Abstract:
An electromagnetic vibrating diaphragm pump is provided with a draining structure which can easily drain water flowed into the pump without a separate member preventing inflow of water. A first communicating passage is formed at a bottom end of a partition wall between a suction chamber and a compression chamber. A bottom portion inside the suction chamber slopes down toward the passage, making its compression chamber side lower than the suction chamber side. A second communicating passage is formed at a bottom end of a partition wall between an exhaust chamber and the compression chamber. A bottom portion inside the compression chamber slopes down toward the passage, making its exhaust chamber side lower than the compression chamber side. A bottom portion inside the exhaust chamber slopes down toward the exhaust port to make the exhaust port side lower. The exhaust port slopes down to make an outlet side thereof lower.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the National Stage of International Application No. PCT/JP2012/056661 International Filing date, 15 Mar. 2012, which designated the United States of America, and which International Application was published under PCT Article 21 (s) as WO Publication 2012/128169 A1 and which claims priority from, and the benefit of, Japanese Application No. 2011-062187 filed 22 Mar. 2011, the disclosures of which are incorporated herein by reference in their entireties. 
     BACKGROUND 
     The presently disclosed embodiment relates to an electromagnetic vibrating diaphragm pump, particularly to an electromagnetic vibrating diaphragm pump with a draining structure. 
     Electromagnetic vibrating diaphragm pumps allowing its pump action to be achieved by a reciprocating motion of an oscillator equipped with a permanent magnet are known as conventional electromagnetic vibrating pumps (See, for example, Patent Documents 1 and 2). In these electromagnetic diaphragm pumps, as shown in  FIGS. 4(   a ) and  4 ( b ), pump action is achieved in such a manner that air taken in from a suction port  107  firstly enters in a suction chamber  102  and then is supplied, via a suction valve  100 , into a compression chamber  104  where the air is compressed by means of a diaphragm (not shown). When a pressure is further applied in the compression chamber  104 , the air moves, via an exhaust valve  101 , to an exhaust chamber  103  provided with an exhaust port  108  and then is exhausted from the exhaust port  108  of the exhaust chamber  103 . In such conventional electromagnetic vibrating diaphragm pump, the suction valve  100  and the exhaust valve  101  are, as shown in  FIGS. 4(   a ) and  4 ( b ), usually mounted nearly on the center of a partition wall  105  (See  FIG. 4(   b )) partitioning the suction chamber  102 , the exhaust chamber  103  and the compression chamber  104 , respectively. Communicating passages  106  for connecting the respective chambers for passing a fluid therethrough are formed nearly on the center of the partition wall  105 . Additional background information may be found in Japanese publications JP 2005-273477 A and JP 2008-280970 A. 
     SUMMARY 
     The conventional electromagnetic vibrating diaphragm pumps having the configuration as mentioned above are, in many cases, located outdoors for the use for purifier tanks, etc., and used in a water-existing environment such as a fish tank, etc. Moreover, there is a case where water comes, via the suction port  107 , into the suction chamber  102 , the compression chamber  104  and the exhaust chamber  103 . This is not limited to the applications mentioned above. In the case of the configuration of conventional electromagnetic vibrating diaphragm pumps, water W remains in the suction chamber  102 , the exhaust chamber  103  and the compression chamber  104  as shown in  FIGS. 4(   a ) and  4 ( b ). If water W remains inside the pump, it causes problems that the members used on the diaphragm pump such as the casing, the diaphragm, the suction valve  100  and the exhaust valve  101  are deteriorated and rusting of fixing parts such as screws for fixing those members arises. 
     Moreover, once water W comes into the inside of the pump, maintenance is very troublesome because the inside of the suction chamber  102 , the exhaust chamber  103  and the compression chamber  104  cannot be seen from the outside in the case of such conventional configuration. Further, when it is found that water remains in a diaphragm pump, the pump itself must be disassembled to remove the water W. 
     Therefore, in conventional electromagnetic vibrating diaphragm pumps, it cannot be said that measures against water is sufficient, and maintenance is very troublesome when water remains in the pump. 
     It can be considered to provide a filter for preventing inflow of water into the suction side of an electromagnetic vibrating diaphragm pump so that water does not flow into the pump. However, the number of components increases, which results in problems from the viewpoint of cost and size. 
     In the light of the above-mentioned problems, an object of the presently disclosed embodiment is to provide an electromagnetic vibrating diaphragm pump equipped with a draining structure which is a simple structure and can easily drain water having flowed into the pump without providing a separate member for preventing inflow of water. 
     The electromagnetic vibrating diaphragm pump of the presently disclosed embodiment comprises magnetic coil portions connected to an alternating-current power source, an oscillator being equipped with a permanent magnet and being driven so as to make a reciprocating motion by applying an alternating voltage to the magnetic coil portions, diaphragms connected to both ends of the oscillator, and pump casings provided with a suction port and an exhaust port for a fluid, wherein each of the pump casings is provided with a suction chamber provided on an upper side of the pump casing and communicating with the suction port, an exhaust chamber provided on a lower side of the pump casing and communicating with the exhaust port, and a compression chamber communicating with the suction chamber via a suction valve and communicating with the exhaust chamber via an exhaust valve, in which an inside pressure of the compression chamber increases and decreases due to deformation of the diaphragm according to the reciprocating motion of the oscillator, wherein a first communicating passage being provided with the suction valve and communicating between the suction chamber and the compression chamber is formed at a bottom end of a partition wall between the suction chamber and the compression chamber, and a bottom portion inside the suction chamber slopes down toward the first communicating passage such that the compression chamber side thereof is lower than the suction chamber side; a bottom portion of the first communicating passage slopes down such that its compression chamber side is made lower; a second communicating passage being provided with the exhaust valve and communicating between the exhaust chamber and the compression chamber is formed at a bottom end of a partition wall between the exhaust chamber and the compression chamber, a bottom portion inside the compression chamber slopes down toward the second communicating passage such that the exhaust chamber side thereof is lower than the compression chamber side; a bottom portion of the second communicating passage slopes down such that its exhaust chamber side is made lower; and a bottom portion inside the exhaust chamber slopes down toward the exhaust port such that the exhaust port side of the bottom portion is made lower, and the exhaust port slopes down such that an outlet side thereof is made lower. 
     It is preferable that a concave portion for drainage is formed on a bottom portion inside the suction chamber being adjacent to the first communicating passage. 
     It is preferable that the suction valve and/or the exhaust valve are arranged such that a clearance is formed between the valve and the partition wall being a valve seat of the suction valve and/or the exhaust valve. 
     According to the presently disclosed embodiment, a first communicating passage being provided with the suction valve and communicating between the suction chamber and the compression chamber is formed at a bottom end of a partition wall between the suction chamber and the compression chamber, a bottom portion inside the suction chamber slopes down toward the first communicating passage such that the compression chamber side thereof is lower than the suction chamber side, and a bottom portion of the first communicating passage slopes down such that its compression chamber side is made lower; a second communicating passage being provided with the exhaust valve and communicating between the exhaust chamber and the compression chamber is formed at a bottom end of a partition wall between the exhaust chamber and the compression chamber, a bottom portion inside the compression chamber slopes down toward the second communicating passage such that the exhaust chamber side thereof is lower than the compression chamber side, a bottom portion inside the exhaust chamber slopes down toward the exhaust port such that the exhaust port side thereof is made lower, a bottom portion of the second communicating passage slopes down such that its exhaust chamber side is made lower, and the exhaust port slopes down such that an outlet side thereof is made lower. Therefore, even if inflow of water from the suction port occurs, water does not remain inside the diaphragm pump because there is formed a difference in height in a fluid passage of the pump, thereby moving water from the suction chamber to the compression chamber, then from the compression chamber to the exhaust chamber, and further unforcedly draining water in the exhaust chamber from the exhaust port. Accordingly, deterioration of the components and rusting due to the remaining water can be prevented, and maintenance of the inside of the pump is unnecessary. Further, another member such as a filter, etc. for preventing inflow of water is not necessary. 
     Moreover, by forming a concave portion for drainage on a bottom portion inside the suction chamber being adjacent to the first communicating passage, water coming into the suction chamber is collected on the concave portion for drainage and can be drained efficiently from the exhaust port. 
     Moreover, by providing a clearance between the valve and the partition wall being a valve seat of the suction valve and/or the exhaust valve, water can be drained from the clearance between the valve and the valve seat even during shut down of the pump. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       ( FIG. 1 ) A longitudinal cross-sectional view of the electromagnetic vibrating diaphragm pump of the presently disclosed embodiment. 
       ( FIG. 2 ) A cross-sectional view of A-A line of  FIG. 1 . 
       ( FIG. 3 ) A partial cross-sectional view for explaining the structure of the valve to be used in the presently disclosed embodiment. 
       ( FIG. 4 ) (a) and (b) are views for explaining a conventional electromagnetic vibrating pump. 
     
    
    
     DETAILED DESCRIPTION 
     The electromagnetic vibrating diaphragm pump of the presently disclosed embodiment is explained below in detail by referring to the attached drawings.  FIG. 1  is a longitudinal cross-sectional view of the electromagnetic vibrating diaphragm pump of the presently disclosed embodiment. As shown in  FIG. 1 , in the electromagnetic vibrating pump  1  of the presently disclosed embodiment (hereinafter referred to simply as pump  1 ), a pair of electromagnetic coil portions  2  is provided in a casing C, and an oscillator  4  having permanent magnets  3  is provided between the pair of electromagnetic coil portions  2 . At both ends of the casing C, a pair of pump casings  6  is provided, and the inside of the casing C is separated from the pump casings  6  by means of a pair of diaphragms  5  provided on the right and left sides in  FIG. 1 . 
     The electromagnetic coil portions  2  are connected with an alternating-current power source, and when the alternating voltage is applied to the electromagnetic coil portions  2 , the oscillator  4  provided with the permanent magnets  3  is driven so as to make a reciprocating motion. The diaphragms  5  are connected to both ends of the oscillator  4  and a periphery of the diaphragms  5  is supported by the casing C. In  FIG. 1 , as the oscillator  4  moves right and left, the pair of diaphragms  5  also deflects right and left to increase and decrease the inside pressure of the compression chamber  61  in the pump casing  6 , thereby operating the pump. Here, the configuration of the electromagnetic coil portions  2 , the permanent magnets  3 , the oscillator  4  and the diaphragms  5  is not limited particularly, and conventional configuration having been used on diaphragm pumps can be used as it is. It goes without saying that improvements over conventional configuration being obvious to a person having ordinary skill in the art are also included in the presently disclosed embodiment. 
     As shown in  FIG. 1  and  FIG. 2 , the pump casings  6  comprise the suction chamber  62  provided with the suction port  7  for taking a fluid such as air thereinto from the outside, the compression chamber  61  into which the fluid flows from the suction chamber  62  through the first communicating passage P 1 , and the exhaust chamber  63  into which the fluid flows from the compression chamber  61  through the second communicating passage P 2  and which is provided with the exhaust port  8  for feeding the fluid toward the outside. 
     As shown in  FIG. 1  and  FIG. 2 , the first communicating passage P 1  is provided with the suction valve V 1  to prevent a backflow of the fluid from the compression chamber  61  into the suction chamber  62 , and the second communicating passage P 2  is provided with the exhaust valve V 2  to prevent a backflow of the fluid from the exhaust chamber  63  into the compression chamber  61 . As far as a backflow of the fluid can be prevented, materials and structures of the suction valve V 1  and the exhaust valve V 2  are not limited particularly, and for example, an umbrella valve made of an elastic material can be used. 
     As shown in  FIG. 1  and  FIG. 2 , the suction chamber  62  is provided on the upper side of the pump casing  6 . The first communicating passage P 1  communicating between the suction chamber  62  and the compression chamber  61  is provided at the bottom end of a substantially vertical partition wall W 1  separating the suction chamber  62  from the compression chamber  61 . A bottom portion  62   a  inside the suction chamber  62  slopes down toward the first communicating passage P 1  such that the first communicating passage side thereof is made lower, and a bottom portion of the first communicating passage P 1  slopes down such that the compression chamber  61  side thereof is lower than the suction chamber  62  side. As mentioned above, by inclining the suction chamber  62  and the first communicating passage P 1 , water flowing from the suction port  7  into the suction chamber  62  can be collected in the first communicating passage P 1 , and further, water collected in the first communicating passage P 1  can be drained into the compression chamber  61 . 
     The second communicating passage P 2  provided with the exhaust valve V 2  and communicating between the compression chamber  61  and the exhaust chamber  63  is provided at a bottom end of a substantially vertical partition wall W 2  separating the compression chamber  61  from the exhaust chamber  63 . A bottom portion  61   a  of the compression chamber  61  is arranged at a position lower than the bottom portion of the first communicating passage P 1 . The bottom portion  61   a  slopes down toward the second communicating passage such that the second communicating passage side thereof is made lower. As mentioned above, by inclining the compression chamber  61  and the second communicating passage P 2 , water flowing from the suction chamber  62  into the compression chamber  61  can be collected in the second communicating passage P 2 , and further, water collected in the second communicating passage P 2  can be drained into the exhaust chamber  63 . 
     As shown in  FIG. 2 , a bottom portion  63   a  of the exhaust chamber  63  slopes down toward the exhaust port  8  such that the exhaust port  8  side thereof is made lower. Also, the exhaust port  8  slopes down so that the outlet side thereof is made lower. Therefore, by inclining the exhaust chamber  63  and the exhaust port  8 , water flowing into the exhaust chamber  63  from the compression chamber  61  can be drained from the exhaust port  8 . 
     As mentioned above, by inclining the bottom portion  62   a  of the suction chamber  62 , the first communicating passage P 1 , the bottom portion  61   a  of the compression chamber  61 , the second communicating passage P 2 , the bottom portion  63   a  of the exhaust chamber  63 , and the exhaust port  8 , thereby providing a difference in a height, water flowing from the suction port  7  can be fed up to the exhaust port by means of a gravity, and therefore, water does not remain inside the pump. Accordingly, it is possible to prevent deterioration of the members to be provided inside the pump casings  6  and generation of rusting of metal fixing means such as screws inside the pump casings  6 , which arise due to the remaining water in the pump casings  6 . 
     As shown in  FIG. 3 , an angle  8  of inclination of the bottom portion  62   a  of the suction chamber  62  and the bottom portion of the first communicating passage P 1  with respect to a horizontal plane is not limited particularly as far as it is an angle being enough for draining the water flowing in the pump. The water can be drained, for example, by setting the angle  8  of inclination to be 3° or more. Such an angle may be applied not only to the bottom portion  62   a  of the suction chamber  62  but also to the bottom portion  61   a  of the compression chamber  61 , the second communicating passage P 2 , the bottom portion  63   a  of the exhaust chamber  63 , and the exhaust port  8 . Moreover, a draining effect can be accelerated by forming not only the bottom portion  62   a  of the suction chamber  62  but also the bottom portion  61   a  of the compression chamber  61 , the second communicating passage P 2 , the bottom portion  63   a  of the exhaust chamber  63 , and the exhaust port  8  by molding a hydrophobic material, or by applying a hydrophobic coating to the bottom portions thereof, and as a result, the angle  8  of inclination can be made smaller. In  FIGS. 1 to 3 , the inclined bottom portions of the suction chamber  62 , the compression chamber  61  and the exhaust chamber  63  are represented in the form of flat surface, but are not required to be in the form of flat bottom surface. The inclined bottom portions may be in the form of curved surface, or a plurality of inclined portions may be provided in a stepwise form. 
     The suction port  7  may be sloped down such that the suction chamber  62  side thereof is made lower, or the inlet side thereof may be made lower so that water hardly flows into the suction chamber from the suction port  7 . 
     The relation of the positions of the suction chamber  62 , the compression chamber  61  and the exhaust chamber  63  is such that the bottom portion  62   a  of the suction chamber  62  is located at a highest position, next the bottom portion  61   a  of the compression chamber  61  is lower than the bottom portion  62   a  of the suction chamber  62 , and the bottom portion  63   a  of the exhaust chamber  63  is lower than the bottom portion  61   a  of the compression chamber  61 . When the relation is as mentioned above, water flowing inside the pump is drained from the exhaust port by means of a gravity. Therefore, it goes without saying that as far as the above-mentioned relation of the positions of the respective chambers with respect to the heights thereof is satisfied, it is included in the presently disclosed embodiment. 
     As shown in  FIG. 2 , in order to make draining of water more efficient, it is possible to provide a concave portion  62   b  for collecting water having a further steep inclination on the bottom portion  62   a  of the suction chamber  62  being adjacent to the first communicating passage P 1 . While in  FIG. 2 , the concave portion  62   b  for collecting water is provided only in the suction chamber  62 , however it goes without saying that a similar concave portion like the concave portion  62   b  for collecting water may be provided in the compression chamber  61  and the exhaust chamber  63 . 
     Next, the function of water draining of the presently disclosed embodiment is explained. When an alternating voltage is applied to the electromagnetic coil portion  2 , the oscillator  4  provided with the permanent magnets  3  is driven so as to make a reciprocating vibration in the right and left directions in  FIG. 1  due to a magnetic action by the electromagnetic coil portion  2 . According to the reciprocating vibration of the oscillator  4 , the diaphragms  5  connected to the both ends of the oscillator  4  also deflect in the right and left directions, thereby changing the volume of the inside of the compression chamber  61  and increasing or decreasing the inside pressure of the compression chamber  61 . For example, when the diaphragm  5  at the right-hand side in  FIG. 1  is deflected toward the left and the inside pressure of the compression chamber  61  is decreased, the suction valve V 1  opens the first communicating passage P 1  and a force for closing the second communicating passage P 2  is applied to the exhaust valve V 2  to close the second communicating passage P 2 . On the contrary, when the diaphragm  5  at the right-hand side in  FIG. 1  is deflected toward the right, the inside pressure of the compression chamber  61  is increased, the suction valve V 1  closes the first communicating passage P 1  and the exhaust valve V 2  opens the second communicating passage P 2 . 
     Accordingly, when water flows in the pump from the suction port  7 , water having flowed in the suction chamber  62  moves toward the first communicating passage P 1  due to the inclination of the bottom portion  62   a  of the suction chamber  62 , and when the oscillator  4  is driven and the suction valve V 1  is opened, water flowing in the first communicating passage P 1  moves into the compression chamber  61  through the clearance between the opened suction valve V 1  and the partition wall W 1 . Similarly, water having flowed in the compression chamber  61  moves toward the second communicating passage P 2  due to the inclination of the bottom portion  61   a  of the compression chamber  61 , and when the oscillator  4  is driven and the exhaust valve V 2  is opened, water moves into the exhaust chamber  63  through the clearance between the opened exhaust valve V 2  and the partition wall W 2 . Further, water having flowed into the exhaust chamber  63  is drained outside of the pump from the exhaust port  8  due to the inclination of the bottom portion  63   a  of the exhaust chamber  63  and the inclination of the exhaust port  8 . As a result, by driving the pump  1 , water having flowed into the pump from the suction port  7  can be drained from the exhaust port  8 , and thus, no water remains inside the pump casings  6 . 
     The above-mentioned embodiment shows the case where water can be drained when the pump  1  is driven. Meanwhile, as shown in  FIG. 3 , even while the pump  1  is shut down, water can be drained by providing clearances between the suction valve V 1  and the partition wall W 1  being a valve seat thereof and between the exhaust valve V 2  and the partition wall W 2  being a valve seat thereof. Namely, when taking the suction valve V 1  as an example, as shown in  FIG. 3 , the clearance Cl is formed between the suction valve V 1  and the partition wall W 1  being a valve seat thereof. The suction valve V 1  is made of an elastic material. While the pump  1  is not driven and a pressure is not applied to the inside of the compression chamber  61 , the skirt portion of the suction valve V 1  is in a stationary state as shown in  FIG. 3 . Therefore, even in the case of the pump  1  being in a shut-down state, when water flows in the pump, water in the suction chamber  62  can be drained in the compression chamber  61  through the clearance Cl. 
     By providing a clearance between the exhaust valve V 2  and the partition wall W 2  in the same manner as in the suction valve V 1 , water can be drained from the compression chamber  61  to the exhaust chamber  63 , and even during the shut-down of the pump  1 , water having flowed into the pump from the suction port  7  can be drained from the exhaust port  8 . Accordingly, it is possible to further prevent deterioration of the members to be provided inside the pump casings  6  and generation of rusting of metal fixing means such as screws inside the pump casings  6 . 
     When the pump  1  is driven and a fluid is taken in from the suction chamber  62  to the compression chamber  61 , the suction valve V 1  is opened due to a pressure drop in the compression chamber  61 , and the skirt portion S of the exhaust valve V 2  is drawn toward the partition wall W 2  to close the exhaust valve V 2 . Moreover, when a fluid is exhausted from the compression chamber  61  into the exhaust chamber  63 , the exhaust valve V 2  is opened due to a pressure drop in the compression chamber  61 , and the skirt portion S of the suction valve V 1  is pressed onto the partition wall W 1  to close the suction valve V 1 . Accordingly, during the shut-down of the pump  1 , water can be drained, and while the pump  1  is driven, the clearance CI is closed and the discharge of the pump  1  can be maintained. 
     Water can be drained through the clearance CI, and in order not to deteriorate performance of the pump  1 , the dimension D of the clearance CI from the skirt portion S of the suction valve V 1  to the partition wall W 1  being a valve seat thereof is not limited particularly and is preferably from 0.2 to 1.0 mm. When it is less than 0.2 mm, water cannot be drained effectively, and when it is more than 1.0 mm, performance of the pump  1  is decreased. 
     EXPLANATION OF SYMBOLS 
     
         
         
           
               1  Pump 
               2  Electromagnetic coil portion 
               3  Permanent magnet 
               4  Oscillator 
               5  Diaphragm 
               6  Pump casing 
               61  Compression chamber 
               62  Suction chamber 
               63  Exhaust chamber 
               61   a ,  62   a ,  63   a  Bottom portion 
               62   b  Concave portion for collecting water 
               7  Suction port 
               8  Exhaust port 
             C Casing 
             Cl Clearance 
             P 1  First communicating passage 
             P 2  Second communicating passage 
             S Skirt portion 
             V 1  Suction valve 
             V 2  Exhaust valve 
             W 1 , W 2  Partition wall