Backpressure unit

Abstract

The utility model relates to the technical field of generator sets, in particular to a backpressure unit which comprises a main steam pipe, the main steam pipe is connected with a guide pipe, the guide pipe is connected with a steam inlet of a steam turbine, the steam inlet is provided with a speed regulation valve, and the steam turbine is connected with a drainage expansion box through a body water conveying pipe. The guide pipe is connected with a drain expansion box through a guide pipe drain pipe, and a guide pipe drain valve is arranged on the guide pipe drain pipe; an automatic main steam valve and an electric main steam valve are arranged on the main steam pipe; by arranging the guide pipe drain pipe and the guide pipe drain valve, the speed regulating valve can be closed, the guide pipe drain valve can be opened, and steam is introduced to fully warm the main steam pipe and the guide pipe; and the problem that the safety of the unit is influenced as the steam temperature is lower than the metal temperature of the cylinder due to over-low temperature of the main steam pipe and the conduit is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of generator sets, in particular to a back pressure generator set. Background Art

[0002] When the back-pressure unit is hot-started, the temperature of the main steam pipe and the duct drops rapidly, while the temperature of the turbine cylinder drops slowly. It is easy for the steam temperature entering the turbine during the run-up to be lower than the cylinder metal temperature. At this time, the expansion difference of the turbine will increase to a negative value. During hot start-up, the speed needs to be increased as soon as possible to increase the steam intake. If the steam intake temperature is lower than the cylinder metal temperature at this time, the critical speed of the turbine will vibrate for more than 10 seconds, which will seriously affect the safety of the unit and cause the unit to fail to start. Utility Model Content

[0003] The main purpose of the utility model is to provide a back pressure unit to solve the problem in the prior art that the steam temperature of the back pressure unit is lower than the cylinder metal temperature.

[0004] In order to achieve the above-mentioned purpose, the utility model provides a back pressure unit, including a main steam pipe, the main steam pipe is connected to a conduit, the conduit is connected to the steam inlet of the turbine, the steam inlet is provided with a speed regulating valve, the steam turbine is connected to a drain expansion tank through a body water pipe; the conduit is connected to the drain expansion tank through a conduit drain pipe, and the conduit drain pipe is provided with a conduit drain valve.

[0005] Furthermore, an automatic main steam valve and an electric main steam valve are provided on the main steam pipe.

[0006] Furthermore, the hydrophobic expansion tank is connected to a pressurized hydrophobic pipe and a non-pressurized hydrophobic pipe.

[0007] Furthermore, the inner diameter of the conduit drain pipe is 20 mm.

[0008] The utility model provides a conduit drain pipe and a conduit drain valve, which can close the speed regulating valve, open the conduit drain valve, and pass steam to fully warm the main steam pipe and the conduit, thereby avoiding the problem that the temperature of the main steam pipe and the conduit is too low, causing the steam temperature to be lower than the cylinder metal temperature and affecting the safety of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The drawings in the specification, which constitute a part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0010] Figure 1 This is a structural diagram of the back pressure unit in the embodiment;

[0011] In the figure: 1. Main steam pipe; 2. Conduit; 3. Steam turbine; 4. Drain expansion tank; 5. Speed regulating valve; 6. Conduit drain pipe; 7. Conduit drain valve; 8. Automatic main steam valve; 9. Electric main steam valve; 10. Pressurized drain pipe; 11. Non-pressure drain pipe; 12. Main water supply pipe. DETAILED DESCRIPTION

[0012] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0013] like Figure 1 As shown, according to an embodiment of the present invention, a back pressure unit is provided, including a main steam pipe 1, the main steam pipe 1 is connected to a conduit 2, the conduit 2 is connected to the steam inlet of a turbine 3, the steam inlet is provided with a speed regulating valve 5, the turbine 3 is connected to a drain expansion tank 4 through a body water supply pipe 12, and a body drain valve is provided on the body water supply pipe 12; the conduit 2 is connected to the drain expansion tank 4 through a conduit drain pipe 6, and a conduit drain pipe 6 is provided with a conduit drain valve 7; the inner diameter of the conduit drain pipe 6 is 20 mm.

[0014] The main steam pipe 1 is equipped with an automatic main steam valve 8 and an electric main steam valve 9. The automatic main steam valve 8 is an actuator in the protection system of the steam turbine 3. When the unit protection is activated, it can immediately cut off the steam supply to the steam turbine 3, which is a fast closing valve. The electric main steam valve 9 is installed before the automatic main steam valve 8 and is responsible for shutting off the steam supply line when the unit is shut down. Its operating device is an electric motor.

[0015] The hydrophobic expansion tank 4 is connected to a pressurized hydrophobic pipe 10 and a non-pressurized hydrophobic pipe 11; the pressurized hydrophobic pipe 10 discharges the hydrophobic water to the atmosphere to ensure sufficient warm-up and maintain unobstructed drainage; the non-pressurized hydrophobic pipe 11 discharges the hydrophobic water to a low-level water tank for recovery.

[0016] The working principle of the above embodiment is:

[0017] Before the steam enters the steam turbine 3, the speed regulating valve 5 is closed, the conduit drain valve 7 is opened, and the main steam pipe 1 and the conduit 2 are fully warmed up; after the pipes are warmed up, the steam is then passed into the steam turbine 3.

[0018] This embodiment avoids the problem that the temperature of the main steam pipe and the conduit is too low, causing the steam temperature to be lower than the cylinder metal temperature, thereby affecting the safety of the unit.

[0019] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A back pressure unit, comprising a main steam pipe (1), the main steam pipe (1) being connected to a conduit (2), the conduit (2) being connected to a steam inlet of a steam turbine (3), the steam inlet being provided with a speed regulating valve (5), the steam turbine (3) being connected to a hydrophobic expansion tank (4) via a main body water delivery pipe (12); characterized in that: The conduit (2) is connected to a hydrophobic expansion tank (4) via a conduit drain pipe (6), and a conduit drain valve (7) is provided on the conduit drain pipe (6).

2. The back pressure unit according to claim 1, characterized in that: The main steam pipe (1) is provided with an automatic main steam valve (8) and an electric main steam valve (9).

3. The back pressure unit according to claim 1, characterized in that: The hydrophobic expansion tank (4) is connected to a pressurized hydrophobic pipe (10) and a non-pressurized hydrophobic pipe (11).

4. The back pressure unit according to claim 1, characterized in that: The inner diameter of the conduit drain pipe (6) is 20 mm.

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