Patent Publication Number: US-6712162-B2

Title: Cooling and flushing means for tools used for working rock

Description:
BACKGROUND OF THE INVENTION 
     The invention is directed to a cooling and flushing arrangement for tools used for working rock, preferably for annular core bits used in diamond core drills for masonry, concrete and rock. 
     In the case of cooling and flushing arrangements for tools or tool devices in general, a fluid coolant and flushing agent, such as water, is conveyed by means of a pump at least over parts of the tool in a closed flushing circulation system including a storage tank. 
     According to EP 36,814, the cooling and flushing arrangement for a tool in the form of a rock saw having a rock saw blade cooled by a coolant and flushing agent comprises a storage tank and a reservoir that are connected via a float valve for automatically refilling the storage tank. This cooling and flushing arrangement without a pump does not form a closed flushing circulation system and, therefore, at least discontinuously, requires filling with coolant and flushing agent. 
     According to U.S. Pat. No. 3,782,501, the cooling and flushing arrangement for a tool device has a float valve located inside a storage tank and that, for a control circuit, determines the flow of coolant and lubricant in a closed circulation system having a reservoir, a pump and a filter and, depending on the flow, blocks the tool device. 
     According to EP 0,941,828, a cooling and flushing arrangement for annular core bits used in diamond core drills has a storage tank with a suction pump and a filter connected via a pressure pump in a closed flushing circulation system. The storage tank, which has to accommodate the entire quantity of coolant and flushing agent, cannot be situated near the tool in all application cases because of its volume and weight whenever large amounts of coolant and flushing agent are needed. 
     SUMMARY OF THE INVENTION 
     The objective of the invention is to provide a cooling and flushing arrangement for tools used for working rock, whose storage tank can be situated near the tool, even when large amounts of coolant and flushing agent are needed. 
     The cooling and flushing arrangement has a coolant and flushing agent in a closed storage tank, which is connected to the ambient atmosphere via a suction pump for generating a negative pressure, and the arrangement has a closed flushing circulation system running from the storage tank through a filter, which is connected via a pressure pump for generating the flushing circulation in order to clean the coolant and flushing agent, and through a collecting member associated with the tool for collecting the dirty coolant and flushing agent flowing back from the tool in a suction line, back to the storage tank. Essentially, this flushing circulation system is combined with a reservoir circulation system in which coolant and flushing agent—conveyed by the suction pump connected to the storage tank and by the negative pressure for drawing in the coolant and flushing agent that is generated by the flow resistance in the flushing circulation system via the collecting member and via the suction line—is drawn in from an open reservoir into the storage tank, when a float valve situated in the storage tank for regulating the filling level is open. The coolant and flushing agent of the reservoir circulation system moves, together with the coolant and flushing agent of the flushing circulation system, through the pressure pump into the filter and flows back into the reservoir via a filter concentrate drain at the lower end of the filter as dirty coolant and flushing agent. 
     When the float valve is completely open, the inflow from the reservoir predominates over the outflow into the reservoir, thus compensating for a shortage of coolant and flushing agent in the flushing circulation system. When the float valve is closed, the outflow into the reservoir predominates over the inflow from the reservoir, thus removing excess coolant and flushing agent from the flushing circulation system. Because of the combined reservoir circulation system, the storage tank can be configured very small and thus can be situated near the tool, as a result of which the drawing in of the coolant and flushing agent via the collecting member can be improved or, with the same storage tank, larger amounts of coolant and flushing agent can be used. 
     Advantageously, a tool device to be cooled is integrated into the flushing circulation system between the filter and the tool. 
     Preferably, the suction pump and the pressure pump are combined by a shared drive which is also advantageously combined with the drive of the tool device. 
     Advantageously, the tool device comprises the storage tank and the reservoir, whereby also advantageously, the tool device is formed as a core drill. 
     Advantageously, the storage tank is configured so as to float on the coolant and flushing agent of the reservoir, as a result of which only a very small negative pressure is needed to pump the reservoir circulation system. 
     Preferably, the collecting member is shaped as a torus that holds an annular core bit coaxially on the inside so as to seal it radially. It is axially open on one end opposite the radial seal and affords an axial seal at the open end against a surface to be worked and the torus has a connection for a suction line. 
     Preferably, water is the coolant and flushing agent, combining a high thermal capacity and cleaning power with biological safety and extremely high availability. 
    
    
     BRIEF DESCRIPTION OF THE INVENTION 
     The invention is explained in greater depth with reference to an advantageous embodiment, and: 
     FIG. 1 is a schematic showing of a cooling and flushing arrangement, and, 
     FIG. 2 is a schematic showing of a collecting device. 
     FIG. 3 is a schematic showing, similar to FIG.  1 . however, with the storage tank in a floating position. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     According to FIG. 1, a cooling and flushing arrangement  1  has a coolant and flushing agent  2  in the form of water in a closed storage tank  3 , which is connected to the ambient atmosphere  5  via a suction pump  4 , and has a closed flushing circulation system  6  running from the storage tank  3  through a pressure pump  7 , then through a filter  8 , to a tool device  9  in the form of a core drill, then over parts of a tool  10  in the form of an annular core bit and finally through a collecting member  11  associated with the tool  10 , and over a suction line  12  back to the storage tank  3 . The flushing circulation system  6  is combined with a reservoir circulation system  13  in which the coolant and flushing agent  2  moves from a large reservoir  14 , open to the ambient atmosphere  5 , via a float valve  15  situated in the storage tank  3  and controlled by the filling level, into the storage tank  3 , then together with the flushing circulation system  6 , through the pressure pump  7  into the filter  8  and via a filter concentrate drain or valve  16  at the lower end of the filter  8  as dirty coolant and flushing agent flows back into the reservoir  14 . The suction pump  4  and the pressure pump  7  are combined with the tool device  9  via a shared drive  17 . 
     According to FIG. 2, the collecting member  11  is formed as a torus that holds an annular core bit of the tool  10  coaxially on the inside with radial gaskets  18  so as to seal radially one end of the collecting member  11 , which is axially open on the other end and is sealed, axially by axial gaskets  19  against a surface  20  to be worked, and that has a connection  21  for the suction line  12  through which the coolant and flushing agent  2 , that has become contaminated with removed material  22 , is discharged.