| Drive device for a dual-cylinder slurry pump and method for operating said pump -> Monitor Keywords |
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Drive device for a dual-cylinder slurry pump and method for operating said pumpRelated Patent Categories: Pumps, Expansible Chamber Type, Distributor Moved By Separate Fluid Responsive SurfaceDrive device for a dual-cylinder slurry pump and method for operating said pump description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070274850, Drive device for a dual-cylinder slurry pump and method for operating said pump. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] The present invention relates to a method for operating a dual-cylinder slurry pump and a drive device for a dual-cylinder slurry pump in accordance with the generic part of claim 1 and the generic part of claim 8. [0002] Dual-cylinder slurry pumps are used, for example, to pump concrete. For this, the concrete is pumped over substantial heights and distances, e.g., via corresponding distributing masts. In such dual-cylinder slurry pumps, the delivery cylinders are connected via a switch, especially a pipe switch, to a common delivery line, with the switch alternately connecting the one or other delivery cylinder to the delivery line, such that overall the flow of slurry or concrete is virtually continuous. [0003] However, the unavoidable changes of connection between the delivery cylinders to the common delivery line by means of the switch create brief interruptions in delivery during the switching operations. [0004] This may be seen for example in the block diagram of FIG. 2, which shows an hydraulic drive for a dual-cylinder slurry pump with a pipe switch. This is a block diagram of a so-called single-circuit system in which the drive cylinders 1, 2 of the delivery cylinders FR, FL and the actuator cylinder SZ of the pipe switch are supplied with hydraulic oil by means of one supply device only or in which the working pressure is generated. This sole supply device has two pumps P1 and P2, which are connected via oil lines L1 and L2 to the switching block 3, which, depending on the operating status, makes the oil delivered by pumps P1 and P2 available to the drive cylinder 1 or the drive cylinder 2 for the delivery cylinders FR and FL via lines L4 or, via further lines L4a , to the actuator or swiveling cylinder SZ of the pipe switch RW. [0005] However, relatively long switching operations occur here because it is only after a stroke of the drive cylinder 1 or 2 that the control block 3 switches such that the full pump capacity of the pumps P1 and P2 is made available to the actuator or swiveling cylinder SZ. [0006] Only after the pipe has swivelled due to actuation of the actuator or swiveling cylinder SZ is the full pump capacity of the pumps P1 and P2 then made available again to the drive cylinders 1 or 2 by switching in the control block 3. [0007] It is known from the prior art that such long switching times can be avoided with a so-called dual-circuit system (see FIG. 3) in which the pumps P1 and P2 are provided separately for the drive cylinders 1 and 2 of the delivery cylinders FR and FL on one hand, and for the actuator or swiveling cylinder SZ of the pipe switch RW on the other. [0008] Thus, a so-called dual-circuit system has two independent pump devices, each having at least one pump P1 and P2. This means it is possible to actuate the delivery cylinders and the actuator cylinder(s) in parallel time to shorten the interruption in pumping. [0009] However, the disadvantage here is the need for two separate pump devices, with pump P1 especially needing a design large enough to provide the necessary hydraulic volume flow to operate drive cylinders 1 and 2. [0010] It is therefore the object of the present invention to ensure rapid switching of the switch for connecting the two delivery cylinders to the common delivery line, while minimizing the outlay on switching and the outlay on the hydraulic drive of the drive or delivery cylinders and of the actuator cylinder of the switch. [0011] This object is solved by a method and a drive device having the characteristics of claims 1 and 8. Advantageous embodiments are the object of the dependent claims. [0012] The invention draws on the knowledge that when a fluid, especially an hydraulic oil, is used to drive the drive cylinders or delivery cylinders of a dual-cylinder slurry pump, full drive power is no longer needed toward the end of the piston displacement, that is at the end of a stroke. Armed with this knowledge, it is possible to use the superfluous drive power to shorten the switching time in such a way that the superfluous drive power can already be used for the actuation of the switch, especially for the drive of a swiveling or actuator cylinder for a pipe switch. Consequently, it is no longer necessary to wait for the stroke in the drive or delivery cylinder to finish, but rather the switching operation and thus the actuation of the pipe switch can be initiated already before the end of a stroke. [0013] For this purpose, the invention provides for monitoring or determining the position of the piston in the drive cylinder or delivery cylinder, and for locating it, at least in a certain position shortly before it reaches the final position, such that, starting with this information, some of the fluid volume flow, preferably hydraulic oil volume flow, can be made available for actuation of the actuator or swiveling cylinder of the switch. [0014] The device employed for the determination may be of mechanical, electrical or hydraulic type, with the last-mentioned especially suitable when overall control over the drive proceeds largely by means of a fluid or hydraulic oil. In that case, it is a simple matter to use corresponding switching valves that are activated via known hydraulic control lines. [0015] Further, in a preferred embodiment, a corresponding device for locating the piston position of the actuator cylinder of the pipe switch may be provided in order that this information may be used for the switching operation. [0016] Preferably, the hydraulic switch may be constructed such that two pump devices are used for providing a corresponding fluid stream or operating pressure, which said pump devices, in a manner comparable to the dual-circuit system, are used primarily independently for the drive of the drive cylinders on one hand and for the drive of the actuator or swiveling cylinder for the switch on the other. On account of the idea of the invention, namely that the drive power for the drive or delivery cylinder no longer has to be 100% shortly before the necessary switching operation of the switch, the two independent pump devices may be combined with each other in a manner such that, during the stroke of the drive cylinder or the delivery cylinder, the second pump device makes its capacity available for the drive or delivery cylinder, whereas, shortly before the switching operation, the second pump device is used exclusively for actuation of the actuator or swiveling cylinder of the switch. In this way, it is possible to use the pump or pump capacity of the drive effectively--and to use components of lower capacity. [0017] Preferably, the drive is designed such that the operating pressure, especially of the second pump device, is available at the actuator or swiveling cylinder during the entire operation. [0018] Diversion of the fluid volume flow may be realized simply by a corresponding switching valve, so that the overall switching outlay can be kept very low. [0019] Although the device is described below using the example of an hydraulic drive with hydraulic oil as fluid, it goes without saying that the invention is also feasible with other suitable fluids and corresponding devices for pressure generation and/or fluid delivery. [0020] Further advantages, characteristics and features of the present invention are apparent from the following detailed description of an embodiment using the enclosed drawings. The drawings show in purely schematic form [0021] FIG. 1 a block diagram of the drive device of the invention; [0022] FIG. 2 a block diagram of a known single-circuit system; and in [0023] FIG. 3 a block diagram of a known dual-circuit system. [0024] FIG. 1 shows a block diagram of an hydraulic drive of a dual-cylinder slurry pump with a first drive cylinder 1 and a second drive cylinder 2, which are connected via the corresponding pistons to a first delivery cylinder FR and a second delivery cylinder FL. Continue reading about Drive device for a dual-cylinder slurry pump and method for operating said pump... Full patent description for Drive device for a dual-cylinder slurry pump and method for operating said pump Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Drive device for a dual-cylinder slurry pump and method for operating said pump patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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