DE245625C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

PATENT LETTERING

CLASS 14 c. GROUP

Regulation of multi-stage steam turbines. Addition to patent 193697 from March 9, 1907. *)

Patented in the German Empire on February 25, 1910. Longest duration: March 8, 1922.

The basic idea of the patent 193697 is that the difference is that of the secondary valve acting, oppositely directed forces to open and close To use live steam ducts to further stages or from further nozzles of the same stage.

Sharing this principle, the present invention is directed to another Development of the patent 193697, in which after the bypass is lifted the steam, which has ■ already flowed through the main inlet valve, to an additional one which is dimensioned in this way The area of the secondary valve has the effect that the latter is moved into its end position and thereby the steam to further stages or further nozzles of the same stage of the turbine can flow without throttling it.

In the drawing, the invention is illustrated using two exemplary embodiments.

In Fig. Ι the secondary valve d closes the channel e to a further stage of the turbine or to further nozzles of the same stage and is connected to an adjustable spring which tends to remove the secondary valve d from its seat, so the channel e to to open. The unthrottled boiler steam has constant access to room k through line h and presses the secondary valve against the action of spring f onto its seat. At i, the steam that has already flowed through the main inlet valve acts. The secondary valve d also has a piston I which slides in a cylinder m. The latter is in connection with the outside air or with the labyrinth stuffing boxes of the turbine at any point of constant low pressure, for example through the channel η. In the latter case, the piston is deliberately made leaky, so that low-voltage leakage steam can escape into the cylinder m , which then flows through the channel η to the stuffing boxes and is used there as sealing steam. The area exposed to the pressure of the unthrottled boiler steam is denoted by F ₁ and the total pressure by P ₁ , the area exposed to the pressure of the steam coming from the main inlet valve by F ₂ and the total pressure by P ₂ . .F ₃ is the additional area according to the invention, which is precisely determined in terms of its size in relation to the area F _2. The pressure acting on this surface after the valve has been lifted is denoted by P ₃ . F ₄ is the area of the piston I and P ^ the low pressure prevailing in the cylinder m.

Under normal load, the secondary valve d closes the access β to further stages or further nozzles of the same stage because

*) Previous additional patents: 224006, 239196.

the pressure of the boiler steam is greater than the _{pressure acting on the surface F 2} of the steam somewhat throttled by the main inlet valve. If the turbine is overloaded, the secondary valve d is lifted according to the main patent. After just a little lifting, however, the steam comes under the larger area F ₃ , which results in an immediate lifting of the valve into its end position, since the area F _{3 is} precisely dimensioned for this purpose. In contrast to the known arrangements, there is therefore no throttling of the steam flowing to the further stage or to further nozzles.

When dimensioning the area in a valve according to FIG. 1, note that the pressure P _{2 acting on area F 2} decreases when the valve is opened, corresponding to the enlarged blade or nozzle cross-section for steam entry into the valve when the secondary valve is open blading of the turbine, as is the tension of the spring is small, while the pressure P acting on the surface F ₃ rises ₃ and acting on the surfaces F ₁ and F ₄ pressures P ₁ and P ₄ remain unchanged. The area F ₃ must now be at least large enough that the decrease in pressure P ₂ and the spring tension is compensated _{for by the increase in pressure P 3.}

In practice, the area F _{3 is} made a little larger so that at the moment of opening there is an upward excess pressure which accelerates the opening. On the other hand, the desired effect does not occur if the area F _{3 is} smaller than the minimum dimension mentioned. Such a valve is shown in patent 193697. The outer diameter of the piston connected to the valve is larger than that of the valve, but this enlargement does not achieve the minimum dimension mentioned; Rather, it was only made for structural considerations in order to be able to use the valve from above.

The embodiment according to FIG. 2 shows a modification in that the channels η for discharging the leakage steam to the stuffing boxes are placed so deeply with respect to the secondary valve d that they are very soon covered when the valve is opened, so that the leakage steam or the air is sealed and serves as a buffer. Also in this example, the ratio of the areas F ₁ F ₂ F ₃ F ₄ is chosen so that an additional spring force can be omitted. In this case, the area F ₃ is to be dimensioned in such a way that the decrease in the pressure P _{2 is} at least compensated _{for by the increase in the pressure P 3.}

The boiler steam presses here on the inner surface F _{1 of} the piston and the air or the leakage steam on the outer surface F ₄ . The position of the additional surface F ₃ is the same as in FIG. 1.

Instead of the boiler steam, the constant pressure on the surface F _{1 can} also be exerted by any pressure fluid by z. B. connects the pressure line of the oil pump of the machine with line h .

Claims (1)

Patent claim: Control of multi-stage steam turbines according to patent 193697, characterized in that that after lifting the secondary valve, the steam from the inlet valve to such a dimensioned area of the The secondary valve has the effect that the latter is immediately moved into its end position and thereby allows the steam to flow to further stages or further nozzles of the same stage of the turbine without throttling it. 1 sheet of drawings.