Dab tsi yog qhov txawv ntawm NPT, BSP thiab G xov qauv?

Qhov yooj yim tshaj plaws overlooked 'pitfall' nyob rau hauv xaiv li qub thiab fittings

Hauv ntau cov neeg siv khoom nug, peb nquag ntsib cov xwm txheej zoo li no:

"Kuv xav tau lub pob valve nrog poj niam xov ntawm ob qho kawg."

"Txoj cai, dab tsi xov txheem koj xav tau?"

"Tsuas yog ib txoj xov txheem - ib yam li ntawm cov kav dej."

Hom kev sib tham no yuav luag txhua lub lim tiam. Xaiv tus qauv xov tsis raug yog ib qho teeb meem feem ntau thiab kim tshaj hauv kev yuav khoom valve. Yog tias lub valve tsis tuaj yeem haum tom qab kev yuav khoom, lossis yog tias nws haum tab sis tsis ua kom zoo, ua rau cov xau, qhov tshwm sim los ntawm kev ncua me me mus rau qhov xav tau rov ua haujlwm tag nrho.

Niaj hnub no, hauv tsab xov xwm luv luv no, peb yuav qhia meej ib zaug thiab rau tag nrho peb cov qauv kev tsis sib haum xeeb tshaj plaws: NPT, BSP thiab G.、、

I. Cia peb pib nrog qhov sib txawv tshaj plaws: ib qho yog 'cone', lwm qhov yog 'cylinder'.

Qhov no tsim lub hauv paus rau kev nkag siab tag nrho lwm qhov sib txawv.

Xov hom

Xov hom	Lub npe	Lub kaum ntse ntse	Qauv	Txoj kev sealing
NPT	American National Tapered Yeeb Nkab Xov	60 °	Tapered xov (1:16 taper)	Sealed los ntawm xov nws tus kheej
BSPT (ib feem ntawm BSP series)	British Standard Tapered Yeeb Nkab Xov	55°	Tapered xov (1:16 taper)	Sealed los ntawm xov nws tus kheej
G (ib feem ntawm BSP series)	British Standard Prismatic yeeb nkab xov (BSPP)	55°	Cylindrical xov (tsis muaj taper)	Sealed los ntawm lub ntsej muag kawg los yog lub gasket
BSP	British Standard Pipe Thread (ua ke)	—	Xws li BSPT (tapered) thiab BSPP (cylindrical)	Nyob ntawm hom tshwj xeeb

Nyob rau hauv ib tug nutshell:

NPT = American standard tapered thread

BSPT = British standard tapered xov

G xov (BSPP) = British standard parallel xov

Ob leeg NPT thiab BSPT yog tapered threads nrog tib taper piv (1:16), tab sis lawv txawv nyob rau hauv xov lub kaum sab xis (NPT yog 60 °, whilst BSPT yog 55 °).

II. Cov Lus Qhia Kom Paub: NPT, BSP thiab G yog dab tsi?

1. NPT Xov (American Standard)

Tus Qauv Zauv: ASME B1.20.1

Yam ntxwv: 60 ° xov lub kaum sab xis, 1: 16 taper

Sealing txoj cai: Sealing yog ua tiav los ntawm kev cuam tshuam haum ntawm cov xov lawv tus kheej; tsis tas yuav tsum tau sealing gasket

Cov cheeb tsam sib xws: Tebchaws Asmeskas, Canada thiab lwm lub tebchaws ua raws li Asmeskas tus qauv

Pob Valve Specifications: 1/4' NPT, 3/8' NPT, 1/2 "NPT

Nco tseg: NPT threads yuav tsum tau daim ntawv thov ntawm PTFE daim kab xev los yog xov sealant; torque tswj yog ib qho tseem ceeb heev thaum lub sij hawm sib dhos, raws li kev nruj heev tuaj yeem ua rau cov poj niam xov sib cais.

2. BSP threads (British Standard)

BSP yog ib lo lus dav dav uas suav nrog ob hom, uas ntau tus neeg xav tsis meej pem:

BSPT (British Standard Pipe Xov)	G xov / BSPP (British Standard Yeeb Nkab Xov)
Standard Number	IB 21	BS 2779 / ISO 228-1
Xov Angle	55°	55°
Kev tsim kho	Tapered xov (1:16 taper)	Cylindrical xov (tsis-tapered)
Txoj Kev Sealing	Self-sealing (yuav tsum tau Teflon daim kab xev)	Muab kaw los ntawm lub ntsej muag foob (xws li O-ring, lub tshuab ntxhua khaub ncaws, tooj dag)
Cov ntawv thov siv	Cov tebchaws nyob sab Europe, thiab thaj chaw ntawm Asia	Siv thoob ntiaj teb, tshwj xeeb tshaj yog nyob hauv Europe thiab Asia
Common Pob Valve Loj	1/4 "BSPT, 3/8" BSPT, 1/2" BSPT	G1/4, G3/8, G1/2

Qhov no yog qhov loj tshaj qhov tsis ncaj ncees lawm: ntau tus neeg xav tias 'BSP threads zoo ib yam li G xov', tab sis qhov no tsis yog tag nrho. G threads yog ib hom BSP, tab sis BSP kuj suav nrog BSPT. G threads yog cylindrical, thaum BSPT threads yog tapered; cov txheej txheem sealing tom qab ob yog sib txawv kiag li, thiab lawv yuav tsum tsis txhob siv sib hloov.

III. Ib lub rooj kom nkag siab txhua qhov sib txawv

Kev sib piv	NPT	BSPT	G (BSPP)
Standard System	American txuj	British Standard	British Standard (International lees paub)
Cov hniav Profile	60 °	55°	55°
Qauv	Tapered xov	Tapered xov	Cylindrical xov
Taper	1:16	1:16	Tsis muaj
Txoj Kev Sealing	Xov foob ( qhwv nrog Teflon daim kab xev)	Xov foob (nrog Teflon daim kab xev)	Lub ntsej muag foob (gasket / O-ring)
The'/ hauv code	e.g. 1/2" NPT	e.g. 1/2" BSPT	e.g. G1/2
Puas yog lawv interchangeable?	Tsis hloov pauv nrog BSP	Tsis hloov pauv nrog NPT	Tsis hloov pauv nrog BSPT

IV. Yuav ua li cas sai sai qhia qhov txawv ntawm kev xyaum?

Yog tias koj muaj cov qauv hauv koj txhais tes yam tsis muaj daim ntawv lo, koj tuaj yeem txheeb xyuas nws raws li hauv qab no:

Txoj Kev 1: Tshawb xyuas cov xov profile (yuav tsum muaj xov ntsuas lossis xov tester)

60 ° xov profile → NPT

55 ° xov profile → BSP series (G lossis BSPT)

Txoj Kev 2: Tshawb xyuas cov qauv sealing

Threads xav tau Teflon daim kab xev los yog sealant → NPT los yog BSPT (tapered threads)

Yuav tsum tau lub tshuab ntxhua khaub ncaws, O-ring lossis tooj dag ntxhua khaub ncaws → G xov (cylindrical threads)

Txoj Kev 3: suav cov xov tooj (txoj kev kwv yees ceev)

Rau tib lub npe loj, cov xov tooj ntawm ib nti txawv ntawm NPT thiab BSP. Piv txwv li, 1/2 ":

NPT: 14 threads ib nti

BSP (G / BSPT): 14 threads ib nti (qhov loj me no zoo ib yam rau ob qho tib si, ua rau lawv yooj yim rau kev tsis meej pem)

Txawm li cas los xij, rau 3/4 ": NPT muaj 14 threads thiab BSP muaj 14 threads (tseem zoo tib yam)

Qhov tseeb qhov txawv yog nyob rau hauv cov xov lub kaum sab xis thiab taper, uas yog qhov nyuaj rau kev pom ntawm qhov muag liab qab; txoj kev txhim khu kev qha tshaj plaws yog siv cov xov gauge.

Txoj Kev 4: Tshawb xyuas lub teb chaws ntawm keeb kwm lossis cov neeg siv khoom xav tau

Yog tias tus neeg siv khoom nyob hauv Asmeskas thiab cov duab kos qhia ASME → NPT

Yog tias tus neeg siv khoom nyob hauv Tebchaws Europe lossis Tebchaws Meskas thiab cov duab kos qhia BS lossis ISO → BSP

Yog tias cov duab kos qhia 'G' ua raws li tus lej (piv txwv li G1/2) → cylindrical xov; yuav tsum muaj lub tshuab ntxhua khaub ncaws

V. Yuav ua li cas yog tias qhov kev xaiv tsis raug? (Cov xwm txheej tiag tiag)

Case 1: Ib lub chaw tsim khoom lag luam tau txais ib pob ntawm pob li qub nrog G1/2 cov xov sab hauv, tab sis cov xov sab nraud ntawm tus neeg siv khoom cov kav dej yog NPT 1/2. Ib tug neeg ua haujlwm tau sim ua kom lub valve los ntawm kev quab yuam rau plaub zaug tab sis tsis tuaj yeem tig nws ntxiv; Thaum siv lub zog ntxiv nrog lub spanner, lub valve lub cev cov xov sib cais, ua rau tag nrho cov pob valve siv tsis tau.

Case 2: Ib lub chaw soj nstuam haum lub pob valve nrog BSPT xov sab nraud rau qhov haum nrog G hauv xov. Nws xav tias 'txog txoj cai' thaum ntsia hlau ntsia, tab sis qhov kev sim siab tau qhia txog qhov xau me ntsis. Nws tau siv peb hnub ntawm kev tshawb nrhiav kom pom tias cov xov tsis sib xws - cov xov tapered tau raug ntsia hlau rau hauv cov xov hauv cylindrical, tsuas yog thawj ob peb lub xov sib cuag, ua rau muaj qhov sib khi tsis txaus.

Zaj Lus Qhia: Thaum nws los txog rau xov tsis sib haum, tsis muaj qhov zoo li 'kaw txaus'. Qhov sib txawv ntawm tsuas yog 1 ° ntawm lub kaum sab xis yog qhov sib txawv ntawm qhov tsis tuaj yeem ua kom haum rau cov khoom siv thiab tsis tuaj yeem ua tiav lub foob.

VI. Cov lus pom zoo kawg rau kev yuav cov neeg ua haujlwm thiab cov engineers

Ua ntej muab qhov kev txiav txim, thov xyuas kom meej tias koj tau lees paub peb cov ntsiab lus hauv qab no:

Xov txheem (NPT lossis BSP / G?)

Xov hom (tapered lossis cylindrical?)

Xov loj (piv txwv li 1/4', 3/8', 1/2 ")

Xyuas kom meej tias qhov ntev ntawm cov duab kos tau teev kom raug:

US tus qauv: sau 1/2-14 NPT

British tapered standard: sau 1/2 BSPT

British parallel standard: sau G1/2 lossis 1/2 BSPP

Tsis paub meej txog koj cov yeeb nkab xov specifications? Peb nyob ntawm no los pab koj txheeb xyuas lawv.

Cov xov sib txuam yog qhov tseem ceeb tshaj plaws - thiab feem ntau ua rau yuam kev - ib feem ntawm lub kav dej. Ib qho kev ua yuam kev ntawm cov qauv xov yuav ua rau tag nrho cov khoom siv li qub tsis tuaj yeem siv tau, lossis txawm tias ua rau xau thiab xav tau kev rov ua haujlwm thoob plaws tag nrho cov kav dej.

Yog tias koj tshwm sim muaj cov qauv xws li pob li qub, cov yeeb nkab fittings lossis cov khoom sib txuas, lossis yog tias koj muaj daim duab ntawm cov xov thiab tsis paub meej ntawm tus qauv - thov xa tuaj rau peb txhua lub sijhawm, thiab peb yuav kuaj xyuas lawv dawb rau koj.

Peb tsis ua 'kev kwv yees ntxhib'; peb hla kev siv cov qauv thiab ntsuas qhov tseeb siv xov gauges los muab cov lus teb meej rau koj.

Yuav ua li cas kom paub meej:

Nqa ib daim duab meej ntawm lub ntsej muag threaded thiab xa tuaj rau peb.

Nws yog qhov yooj yim dua yog tias koj muaj cov qauv ntawm lub cev, raws li peb tuaj yeem ntsuas nws ncaj qha los ntawm kev siv xov xov.

Koj tuaj yeem tiv tauj peb ntawm WeChat, xov tooj lossis email (thov cov ntsiab lus): clvy@shenchihb.com

Xov hom peb tuaj yeem muab tau:

Peb lub pob li qub thiab cov yeeb nkab fittings tuaj yeem ua raws li ntau yam ntawm cov qauv xov, suav nrog NPT, BSPT thiab G (BSPP), kom ntseeg tau 100 feem pua ​​​​ntawm koj cov kav dej. Seb rau kev lag luam hauv tsev lossis rau kev xa tawm, peb tuaj yeem tsim rau koj cov duab kos.

Xaiv cov xov zoo thiab zam qhov teeb meem tsis tsim nyog. Yog tias koj tsis paub meej, cia nws rau peb kom paub meej.