Quatest1
L4/QT 19
L nung, T sy, bung nhit Quy trnh hiu chunFurnace, drying
cabinet, chamber Methods and means of calibration
h ni - 2009
quy trnh hiu chun ni b1
L4/QT 19
L nung, t sy - Quy trnh hiu chun1. Phm vi p dngVn bn k thut ny
quy nh quy trnh hiu chun l nung, t sy, bung nhit c phm vi o nhit :
Ti 300 0C v n nh nhit 1 oC vi t sy v bung nhit. Ti 1200 0C v n nh
nhit 5 oC
2. Cc php hiu chunPhi ln lt tin hnh cc php hiu chun ghi trong
bng sau: TT Tn php hiu chun Theo iu mc ca QTHC 5.1 5.2 5.3 5.3.1
5.3.2
1 2 3 4 5
Kim tra bn ngoi Kim tra k thut Kim tra o lng Xc nh lch gi tr
nhit Xc nh n nh theo thi gian
3. Phng tin hiu chun3.1 Thit b o nhit a im. Phm vi o (0 50) oC,
phn gii 0,1 oC. 3.2 u o nhit chun
3.3 Phng tin o thi gian, c gi tr chia 0,01 s. 3.4 Phng tin o m v
nhit mi trng.
Phm vi o m: (0 100) %RH, gi tr chia 2 %RH; Phm vi o nhit : (0
50) oC, gi tr chia 1 oC.
4 iu kin hiu chun v chun b hiu chun4.1 iu kin hiu chun Khi tin
hnh hiu chun phi m bo cc iu kin sau y: - Nhit : (23 2) oC; - m tng
i: (40 70) %RH. 4.2 Chun b hiu chun Trc khi tin hnh hiu chun phi
thc hin cc cng vic chun b sau y: - Vn hnh t BOD theo hng dn s dng
ca ca phng tin ny n nh hot ng. - Vn hnh thit b o nhit nhiu im n nh
hot ng.
5 Tin hnh hiu chun5.1 Kim tra bn ngoi Phi kim tra k thut theo cc
yu cu sau y: Kim tra bng mt xc nh s ph hp ca t BOD i vi cc yu cu
quy nh trong ti liu k thut, v hnh dng, kch thc, ch th nhit , ngun
in s dng, nhn hiu, c cu m bo kn ca t, ti liu v ph tng km theo. 5.2
Kim tra k thut Kim tra trng thi hot ng bnh thng ca t BOD theo hng
dn s dng c nu trong ti liu k thut km theo. 5.3 Kim tra o lng T xc
nh nhu cu oxi sinh ho c kim tra o lng theo trnh t ni dung, phng php
v yu cu sau y:3
5.3.1 Xc nh lch gi tr nhit Phng php hiu chun t BOD l o trc tip
nhit trong nc ct trong t bng thit b o nhit nhiu im c b tr trong t
cn hiu chun theo s di y vi s im o ti thiu l 9.
lvn 127 : 2003
Tin hnh hiu chun theo trnh t sau: - t nhit ca t l 20 oC; - t cc
u o phn b trn mt bng t mu trong t theo s phn b; - Sau 1 gi ghi s ch
ca my o nhit vo bin bn hiu chun ph lc 1; - Sai lch nhit ti tng im
hiu chun c tnh bng hiu gia gi tr nhit c t trc ca t BOD v gi tr nhit
o c bng my o nhit : T = TT To Trong : T: gi tr sai lch nhit ti nhit
20 oC;
TT: nhit t trc ca t cn hiu chun ti nhit 20 oC; To: nhit o c bng
my o nhit 20 oC. - Sai lch ti cc im hiu chun khng c ln hn sai s cho
php ca t BOD (khng c ln hn 1 oC). 5.3.2 Xc nh n nh theo thi gian -
Thc hin o nh mc 5.3.1 trong 8 gi, mi gi mt ln. Ghi kt qu o c vo bin
bn hiu chun ph lc 1.
lvn 127 : 2003- n nh ti cc im hiu chun khng c ln hn sai s cho
php ca t BOD (khng c ln hn 1 oC).
6 X l chung6.1 T BOD sau khi hiu chun c dn tem, cp giy chng nhn
hiu chun km theo thng bo kt qu hiu chun. 6.2 Chu k hiu chun ca t
BOD c khuyn ngh l 01 nm.
5
Ph lc 1
Tn c quan hiu chun............................ Tn phng tin o: T
BOD Kiu: C s sn xut: c trng k thut: Ni s dng: Phng php thc hin:
Chun, thit b chnh c s dng: iu kin mi trng: Ngi thc hin: Ngy thc
hin:
Bin bn Hiu chun
S: Nm sn xut:
Kt qu hiu chun 1 Kim tra bn ngoi 2 Kim tra k thut 3 Kim tra o
lng Xc nh lch gi tr nhit im o Khong thi gian Nhit c t ca t (oC )
Nhit o c (oC ) Sai lch Sai s cho php
1
2 3 4 5 6 7 8 9
Xc nh n nh nhit im o Khong thi gian 1h Nhit t ca t (oC ) Nhit o
c (oC ) Sai s cho php
Sai s
2h 3h 4h 5h 6h 7h 8h Kt lun:
Ngi sot li thc hin
Ngi
7
1 n q = qk n k =1
ph lc 2
Xc nh khng m bo o khng m bo o c xc nh t nhng thnh phn sau: 1
khng m bo loi A TT Gi tr t 1 2 3 4 5 6 7 8 Gi tr trung bnh Trong :
qk: gi tr o th k n: s ln o Gi tr o c Trung bnh lch chun
s
uc = lch chun s(qk):
(uA)2 + (uB)2 s(q k ) uA = ns (q k ) = 1 (q k q ) 2 n 1
Do khng m bo chun loi A uA: 2 khng m bo loi B Cc yu cu k thut ca
chun c khng m bo m rng UCh, h s ph k, khng m bo loi B l:uB = U Ch
k
Trong : UCh: khng m bo m rng ca chun k: h s ph (ly bng 2) khng m
bo tng hp uc c tnh bng cng thc:
khng m bo m rng U c tnh bng khng m bo tng hp nhn vi h s ph k: U
= k.uc H s ph k c ly bng 2 tng ng vi mc tin cy p = 0,95
9
ng c?c Ti?u chu?n- ?o l??ng -Ch?t l??ng ch?u ch nhi?m xu?t b?n ,
ph?t h?nh v? gi/ b?n quy?n n b?n k? thu?t ?o l??ng Vi?t Nam. Kh?ng
???c sao, ch?p l?i n?u ch?a ???c ph?p c?a t?ng c?c u chu?n -?o
l??ng -Ch?t l??ng. LVN 127 : 2003 a ch? : 70 Tr?n H?ng ??o -H? N?i
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