Where are safety barriers used, and how many are there?

I know two kinds of safety barriers, a Zener type safety barrier, but few people use it now, and there is also an isolated safety barrier, I have used Hongrun NHR-A31 quality is OK, you can try it.

The main function of the safety barrier is to limit the entry of hazardous energy into the hazardous place in the safe place, and to limit the voltage and current sent to the dangerous place. Safety barriers are also known as safety retainers. The safety interface of the intrinsically safe circuit, which transmits electrical signals in both directions between the safety zone (intrinsically safe) and the danger zone (non-intrinsically safe) and restricts the transfer of energy from the safety zone to the danger zone due to faults.

Safety barriers, also known as safety energy limiters, are an important part of intrinsically safe systems. There are mainly two types of safety barriers: Zener safety barriers and isolated safety barriers. The main function of the safety barrier is to limit the current and voltage, and the silver mill ensures that the energy available to the field instrument is within the safe range.

The safety barrier is an energy-limiting circuit between the field equipment and the control room equipment, which is used to limit the electrical energy supplied to the field instrument in the control room to neither produce a spark sufficient to detonate the dangerous gas, nor the surface temperature of the instrument sufficient to detonate the dangerous gas, thereby eliminating the detonation source.

Since its birth, the safety barrier has experienced decades of development, extending several categories and dozens of varieties. In general, the industry classifies safety barriers according to the following methods.

First, from the use of standards, and application occasions, it can be divided into mine standard safety barriers and factory standard safety barriers, and factory standard safety barriers can be divided into combustible gas environmental safety barriers and dust environmental safety barriers.

Second, from its own structural characteristics and implementation form, it is divided into Zener type and isolated safety barrier, and the isolated safety barrier can be divided into photoelectric isolation safety barrier and magnetoelectric isolation circular disturbance safety barrier.

Third, from the power supply mode of the safety barrier, it can be divided into independent power supply safety barrier (also known as active safety barrier) and loop power supply safety barrier (also known as passive safety barrier).

Fourth, from whether MCU is used or not, it is divided into intelligent safety barriers and non-intelligent safety barriers.

Fifth, from the explosion-proof level reached, it can be divided into IIC, IIB, IIA level safety barriers.

Sixth, from the safety factor achieved, it can be divided into IA type safety barrier (safety factor) and IB type safety barrier (safety factor.

Seventh, from the function in the system, it can be divided into input type safety barrier, and output type safety barrier (generally with the control room as a reference).

Eighth, in terms of the type of signal transmitted, it can be divided into analog safety barrier, switching safety barrier, communication safety barrier, temperature safety barrier, frequency signal safety barrier, etc.

Ninth, from whether it can be automatically restored from the fault state to the normal state, it can be divided into self-recovery safety barrier and non-self-recovery safety barrier.

In short, there are many kinds of classification methods for safety barriers, and according to different working conditions and different requirements, it is necessary to choose the appropriate safety barrier from different angles. If the customer is in contact for the first time, you can apply for the technical support of the manufacturer, so as to better choose the right safety barrier.

The most basic safety barrier has the detection end of the safety barrier, the operation end of the old Beisen safety barrier, the wet node safety barrier, the dry node safety barrier, the lightning protection safety barrier, the LCD safety barrier, the longest use of the inspection service mu measurement end of the rolling simple full gate, the market after the lightning protection safety barrier is still good, especially in the south, the most important role is to shield the dangerous model, protect your system.

Flameproof instruments do not require a safety barrier.

The safety barrier is an energy-limiting circuit between the field equipment and the control room equipment, which is used to limit the electrical energy supplied to the field instrument in the control room to neither produce a spark sufficient to detonate the dangerous gas, nor the surface temperature of the instrument sufficient to detonate the dangerous gas, thereby eliminating the detonation source. When selecting the safety barrier, it is necessary to consider the adaptation of its model to the type of field instrument, and also to consider the compatibility of the safety barrier with the requirements of the intrinsic safety instrument and the impedance matching of the intrinsically safe system. China adopts the method of "loop certification" to certify the intrinsic safety system, that is, according to the joint forensics of the instrument used in hazardous environments, the safety barrier that has been jointly forensics with it is selected, and once the joint forensics is obtained, the field instrument and the safety barrier will be fixed and combined to form an intrinsic safety system.

In practice, this approach has great limitations on the selection of safety barriers and field instruments. The widespread use is an intrinsically safe certification technology that has gradually formed over the years, that is, "parametric certification".

Use note: first, pay attention to the capacitive and inductive reactance of cables and field equipment, intrinsically safe explosion-proof is the system explosion-proof, in addition to the safety barrier needs to achieve the required explosion-proof level, the energy storage of cables and field equipment is also a key issue. Especially after the certification of the parametric certification substitution system, the engineering company should pay special attention to this problem.

Second, it is necessary to pay attention to intrinsically safe grounding, Zener safety barrier needs intrinsically safe grounding, and the grounding resistance should be less than 1.

Third, intrinsically safe cables and non-intrinsically safe cables should be laid separately in different trunkings. and should be clearly marked.

Fourth, pay attention to power failure when replacement.

<>1. The safety barrier is connected between the intrinsically safe circuit and the non-intrinsically safe circuit. It is a device that limits the voltage and current of the whole circuit of the intrinsic safety car to a certain safety range.

2. Safety barrier, also known as safety energy limiter, is an important component of the intrinsic safety system, and the safety barrier mainly includes two categories: Zener safety barrier and isolated safety barrier; The core components of the Zener safety barrier are Zener diodes, current limiting resistors and fast fuse wires.

3. The isolated safety barrier not only has the function of limited energy, but also has the function of isolation, which is mainly composed of the circuit energy-limiting unit, the signal and power isolation unit, and the signal processing unit; The main function of the safety barrier is to limit the current and voltage, to ensure that the energy available to the field instrument is within the safe range.