Walter Hofmann Gmbh

Firma Walter Hofmann

Walter Hofmann Maschinenfabrik

Firma Walter Hofmann Maschinenfabrik

Hofmann Gmbh Maschinenfabrik Und Vertieb

Hofmann Gmbh Maschinenfabrik Und Vertrieb

Frank Hofmann

Egbert Junge

A method for operating a reciprocating positive displacement pump for the simultaneous low-pulsation discharge of a plurality of liquids, having for each liquid at least two pump chambers and displacement devices capable of movement therein, of which the one displacement device takes in liquid during the actual discharge phase of the other displacement device, and at the end of its intake stroke reverses its direction of movement, and, in a pre-compression phase, pre-compresses the liquid taken into the associated pump chamber and when a predeterminable pre-compression pressure has been achieved comes to a standstill, and remains at the standstill until the other displacement device has ended its liquid discharge, and, subsequent to this discharge, begins its own discharge. The method includes the steps of carrying out a pressure compensation during the subsequent discharge stroke preventing a pressure compensation between the individual pump chambers during the subsequent discharge stroke.

Method of operation of a reciprocating positive-displacement pump and reciprocating positive-displacement pump

A method and apparatus for supplying liquids by means of a pump combination comprising two single oscillating displacement pumps is provided, wherein a supply pressure of the pump supplying liquid into a user duct is used as a control value of a pressure controller, such that a pressure stroke movement of the other pump which is generating a pre-compression pressure, is discontinued when the pre-compression pressure equals the supply pressure, and the pre-compression pressure is maintained.

Method for supplying liquids by means of a pump combination comprising

A road marking machine comprising a spray gun and a combination of two displacement pumps for supplying the marking substance to the spray gun, wherein the combination is driven in proportion with the traveling speed and wherein the pumps, each after starting the positive displacement operation thereof, which starts during the supply operation of the corresponding other displacement pump, pre-compress the marking substance, then stops and continues the pressure stroke when the other displacement pump ends its supply, with hydraulic cylinders for driving the displacement pumps.

Road marking machine with a pump combination driven in proportion with

A device for counting or measuring the length of road marking lines or for a total counting of road marking line segments on roads or the like, characterized in that the control or the switching on or off counters of a known type is carried out by the application device, e.g., a spray gun for making the road marking lines.

Device for measuring the length of road marking lines

A device for providing pulsation-free feeding of a liquid medium from a supply container to a consuming device for use in a road-marking machine is disclosed. Two statically-operating reciprocating-piston pumps are arranged between the supply container and the consuming device such that when one pump is on suction stroke, the other is on a feed stroke. The pump flow rate is proportional to the drive speed of the road-marking machine and the feed flow of each pump has zones which overlap the other. The feed sides of the pumps are connected to a change-over means which alternately connects delivery flows from the pumps to the consuming device and also connects the pressure side of the pumps simultaneously to the consuming device and to the supply container, which prevents pressure flow fluctuations as the back-pressure to each pump is the same.

Arrangement for pulsation-free feeding of a liquid medium

In a method for making marking strips and marking interruptions like broken traffic lines on roads etc., the application of the marker strips and the running past the marker interruptions are carried out at different speeds, whereby the speed during application of the marking strip on the ground is reduced with respect to the speed during the subsequent marking interruptions. Devices for carrying out the method are also disclosed.

Method and devices for making traffic lines or the like

A spray gun for applying granulated material onto a surface, preferably glass beads onto roadway markings, or the like, is characterized in that a bead spray gun with an ejection effect is coupled with a mechanical dosaging device in one structural unit. Preferably, the mechanical dosaging device is a roller bead sprayer and is mounted immediately in the housing of the air spray gun above an ejection air nozzle.

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Hamburg, Germany

Frank Hofmann