초록 ▼

Disclosed herein is an improved pumping system for self-contained and, if desirable, portable machines adapted to efficiently spray or squeegee viscous sealing fluids on roadway pavement and parking lots, which fluids may contain suspended solid matter. For example, this fluid pumping assembly is es

Disclosed herein is an improved pumping system for self-contained and, if desirable, portable machines adapted to efficiently spray or squeegee viscous sealing fluids on roadway pavement and parking lots, which fluids may contain suspended solid matter. For example, this fluid pumping assembly is especially suitable for spraying asphaltic or coal-tar-pitch emulsions containing sand onto asphalt road surfaces. Also disclosed is an improved hydraulic drive cylinder assembly and control means therefor employing an improved electrically controlled hydraulically operated drive network.

대표청구항 ▼

A method for controlling the flow and pressure requirements of apparatus for spraying asphalt or coal-tar-pitch emulsion material comprising: providing a reservoir containing said emulsion, providing spray means for spraying said emulsion, providing an on-off valve means for controlling the flow of

A method for controlling the flow and pressure requirements of apparatus for spraying asphalt or coal-tar-pitch emulsion material comprising: providing a reservoir containing said emulsion, providing spray means for spraying said emulsion, providing an on-off valve means for controlling the flow of emulsion to said spray means, providing pumping means for pumping said emulsion through discharge line means to said on-off valve and thence to said spray means, providing hydraulic drive cylinder means to reciprocate a materials pump and thereby pump said emulsion to said spray means, controlling and operating said apparatus so that the discharge volume of emulsion at the spray means is less than the pressure and volume of emulsion being generated and supplied by the materials pump thus creating an “over supply”of emulsion in said discharge line upstream of said on-off valve, the resulting rise in material pressure within said materials pump causing a corresponding rise in hydraulic pressure in the hydraulic drive cylinder means, providing variable volume pressure compensated hydraulic pump means controlled and actuated by electrical circuit means to reciprocate said hydraulic drive cylinder means, said hydraulic pump means and said hydraulic cylinder means comprising hydraulic fluid system means, providing sensing means and operating said apparatus for spraying so that said rise in hydraulic pressure in said hydraulic drive cylinder means causes said variable volume pressure compensated hydraulic pump to reduce its volume of a hydraulic oil being pumped and supplied to said hydraulic drive cylinder means so as to maintain a preset, maximum compensated pressure (e.g. 650 psi) in the hydraulic fluid system means, said reduction in volume in turn reducing the hydraulic oil supply to the reciprocating hydraulic drive cylinder means thereby causing the drive cylinder means to reduce its speed of reciprocation, thereby in turn reducing and regulating the speed of the materials pump driven by said hydraulic drive cylinder means which in turn decreases the materials pressure in the discharge line thereby controlling said discharge line pressure to a maximum preset emulsion material pressure of, for example, approximately 70 psi, which corresponds to a maximum preset design pressure in the hydraulic fluid system means of, for example, the previously mentioned 650 psi, whereby when the apparatus for spraying emulsion is again turned on at the on-off valve by the operator, the emulsion pressure immediately falls activating said sensing means and causing the variable volume pressure compensated hydraulic pump to again begin to supply the hydraulic drive cylinder with hydraulic oil to automatically maintain material pressure in response to the volume of material flow.