Special thermocouples for petrochemical industry include: Multi-point armored thermocouple, multi-point flameproof type, armored integral multi-point type, high-pressure type, internal leakage-proof suit type, furnace tube blade type, special for cracking furnace, wear-resistant cut-off type, wear-resistant leak-proof type , Blowing thermocouple, etc.

The whole product of multi-point thermocouple is composed of multiple insulated armored thermocouples with different lengths (according to user requirements) but the same outer diameter. Its terminals co-exist in the same junction box, and the product has no outer protective tube. The structure of multi-point thermocouple has WR□KT□/□-□2□DD, WR□KT□/□-□3□DD, WR□KT□/□-□4□DD. Multi-branch multi-point thermocouple adopts various fixing devices such as straight thread, tapered pipe thread or flange. It can be installed and used on various equipment, withstands pressure and shock resistance, and has stable and reliable performance. There is a good blocking structure between the armored core and the junction box to prevent the penetration of the medium after the protection tube is damaged.

Application of multi-point thermocouple

The multi-point armored thermocouple is a special temperature measuring instrument designed for the fertilizer industry. It is used to measure the temperature at different depths in equipment such as synthesis towers and reaction tanks. When the diameter of the thermocouple is below Φ5, the maximum depth can reach more than 30 meters. When using this product, the user needs to prepare an external protection tube, otherwise, the wisdom can only measure normal pressure and non-corrosive media.

Features of multi-point thermocouple

1. Adopt various types of fixing devices such as straight thread, tapered pipe thread or flange. It can be installed and used on equipment in different countries.
2. There are many types of junction boxes:
It can work reliably in general occasions (common waterproof box), explosive atmosphere (flameproof junction box) or corrosive environment (stainless steel explosion-proof box).
3. The armored measuring element is adopted, which is resistant to pressure and shock, and is stable and reliable.
4. Between the armored core and the junction box, there is a blocking structure that prevents the measurement medium from intruding after the protective tube is damaged.
5. It has a variety of explosion-proof J products (such as dIIBT4, dIICT4, dIICT5, etc.) that meet the IEC standards of the International Electrotechnical Commission. It is suitable for temperature measurement in explosion-proof occasions with different J requirements.

Standard specification of multipoint thermocouple

 

Variety	Index number	Measuring range (℃)	Armour material	Points and armor diameter d(mm)			J accuracy etc.	Remarks
Platinum Rhodium 10-Platinum	S	0-1200	CH30 alloy	Φ3 Φ4 Φ5 Φ6 Φ8	Φ3 Φ4 Φ5 Φ6	Φ3	I or II	1. When two signals are output at each point, the number of measurement points is halved accordingly. 2. When the thermal resistance is a two-wire output mode and the transmission is a three-wire system, one wire can be connected to one terminal; Connect two wires to the other terminal.
Nickel Chromium-Nickel Silicon	X	0-1100
		0-800	1Cr18Ni9Ti
Nickel Chromium-Constantan	E	0-700
Iron-Constantan	J	0-600
Copper-Constantan	T	-200-300
Platinum resistance	Pt100	-200-500

 
 
Multi-point armored thermocouple selection table

WR

Multi-point armored thermocouple

Code

Type of thermoelectric J

Q

R graduation number | platinum rhodium 13-platinum

P

S index number | platinum rhodium 10-platinum

R

B indexing number | platinum rhodium 10-platinum

N

Nickel-chromium-nickel-silicon, index number K

E

Ni-Cr-Constantan, index number E

F

Iron-Constantan, index number J

C

Copper-Constantan. Index T

Code

structure type

K

Armored structure

Code

Number of measurement points (between 2 and 12, in a sequence of positive integers)

2

The measuring points of different depths are 2 points

※

―――――――

※

―――――――

12

The number of measurement points at different depths is 12

Code

Fixing device form

l

No fixed, suitable for ≤6 points

2

Fixed thread, suitable for ≤6 points

3

Tapered pipe thread with active joint, suitable for ≤12 points

4

Fixed flange, suitable for ≤12 points

5

Straight thread with blowing device, suitable for ≤12 points

Code

Junction box form

2

Splash-proof, suitable for ≤12 points

3

Waterproof type, suitable for ≤6

4

Explosion-proof type, suitable for ≤6 points, explosion-proof mark; dIIcT4, ibIIcT5, dIICT5

7

Stainless steel explosion-proof box, suitable for ≤12 points, explosion-proof mark; dIICT5, ibⅡcT5

Code

Measuring terminal form

l

J edge style

2

Shell connection type, not suitable for explosion-proof products

Code

Multi-point thermocouple outer protective tube material

0

1Cr18Ni9Ti, regular supply

1

GH30 alloy, only S and B index numbers are used

DD

Multi-branch multi-point armored thermocouple

Code

The diameter of the sheath of the galvanic couple (between 3 and 8, in a sequence of positive integers)

3

Galvanic armor diameter Φ3Φ3

※

―――――――

※

―――――――

8

The diameter of the galvanic sheath is from Φ8

Code

Multi-point thermocouple accuracy etc. J

II

IIJ; regular supply

I

IJ; supply by agreement; additional price required

Code

Insertion depth of each element l (sorted from short to long) mm

l1

One measuring point with short length

※

―――――――

※

―――――――

ln(n=number of measuring points)

A long measuring point

WR

□

K

□

-□

□

□

□

DD

□

□

□/□/.../□

Outline structure drawing
① Waterproof multi-point armored thermocouple without fixing device
Multi-point armored thermocouple
Outline structure drawing
　① Waterproof multi-point armored thermocouple without fixing device
 

　② Multi-point armored thermocouple with waterproof fixed threaded device
 

　③ Flameproof multi-point armored thermocouple with blow-through straight thread
 

　④ Splash-proof multi-point armored thermocouple with taper pipe thread with active joint
 

　⑤ Multi-point armored thermocouple with stainless steel fixed flange
 

Common specifications and models of multi-point armored thermocouples
Multiple thermocouples at a single point. Four armor wires: T1=2350mm, T2=2650mm, T3=2900mm, T4=3200mm
T1 temperature measurement point (L1=1850mm, L2=2150mm, L3=2350mm)
T2 temperature measurement point (L4=2150mm, L5=2450mm, L6=2650mm)
T1 temperature measurement point (L7=2400mm, L8=2700mm, L9=2900mm)
T1 temperature measurement point (L10=2700mm, L11=3000mm, L12=3200mm)
Multiple thermocouples at a single point. Two armor wires: T1=3920mm T2=3620mm
T1 temperature measurement point (L1=2120mm, L2=3020mm, L3=3920mm)
T2 temperature measurement point (L4=1875mm, L5=2775mm, L6=3675mm)