SU1710443A2 - Control device of explosion protection system of electrical equipment - Google Patents

Abstract

The invention relates to shipbuilding, and more specifically to control devices for the explosion protection system of electrical equipment installed in hazardous areas. The purpose of the invention is to expand the operational capabilities of the device by ensuring its use for switching on an electrical heater of electrical equipment. In the control device, the pressure sensor is equipped with an additional switching contact, and in the control unit there is a control relay for closing the exhaust duct. An additional switching contact is electrically connected to a control relay, which is connected to an electric heater control circuit. 2 Il. s

Description

The invention relates to shipbuilding, in particular, to control devices for the explosion protection system of electrical equipment installed in hazardous areas, and is an improvement to the device of the present invention. Nb 1641703.

The purpose of the invention is to expand the operational capabilities of the device by ensuring its use to turn on the electrical heater of electrical equipment ..

1 shows a control device of an electrical equipment explosion protection system; Fig. 2 is an electrical system control circuit.

The device contains a pressure sensor 1 mounted on the shell

2 electric equipment under pressure (for example, blown by air) installed in the hazardous area

3sea drilling rig. Pressure sensor 1 is electrically connected through control unit 4 with detector 5. In Ex zone 3, sensor 6 contains maximum permissible explosive concentrations of oil and gas vapors and sensor 7 maximum permissible concentrations of hydrogen sulfide, which through their secondary devices 8, 9 are connected. are connected with the detector 5. The electrical equipment shell 2 is connected by a supply air duct 10 to the fan 11, and the exhaust air duct 12 is connected to a non-explosive overboard space. The control unit 4, the secondary devices 8.9 and the fan 11 are installed in the non-hazardous area 1.3. Sensor 1 contains a make contact 14, which closes at a pressure in shell 2 that is sufficient to provide electrical protection. The control unit 4 contains intermediate relays 15,16. time relay 17 and switch 18 electrical equipment. Intermediate relay 15 is included in the circuit

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of the tactile contact 19 of the secondary device 8 of the sensor 6, and the intermediate relay 16 - into the closing contact circuit 20 of the secondary device 9 of the sensor 7. Time relay 17 is included in the purpose of the closing contact 14 of the pressure sensor 1. The series-connected disconnecting contacts 21, 22 of the respective intermediate relays 15, 16 and the closing contact 23 of the electrical equipment switch 18, in parallel with which the closing contact is connected with a time delay sufficient for pre-start blowing of the electrical equipment shell, time relay 17 of the relay 17, are included in the power circuit of the electrical equipment switch 18 . The closing contacts 25,26 and 27, 28 of the corresponding intermediate relays 15,16 and the disconnecting contacts 29, 30 of the time relay 17 are included in the detector circuit 5.

In addition, the pressure sensor 1 is provided with an additional contact 31, which closes when the pressure in the shell 2 arises after closing the exhaust duct 12 when the fan 11 is turned on. In control unit 4, relay 32 controls the closing duct outlet 12, which is connected to integral contact 31. The series-connected switch 33 of the electric heater 34 and the closing contact 35 of the relay 32 are connected in parallel with the switch 18 of the electrical equipment.

The control switch 36 is inserted in the power supply circuit of the switches 18, 33.

The electric heater 34 is installed inside the shell 2 and is designed to prevent dew on the internal parts of the disconnected electrical equipment, which is operated at a considerable ... humidity.

The device works as follows.

In the initial position, the fan 11 is turned off, the overpressure in the cylinder 2 of the electrical equipment is absent, the contacts 14, 31 of the pressure sensor 1 are open, the time relay 17 is turned off. When voltage is applied to the control unit 4, the time detector 17 is turned on through the closed contacts 29, 30 of the time relay 17, signaling that there is no overpressure in the electrical equipment shell 2. To remove the primary medium from shell 2 and ducts 10,12, they are pre-purged. For this, the fan 11 is turned on. Air under pressure enters through the duct 10 into the shell 2 and exits through the duct 12. The pressure in the shell 2 rises. The contact 14 of the pressure sensor 1 closes and turns on the time relay 17, which switches off the detector 5 with its contacts 29, 30 and closes its contact 24 in the circuits after the purge time has elapsed

switch 18 electrical equipment and switch 33 electric heater. In the case of electrical equipment start, the control key 36 is in the position closing the power circuit of the switch 18, which operates and gives a signal to turn on the electrical equipment and becomes self-locking through its closing contact 23.

In the absence of zone 3. where installed 5 electrical equipment, explosive concentrations of oil vapor (or gas) or maximum allowable concentrations of hydrogen sulfide contacts 19, 20 of the corresponding secondary devices 8, 9 sensors 6, 7

0 are in the open state, intermediate relays 15, 16 are disconnected, and their contacts 21, 22 in the circuit of the switch 18 are closed. As a result, when the pressure in the casing 2 of the electrical equipment is reduced to a value below the allowable (the fan is turned off, the encapsulation of the casing is broken), the contact 14 of the pressure sensor 1 is disconnected, the time relay 17 is turned off and the switch 24 is disconnected

0 electrical equipment is not disabled. In this case, the detector 5 is switched on via contacts 29, 30 of the time relay 17, indicating that there is no overpressure in the shell 2 of the electrical equipment and the need

5 switching on the backup fan or preparing and starting the backup equipment. In case of occurrence of explosive concentrations of oil (or gas) vapor or maximum permissible concentrations of hydrogen sulfide in zone 3, contact 19 or contact 20 is switched on, respectively, intermediate relay 15 or 16 is activated, which opens its contact 21 or 22 in the circuit of electrical equipment switch 18 and

5 closes its contacts 25. 26 or 27, 28 in the detector circuit 5. The switch 18 is turned off and the electrical equipment is turned off. In this case, the detector 5 is turned on, signaling that there are explosive concentrations of oil (or gas) vapor in zone 3 with maximum allowable concentrations of hydrogen sulfide and the need for additional ventilation of zone 3.

When switching on the electric heater 34

5, the key 36 closes the power circuit of the switch 33. The shell 2 is purged. After the purge time, when the relay: 17 time closes its contact 24 to prevent heat from the electrical equipment shell, the exhaust duct 12 is closed. At the same time, the pressure in the shell 2 increases , the contact 31 of the pressure sensor 1 closes and the relay 32 operates, which closes its contact 35 in the supply circuit of the switch 33. The switch 33 operates and gives a signal to turn on the electric heater.

Claims (1)

i Formula of invention The control unit of the electrical equipment explosion protection system of the autor. 0 No. 1641703, characterized in that. in order to expand its operational capabilities by enabling it to turn on electrical electrical equipment, the pressure sensor is provided with an additional contact, and the control unit has a relay ducting control relay electrically connected to the said contact and included in the electrical equipment control circuit. / Phys. 1