Regulator (steam engine)

from Wikipedia, the free encyclopedia

In a steam engine, the regulator (also known as regulator) is the control device that controls the amount of steam. The regulator must not be confused with the control of the slides for the cylinders, which are responsible for filling the cylinders. The output of a steam engine depends on the setting of both control devices. The regulator is used to set the amount of steam that the boiler should make available to the control system. The filling level of the cylinders is set with the control.

construction

In larger machines, the regulators are usually designed as flat slide regulators. Valve regulators are also found in small machines.

The regulators must be designed in such a way that they can be dosed well even with a small amount of steam, but do not offer too much resistance with large amounts of steam. This is achieved through a two-stage opening method. This initially only reveals a small cross-section, which is only expanded in the second phase. This dichotomy is also common in order to prevent the actuating force from becoming excessively large, as the full pressure difference between the boiler and outside air can weigh on the regulator. The operation of the regulator in steam locomotives can be done in two ways, which is called a front regulator or a side regulator depending on the introduction of the operating rod . With both types of adjustment, the regulator is operated by turning the rod that enters the boiler. The entries into the boiler are usually designed as a stuffing box . With the forehead regulator, there is a rod inside the boiler in the longitudinal direction of the boiler, which operates the regulator. With the side regulator, the operating shaft is arranged transversely to the boiler axis, and the shaft emerges from the side of the boiler. This means that the fixed point for deflecting the control rod is outside the boiler. Consequently, the two versions also differ in terms of operation in the driver's cab. Although the operating elements are usually the same in both variants, they work in the longitudinal direction of the car with the side regulator and in the transverse direction of the stin regulator. In general, they are designed as locking levers.

Flat slide regulator

The flat slide regulator has an outer and an inner slide for better regulation. The outer slide opens a narrow slot with a rectangular cross-section to allow little steam to pass through, while the inner slide is designed with a triangular or trapezoidal cross-section and thus enables a larger cross-section to be released quickly. As a result, the pressure difference is distributed over two slides with small amounts of steam. At first only the outer slide is moved, while the inner slide has a fixed small passage.

Valve regulator

The valve regulator is usually designed as a double seat valve. That means: on a large valve cover there is a small valve cover that is lifted off first. When this small valve is fully open, the outer large valve opens and quickly releases a large cross section. If you were to work with only one valve, it would have to be the same size as the large valve cover on the two-stage valve. The full pressure is on this large valve cover, which would require a great deal of force to open, but which stands in the way of fine regulation.

Installation in steam locomotives

Often the regulator is built into the steam dome . It is also possible to install it in its own housing, this type of construction is mainly found in locomotives with a Crampton type steam regulator . This housing must be able to absorb the full boiler pressure.

In wet steam engines, the regulator is the first moving component in the steam flow to the cylinder. With newer superheated steam machines (superheated steam machines of the second generation e.g. standard locomotives of the DR) there is only an auxiliary shut-off valve at this point, the regulator is only installed after the superheater (in this case one speaks of a superheated steam regulator). In older superheated steam locomotives (e.g. SBB C 5/6 ) the regulator was installed in front of the superheater, but this had the disadvantage that it is exposed to higher temperatures when steam is not used, as the steam in it is not in contact with the boiler stands. For the auxiliary services, too, only wet steam is available, as their steam branch must be located in front of the regulator, since they also need steam when the locomotive is at a standstill. In the newer steam locomotives with regulator after the superheater, superheated steam is also available for the auxiliary operations.

Alternative names

The more modern designation regulator instead of regulator became generally accepted only after the heyday of the steam locomotive. The term controller in connection with the steam locomotive has not really caught on and generally only refers to the controls in the driver's cab and not to the entire steam control system.

Often the term superheated steam regulator or wet steam regulator is used for the regulator and its operating device in steam locomotives , in order to point out some structural differences of the regulator in structure and arrangement. In the case of stationary operated machines, the distinction between high-pressure steam engine and low-pressure steam engine is usually sufficient in order to identify the structural differences in the regulation.

Locomotives without superheaters have a wet steam regulator. The superheated steam regulator is only used in locomotives that also have a superheater ; the regulator is then placed after the superheater. A hot steam regulator is exposed to much higher temperatures than a wet steam regulator. Its advantage is that superheated steam is immediately available for start-up. If the regulator is installed in front of the superheater, it is still a steam locomotive with a wet steam regulator despite the superheater. Then the superheater is almost pressureless when the regulator is closed; when the wet steam regulator is opened, the steam must first be dried in the superheater, so the drive reacts more slowly. Because of the technical problems that were difficult to control and the foreseeable end of steam locomotive operation, hot steam regulators no longer prevailed in German steam locomotives despite their advantages.

swell