TIU CH PHNG N nh ngha tiu ch phng n

Tiu ch phng n l k hiu miu t vng (khu vc) s dng thch hp, loi phng n, s khc bit v nhit , cp phng n ca cc thit b kh in phng n.

S t hp ca tiu ch phng n

Cc thit b kh in phng n cn c vo yu cu tiu chun GB3836 ca Trung Quc Ni dung ta c tiu ch phng n ca thit b kh in phng n bao gm:

Hnh thc phng n + loi thit b + loi th kh + loi nhit .

1. Hnh thc phng n

Da vo cc bin php phng n s dng, c th phn bit loi cc kh c in phng n theo biu 1 vi ni dung nh sau: loi cch n, loi tng cng an ton, loi an ton bn cht, loi p lc dng, loi ngm du, loi cha ct, loi bc kn, loi n, loi c bit, loi phng n bi.

Biu 1 loi hnh phng n c bn

Loi phng n K hiu phng n Loi cch n EX D Loi tng cng an ton EX E Loi p lc dng EX P Loi an ton bn cht EX IA Loi an ton bn cht EX IB Loi ngm du EX O Loi cha ct EX Q Loi bc kn EX M Loi N EX N Loi phng n bi DIP A Loi phng n bi DIP B Loi c bit EX S

2. Loi thit b

Thit b kh in dng trong mi trng kh n chia lm nhng loi sau:

Loi I: thit b kh in dng trong hm l m than

Loi II: thit b kh din dng trong mi trng kh n khng bao gm mi trng hm l.

Thit b in Loi cch n "d" II v loi an ton bn cht " I " chia ra loi IIA, IIB, IIC.

Thit b kh in dng trong mi trng bi d chy chia ra nhng loi sau:

Thit b kn bi loi A

Thit b kn bi loi B

Thit b phng bi loi A

Thit b phng bi loi B

3. Loi th kh

Kh nng ly n ca cc hn hp kh n dung th hin mc gy n nguy him cao hoc thp. Kh nng ly n ca hn hp kh n cng ln, tnh nguy him cng cao. Kh nng ly n ca hn hp kh n c th c biu th bi " khng gian an ton ln nht trong thc nghim". ng thi, Mc kh hoc d bc chy ca kh n, th lng bc hi v khi dy th hin mc gy n nguy him cao hoc thp. Mc kh hoc d bc chy ca kh n, th lng bc hi v khi dy c th c biu th bi " t l dng in t chy". Thit b kh in loi cacsch n II hoc thit b kh in an ton bn cht cn c vo " khng gian an ton ln nht trong thc nghim " v " t l dng in t chy " chia thnh IIA,IIB,IIC. Xem biu 2

Biu 2: Mi quan h gia loi hn hp kh n v " khng gian an ton ln nht trong thc nghim " , " t l dng in t chy "

Loi kh Khng gian an ton ln nht trong thc

nghim MESG (mm) T l dng in t

chy MICR

IIA MESG0.9 MICR0.8 IIB 0.9MESG0.5 0.8MICR0.45 IIC 0.5MESG 0.45MICR

4. Loi nhit

Nhit dn chy ca hn hp kh n l gi tr nhit c th t chy cc hn

Thit b kh in cn c vo b mt nhit ln nht chia lm T1~T6. Nh vy thit b kh in thuc T1~T6 c nhit b mt ln nht khng vt qu gii hn cho

php ca loi nhit tng ng. Mi quan h gia nhit dn chy ca kh chy hoc kh hi v nhit b mt thit b, loi nhit xem biu 3.

Biu 3: Mi quan h gia nhit dn chy ca kh chy hoc kh hi v nhit b mt thit b, loi nhit

Cp nhit

IEC/EN/GB 3836

Nhit b mt ln nht ca thit

b T (0C) Nhit t chy ca vt cht (0C)

T1 450 T450 T2 300 450T300 T3 200 300T200 T4 135 200T135 T5 100 135T100 T6 85 100T85