutes the size of the spacing of the gaps between the respective circular ring members  14   a  and  14   b . Ordinarily, the thickness of the spacers  44  is selected so as to match the thickness of the flat-plate-form protruding elements  22  disposed between the respective circular ring members  14   a  and  14   b  and to be at substantially the same thickness. In cases where the friction that is generated between the flat-plate-form protruding elements  22  and the respective circular ring member  14   a  and  14   b  is large, then the thickness of the spacers  44  is set slightly larger than the thickness of the flat-plate-form protruding elements  22 . 
     Spokes in, for instance, letter Y-shape are formed so as to be connected to the inner edges of the circular ring members  14   a  and  14   b ; and a rotating shaft  48  is installed in the center of these spokes  46 . Both ends of the rotating shaft  48  are rotatably supported on the casing  24 . At least one end of the rotating shaft  48  protrudes to the outside of the casing  24 , and this end is rotationally driven by the driving device  36 . The strainer  12  is thus rotated in the direction of arrow D. Various structures are conceivable as the connecting structures between the Y-shaped spokes  46  and the strainer  12 . In one example, two sets of Y-shaped spokes  46  are used, and these Y-shaped spokes  46  are connected to two circular ring members  14  positioned at both ends of the strainer  12 . 
     The second circular ring members  14   b  which have the outer projections  38  on their outer circumferential surfaces are arranged so that the outer projections  38  form the ribs  50  on the outer circumferential surface of the strainer  12 . Thus, the ribs  50  extend in the axial direction of the strainer  12 . In other words, when the strainer  12  is viewed from one end thereof, the outer projections  38  of one second circular member  14   b  is positioned directly behind the outer projections  38  of the next second circular ring member  14   b  so that the ribs  50  are formed by these outer projections  38 . As a result, a plurality of ribs  50  that extend parallel to the axis of the strainer  12  are formed on the outer circumferential surface of the strainer  12 . Since the first circular ring members  14   a  that have no outer projections  38  are interposed between the second circular ring members  14   b , spaces are formed in the ribs  50 . 
     The ribs  50  push and transfer the separated solid matters  16  to the discharge opening  34  along the inner surface of the tubular accommodating section  26 . 
     The strainer  12  is installed inside the tubular accommodating section  26  so that the axis of rotation of the strainer  12 , i.e., the rotating shaft  48  that is connected to the strainer  12 , is oriented in a horizontal direction. The openings at both ends of the strainer  12  are closed off by a pair of opposite inside wall surfaces of the tubular accommodating section  26  of the casing  24 . Thus, the movement of the liquid between the outer region C and inner region B of the strainer  12  is accomplished mainly by the gaps between the circular ring members  14   a  and  14   b.    
     In the solid-liquid separating apparatus  10  shown in FIG. 8, the intake port  28  is located at a lower position than the outlet port  30 . Thus, the mixture constantly accumulates in the lower portion of the tubular accommodating section  26 , the lower portion of the strainer  12  is immersed in the mixture, and the upper portion of the strainer  12  is exposed above the liquid level F of the mixture. 
     The discharge opening  34  is opened in the upper portion of the tubular accommodating section  26  so that the discharge opening  34  is located in the outer region C of the strainer  12 . The discharge opening  34  extends in the direction of the axis of rotation of the strainer  12 , so that it allows the solid matter  16 , that has been separated from the liquid and carried along the inner circumferential surface of the tubular accommodating section  26  by the ribs  50 , to be discharged to the outside of the casing  24 . 
     The discharge opening  34  opens into the space of the tubular accommodating section  26  above the liquid level F of the mixture. The discharge opening  34  is located on the downstream side of the top area of the strainer  12  with respect to the direction of rotation of the strainer  12  and is on the upstream side of the scraper  20  with respect to the direction of rotation of the strainer  12 . 
     A cover member  52  is disposed on the discharge opening  34  of the casing  24  so as to close the discharge opening  34 . More specifically, one end of the cover member  52  is pivotally connected to the edge of the discharge opening  34  located on the upstream side of the discharge opening  34  with respect to the direction of rotation D of the strainer  12 , so that the other end of the cover member  52  that is on the downstream side with respect to the direction of rotation D of the strainer  12  is moved or swings toward and away from the discharge opening  34  as indicated by two-head arrow in FIG.  8 . 
     The cover member  52  is constantly urged toward the strainer  12  by an urging means such as a spring,  54 . The spring  54  is coupled at one end thereof to the casing  24  and at another end thereof to the cover member  53 . 
     By way of bias of the spring  54 , the cover member  52  presses the solid matter  16  that is pushed and moved by the ribs  50  of the strainer  12  against the outer circumferential surface of the strainer  12  and squeezes the liquid out of the solid matter  16 . 
     As seen from FIG. 10, the scraper  20  is constructed by stacking a plurality of flat plates sideways. The scraper  20  is, as shown in FIG. 8, disposed on the downstream side of the top area of the strainer  12  with respect to the direction of rotation D of the strainer  12 . In addition, the scraper  20  is disposed near the discharge opening  34  so that it is located on the downstream side of the discharge opening  34  with respect to the direction of rotation D of the strainer  12 . 
     The scraper  20  will be further described below in regards to its more concrete structure. 
     The scraper  20  is comprised of plate-form first protruding elements  56 , plate-form second protruding elements  58  and supporting elements  60 . 
     Each of the first protruding elements  56  is formed from a plate material that has the same thickness as that of the respective first circular ring members  14   a  that make up the strainer  12 , and the tip end (upper end in FIG. 10) of the first protruding element  56  protrudes toward the outer circumferential surface of each one of the first circular ring members  14   a  so as to scrape away solid matter  16  adhering to the outer circumferential surfaces of the first circular ring members  14   a.    
     Each of the second protruding elements  58  is formed from a plate material that has the same thickness as each one of the gaps between the first circular ring members  14   a  and second circular ring members  14   b . The tip end (upper end in FIG. 10) of the second protruding element  58  advances into the gaps between the first and second circular ring members  14   a  and  14   b  so as to scrape away solid matter  16  adhering to the respective flat end surfaces of the circular ring members  14   a  and  14   b.    
     Each of the supporting elements  60  is formed from a plate material that has the same thickness as that of the respective second circular ring members  14   b  are formed with outer projections  38  on their outer circumferential surfaces. 
     The first protruding elements  56 , second protruding elements  58  and supporting elements  60  are, as seen from FIG. 9, disposed in a specified order in accordance with the disposing order of the first circular ring members  14   a  and second circular ring members  14   b  that make up the strainer  12 . More specifically, the first protruding elements  56  are positioned so as to face the circumferential surfaces of the first circular ring members  14   a , the second protruding elements  58  are positioned so that pointed end areas thereof enter into the gaps between the circular ring members  14   a  and  14   b , and the supporting elements  60  are positioned so as to face the circumferential surfaces of the second circular ring members  14   b . The first protruding elements  56 , second protruding elements  58  and supporting elements  60  are further formed into an integral unit by second stays  64  that pass through through-holes  62  formed in these elements. 
     In this structure, the gaps between the respective circular ring members  14   a  and  14   b  are set to be smaller than the thickness of the respective circular ring members  14   a  and  14   b . As a result, the thickness of the second protruding elements  58  that advance into the gaps between the respective circular ring members  14   a  and  14   b  is smaller than the thickness of the circular ring members  14   a  and  14   b . Thus, the strength of the second protruding elements  58  might be insufficient. Accordingly, the second protruding elements  58  are reinforced by being interposed between the first protruding elements  56  and the supporting elements  60  that are positioned on both sides of the second protruding elements  58 . 
     In the structures shown in FIGS. 9 and 10, the first circular ring members  14   a  are positioned at both ends of the strainer  12  (which is a cylindrical shape as a whole). Accordingly, the first protruding element  56 , the second protruding element  58  and the supporting element  60  are disposed in this order from one end of the scraper  20 , thus forming a “unit”; and this “unit” is repeated in the direction of the second stays  64 , and the first protruding element  56  is disposed at another end of the scraper  20 . 
     Here, the first protruding elements  56 , supporting elements  60  and second stays  64  also function as a supporting member  32  which holds and supports the second protruding elements  58  that enter the spaces between the first circular ring members  14   a  and second circular ring members  14   b  and scrape away the solid matter  16 . 
     In the structure shown in FIG. 10, the first protruding elements  56  which are positioned at both ends of the scraper  20  differ in shape from other first protruding elements  56  positioned in the intermediate portions of the scraper  20 . In other words, the first protruding elements  56  at both ends are larger and have a broader area compared to other first protruding elements  56 . The intention is to have these first protruding elements  56  at both ends hold the cover member  52  (positioned on the upstream side of the scraper  20  with respect to the direction of rotation D of the strainer  12 ) from both sides so that both ends of the cover member  52  are covered by these first protruding elements  56 . 
     The solid material  16  moved by the strainer  12  are scraped away while being traveling downward from the top area of the strainer  12 , thus being separate from the strainer  12  and discharged out through the discharge opening  34 . 
     However, the above-described solid-liquid separating apparatus has problems. 
     What determines the solid-liquid separating performance of the strainer  12  is, as described above, the dimension (width) of the gaps between (the end surfaces of) the respective circular ring members  14  that are disposed next to each other; and this dimension is determined by the thickness of the flat-plate-form protruding elements  22  which are inserted into only limited portions of the ring-shape gaps between the respective circular ring members  14 . 
     Therefore, in order to improve the solid-liquid separating performance of the strainer  12 , it is necessary to narrow these gaps. However, if it is desired to ensure the durability and mechanical strength of the flat-plate-form protruding elements  22 , there are limits to how far the thickness of the flat-plate-form protruding elements  22  can be reduced. 
     In other words, in the prior art apparatus, the solid-liquid separating performance of the strainer  12  is limited by the thickness of the flat-plate-form protruding elements  22  of the scraper  20 . 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention solves the above-described problems. 
     The object of the present invention is to provide a solid-liquid separating apparatus that provides an improved solid-liquid separating performance of the strainer without being affected by the structure of the scraper. 
     The above object is accomplished by a unique structure for a solid-liquid separating apparatus that is comprised of: 
     a strainer that is a cylindrical body formed by a plurality of flat-plate-form circular ring members with gaps in between; 
     a casing with an accommodating section for accommodating therein the strainer, the accommodating section being divided by the strainer into an internal region that is inside the strainer and an external region that is outside the strainer, an intake port that introduces a mixture of solid matter and liquid being formed in the external region, and an outlet port that discharges to the outside the liquid that passes between the circular ring members and advances into the internal region being formed in the internal region, and 
     a plurality of scrapers that are provided in the gaps between the circular ring members, the scrapers being moved along the outer circumferential surfaces of the circular ring members so as to scrape away the solid matter adhering to the circular ring members, 
     wherein the unique structure of the present invention is that the each of the scrapers is comprised of: 
     a flat-plate-form auxiliary circular ring member having an external diameter that is smaller than the external diameter of the circular ring members and is larger than the internal diameter of the circular ring members, and 
     a flat-plate-form protruding element extending from the outer circumferential surface of the auxiliary circular ring member, the protruding element being in the same plane as the auxiliary circular ring member, and wherein 
     the auxiliary circular ring member is disposed in coaxial with the circular ring members, and the flat-plate-form protruding element has a length that reaches the outer circumferential surfaces of the circular ring members. 
     With the above structure, the solid-liquid separating performance of the strainer is determined by the dimension of the gaps between the end (flat) surfaces of the circular ring members that form the strainer and the end (flat) surfaces of the auxiliary circular ring members of the scraper that are disposed between the circular ring members in coaxial with the circular ring members. In other words, the solid-liquid separating performance of the strainer is not affected by the thickness of the auxiliary circular ring members. As a result, the present invention provides an improved solid-liquid separating performance while the thickness of the auxiliary circular ring members is kept at dimensions that ensure the strength and durability of the auxiliary circular ring members. 
     Furthermore, in the present invention, a plurality of the flat-plate-form protruding elements are installed by being lined up in a single row. With this arrangement, the end surfaces of the flat-plate-form protruding elements located on the upstream side with respect to the direction of rotation of the strainer collectively form a single scraping surface. Thus, solid matter is efficiently scraped away by the scraper and easily discharged to the outside of the casing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an explanatory diagram that illustrates the basic concept of the solid-liquid separating apparatus according to the present invention; 
     FIG. 2 is a front view of a scraper of the present invention comprising the auxiliary circular ring member and the flat-plate-form protruding element; 
     FIG. 3 is a sectional front view of the solid-liquid separating apparatus according to the present invention; 
     FIG. 4 is a front view of another scraper of the present invention comprising the auxiliary circular ring member and the flat plate-form protruding element; 
     FIG. 5 is an enlarged sectional view of the essential portion of the strainer taken along the axis line thereof, illustrating the positional relationship between the circular ring members that form the strainer and the auxiliary circular ring members that form the scraper; 
     FIG. 6 is an explanatory diagram of the basic concept of a prior art solid-liquid separating apparatus; 
     FIG. 7 is a sectional view taken along the axis of rotation of the strainer in the apparatus of FIG. 6; 
     FIG. 8 is a sectional front view of the structure of the prior art solid-liquid separating apparatus; 
     FIG. 9 is a side view of the strainer of the separating apparatus of FIG. 8; and 
     FIG. 10 is an exploded disassembled view of the strainer shown in FIG.  8 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Preferred embodiments of the solid-liquid separating apparatus of the present invention will be described below in detail with reference to the accompanying drawings. 
     The constituting elements of the solid-liquid separating apparatus  70  of the present invention shown in FIGS. 1 and 2 are substantially the same as those of the solid-liquid separating apparatus  10  shown in FIGS. 6 and 7. Accordingly, the elements that are the same as those of FIGS. 6 and 7 are labeled with the same reference numerals, and a description of such elements is omitted. Only the constituting elements that differ from the shown prior art and make the characterizing features of the present invention will be described below. 
     As seen from FIG. 1, the solid-liquid separating apparatus  70  of the present invention substantially comprises the strainer  12 , the casing  24 , a scraper  72  and the driving device (not shown but is the same as the driving device  36  shown in FIG.  7 ). 
     The feature of the solid-liquid separating apparatus  70  of the present invention is the scraper  72 . In the present invention, the scraper  72  comprises a flat-plate-form circular ring member (auxiliary circular ring member)  74  that is integrally connected to the tip end of the flat-plate-form protruding element  22 . In other words, the scraper  72  takes a structure in which the flat-plate-form protruding element  22  is extended from the outer circumferential surface of the auxiliary circular ring member  74 ; and the auxiliary circular ring member  74  has the same thickness as the flat-plate-form protruding element  22 , so that the protruding element  22  is in the same plane as the auxiliary circular ring member  74 . For convenience of description, the auxiliary circular ring member  74  and flat-plate-form protruding element  22  will hereafter be collectively referred to as a “scraper component(s)  76 ”. 
     The structure of the scraper component  76  will be described in detail with reference to FIGS. 1 and 2. 
     First, the auxiliary circular ring member  74  is formed so that the external diameter is smaller than the external diameter of the circular ring members  14  that form the strainer  12 . Also, the external diameter of the auxiliary circular ring member  74  is larger than the internal diameter of the circular ring members  14 . In the shown embodiment, the internal diameter of the auxiliary circular ring members  74  is smaller than the internal diameter of the circular ring members  14  (see FIG.  5 ). However, the present invention is not limited to this arrangement. The internal diameter of the auxiliary circular ring member  74  can be the same as the internal diameter of the circular ring members  14  or greater than the internal diameter of the circular ring members  14 . 
     The flat-plate-form protruding element  22  of scraper component  76  is formed so as to extend from the outer circumferential surface of the flat-plate-form auxiliary circular ring member  74  as an integral part of the auxiliary circular ring member  74 . The flat-plate-form protruding element  22  is on the same plane as the flat surface of the auxiliary circular ring members  74 . 
     A plurality of scraper components  76  are respectively provided between gaps between adjacent circular ring members  14 . In other words, one scraper component  76  is disposed in intermediate position in each of the gaps between the circular ring members  14  which are arranged side by side, the gaps being slightly greater than the thickness of the scraper component  76 . The auxiliary circular ring members  74  (of the scraper components  76 ) are installed so as to be coaxial with the circular ring members  14 . The outer ends of the flat-plate-form protruding elements  22  reach the outer circumferential surfaces (or protrude over the outer circumferential surfaces) of the circular ring members  14 . 
     As a result of this arrangement, when the strainer  12  with the scraper components  76  assembled therein is viewed from one end, as seen from FIG. 1, some or all of the auxiliary circular ring members  74  of the scraper components  76  overlap in the entire inner circumferential area of the circular ring members  14  for an annular region that has a width G (see FIGS.  3  and  5 ). 
     Accordingly, when the liquid  18  passes from the external region C into the internal region B in the strainer  12 , this liquid inevitably passes through the annular region that has the width G. Furthermore, in this annular region, the liquid  18  passes through the gaps that are formed between the end (flat) surfaces of the auxiliary circular ring members  74  and the end (flat) surfaces of the circular ring members  14  that face each other. In the present invention, these gaps can be freely set without taking the thickness of the scraper components  76  or the thickness of the auxiliary circular ring members  74  into consideration and can therefore naturally be set smaller than the thickness of the auxiliary circular ring members  74 . The solid-liquid separating performance of the solid-liquid separating apparatus  70  of the present invention is thus significantly better than that of the prior art solid-liquid separating apparatus  10  in which the solid-liquid separating performance is limited by the thickness of the flat-plate-form protruding elements  22 . 
     Furthermore, the flow path for the liquid  18  that contains solid matter  16  and has once entered the gaps between the circular ring members  14  is constricted by the auxiliary circular ring members  74  that are disposed on the inner circumferential side of the circular ring members  14 ; as a result, the force of the liquid is weakened. Accordingly, the liquid  18  resides in the gaps between the circular ring members  14  for a longer time, and the amount of solid matter  16  that adheres to the end (flat) surfaces of the circular ring members  14  increases. The solid-liquid separating performance is thus enhanced. 
     Next, the structure of the solid-liquid separating apparatus  70  will be described in a more concrete fashion with reference to FIGS. 3 through 5. The basic structure is the same as that of the prior art solid-liquid separating apparatus  10  shown in FIGS. 8 through 10. Accordingly, the same constituting elements will be labeled with the same reference numerals, and a description of such elements will be omitted. 
     The characterizing features of the solid-liquid separating apparatus  70  of the present invention lie in the scraper  72  as described above. In the present invention, instead of the prior art second protruding elements  58  shown in FIG. 10, a scraper component  76  as shown in FIG. 4 is provided between the first and second circular ring members  14   a  and  14   b  so that the auxiliary circular ring member  74  is coaxial with the circular ring members  14   a  and  14   b.    
     More specifically, the flat-plate-form protruding element  22  of the scraper component  76  is substituted for the prior art second protruding element  58  and is disposed in a position of the second protruding element  58  shown in FIG.  10 . The flat-plate-form protruding element  22  has the length so as to traverse the external region C of the casing  24 ; and as best seen the tip end of this flat-plate-form protruding element  22  is fixed to the casing  24 . Second stays (that are referred to by the reference numeral  64  in FIG. 10) are passed through a plurality of protruding elements  22 , so that the protruding elements  22  or the scraper components  76  are held and supported by the first protruding elements  56  and supporting elements  60 . 
     The positional relationship between the first and second circular ring members  14   a  and  14   b  and the auxiliary circular ring members  74 , which are integrally connected to the flat-plate-form protruding elements  22  that enter the gaps between the first and second circular ring members  14   a  and  14   b , is substantially the same as that in the first embodiment. In other words, as seen from FIG. 5, the auxiliary circular ring members  74  are positioned on the inner circumferential side of the ring-form gaps formed between the first and second circular ring members  14   a  and  14   b , and the area of mutual overlapping is defined as an annular region that has a width G. 
     Furthermore, the width W of the gaps H between the first circular ring members  14   a  and second circular ring members  14   b  (i.e., the width along the axial direction of the strainer  12  (right and left directions in FIG.  5 )) is set so as to be greater than the thickness T of each of the scraper components  76 ; and the scraper components  76  are disposed in intermediate positions in the gaps H. As a result, gaps I are formed between the end (flat) surfaces of the auxiliary circular ring members  74  of the scraper components  76  and the end (flat) surfaces of the first and second circular ring members  14   a  and  14   b  that face the end surfaces of the auxiliary circular ring members  74 ; and such gaps I on both sides of each of the auxiliary circular ring member  74  have the same size of width X. Working precision or assembly precision would cause the auxiliary circular ring members  74  to shift positionally; and in such a situation, there may be some variation in the width X of the gaps I on both sides of each one of the scraper components  76 . 
     When the liquid  18  that contains solid matter  16  flows into the internal region B of the strainer  12  from the external region C, this liquid  18  inevitably passes through the annular region that has the width G. Accordingly, the width X of the very narrow gaps I between the first and second circular ring members  14   a  and  14   b  determines the solid-liquid separating performance. 
     The width X of the gaps I can be independently set without being affected by the thickness T of the scraper components  76  (i.e., the thickness of the flat-plate-form protruding elements  22  and auxiliary circular ring members  74 ). Accordingly, unlike the prior art in which the width W of the gaps H between the first and second circular ring members  14   a  and  14   b  cannot be set smaller than the thickness of the flat-plate-form protruding elements  22 , the solid-liquid separating performance (filtration performance) in the present invention is greatly improved while maintaining the thickness T of the scraper components  76  at a dimension that ensures the strength and durability. 
     The above embodiments are described with reference to a solid-liquid separating apparatus that is used in a raw contaminant dehydration treatment device and separates pulverized raw contaminants and water. It goes without saying that the present invention can be used for other than the separation of raw contaminants and water. 
     As seen from the above, in the solid-liquid separating apparatus of the present invention, gaps that determine the solid-liquid separating performance are obtained by the spaces between the auxiliary circular ring members of the scraper and the circular ring members of the strainer. Accordingly, unlike the prior art structure, the width of these gaps can be set smaller than the thickness of the scraper. In the prior art structure, however, the width of the gaps between the circular ring members of the strainer that determine the solid-liquid separating performance is affected by the thickness of the flat-plate-form protruding elements of the scraper and the width of such gaps cannot be set smaller than the thickness of the flat-plate-form protruding elements. Furthermore, in the present invention, the gaps that are present between the circular ring members and determine the solid-liquid separating performance can be set at the minimum without being affected by the thickness of the scraper. Accordingly, the present invention provides a greatly improved solid-liquid separating performance while the scraper has a thickness of sufficient strength and durability.