Do you need to isolate safety barriers for flameproof instruments, and do you need isolation barrier

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 a safety barrier, it is necessary to consider the suitability of its model to the type of field instrument, as well as the safety barrier and intrinsic safety.

Instrument requirements are compatible and the impedance matching problem formed in 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".

Attention to use: First, pay attention to the capacitance of cables and field devices.

and inductive reactance, intrinsically safe explosion-proof is the explosion-proof system, in addition to the safety barrier needs to achieve the required explosion-proof level.

In addition, the energy storage of cables and field devices 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, and Zener safety barriers need intrinsically safe grounding and grounding resistance.

It 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.

Safety barriers are used in intrinsically safe circuits to limit the energy entering the hazardous area by limiting voltage and current so that it is not sufficient to cause a spark that ignites combustibles.

Suzhou Bejiafu Safety Barrier Equipment Co., Ltd. provides easy-to-use safety barriers.

1. The power consumption of the instrument designed in the form of flameproof is generally large, and the safety barrier may not move.

2. The non-intrinsically safe field instrument cannot reach the intrinsically safe level even if the safety barrier is added.

3. The flameproof instrument has strict installation requirements, such as the installation clearance and creepage distance of the junction box.

4. The intrinsically safe system has strict requirements for the installation and wiring of related equipment, that is, safety barriers.

5. Shanghai Yibei technical department can provide you with more detailed support.

The safety barrier is the related product of intrinsically safe explosion-proof instruments and instruments, which does not affect the function of the measurement system under normal conditions, and is set on one side of the safe place, when the intrinsically safe explosion-proof system fails (such as short circuit), it can limit the electrical energy that escapes into the dangerous place within a safe range, so as to ensure the safety of on-site production. For this reason, flameproof pressure transmitters should be equipped with safety barriers if they are installed in hazardous locations.

Yes, if you don't need to drive a field instrument.

The intrinsically safe card cannot provide enough power to drive, so it is fine if it only receives a signal.

First of all, the isolated barrier adopts a circuit structure that electrically isolates the input, output, and power supply from each other, and at the same time meets the requirements of intrinsically safe energy limiting. Compared with the Zener safety barrier, it has the following significant advantages: (1) The three-party isolation method is adopted, so there is no need for the system grounding line, which brings great convenience to the design and on-site construction.

2) The signal line does not need to be grounded, which greatly enhances the stability and anti-interference ability of the detection and control loop signal, and improves the reliability of the whole system. (3) It has stronger input signal processing ability, and can receive and process temperature, frequency and other signals, which is not possible with Zener safety barriers. (4) The isolated safety barrier can output two mutually isolated signals to provide two devices using the same signal source, and ensure that the signals of the two devices do not interfere with each other, and improve the electrical safety insulation performance between the connected equipment at the same time.

The explosion-proof level is two levels higher than the intrinsically safe type, and the explosion-proof level will not interfere with the environment outside the instrument even if the instrument is inside, and the intrinsically safe type is not equipped with safety barrier drop or slag pressure, it is likely to cause ** or flash explosion, and the dangerous area is also determined according to the economy and the surrounding environment.

Explosion-proof refers to the prevention of **, which is a technical requirement.

Flameproofing refers to a means of achieving explosion protection. Commonly used explosion-proof means include intrinsically safe explosion-proof and flame-proof explosion-proof. The following is an excerpt from an explosion protection application in PLC:

Intrinsically safe and flameproof control cabinets are usually installed in a safe area. The intrinsically safe explosion-proof technology usually adopts a PLC control system, and the cabinet is equipped with a safety barrier, and the signal line returned from the danger area is processed by the safety barrier and then connected to the PLC input and output module. At present, intrinsically safe explosion-proof technology is usually used for PLC input signals in China, which can limit the input current in the dangerous area to less than 2mA, because the current is very small and is essentially safe.

1. Specific meaning.

1. Flameproof is to use a shell to install the electrical components, and the electrical components become the ignition source to cause the high-temperature and high-pressure gas, which is discharged to the outside world through the gap of the shell (flameproof gap) to reduce temperature and pressure, and the gas after temperature and decompression is not enough to cause the outside of the shell. Therefore, explosion-proof refers to isolating the energy inside the cavity, rather than isolating the dangerous gas outside the cavity, and pouring is to isolate the external gas.

2. Explosion-proof refers to preventing the occurrence of **. Generally, we start from the principle of ** and block the conditions for **.

3. Intrinsically safe technology is generally applied to instruments, by limiting the energy in the electrical circuit and cooperating with the structural design of electrical equipment, it is impossible to produce points in the circuit that meet the requirements of the ignition source under normal and accident conditions. Intrinsically safe technology is generally used in complete sets, and a safety barrier should be set up in the safety area, and the loops behind the safety barrier are intrinsically safe equipment. Clamps, terminals, cables, and plastic golans of intrinsically safe circuits are marked with light blue.

2. Differences. 1. Distinguish from the definition.

Flameproof will produce **, but the energy of ** is isolated inside the cavity and cannot cause ** outside the shell.

Explosion-proof is to prevent the occurrence of **, and explosion-proof and intrinsically safe are two ways of explosion-proof.

The intrinsically safe type does not produce **, and any electrical spark or any thermal effect generated under the conditions specified in the standard (including normal operation and specified fault conditions) cannot ignite the circuit of the specified ** gas atmosphere (Zone 0 i explosion-proof technology).

3. Distinguish from the principle of explosion-proof.

Flameproof requires that the enclosure must have sufficient strength; And each enclosure joint surface must have a sufficiently long meshing length and a sufficiently small gap to ensure that the internal ** does not pass through the flameproof joint surface and cause the external environment**.

Intrinsically safe is a "safe" technology that uses ignition source energy suppression as an explosion-proof means. It is required that the electrical spark or thermal effect that may be generated by the equipment in normal operation or fault state is less than the minimum ignition energy and autoignition temperature of the most dangerous gas, respectively. For example:

Hydrogen 19uj 560.

2. Distinguish from the application area.

Flameproof type applicable area: can only be installed in Zone 1 or Zone 2 hazardous locations.

Intrinsically safe type applicable area:

1) EXIA: Equipment that maintains explosion-proof performance until two or other types of component failures. Intrinsically safe equipment can be installed in Zone 0, Zone 1 and Zone 2 hazardous locations. EXIA intrinsically safe equipment is the only explosion-proof electrical equipment that can be installed in Zone 0.

2) EXIB: Equipment that maintains explosion-proof performance until the failure of one element or other type. Intrinsically safe equipment can be installed in Zone 1 and Zone 2 hazardous locations.

1. Flameproof technology is to use a shell to install the electrical components, and the high-temperature and high-pressure gas generated by the electrical components become the ignition source, and the temperature and pressure reduction are discharged to the outside through the gap of the shell (explosion-proof gap). The decompressed gas is not enough to cause ** outside the shell. Therefore, explosion-proof refers to isolating the energy inside the cavity, rather than isolating the dangerous gas outside the cavity, and pouring is to isolate the external gas.

2. Explosion-proof refers to preventing the occurrence of **. Generally, we start from the principle of ** and block the conditions for **.

3. Intrinsically safe technology is generally applied to instruments, by limiting the energy in the electrical circuit and cooperating with the structural design of electrical equipment, it is impossible to produce points in the circuit that meet the requirements of the ignition source under normal and accident conditions. Intrinsically safe technology is generally used in complete sets, and a safety barrier should be set up in the safety area, and the loops behind the safety barrier are intrinsically safe equipment. Clamps, terminals, cables, and plastic golans of intrinsically safe circuits are marked with light blue.

Flameproof (EX D) technology is to use a shell to install the electrical components, and the high-temperature and high-pressure gas generated by the electrical components become the ignition source, which is discharged to the outside world through the gap of the shell (explosion-proof gap) to reduce temperature and pressure. The decompressed gas is not enough to cause ** outside the shell. Therefore, explosion-proof refers to isolating the energy inside the cavity, rather than isolating the dangerous gas outside the cavity, and pouring is to isolate the external gas.

Intrinsically safe (EX IAIB) technology is generally used in instrumentation, by limiting the energy in the electrical circuit and matching with the structural design of the electrical equipment, it is impossible to generate a point in the circuit that meets the ignition source requirements under normal and accident conditions. Intrinsically safe technology is generally used in complete sets, and a safety barrier should be set up in the safety area, and the loops behind the safety barrier are intrinsically safe equipment. Clamps, terminals, cables, and plastic golans of intrinsically safe circuits are marked with light blue.

Explosion-proof and intrinsically safe are two ways to prevent vandalism. Flameproof isolates substances from hazardous energy sources through enclosures and additives. Intrinsic safety requires that the substances used in hazardous areas are intrinsically safe and will not produce the best energy.

Your problem is the first time to see, no knowledge of this, sorry.