How to choose the material for the protective sleeve of the temperature sensor?

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Date: 2018-08-20Read: 5

How to choose the material for the protective sleeve of the temperature sensor?

How to choose the material for the protective sleeve of temperature sensors (thermal resistance thermocouples)?

The material selection of temperature sensor protective sleeve is very important, as it directly affects the service life of the temperature sensor. Customers should choose the corresponding temperature sensor protective sleeve according to different usage environments. Our company can customize various types of thermocouples, thermistors, bimetallic thermometer protective sleeves, and other special types of temperature sensor protective sleeves and flanges based on customer samples, drawings, and usage environments. Our company is the largest temperature instrument production base in China and is currently cooperating with ABB, a German company, to produce a series of temperature, pressure, and flow control instruments.

Detailed information on temperature sensor protective sleeve:

1Application

Used in conjunction with thermocouples to protect their normal operation. And it can be used for special occasions such as anti-corrosion, high pressure and high flow rate.

2Characteristics

All designed in accordance with IEC standards
Blind hole processing, high pressure resistance
Manufacturing and installation simultaneously with the equipment
Different pressure levels can meet different needs.

3Main technical parameters

Nominal pressure: generally refers to the static external pressure that the protective tube can withstand at room temperature without breaking. The allowable working pressure is not only related to the material, diameter, and wall thickness of the protective tube, but also to its structural form, installation method, and the flow rate and type of the measured medium.

Water pressure test: When there are requirements for the pressure resistance and leakage inspection of the protective tube, the protective tube must be tested. The test pressure is 15 times the pressure resistance level of the protective tube. X-ray flaw detection test: When there are requirements for checking the wall thickness, eccentricity, and other items of the protective tube, the inspection must be carried out according to the user's requirements.

4Method for naming models

Material selection table for temperature sensor sleeve protection tube:

material	Operating temperature ℃	Characteristics and Applications
1Cr18Ni9Ti	-200—800	It has high temperature and corrosion resistance, and is usually used as a general heat-resistant steel
304	-200—800	Low carbon content, with good intergranular corrosion resistance, usually used as a general heat-resistant steel
316	-200—750	Low carbon content, with good intergranular corrosion resistance, used as a corrosion-resistant steel
316L	-200—750	Ultra low carbon content, with good intergranular corrosion resistance, used as a corrosion-resistant steel
MonelK500	-100—700	Nickel copper alloy, with good intergranular corrosion resistance, suitable for corrosive environments such as strong sulfuric acid
Hastelloy H.Alloy-276	-100—700	Has good resistance to intergranular corrosion and is used as a corrosion-resistant steel
Incone1600	-100—1000	Nickel chromium iron alloy, with excellent high-temperature oxidation resistance, is commonly used as a heat-resistant steel
310S	-200—1000	High temperature oxidation resistance and corrosion resistance are commonly used as heat-resistant steels
GH3030	0—1100	Nickel based high-temperature alloy steel has excellent oxidation resistance and corrosion resistance, and is usually used as a heat-resistant steel
GH3039	0—1300	Nickel based high-temperature alloy steel has excellent oxidation resistance and corrosion resistance, and is usually used as a heat-resistant steel
High alumina	0—1300	Industrial ceramic tube, with excellent oxidation resistance and corrosion resistance
Steel jade tube	0—1600	Industrial ceramic tube, with excellent oxidation resistance and corrosion resistance
3YC52	0—1300	High temperature alloy, with excellent oxidation resistance, corrosion resistance, and good mechanical properties, suitable for high-temperature environments
Molybdenum disilicide MoSi2	0—1600	Has excellent oxidation resistance, corrosion resistance, and good mechanical properties, suitable for high-temperature environments

Types and characteristics of metal protective tubes

Types	Steel grade	Chemical composition%	Common temperature (℃)	characteristic
Titanium	TB35	0.2Fe-Ti	250	Corrosion resistant at low temperatures, especially to seawater corrosion.
brass	C3601	59-63 Cu-Zn	400	Low temperature use, good processing performance.
Nickel copper alloy	NCu	63-70 Ni-Cu	500	High strength, excellent corrosion resistance to alkali, non oxidizing acids, and saltwater.
low-carbon steel	STPG	0.25-0.3C 0.3-1.0MnYu Fe	600	The antioxidant performance is weak and should be used in non corrosive fluids. After surface modification with glass or resin, the corrosion resistance can be improved.
Forged steel for high-temperature pressure vessels	Sfvaf 22	2.25Cr-1Mo-Fe C≤0.15	600	Low carbon alloy steel has good corrosion resistance at high temperatures due to the addition of Mo and Cr.
austenite stainless steel	SS304	18Cr-8Ni-Fe	900	The most widely used stainless steel.
	SS316	18Cr-12Ni-2.5Mo-Fe	900	Corrosion resistant materials. Various media mainly composed of seawater have better corrosion resistance than 304.
	SS310S	25Cr-20Ni-Fe	1000	Anti oxidation performance *, as a heat-resistant steel, it has poor resistance to sulfides.
	SS321	18Cr-9Ni-Ti-Fe	900	Adding Ti enhances the resistance to grain boundary corrosion.
	SS347	18Cr-9Ni-Nb-Fe	900	Adding Nb enhances the resistance to grain boundary corrosion.
Austenitic and ferritic stainless steel	SUS329J1	25Cr-4.5Ni-2Mo	800	It has a two-phase structure, strong acid and corrosion resistance, and high strength.
ferrite heat-resistant steel	SUH446	25Cr-0.2N-0.2C	1000	Strong resistance to high temperature corrosion, up to 1082 ℃, does not produce easily peeled iron sheets, and is resistant to sulfur corrosion.
Heat resistant and corrosion-resistant superalloy	NCF600	15.5Cr-72Ni-7Fe	1050	Corrosion resistance under high-temperature oxidizing and reducing atmospheres. Strong resistance to carburizing and nitriding.
Heat resistant and corrosion-resistant superalloy	NCF800	20.5Cr-32Ni-44.5Fe Ti-Al-Cu	1000	Strong resistance to carburizing and internal oxidation, with a stable austenitic structure and good corrosion resistance. It has high high-temperature strength, creep strength, and fracture strength.
Nickel based heat-resistant Corrosion-resistant alloy	—	15Cr-52Ni-16Mo 5.5Fe-4W	1000	Can be used in oxidizing and reducing atmospheres. Acid and mixed acid corrosion resistance.
Nickel based heat-resistant Corrosion-resistant alloy	—	22Cr-48Ni-9Mo 18Fe-1.5Co-0.6W	1150	A typical heat-resistant alloy. It still has high strength and antioxidant properties at 1090 ℃. Corrosion resistance in oxidizing, reducing, and neutral atmospheres.
Cobalt based heat-resistant Corrosion-resistant alloy	UMCO50	28Cr-21Fe-1Si 50Co	1150	Heat resistant impact, wear-resistant material, resistant to sulfide and vanadium corrosion, high temperature strength.
Wear-resistant alloy	HR1230	Ni-Fe-Cr-Al	800～1200	Has * strength and wear resistance, suitable for harsh wear environments such as fluidized beds.
iron-based alloy	MPT-1	Fe-Cr	1000	Resistant to liquid corrosion of aluminum and aluminum alloys.
iron-based alloy	MPT-2	Fe-Cr	1000	Resistant to fluoride cryolite corrosion.
耐热合金管	3YC52	Ni45Cr17Al	1300	The usage temperature and high-temperature oxidation resistance are superior to similar high-temperature alloys.
耐热合金管	OR1300	Ni-Cr-W-Mo-Al	1300

Types and characteristics of non-metallic protective tubes

material		symbol	Chemical composition%	Commonly Used Temperatures ℃	Maximum operating temperature ℃	characteristic
Chlorinated ethylene resin polyethylene fluororesin			Ethylene chloride ethylene ethylene	50 80 250		The composition and formula are different, and the commonly used temperature is also different. It has corrosion resistance to both acids and bases, but its safety decreases with increasing temperature. To give plastic mechanical strength, it is usually used on the surface of a metal protective tube.
quartz		QT	SiO2	1000	1100	Good heat shock resistance, but low strength, strong acid resistance, poor alkali resistance, and poor airtightness in H2 and reducing gases.
Clay ceramic tube High alumina ceramic tube Jadeite porcelain tube		CB3 CB2 CB1	Al2O3 99.5	1000 1400 1600	1500 1800	Al2O3The higher the purity, the better its high-temperature strength, electrical insulation performance, and wear resistance. It can also be used at very high temperatures in oxidizing or reducing atmospheres.
magnesium oxide			MgO 97	1800		MgOEasy to hydrolyze. High density materials fired at high temperatures, resistant to corrosion from inorganic salts and oxidizing gases.
zirconium oxide		ZR	ZrO2 94 CaO 6	1800	2400	Difficult to react with oxidizing and neutral substances at high temperatures, but susceptible to alkaline oxide corrosion.
carbon transform silicon	Recrystallized SiC	Y1	SiC 98	1650		Good airtightness, strong heat shock resistance, heat resistance at high temperatures, and excellent wear resistance. It can be used up to 1700 ℃ in oxidizing and reducing atmospheres.
	Silicon bonded SiC	Y3	SiC 89Si 9	1500	1700	Good thermal conductivity and strong resistance to thermal shock.
	Si3N4Combining SiC	Y4		1550	1750	Due to the presence of Si3N4, it is resistant to corrosion by molten aluminum.
Si3N4			Si3N4 97	1600		Si3N4The oxidation product is the same as SiC, forming a SiO2 protective film on the surface of Si3N4 during the initial oxidation stage.
	Theron	HCN	Si-Al-O-N	1250		Resistant to aluminum liquid corrosion, minimal pollution, and has a longer lifespan than cast iron pipes, reaching over one year.
graphite			C	1500	2300	High temperature resistance, easy oxidation, good heat shock resistance, and alkali corrosion resistance.

Types and characteristics of metal ceramic protective tubes

model	main ingredients	Common temperature ℃	Zui high temperature ℃	Specification mm	medium	characteristic
LT1	Al2O3-Cr	1300	1400	28×16	Non ferrous metal melts other than aluminum	Heat resistance and wear resistance*
CT	ZrO2-Mo	1600	2200	12×6	liquid metal	Good thermal conductivity and strong thermal shock resistance, not suitable for oxidizing atmosphere.
MCPT-3	MgO-Mo-Cr	1600	1800	Φ30×18×500	Molten steel, molten iron	Molybdenum based metal ceramics are not suitable for oxidizing atmospheres.
MCPT-4	Al2O3-Cr2O3-TiO2-Mo	1200	1400	Φ23×15×280	BaCl2
MCPT-6	Al2O3-Cr2O3-MgO-Mo-TiO2-Cr	1100	1300	Φ23×15×280	Copper and copper alloys

1、 Product Overview

Industrial platinum resistors are commonly used as temperature measurement transmitters, paired with display, recording, and regulating instruments, to directly measure liquids, vapors, and gases in the range of -200 ℃ to 500 ℃ during various production processes
Surface temperature of gas media and solids.

2、 Model specifications

1. Non fixed device type thermistor

Category	model	graduation mark	Temperature measurement range ℃	protective tube material	Diameter d mm	thermal response time t0.5 S
Single platinum thermistor	WZP-130	rtd	-200~420	stainless steel 1Cr18Ni9Ti stainless steel 0Cr18Ni12M02Ti	Φ16	≤90
Single platinum thermistor	WZP-131				Φ12	≤30
Double platinum thermistor	WZP2-130				Φ16	≤90
Double platinum thermistor	WZP2-131				Φ12	≤45
Copper thermistor	WZC-130	Cu50	-50~100	Brass H62 stainless steel 1Cr18Ni9Ti	Φ12	≤120

Thermal resistance length specification (mm)

Waterproof 130, 131

Φ16		Φ12
Total length L	Depth I	Total length L	Depth I
300 350 400 450 550 650 900 1150 1400 1650 2150	150 200 250 300 400 500 750 1000 1250 1500 2000	225 250 300 350 450 550 650 900 1150	75 100 150 200 300 400 500 750 1000

2Fixed thread thermistor

Category	model	graduation mark	Temperature measurement range ℃	protective tube material	Diameter d mm	thermal response time t0.5 S
Single platinum thermistor	WZP-230	rtd	-200~420	stainless steel 1Cr18Ni9Ti stainless steel 1Cr18Ni12M02Ti	Φ16	≤90
Single platinum thermistor	WZP-231				Φ12	≤30
Double platinum thermistor	WZP2-230				Φ16	≤90
Double platinum thermistor	WZP2-231				Φ12	≤45
Copper thermistor	WZC-230	Cu50	-50~100		Φ12	≤120

Comparison Table of Fixed Thread Model Specifications

Product Model	Fixed thread specification
WZP-230	M27×2
WZP-231	M27×2
WZP2-230	M27×2
WZP2-231	M27×2
WZC-230	M27×2

Thermal resistance length specification (mm)

Waterproof 230, 231

Φ16		Φ12
Total length L	Depth setting l	Total length L	Depth setting l
300 350 400 450 550 650 900 1150 1400 1650 2150	150 200 250 300 400 500 750 1000 1250 1500 2000	225 250 300 350 450 550 650 900 1150	75 100 150 200 300 400 500 750 1000

3Active flange type thermistor

Category	model	graduation mark	Temperature measurement range ℃	protective tube material	Diameter d mm	thermal response time t0.5 S
Single platinum thermistor	WZP-330	rtd	-200~420	stainless steel 1Cr18Ni9Ti stainless steel 0Cr18Ni12M02Ti	Φ16	≤90
Single platinum thermistor	WZP-331				Φ12	≤30
Double platinum thermistor	WZP2-330				Φ16	≤90
Double platinum thermistor	WZP2-331				Φ12	≤90
Copper thermistor	WZC-330	Cu50	-50~100	stainless steel 1Cr18Ni9Ti	Φ12	≤120

Thermal resistance length specification (mm)

Waterproof 330, 331

Φ16	Φ12
Total length L	Total length L
300 350 400 450 550 650 900 1150 1400 1650 2150	225 250 300 350 450 550 650 900 1150

4Fixed flange type thermistor

Category	model	graduation mark	Temperature measurement range ℃	protective tube material	Diameter d mm	thermal response time t0.5 S
Single platinum thermistor	WZP-430	rtd	-200~420	stainless steel 1Cr18Ni9Ti stainless steel 0Cr18Ni12M02Ti	Φ16	≤90
Single platinum thermistor	WZP-431				Φ12	≤30
Double platinum thermistor	WZP2-430				Φ16	≤90
Double platinum thermistor	WZP2-431				Φ12	≤90
Copper thermistor	WZC-430	Cu50	-50~100	stainless steel 1Cr18Ni9Ti	Φ12	≤120

Comparison Table of Fixed Flange Models and Specifications

Product Model	Fixed flange specifications (professional standards)
Product Model	D0	D1	D2	D3
WZP-430	F95	F65	F45	F16
WZP-431	F95	F65	F45	F12
WZP2 -430	F95	F65	F45	F16
WZP2 -431	F95	F65	F55	F12

Thermal resistance length specification (mm)

Waterproof 430, 431

Φ16		Φ12
Total length L	Depth setting l	Total length L	Depth setting l
300 350 400 450 550 650 900 1150 1400 1650 2150	150 200 250 300 400 500 750 1000 1250 1500 2000	225 250 300 350 450 550 650 900 1150	75 100 150 200 300 400 500 750 1000

5Fixed thread conical protective tube type

Thermal resistance category	Product Model	graduation mark	measurement range ℃	protective tube material	specification		thermal response time T0.5S
					Total length L mm	Depth setting l mm
Single platinum thermistor	WZP-631	rtd BA1 BA2	-200~400	stainless steel 1Cr18Ni9Ti	300 350 450 550	150 200 300 400	≤90
Double platinum thermistors	WZP2-631

Comparison Table of Model and Specification of Fixed Thread Conical Protective Tube

Product Model	Fixed thread specification
WZP-631	M33×2
WZP2-631	M33×2

Fixed thread conical protective tube

Waterproof 630 and 631 types

3、 Anhui Tiankang Group Thermal Resistance Platinum Resistance Model Representation

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