Explosion-proof grounding device SHGVA-UZG (CCA-GRD)

+
+
x
<
>
Explosion-proof grounding device SHGVA-UZG (CCA-GRD)PURPOSE AND SCOPE OF APPLICATION Новая усиленная конструкция, без изменения весо-габаритных параметров оболочек, позволила расширить область применения оборудования для подгруппы IIC.

Explosion-proof electronic grounding device SHGVA-UZG ensures grounding during loading and unloading of flammable liquids and explosive gases. Its operation is based on the control of the resistance circuit which guarantees grounding and control of the operation of a pump or other electric loading-unloading device.

Explosion-proof grounding device type SHGVA-UZG is intended for grounding and static charge removal from the surface of tank cars and railroad tankers, fuel reservoirs, ship fuel storage tanks. Intrinsic safety barrier [ia] is used in the grounding device SHGVA-UZG for protection during connection. If the clamps are removed during loading and unloading or if the grounding is lost (accidental fault or high voltage caused by latent oxidation), feeding pump or other electric loading and unloading device will be de-energized.

SHGVA-UZG grounding device is assembled on the base of SHORV171712-О09 enclosure made of aluminum-silicon alloy; clamps are made of stainless steel (galvanized steel upon request), contact pads on clamps are made of copper.

For direct insertion of cables and wires into Exd enclosure of the grounding device, the following specially developed Exd glands for direct insertion with sealing are applied KNV, KOV, KNVTN, KNVTV, KNVM and with encapsulation KNVZ series. According to the mandatory requirements, this characteristic is specified in the certificate. This helps to refuse from inlet junction box (except for mining version РВ), which makes the products of "ZAVOD GORELTEX" Co. Ltd. unique compared with products of other companies.

Full production cycle starting from casting molds and to ready product is performed at the explosion-proof equipment plant “ZAVOD GORELTEX” Co. Ltd. on the territory of the Russian Federation.

ADVANTAGES
1. The device does not require set up and is ready for operation right after the installation.
2. The device can withstand accidental voltage 220 V on grounding clamps and various electrostatic charges.
3. Automatic locking of the operating mechanisms of loading-unloading in case of break of grounding circuit by means of two potential-free changeover contacts (of a pump and of APCS).
4. Length of cable of grounding clamps is 10, 20, 30 m; 100 m on customer‘s request.
5. Contrast perception of the information on a display from distance in any lighting.
6. Small size.
7. Reasonable price.

Scope of application - hazardous indoor and outdoor areas in accordance with explosion protection marking, GOST 30852.13-2002 (IEC 60079-14:1996) and areas hazardous with combustible dust ignition, as per GOST IEC 61241-3-2011, dangerous production facilities of I, II, III, IV hazard classes under supervision of Rostekhnadzor and national supervisory bodies of the CU and the CIS countries.

COMPLETENESS

Internal electronic system with a grounding state indication unit, clamps, brackets for mounting, cable of length 10 m - 30 m or other length upon approval.

+
CONFORMITY TO STANDARDS IN RUSSIA
ГОСТ Р МЭК 60079-0-2011, ГОСТ 14254-96 (МЭК 529-89), ГОСТ 30852.10-2002 (МЭК 60079-11:1999), ГОСТ IEC 60079-1-2011, Гл. 7.3 ПУЭ, Гл. 7.4 ПУЭ, РД 5.2-093-2004, ТР ТС 012/2011
+
CERTIFICATES
Маркировка взрывозащиты Marking:
1Ex db [ia Ga] IIС T6 Gb
Ex tb [ia Da] IIIС T85°С Db
Protection:
+
TECHNICAL DATA
Ambient temperature, °С:
-60...+60 (T6/85 °С)
Maximum supply voltage, V:
~160...260 (50/60 Hz)
Maximum switched current of power output, A:
0.25 (for 250VAC)
2 (for 30VDC)
Consumed power, W:
max. 16
Coating:
Antistatic polymer-epoxy coating, frictionally intrinsically safe, resistant to operating environment
and ionizing radiation. Color RAL 7035
Enclosure material:
Modified corrosion-resistant aluminum-silicon alloy, resistant to salt spray and other chemical substances including hydrogen sulfide and hydrochloric acid vapors, to saline and acidic mine waters, frictionally intrinsically safe.
Threshold resistance on input, Ω:
max. 80
Type of signal contact:
Two dry potential-free contacts of an electromagnetic relay.
Time between grounding clamps disconnection from grounded object on output, ms:
max. 10
Electric shock hazard protection class:
I
Mass, kg:
5
Climatic version:
NF1 (upon request NF2, NF3, NF4, NF5, F1, F2, F3, F5, T1, T2, T3, T5, MU1, MU2, MU3, MU4, W2.1, W5)
+
OVERALL AND MOUNTING DIMENSIONS
Взрывозащищенные устройства заземления УЗГ

Number and dimension type of cable glands are determined in accordance with customers request.

+
FORMATION OF MARKING
SHGVA-UZG - X - X  – TU 3400-005-72453807-07






          Product name
          Grounding cable length, m: 10, 20, 30 (other upon approval)
          Number and dimension type of cable glands

Example: SHGVA-UZG-20-2KOV2-TU 3400-005-72453807-07

+

CONNECTION AND OPERATION:

Контрастное восприятие информации на световом табло из далека при любой освещенности

Clamps are connected to the metal part of the road tanker’s body. After pressing of “MEASURING” button, static electricity flows from the road tanker to the earth main line (PE). The second wire measures resistance of ground circuit resistance, transition resistance between clamps’ contacts, and resistance of wires of grounding conductor. If summarized measured resistance does not exceed (60±20) Ohm, “GROUNDED” indicating sign lights up allowing road tanker unloading-loading operations. 

The following sequence of actions shall be followed in order to measure transition resistance:

1. Connect clamps of grounding conductor to the non-painted metal part of the road tanker.

2. Get “MAINS” switch to “ON” position. Observe lighting up of “NOT GROUNDED” (red indicating sign).

3. Press and hold “MEASURING” button for 2 seconds.

4. If summarized transition resistance is within (60±20) Ohm, light indication “NOT GROUNDED” shall go out (red indicating sign) and “GROUNDED” light indication lights up (orange indicating sign). Road tanker unloading-loading operation will start within 5 seconds after lighting up of “GROUNDED” light indication and “PUMP IS ON” indicating sign will light up (green indicating sign).

5. If light indication does not change after 2 seconds, “MAINS” switch shall be switched to “OFF” position, connection of measuring clamps shall be checked and actions in clauses 2-4 shall be repeated.

+

Grounding control during loading and unloading of explosive products and prevention of ignition due to electrostatic charge

Careful examination of production and technological processes reveals many sources of electrostatic charge which cannot be easily detected and which could be missed, and as a result they become a source of ignition in hazardous areas.

There are a lot of cases of explosions and fires caused by static electricity during loading and unloading of flammable and explosive liquid and loose products.

Contact potential difference occurs when two bodies come into contact, especially in case of friction. The value of CPD depends on a number of factors, such as dielectric properties of the materials, value of their mutual pressure during contact, moisture and surface temperature of these bodies, climatic conditions. When these bodies are separated, each of them keeps its charge, and as the distance between them increases, (and electric capacity of the system decreases), contact potential difference increases because of the work on the separation of charges and it could reach tens and hundreds of kV. If field force reaches breakdown as a result of physical contact or a level of charge, then a discharge occurs. Discharge energy can reach a value which exceeds minimum ignition energy of all groups of potentially explosive gas atmospheres.

Object
Energy storage at 10 kW
Energy storage at 30 kW
Minimum ignition energy
propanol
methane
hexane
Road tanker
250 mJ
2,250 mJ
0,65 mJ
0,28 mJ
0,24 mJ

Static discharge in a hazardous area must be prevented by any means because of a potential risk of an ignition or an explosion. The most important protection is a safe leak of a static charge by means of electrical bonding or grounding. It is not allowed to use the materials with low conductivity in a hazardous area.

Electrostatic charge could form during transportation, loading and unloading of chemical and oil-and-gas products. Any transportation and moving of raw materials involve friction which is the main cause of the electrostatic charge especially in case of transportation of big loads of cargo, e.g. loading and unloading of big tankers. Stationary reservoirs do not pose a problem due to safe leak of charge through grounding connection. Constant grounding connection is impossible in case of mobile reservoirs, e.g. tank cars and road tankers. Hence, safe grounding during loading and unloading must be provided by means of special devices.

+