JPH0141843Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a turbine trip hydraulic circuit used for a turbine safety device, a highly reliable hydraulic circuit, and the like.

FIG. 1 shows a conventionally used turbine trip hydraulic circuit, and FIG. 2 shows an explanatory diagram of a solenoid valve. The symbols in the figure are as follows.

1-4: Solenoid valve, 5, 6: Orifice, 7,
8: Pressure switch, 9: Oil tank, 10: Coil, 11: Spring, P _S : Supply oil pressure, Pl: Circuit oil pressure,
P _T : Oil tank oil pressure The solenoid valves 1 to 4 are valves that close when energized, and are normally closed. That is, in the operational diagram of the electromagnetic valve 1 shown in FIG. 2, the supply hydraulic pressure P _S is in a state where the oil passage is cut off when energized and is not transmitted to the circuit hydraulic pressure Pl. In this state, when the coils 10 of the solenoid valves 1 to 4 are no longer energized (de-energized state), the electromagnetic force generated in the coil 10 becomes zero, and the tension of the spring 11 switches the oil path and supplies the oil. Hydraulic P _S and circuit hydraulics
Pl becomes equal. That is, the supply hydraulic pressure P _S is transmitted to the circuit hydraulic pressure Pl.

In FIG. 1, the solenoid valves 1 to 4 are closed, and the supplied hydraulic pressure P _S passes through the orifices 5 and 6 to the oil tank 9 because the oil path is cut off at the solenoid valves 1, 2 and 3, 4. It flows as a drain.

The pressure switches 7, 8 are for monitoring the operation of the solenoid valves 1-4. That is, solenoid valve 1 or 2
When is operated (oil path open), circuit oil pressure Pl becomes Pl≒P _S. When this is detected by the pressure switch 7, it can be detected that the solenoid valve 1 or 2 has operated. Further, when the solenoid valves 1 and 2 are closed, when the solenoid valve 3 or 4 is operated, the circuit oil pressure Pl becomes Pl≒P _T ≒0. When this is detected by the pressure switch 8, it can be detected that the solenoid valve 3 or 4 has operated.

Here, solenoid valves 1 and 2 are considered as one set, and solenoid valves 3 and 4 are
If we take 1 set, there will be 2 sets, 1 out of 2. This 1 out of 2 means that an output is produced when one of the two operates, and is a means of improving reliability.

In this way, either one of the solenoid valves 1 and 2
When either one of the solenoid valves 3 and 4 operates, the supplied hydraulic pressure P _S becomes P _S ≒Pl≒P _T ≒0. If this supply oil pressure P _S is the emergency shutdown oil pressure of the turbine, then
Even when a turbine trip signal is received, the solenoid valves 1 and 2
3 and 4 are operated, the emergency shutoff oil becomes zero, and the steam valve of the turbine (not shown) is quickly closed, thereby protecting the turbine.

Now, when conducting a test to confirm the soundness of the turbine's protective function, if either solenoid valve 1 or 2 is malfunctioning due to stick, then either solenoid valve 1 or 2 is damaged. By operating, the circuit oil pressure Pl becomes _Pl≈PS , and the pressure switch 7 is operated. Therefore, failure of the solenoid valve 1 or 2 cannot be detected. The same applies to the solenoid valves 3 and 4.

As a countermeasure to the above, if the solenoid valves 1 to 4 are operated individually, the failure of the solenoid valves 1 to 4 can be detected by the pressure switches 7 and 8;
Alternatively, if one set of solenoid valves 3 and 4 fails, the turbine protection function is lost. That is, any one of the solenoid valves 1 and 3, 1 and 4, 2 and 3, and 2 and 4 is required to be always healthy. Furthermore, if the solenoid valve 3 or 4 malfunctions during the test of the solenoid valve 1 or 2, there is a risk of accidentally tripping the turbine.

In view of the above circumstances, this invention satisfies the fact that failures of solenoid valves can be detected individually through testing, and that even if other solenoid valves malfunction during testing of solenoid valves, the turbine will not be accidentally tripped. The purpose is to provide a hydraulic circuit that allows

This invention includes a first block which is provided with eight solenoid valves that have a built-in orifice and has a short circuit function and four pressure detectors, and in which the solenoid valves are connected in parallel;
A second block in which two blocks connected in series are connected in parallel, and a third block in parallel are connected in series, the pressure detector is provided at the solenoid valve connection part, and the two solenoid valves are connected in one block. This invention relates to a turbine trip hydraulic circuit characterized in that it is operated as a set.

This invention will be explained with reference to embodiments shown in the accompanying drawings.

In Figures 3 and 4, 20-27: Solenoid valve, 30-33: Pressure detector, 40-49: Hydraulic line, P _S : Supply oil pressure, Pl: Circuit oil pressure, P _T : Oil tank oil pressure ( (drain), 9: oil tank, 10: coil, 11: spring, 12: orifice.

Fig. 4 shows a state in which the coil 10 is energized, and when the coil 10 is de-energized, the electromagnetic force generated in the coil 10 disappears, and the oil path is switched by the force of the spring 11, so that P _S ≒ Pl. Become. When the coil 10 is energized, the coil 1
The electromagnetic force generated at 0 overcomes the spring force of the spring 11, and the oil passage is switched, and the supplied hydraulic pressure P _S is transmitted through the orifice 12 to the circuit hydraulic pressure Pl. The solenoid valves 20 to 27 operate as described above. The pressure detectors 30-33 detect the pressure in the oil passages 41-46.

The supply oil path P _S passes through the oil path 40 and connects the solenoid valves 20 and 2.
4 has been transmitted. The outlet sides of the solenoid valves 20 and 24 are connected to the solenoid valve 21 via oil passages 41 and 44, respectively.
and 25. The oil passages 41 and 44 are connected by an oil passage 47, and a pressure detector 30 is further connected to the oil passage 41. That is, oil path 4
The pressures at 1, 44, and 47 are detected by a pressure detector 30.

The solenoid valve 22 and a pressure detector 31 are connected to the outlet side of the solenoid valve 21 via an oil passage 42 , and the pressure of the oil passage 42 is detected by the pressure detector 31 . Similarly, the outlet side of the solenoid valve 25 is connected to the solenoid valve 26 and a pressure detector 33 via an oil passage 45, and the pressure of the oil passage 45 is detected by the pressure detector 33.

Oil passages 4 are provided on the outlet sides of the solenoid valves 22 and 26, respectively.
3 to the electromagnetic valve 23 and the pressure detector 32, and an oil passage 46 to the electromagnetic valve 27, and the oil passages 43 and 46 are further connected to each other via an oil passage 48. Therefore, the pressure on the outlet side of the solenoid valves 22 and 26, that is, the pressure in the oil passages 43, 46, and 48, is detected by the pressure detector 32.

The outlet sides of the electromagnetic valves 23 and 27 are connected to the oil tank 9 via an oil passage 49. That is, the solenoid valve 23,
The pressure in the oil passage 49 on the outlet side of the oil tank 27 is the oil tank oil pressure P _T and is zero.

To describe the operation of the present invention, the coils 10 of the solenoid valves 20 to 27 are normally in a energized state, so the inlet and outlet sides of the solenoid valves 20 to 27 are connected via the orifice 12. The solenoid valves 20-27 are all the same, and the orifices are all the same.

In the above state, the supplied hydraulic pressure P _S is applied to the oil passage 40, the orifice 12 of the solenoid valve 20,
1. Passes through a circuit consisting of the orifice of the solenoid valve 21, the oil passage 42, the orifice of the solenoid valve 22, the oil passage 43, and the orifice of the solenoid valve 23; The oil passes through a circuit consisting of an orifice 25, an oil path 45, an orifice of an electromagnetic valve 26, an oil path 46, and an orifice of an electromagnetic valve 27, merges at an oil path 49, and flows into the oil tank 9 as a drain.

Here, since the solenoid valves 20 to 27 are the same, oil passage 47 connecting oil passages 41 and 44, oil passage 43 and 4
Almost no oil flows into the oil passage 48 connected to 6.
Therefore, the pressure detector 31 provided in the oil passage 42 and the pressure detector 33 provided in the oil passage 45
The pressures detected at are equal. Further, the pressure detected by the pressure detector 30 provided in the oil passage 41 is higher than the pressure detected by the pressure detector 31, and the pressure detected by the pressure detector 32 provided in the oil passage 43 is higher than the pressure detected by the pressure detector 31. The pressure is lower than the pressure detected by the pressure detector 31.

If the coil 10 of the solenoid valve 20 fails in this state, the oil passages are switched by the tension of the spring 11, and the oil passages 40 and 41 are directly connected. As a result, the pressure in the oil passage 41 becomes approximately equal to the supply oil pressure _PS , and the pressure detector 30 detects the pressure that has become approximately equal to the supply oil pressure _PS . A failure of the electromagnetic valve 20 can be detected by processing the pressure detected by the pressure detector 30 in an external circuit (not shown) (detecting a pressure equal to or higher than a set pressure value). In addition, if the coil 10 of the solenoid valve 22 fails, the oil path 4
2 and 43 are directly connected, the pressure detected by the pressure detector 31 and the pressure detector 32 are equal, and the solenoid valve 22 is detected by an external processing circuit (not shown) (when the pressure of the pressure detector 31 is below the set value). failures can be easily detected.

Next, a method of confirming the soundness of the electromagnetic valves 20 to 27 will be explained. Currently, all solenoid valves 20~
27 is normal, and the pressure detectors 30 to 33 are assumed to be normal. Solenoid valves 20 and 21, 22 and 24,
It is assumed that 23 and 25, and 26 and 27 are driven by the same signal.

When the coils 10 of the solenoid valves 20, 21 are de-energized, the oil passages 40, 41, 42 are directly connected, and the pressures detected by the pressure detectors 30, 31 become equal, indicating that the solenoid valves 20, 21 have operated. I understand.
During the test of the solenoid valves 20, 21, the solenoid valves 23,
25 fails and the oil passages 43 and 49, and 44 and 45 are directly connected, the solenoid valves 22 and 26 are healthy, so the supply oil pressure P _S does not become the oil tank oil pressure P _T , so the turbine is tripped. do not. Furthermore, the failure of the solenoid valves 23 and 25 at this time is because the pressure detected by the pressure detector 32 is equal to the oil tank oil pressure P _T , and the pressure detected by the pressure detector 33 is equal to the supply oil pressure P _S. It can be detected from the fact that they are equal.

Furthermore, during the test of solenoid valves 20 and 21, solenoid valve 2
Even if solenoid valves 2 and 24 fail, the supplied oil pressure P _S will not become the oil tank oil pressure P _T because the solenoid valves 23 and 27 are healthy, and the turbine will not be accidentally tripped. At this time, if the solenoid valve 22 malfunctions, the pressure detector 3
Since the pressure detected in step 2 is equal to the supplied hydraulic pressure P _S , it can be easily detected.

Although the operation of the electromagnetic valves 20 and 21 during the test has been described above, the same applies to the tests of the other electromagnetic valves 22 to 27.

Next, when an abnormality occurs in the turbine and causes the turbine to trip, the solenoid valves 20-23, 20-2
2 and 27, a set of solenoid valves 20 and 21, 2
If three of the four groups, groups 2 and 24, groups 23 and 25, and groups 26 and 27, operate, the supply oil pressure P _S becomes equal to the oil tank oil pressure P _T when the current is turned off, and the turbine is tripped. can be done. That is, the turbine can be protected even if one set of solenoid valves is stuck.

With this invention, during normal operation it functions as a 3 out of 4 multiplexed hydraulic circuit, and during testing it becomes a 2 out of 3 multiplexed hydraulic circuit, resulting in extremely high reliability.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional turbine trip hydraulic circuit, Fig. 2 is an explanatory diagram of the operation of a solenoid valve in the same hydraulic circuit, Fig. 3 is a circuit diagram of a turbine trip hydraulic circuit of the present invention, and Fig. 4 is a circuit diagram of a conventional turbine trip hydraulic circuit. It is an explanatory diagram of the operation of the solenoid valve of the same hydraulic circuit. 20-27... Solenoid valve, 30-33... Pressure detector, 40-49... Oil path, P _S ... Supply oil pressure, Pl
...Circuit oil pressure, P _T ...Oil tank oil pressure, 9...Oil tank, 10...Coil, 11...Spring, 12...
...orifice chair.

Claims (1)

[Scope of utility model registration request] A first block has eight solenoid valves with a built-in orifice and a short circuit function and four pressure detectors connected in parallel, and a second block has two solenoid valves connected in series in parallel. and a third block connected in parallel are connected in series, the pressure detector is provided at the solenoid valve connection part, and the two solenoid valves are operated as a set. hydraulic circuit.