Abstract:
Two cylindrical pump cylinders are mounted end-to-end. A first piston is placed in the first cylinder, a second piston is placed in the second cylinder, and the pistons are interconnected. In one embodiment compressed air alternately drives the first piston in either direction, causing the interconnected second piston to draw and pump high viscosity liquid in the second cylinder through the use of check valves. In another embodiment compressed air is alternately injected into one side of the first piston and one side of the second piston, thus alternately drawing and pumping liquid on the other side of the pistons. A heating jacket is placed around the cylinder pumping the liquid to heat and thus lower the viscosity of the liquid. Piston movement sensors that sense the limits of piston movement within the cylinders are mounted in the cylinder wall.

Description:
BACKGROUND 
     The present invention relates to a pump for feeding liquid substances, and more particularly to a pump having a structure suitable to feeding semi-liquid substances having high viscosity, in which feeding is achieved consecutively rather than intermittently. 
     In general, the conventional two-stroke type cylinder pump acts using inhalation and compression. This type of pump has the disadvantage in that the operations of inhalation and compression are conducted intermittently. A centrifugal pump feeds by using the centrifugal force of an impeller and has an advantage of continuous feeding. This pump is very sensitive to the viscosity of the substance being fed and thus has the disadvantage that substances having some viscosities cannot become the object of feeding. 
     In order to feed viscous substances, a pump having a structure similar to a vane pump is mainly used. This pump, being driven according to the viscosity, especially should be controlled by the substance being fed by means of continuous use. For this reason, it has the disadvantage of rising maintenance fees and frequent troubles. It also has the drawback of low volume ratio. 
     Further, a pump using a diaphragm was conceived in recent years. This pump settled some problems of the general pump. However, in pumps having such structure, the diaphragm consisting of soft rubber is restricted to the pressure limit enabling the feeding. For this reason, it has a problem in which the diaphragm is frequently torn when feeding a high viscosity substance. 
     To solve the conventional problems described above, the present invention was conceived. A pump according to the present invention has a structure which does not require any separate controller for controlling the driving of the pump, and by which continuous feeding can be performed without interruption, as the pump is automatically operated without regard to the viscosity of the substance being fed. 
     There is another invention related to the present invention, which was filed in Korea on Aug. 8, 1996 by the present applicant (Utility Model Application No. 23928). 
     SUMMARY 
     The present invention was conceived to solve the conventional problems described above. An object of the present invention is to provide a pump having a structure that enables consecutive feeding. Inhalation and discharge of the substance being fed are achieved by means of interlocking pump piston operation. The piston rod of the air cylinder is reciprocated with the power of compressed air, and the reciprocating stroke operation of the pump is automatically adjusted by the flexible match of compressed air in accordance with the viscosity of the substance being fed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view illustrating a first example of the present invention. 
     FIG. 2 is a sectional perspective view illustrating the first example of the present invention. 
     FIG. 3 is a front sectional view illustrating the first example of the present invention. 
     FIG. 4 is an exploded perspective view illustrating the first example of the present invention. 
     FIG. 5 is a perspective view illustrating a second example of the present invention. 
     FIG. 6 is a sectional perspective view illustrating the second example of the present invention. 
     FIG. 7 is a front sectional view illustrating the second example of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Hereinafter, desirable examples of the present invention will be described with reference to the accompanying drawings. 
     FIG. 1 is a general perspective view illustrating a pump according to the present invention. A pump cylinder  1  is placed at the bottom, an air cylinder  100  driving the pump cylinder  1  is placed at the top, and the cylinders are interconnected. A lower block  10  and an intermediate block  20  are mounted opposing the top and bottom of pump cylinder  1 . At the top of the air cylinder  100  an upper block  150  is mounted and assembled into a base  30 . 
     The pump having such construction is described with reference to FIG. 2 to FIG.  4 . At the bottom of a base  30  four assembly screw holes are drilled. Outside of the screw holes a plurality of erection holes are drilled. The lower block is erected on the top. A lower suction hole  11  is formed on the left, drilled at right angles with a cylinder jaw  12  with a helix formed outside. Symmetrically to it, a lower discharge hole  15  is drilled at right angles with the cylinder jaw with a helix formed outside. On the peripheral curved surface of the cylinder jaw  12  a packing groove  14 - 1  is formed in which a packing  14  is put in, and at each edge an assembly hole  13  is drilled. 
     Cylindrical pump cylinder  1  is put into cylinder jaw  12 . Piston ring  2 - 1  is inserted on the peripheral surface of pump piston  2 . The piston is engaged with a rod bolt  3 - 1  that is formed at the bottom of a pump cylinder rod  3 , also having a rod nut  3 - 2  at the top. The piston is assembled into the inside of pump cylinder  1 . 
     A packing  24  is put into a pump cylinder jaw  22  that is formed at the bottom of the intermediate block  20 . The assembled pump cylinder rod  3  passes through rod hole  26 , formed in the middle of the intermediate block, and is assembled into the pump cylinder described above. On the left, an upper suction hole  21  is drilled at right angles on the pump cylinder jaw  22  and a helix is externally formed. Symmetrically to it, on the right an upper discharge hole  25  is drilled at right angles on the pump cylinder jaw  12  and a helix is externally formed. At the top of the intermediate block  20  an air cylinder jaw  22 - 1  is formed and packing  24 - 1  is inserted. Lower compressed air hole  27  is drilled at right angles in the front of intermediate block  20  and a helix is externally formed. Jaw  22 - 1  is assembled into cylindrical air cylinder  100 . 
     Air piston  101  is placed on a part  102 - 2  that is integrally formed at the lower end of air cylinder rod  102 . Limit helix part  102 - 3  at the top is such that rod bolt  102 - 1  is inserted through air piston  101 . A rod nut  3 - 2  of the pump cylinder rod  3  is screwed with rod bolt  102 - 1 , and air piston  101  is fixed between air cylinder rod  102  and pump cylinder rod  3  such that the air piston  101  is positioned in air cylinder  100 . 
     Under the assembled state as described above, upper block  150 , having air cylinder jaw  152  at the bottom, is assembled into the top of air cylinder  100 . Air cylinder rod  102  passes through air cylinder rod hole  162  in rod bushing  160 . Bushing packing  161  is in the middle of rod hole  162 . Rod bushing  160  is inserted into rod bushing hole  156  formed in the middle of the upper block. An upper compressed air hole  157  is drilled at right angles in the front surface of upper block  150 , and a helix is externally formed. At each edge of upper block  150  an assembly hole  153  is drilled. 
     At the top of upper block  150  an assembly plate  170  is assembled. Rod bushing hole  171  is drilled in the middle of assembly plate  170 , and rod bushing  160  is assembled into hole  171 . An assembly hole  173  is drilled through at each edge of assembly plate  170 . An assembly bolt  180 , having an upper bolt  181  and a lower bolt  182 , passes through assembly holes  13 ,  23 ,  153 , and  173 , drilled at the edge of upper block  150 , intermediate block  20 , and lower block  10 , such that lower bolt  181  is screwed into assembly screw hole  31  of base  30 . By fastening assembly nut  183  with assembly nut  182  on the other side of nut  183 , the aforesaid parts are securely assembled. A limit  190  is inserted onto a limit helix part that is formed at the top of air cylinder rod  102 , and limit nut  191  is placed thereon. 
     Upper suction check valve flanged tube  221  is attached on upper suction hole  21  of intermediate block  20 . Lower suction check valve flanged tube  222  is attached on lower suction hole  11  of lower block  10 . Upper suction flanged tube  211  and lower suction flanged tube  212  are integrally connected with flanged tube  221  and with confluent suction flanged tube  200 . 
     Also, upper discharge check valve flanged tube  321  is attached on the upper discharge hole  25  of the intermediate block  20 . Lower discharge check valve flanged tube  322  is attached on lower discharge hole  15  of lower block  10 . Upper discharge flanged tube  311  and lower discharge flanged tube  312  are integrally connected with lower discharge check valve flanged tube  322  and with confluent discharge flanged tube  300 . 
     Each of the aforesaid check valves has a common structure comprising a check valve ball  400 , a valve mount  401 , a valve spring  402 , and a spring bench  403 . 
     Hereinafter, the operation and effects of the present invention having the aforesaid construction will be described. 
     As shown in FIG. 3, the operation is advanced in a direction expressed in a solid line. Air cylinder  100  is filled with air by injecting compressed air through lower compressed air hole  27  of intermediate block  20 . As air piston  101  moves upwardly, pump cylinder rod  3  is interlocked by being connected with air cylinder rod  102 . If pump piston  2 , connected with pump cylinder rod  3 , is going up, upper suction check valve flanged tube  221 , having a check valve, is closed and lower suction check valve flange  222  is opened. 
     The upper discharge check valve flanged tube  321  is opened, and lower discharge check valve flanged tube  322  is closed so that compressive feeding and suction can be achieved by the movement of the feeding substance at the same time. 
     Operation being advanced in an opposite direction is explained herebelow. As shown in a broken line of FIG. 3, when compressed air is injected through upper compressed air hole  157 , formed in upper block  150 , air piston  101  moves to the bottom. When air piston  101  is going down, pump piston  2 , engaged with the end of pump cylinder rod  3  that is connected with the air piston is going down. In this case, upper suction check valve flanged tube  221  is opened and lower suction check valve flange  222  is closed. 
     The upper discharge check valve flanged tube  321  is closed and the lower discharge check valve flanged tube  322  is opened so that feeding substance sucked at the bottom is compressively fed and the bottom of the pump cylinder  1  is made vacuous. Consecutive compressive feeding from the confluent suction flanged tube  200  to the confluent discharge flanged tube  300  is enabled by means of consecutive pumping operation. 
     In the present invention having such operation, the quantity of compressed air is compressed according to the viscosity of the substance being fed and can be adjusted in proportion to the compression ratio of the compression generator. In the event that feeding of the substance being fed is smoothly performed without regard to the compression ratio, air piston  101  in air cylinder  100 , being operated by injected air, reciprocates the full distance between a top dead center and a bottom dead center. A substance having relatively high viscosity, in relation to the air pressure having the compression ratio described above, is not smoothly fed and thus the air piston  101  of the air cylinder does not reach the top dead center and the bottom dead center. Despite this, air being injected is compressed more than the pressure of the air being injected, thereby, according to the viscosity of the feeding substance, not reciprocating the stroke distance of the pump piston  2  unreasonably so that the pumping apparatus can be protected. 
     Taking the feeding object of a chocolate or glucose as an example, the viscosity of a substance being fed varies according to the temperature of the environment using this apparatus or the temperature inside the apparatus according to the driving hours of this apparatus. The higher such temperature is, the lower the viscosity is. Consequently, feeding is performed more smoothly. 
     At the time of initial operation, the temperature of this apparatus is in a low state, and accordingly it is operated in the state of high viscosity. As a result, feeding is not smoothly performed. 
     Even when the feeding substance is of high viscosity, compressed air being injected into the air cylinder  100  reciprocates the air piston  101  of the air cylinder  100  flexibly, thereby not applying unreasonable pressure to pump cylinder  1 . 
     Further, the construction and operation of other examples of the present invention may be seen. Upper suction tube  501  is mounted on the left of upper block  500  and is drilled to pass through to pump cylinder  510 . On the right, upper discharge tube  502  passes through to upper cylinder pump  510 . At the bottom of upper block  500  the upper pump cylinder  510  is mounted. 
     Inside of it an upper piston  520  is inserted and in the middle of upper piston  520  a piston rod  630  is connected. Rod  630  is engaged with lower piston  620  mounted inside lower pump cylinder  610  by passing through rod hole  605  in intermediate block  600 . On the left of intermediate block  600  a lower compressed air supply tube  603  is mounted so that the compressed air can flow into the inside of intermediate block  600 . And on the right an upper compressed air supply tube  604  is mounted so that the compressed air being supplied through the supply tube flows into upper pump cylinder  510 . 
     On upper suction tube  501  an upper suction check valve flanged tube  503 , being opened in a suction direction only, is mounted. On lower suction tube  701  of lower block  700  a lower suction check valve flanged tube  703  is mounted so that the upper suction check valve flanged tube  503  is connected with suction tube  800 . 
     Further, on upper discharge tube  502  an upper discharge check valve flanged tube  504 , being opened in a discharge direction only, is mounted. On lower discharge tube  702  of lower block  700  a lower discharge check valve flanged tube  704 , being opened in a discharge direction only, is mounted so that the upper discharge check valve flanged tube  504  is connected with discharge tube  900 . 
     The operation of a second example of the present invention having such construction is explained herebelow. By injecting compressed air through lower compressed air supply tube  603 , as expressed in a solid line shown in FIG. 7, the compressed air pushes lower piston  620  mounted inside lower cylinder pump  610 . Thus lower piston  620  feeds the feeding substance in lower cylinder pump  610  to discharge tube  900  while lower piston  620  is going down. Upper piston  520 , being interlocked with piston  620 , sucks the feeding substance from upper suction tube  501 . According to the pump&#39;s operation, lower suction check valve flanged tube  703  is closed and lower discharge check valve flanged tube  704  is opened, thereby compressively feeding the substance sucked inside the lower cylinder to discharge tube  900  while the lower piston  620  is going down and being compressed. 
     Further, the operation of the upper cylinder pump  510  is seen. Upper suction check valve flanged tube  503  is opened and upper discharge check valve flanged tube  502  is closed while lower piston  620  is going down in accordance with interlocking movement. Thus the feeding substance is sucked from suction tube  800  to upper suction pipe  501  by means of the vacuum of upper pump cylinder  510 . 
     By injecting compressed air into upper compressed air supply tube  604 , upper piston  520  goes up and upper suction check valve flanged tube  503  closes so that the feeding substance sucked in upper pump cylinder pump  510  is compressively fed to discharge tube  900  through upper discharge check valve flanged tube  504  that opens. And the interlocking lower piston  620  that is connected with upper piston  520  and piston rod  630  goes up and lower suction check valve flanged tube  703  opens by means of lower check valve flanged tube  702  being closed, thereby sucking the feeding substance. 
     A bottom dead center sensor  801  is mounted which senses the downward movement limit of upper piston  520 . Also, a bottom dead center sensor  802  which senses the upward movement limit of lower piston  620  is mounted and connected with a controller which controls the supply of compressed air. Thus the reciprocating limit of the upper piston  520  and the lower piston  620  is sensed for smooth reciprocating operation. 
     Further, on the peripheral curved surface of upper pump cylinder  510  and lower pump cylinder  610 , heating circular jackets  511 ,  611  are attached and heated for smooth feeding of substances having high viscosity. This heating prevents the feeding substance&#39;s viscosity from rising, especially during the winter season. 
     The present invention having such operation has a construction suitable for feeding substances having relatively high viscosity. It was conceived to solve the drawbacks which the conventional pump has in general. In the conventional pump, a tachometer driving the pump may cause overheating according to high load due to the feeding resistance resulting from feeding substances having viscosity. Especially in the case of a diaphragm pumping apparatus, the present invention solves the problem of the diaphragm being easily broken or damaged. Accordingly, the present invention has an advantage in which reciprocating movement distance of the piston being operated inside the pump according to the viscosity of the feeding substance is suitably adjusted in accordance with the feeding resistance. 
     In the meantime, it is obviously understood by the person skilled in the art that the present invention is not limited to the particular examples disclosed herein as the best mode contemplated for carrying out the present invention, and that various alterations or modifications thereof can be made within the present invention.