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.
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 agentxe2x80x94conveyed 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 linexe2x80x94is 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.