GB 5959.13-2008Safety in electroheat installations - Part 13: particular requirements for electroheat installation with explosive atmosphere (English PDF)

6.1.1 Furnace Design

6.1.1.1 furnace chamber to avoid the possibility of local overheating generation. It should be equipped with temperature indicator (display), temperature control, over-temperature Control instruments. Design

6.1.1.2 furnace shell and the workpiece transport mechanism, should ensure that the device does not occur during normal operation due to local friction, collisions Fire.

6.1.1.3 When using the conveyor chain workpiece, with a low flash point mechanical lubricant.

6.1.1.4 Place the furnace should be set to be processed workpiece mounting bracket.

6.1.1.5 Fixation, furnace shell and the insulation layer must be non-flammable material.

6.1.2 Heating element

6.1.2.1 The heating element should have sufficient strength, such as the use of frangible heating element, should guard against mechanical damage caused by fire And electric shock.

6.1.2.2 The heating element surface temperature should not exceed the workpiece release flammable and explosive gas ignition temperature of 80%.

6.1.2.3 resistive heating elements tubular heating elements should be used to prevent fire caused by burning. Tubular heating element jacket should be airtight , And is made of a material resistant to oxidation at operating temperature.

6.1.2.4 Setting the heating elements should be considered flammable surface of the workpiece, explosive solution should not drip on the heating element surface.

6.1.3 Air circulation and ventilation safety

6.1.3.1 Ventilation systems should not be used for natural ventilation, air circulation system should be set up to provide sufficient air to the furnace the furnace chamber flammable, Does not produce explosive gases accumulate ensure flammable, explosive gases highest volume concentration should not exceed 25% of the lower explosive limit.

6.1.3.2 vent should be set at the highest area of flammable, explosive gas concentrations.

6.1.3.3 Each unit should set up a separate exhaust pipes, exhaust duct should share with other devices.

6.1.3.4 Multi-zone furnace, allowing a set exhaust manifold, but under various working conditions, each branch displacement provided not less than Dollars.

6.1.3.5 ventilation system using air flow control valve in the system to adjust the normal range should be able to achieve the required air flow and set the valve Minimum safe opening of the limiter.

6.1.3.6 Air circulation blower and exhaust system used must be provided with reliable measures to prevent sparks.

6.1.3.7 exhaust pipe and manhole should maintain good air tightness.

6.1.4 Control and Interlocking

6.1.4.1 should be set to automatic temperature control and over-temperature alarm device to ensure that explosive gases below the ignition temperature.

6.1.4.2 forced ventilation stove, after circulating fan and exhaust fan starts to start the heating system and the work conveying system. plus After the heating system and the work conveyance system is shut down, the fan to stop running. Ventilation failure of the heating system should be self-closing.

6.1.4.3 Setting ventilation safety monitoring device in the furnace, the concentration of combustible gas detection and alarm systems should be interlocked with the heating system.

6.1.5 Explosion relief and

6.1.5.1 furnace room should set the appropriate size and intensity of the action or explosion-proof gate valve. Per cubic meter furnace volume should be set not less than 0.05m2 relief area.

6.1.5.2 blast doors or position of the valve and mechanical strength should be able to ensure the release of the internal pressure to not endanger regional staff.

6.2 Electrical Equipment Electrical equipment design, installation, maintenance should be consistent with GB 50058-1992, GB 3836.1-2000 and GB 3836.13-1997, GB 3836.14-2000GB 3836.15-2000 and safety requirements for specific provisions.

6.2.1 motor used on the stove, should comply with the relevant explosion-proof electrical standards.

6.2.2 stove Under normal operating conditions, the entire current flows through the conductor does not cause nearby components, insulation materials and electric devices out Now dangerous fever.

6.2.3 The selected arrangement of electrical equipment should be noted that it is not in normal operation due to the harmful effect of the atmosphere and damage.

6.2.4 heating element and the furnace temperature insulation resistance should not be less than 1MOmega.

6.2.5 furnace shell must be grounded, grounding resistance should be less than 10Omega.

6.2.6 should be set static protection grounding, the grounding resistance should be less than 100Omega.

6.2.7 should ensure good electrical contact. When electrical equipment in order to avoid the line insulation strength is reduced or destroyed, resulting in live shell or an electrostatic device Electrostatic induction makes equipment enclosure gathered; fasteners should be avoided due to corrosion caused by the grounding resistance increases, the spark discharge to ground, to form an explosive gas Mixture ignition source.

6.2.8 wire heating element and should be reliable electrical connection terminals location should be easy to check. The introduction of the heating element should be sealed Reliable, to prevent leakage of furnace gas.

6.3 Installation

6.3.1 the siting of the furnace arrangement, we should first take into account as far as possible away from the high-pressure electrostatic effects work area and have flammable objects Kobo, Warehouses and densely populated areas.

6.3.2 exhaust duct from the ground within 2m (over 70 °C) should be added protective measures to avoid burns staff.

6.4 Other

6.4.1 For labor racking workpiece large batch furnace, and the furnace door should set security indoor signaling device to prevent staff accidentally shut In the furnace chamber.

6.4.2 The device should be low-noise products.

7 isolation and opening and closing

Chapters 7 and according to GB 5959.1-2005 safety requirements for specific provisions.

8 is connected to the grid connection and internal

Chapters 8 and according to GB 5959.1-2005 safety requirements for specific provisions.

9 electric shock protection

Chapter 9, according to GB 5959.1-2005 safety requirements for specific provisions. 10 overcurrent protection Chapter 10 and by GB 5959.1-2005 safety requirements for specific provisions.

11 Equipotential bonding By chapter 11 of GB 5959.1-2005 safety requirements for specific provisions. The control circuit 12 and control functions Chapter 12 by GB 5959.1-2005 safety requirements for specific provisions. Protective Effect of heat

13 According to chapter 13 GB 5959.1-2005 safety requirements for specific provisions. 14 fire, explosion-proof, anti-suffocation, and poisoning Except for the following additional provisions, the rest should be GB 5959.1-2005 Article 14 and the relevant regulations and special safety requirements in this section Chapter

6 Supplementary Provisions.

14.1 should be strictly in accordance with the manufacturer's instruction manual to operate.

14.2 should take effective measures against possible leakage of flammable, explosive gases or harmful gases to harmless treatment in a timely manner, so as not to cause Explosion or damage to the health of staff. Proposed measures include.

--- Exhaust gas emission standards should be consistent with the provisions of the environmental protection department of the atmosphere;