Molten metal is injected uniformly into a horizontal mold from a feed chamber in a horizontal or vertical direction at a controlled rate, directly on top of the metal already within the mold. A phase detector is connected directly to the input, a charge pump is connected directly to the phase detector, and a loop filter is connected directly to the charge pump. In one embodiment, for instance, the gateway places a PSTN modem-to-modem call to the address mapper and conveys its IP address as a modulated data stream, while the address mapper may determine the telephone number of the gateway through established automatic calling number delivery procedures. Therefore, a serious technical difficulties have been solved that the sensor made by the prior art can’t measure different corrosion states of actual heat-exchanger tubes, that the corrosion rate measured is different from the corrosion rate of actual heat-exchanger tubes, and that the cost of anti-corrosive treatments is high. A device for generating a force, which is dependent on the neutral position, of the spring device is provided, wherein when a neutral setting is not present, the force action of the spring arrangement prevents the electrohydraulic solenoid valve from enabling the braking system, by acting counter to the electrical operation of the magnet of said solenoid valve.