Slide valve for a twin-cylinder pump for viscous fluids

A slide valve device for a viscous fluid pump comprising a material feed container, a pump having two oppositely working conveying cylinders for a conveyance of viscous fluid supplied to the pump from the material feed container, the conveying cylinders having orifices communicating through a wall of the material feed container into an interior of the material feed container, an essentially C-shaped pivoting pipe positioned in the material feed containers, a conveying conduit for transporting the viscous fluid to a desired location, a rotary pipe connection adapted to rotatably fluidly connect an upper end of the pivoting pipe to the conveying conduit, a changeover means for rotating the rotary pipe connection about an axis that extends essentially parallel to axes of the conveying cylinders, a lower end of the pivoting pipe having a wear ring fixed thereon alternately connectable to one of the orifices of the conveying cylinders in response to an operation of the changeover means, a wear plate positioned on a wall of the material feed container surrounding the orifices, a tensioning means for pressing the wear ring against the wear plate, the changeover means having a changeover lever arranged on an outside of the wall of the material feed container above the conveying cylinders, a first end of the changeover lever being rigidly connectable to the upper end of the pivoting pipe, two oppositely actuatable drive cylinders oriented generally transversely to the conveying cylinders and to the conveying conduit, the conveying cylinders having a support means for supporting the drive cylinders on opposite sides, a second end of the changeover lever being supported on the drive cylinders, the drive cylinders having pistons with mutually confronting articulated ends, the drive cylinders having supporting points connected to the support means of the conveying cylinders and located on the articulated ends, the supporting means and the second end of the changeover lever having ball sockets and the articulated ends of the drive cylinders and an end of the drive cylinders distal the articulated ends having ball heads received in the ball sockets, the drive cylinders forming with one another along the longitudinal direction thereof an obtuse angle open to the wall of the material feed container, the changeover lever having a supporting arm extending outside the material feed container, and the conveying conduit having an extension pipe connected to the upper end of the pivoting pipe, the supporting arm supporting the extension pipe.