Richards metal thermocouple protection tubes are manufactured using our special processes to maximize the tube service life. This is evident by our uniquely shaped, heavy mass tips, which have been proven in the field for years. Prior to shipment, each tube goes thru our Hydro pneumatic testing to check for porosity and structural integrity. Metal protection tubes are typically made with a closed hot end and a threaded cold end, but they can be made with open or partially open ends and various threading configurations. We stock all high temperature and corrosion resistant alloys in a variety of pipe sizes and schedules to insure quick delivery. We purchase our pipe in mill shipments and pass the savings on to our customers. Some of the more common metal protection tube materials are shown on this page, but we can manufacture protection tubes from any material which may be required.

NPT Pipe Sizes

Description Construction 1" NPT, Plain 3/4" NPT, Plain 3/4" NPT, Special 1/2" NPT, Plain 3/8" NPT, Plain 1/4" NPT, Plain 1/8" NPT, Plain

 

Pipe Size Dimensions (NPT) **The proper selection of protection tube will extend life of both tubes and thermocouples. Insufficient insertion of the protection tube may cause low readings. Response time will usually be faster with smaller tubes, slower with larger heavier walled tubes.
Pipe Size	Inches OD	MM OD	Standard Weight-Sch.40				Extra Heavy Weight-Sch.80				Extra Heavy Weight-Sch.80
			Inches		Millimeters		Inches		Millimeters		Inches		Millimeters
			ID	Wall	ID	Wall	ID	Wall	ID	Wall	ID	Wall	ID	Wall
1/8	.41	10.4	.27	.068	6.9	1.73	.22	.095	5.6	2.41	-	-	-	-
1/4	.54	13.7	.36	.088	10.1	2.24	.30	.119	7.6	3.02	-	-	-	-
3/8	.68	17.2	.49	.091	12.4	2.31	.42	.126	10.7	3.20	-	-	-	-
1/2	.84	21.3	.62	.109	15.7	2.77	.55	.147	14.0	3.73	.25	.29	6.4	7.37
3/4	1.05	26.7	.82	.113	20.8	2.87	.74	.154	18.8	3.91	.43	.31	10.1	7.87
1	1.32	33.5	1.05	.133	26.7	3.38	.96	.179	24.4	4.55	.60	.36	15.2	9.14

Back to Top

Application	Alloy	Part Number	Pipe Size	Inches		Pounds Per Foot	Millimeters		Kilos Per Meter
				OD	ID		OD	ID
General Furnace use to 1150C (2100F) No sulfur	# 6 Alloy (601) Seamless 60% Nickel 23% Chromium	601-*	1" Std.	1.32	1.05	1.80	33.5	26.7	2.66
		634-*	3/4" Std.	1.05	0.82	1.20	26.7	20.8	1.79
		634SP-*	3/4" NPT	1.25	0.56	3.20	31.8	14.2	4.76
		622	1/2" Std.	0.84	0.62	0.91	21.3	15.7	1.35
		638-*	3/8" Std.	0.68	0.49	0.61	17.3	12.4	0.91
Back to Top
For use to 1150C (2100F) particularly in Sulfurous Atmospheres. Use Extra Heavy Seamless Drawn tube for Hydrogen atmospheres. More resistant to abrasion than #10 Alloy.	# 7 Alloy (446) Seamless 23% Chromium iron Type 446 Stainless	701-*	1" Std.	1.32	1.05	1.68	33.5	26.7	2.50
		734SP-*	3/4" NPT	1.25	0.56	3.20	31.8	14.2	4.76
		734XH-*	3/4" XH	1.05	0.74	1.47	26.7	18.8	2.19
		722-*	1/2" Std.	0.84	0.62	0.85	21.3	15.7	1.27
		712SP-*	3/4" NPT	1.00	0.56	1.87	31.8	14.2	2.78
		738-*	3/8" Std.	0.68	0.49	0.57	17.3	12.4	0.85
		714XH-*	1/4" NPT	0.50	0.25	0.48	12.7	6.4	0.72
Back to Top
Chemical Applications to 870C (1600FF) More resistant to abrasion than # 9 Alloy	# 8 Alloy (600) Seamless 76% Nickel 15% Chromium Type 304 Stainless Steel	801-*	1" Std.	1.32	1.05	1.80	33.5	26.7	2.66
		834-*	3/4" Std.	1.05	0.82	1.80	26.7	20.8	1.81
		834SP-*	3/4" NPT	1.25	0.56	3.20	31.8	14.2	4.76
		834XH-*	3/4" XH	1.05	0.74	1.51	26.7	18.8	2.25
		822-*	1/2" Std.	0.84	0.62	0.91	21.3	15.7	1.35
		812XH-*	1/2" XH	0.84	0.55	1.17	21.3	14.0	1.74
		838-*	3/8" Std.	0.68	0.49	0.61	17.3	12.4	0.91
		814-*	1/4" Std.	0.54	0.36	0.46	13.7	9.1	0.68
		818-*	1/8" Std.	0.41	0.27	0.26	10.4	6.9	0.39
Back to Top
General Furnace use to 1150C (2100F) No sulfur	# 9 Alloy (600) Seamless 76% Nickel 15% Chromium	901-*	1" Std.	1.32	1.05	1.80	33.5	26.7	2.66
		934-*	3/4" Std.	1.05	0.82	1.80	26.7	20.8	1.81
		934SP-*	3/4" NPT	1.25	0.56	3.20	31.8	14.2	4.76
		934XH-*	3/4" XH	1.05	0.74	1.51	26.7	18.8	2.25
		922-*	1/2" Std.	0.84	0.62	0.91	21.3	15.7	1.35
		912XH-*	1/2" XH	0.84	0.55	1.17	21.3	14.0	1.74
		938-*	3/8" Std.	0.68	0.49	0.61	17.3	12.4	0.91
		914-*	1/4" Std.	0.54	0.36	0.46	13.7	9.1	0.68
		918-*	1/8" Std.	0.41	0.27	0.26	10.4	6.9	0.39
Back to Top
General Furnace use to 1150C (2100F) oxidizing or reducing atmospheres. Cyanide baths. More resistant to Sulfur than # 16 Alloy.	# 10 Alloy (800) Seamless 32% Nickel 21% Chrome	1001-*	1" Std.	1.32	1.05	1.72	33.5	26.7	2.66
		1034-*	3/4" Std.	1.05	0.82	1.20	26.7	20.8	1.71
		1012XH-*	1/2" XH	0.84	0.55	1.17	21.3	14.0	1.66
Back to Top
	# 16 Alloy (316) Seamless 12% Nickel 17% Chromium Type 316 Stainless	1601-*	1" Std.	1.32	1.05	1.68	33.5	26.7	2.50
		1634-*	3/4" Std.	1.05	0.82	1.13	26.7	20.8	1.68
		1634SP-*	3/4" NPT	1.25	0.56	3.20	31.8	14.2	4.76
		1634XH-*	3/4 " XH	1.05	0.74	1.47	26.7	18.8	2.19
		1612XH-*	1/2" XH	0.84	0.55	1.09	21.3	14.0	1.62
		1638-*	3/8" Std.	0.68	0.49	0.57	17.3	12.4	0.85
		1614XH-*	1/4" NPT	0.50	0.25	0.48	12.7	6.4	0.72
		1618-*	1/8" Std.	0.41	0.27	0.24	10.4	6.9	0.36
Back to Top
General use and Chemical Applications to 1150C (2100F)	# 20 Alloy (310) Seamless 20% Nickel 25% Chromium Type 310 Stainless	2001-*	1" Std.	1.32	1.05	1.68	33.5	26.7	2.50
		2034-*	3/4" Std.	1.05	0.82	1.13	26.7	20.8	1.68
		2022-*	1/2" Std.	0.84	0.62	0.85	21.3	15.7	1.27
		2014-*	1/4" Std.	0.54	0.36	0.42	13.7	9.1	0.63
		2018-*	1/8" Std.	0.41	0.27	0.24	10.4	6.9	0.36
Back to Top
Low temperature applications: tin, babbit, oil baths, galvanizing, Magnesium or Zinc. Scales readily over 650C (1200F)	Carbon Steel Seamless Extra Heavy	SS0IDXH-*	1" DXH	1.32	0.60	3.10	33.5	15.2	4.61
		SS34XH-*	3/4 " XH	1.05	0.74	1.40	26.7	18.8	2.08
		SS12XH-*	1/2" XH	0.84	0.55	1.00	21.3	14	1.49
		SS14-*	1/4" Std.	0.54	0.36	0.42	13.7	9.1	0.62
		SS18-*	1/8" Std.	0.41	0.27	0.24	10.4	6.9	0.36

Back to Top  

We stock a complete line but more important we have manufacturing facilities "Ready to go".

Lower your maintenance costs with Richards protection tubes.

Personal Service - Contact Us   

Back to Top    

PROTECTION TUBES - METAL, MINIATURE
Miniature tubes can be used with thermocouples made from insulated thermocouple wire.
They may also be used as replacement parts for miniature assemblies.  

Flared End (Standard)

Flare is provided to help prevent fraying or wearing of insulated wire leaving the tube.
Example: 9M2-12

Compression Fitting (CF)

Compression Fitting is screwed in place, tube adjusted to desired insertion, then
compressing nut is tightened on inside ferrule to hold the tube firmly in place.
Example: 9M2-12- CF  

Hex Fitting (HX) (Stainless Steel)

Used where 1/2" x 1/2" NPT fitting is desirable for mounting to furnace and head.
Example: 9M2-HX-12  

No Flare

A tube without a flare is available for applications where the increased Outside Diameter (OD)
of the flare becomes a hindrance.
Example: 9M2-NF-12  

Pointed Probe

A pointed probe is used to penetrate a soft materials such as food produces. When used with
food products the probe should be made of a material such as 316 Stainless Steel.
Example: 16M3-PN-12

Back to Top

Application	Alloy	Part Number	Inches			Millimeters
			OD	ID	Wall	OD	ID	Wall
Corrosive applications and general use to 540C (1000F)	# 6 Alloy (601) Seamless 60% Nickel 23% Chromium	6M12-*	0.750
		6M08-*	0.500	0.370	0.065	12.4	9.4	1.65
		6M04-*	0.250	0.180	0.035	6.4	4.57	0.89
		6M03-*	0.188	0.148	0.020	4.8	3.76	0.51
		6M02-*	0.125	0.085	0.020	3.2	2.16	0.51
		6M01-*	0.063	0.043	0.010	1.6	1.09	0.25
Back to Top
General use to 540C (1000F)	# 7 Alloy (446) Seamless 23% Chromium Iron - Type 446 Stainless	7M12-*	0.750	0.620	0.065	19.1	15.8	1.65
		7M08-*	0.500	0.370	0.065	12.4	9.4	1.65
		7M04-*	0.250	0.180	0.035	6.4	4.57	0.89
		7M03-*	0.188	0.148	0.020	4.8	3.76	0.51
		7M02-*	0.125	0.085	0.020	3.2	2.16	0.51
		7M01-*	0.063	0.043	0.010	1.6	1.09	0.25
Back to Top
Chemical applications and general use to 540C (1000F)	# 8 Alloy (600) Seamless 76% Nickel 15% Chromium Type 304 Stainless Steel	8M14-*	0.875	0.500	0.188	22.2	12.7	4.76
		8M12-*	0.750	0.620	0.065	19.1	15.8	1.65
		8M10-*	0.625	0.495	0.065	15.9	12.6	1.65
		8M08-*	0.500	0.370	0.065	12.4	9.4	1.65
		8M06-*	0.375	0.245	0.065	9.53	6.25	1.65
		8M04-*	0.250	0.180	0.035	6.4	4.57	0.89
		8M03-*	0.188	0.148	0.020	4.8	3.76	0.51
		8M02-*	0.125	0.085	0.020	3.2	2.16	0.51
		8M01-	0.063	0.043	0.010	1.6	1.09	0.25
Back to Top
Corrosive applications and general use to 540C (1000F)	# 9 Alloy (600) Seamless 76% Nickel 15% Chromium	9M14-*	0.875	0.500	0.188	22.2	12.7	4.76
		9M12-*	0.750	0.620	0.065	19.1	15.8	1.65
		9M10-*	0.625	0.527	0.049	13.39	13.39	1.24
		9M08-*	0.500	0.370	0.065	12.4	9.4	1.65
		9M06-*	0.375	0.277	0.049	9.53	7.04	1.24
		9M04-*	0.250	0.180	0.035	6.4	4.57	0.89
		9M03-*	0.188	0.148	0.020	4.8	3.76	0.51
		9M02-*	0.125	0.085	0.020	3.2	2.16	0.51
		9M01-*	0.063	0.043	0.010	1.6	1.09	0.25
Back to Top
General use to 540C (1000F)	# 10 Alloy (800) Seamless 32% Nickel 21% Chrome	10M08-*	0.500	0.370	0.065	12.4	9.4	1.65
		10M04-*	0.250	0.180	0.035	6.4	4.57	0.89
		10M03-*	0.188	0.148	0.020	4.8	3.76	0.51
		10M02-*	0.125	0.085	0.020	3.2	2.16	0.51
		10M01-*	0.063	0.043	0.010	1.6	1.09	0.25
Back to Top
Chemical applications and general use to 540C (1000F)	# 16 Alloy (316) Seamless 12% Nickel 17% Chromium Type 316 Stainless	16M12-*	0.750	0.620	0.065	19.1	15.8	1.65
		16M08-*	0.500	0.370	0.065	12.4	9.4	1.65
		16M06-*	0.375	0.245	0.065	9.53	6.25	1.65
		16M04-*	0.250	0.180	0.035	6.4	4.57	0.89
		16M03-*	0.188	0.148	0.020	4.8	3.76	0.51
		16M02-*	0.125	0.085	0.020	3.2	2.16	0.51
		16M01-*	0.063	0.043	0.010	1.6	1.09	0.25
Back to Top
General use to 540C (1000F)	# 20 Alloy (310) Seamless 20% Nickel 25% Chromium Type 310 Stainless	20M08-*	0.500	0.370	0.065	12.4	9.4	1.65
		20M04-*	0.250	0.180	0.035	6.4	4.57	0.89
		20M03-*	0.188	0.148	0.020	4.8	3.76	0.51
		20M02-*	0.125	0.085	0.020	3.2	2.16	0.51
		20M01-*	0.063	0.043	0.010	1.6	1.09	0.25

Some General Suggestions For Effective Metal Protection Tube Use:

• Carefully select the proper protection tube alloy for your process to maximize the service life.
• Use a thick walled tube, such as schedule 80, double extra heavy, or Richards heavy duty SP size for longer service life.
• Use a thin walled tube, such as schedule 40, or smaller O. D. tube, if you require a quicker temperature response time.
• If the protection tube will be subject to severe mechanical shock or abrasion, use the Richards heavy duty SP size.
• Protection tubes should be inserted into fluids a minimum of six times the O. D. of the tube.
• Protection tubes should be inserted into gases a minimum of eight times the O. D. of the tube.
• Insertion lengths for furnaces and salt baths are typically a minimum of 6” (152.4mm).
• Protection tubes, which pass through a hot zone (muffle furnace), should be inserted at least 12” (304.8mm).
• In molten salt baths, angle assembly tube lengths should be a minimum of 18”, to protect the elbow from level changes.
• If the elbow on angle assemblies will be subject to high temperatures, an all alloy bent type tube should be used.
• Replace all metal protection tubes on a regular basis, since they will become become porous over time.
• Never shorten the life of new thermocouple elements by placing them into old, worn-out, porous, protection tubes
• Protection tube overall lengths should be long enough to insure that the head temperature will not exceed 400°For 204°C.
• Use large O. D. or thick walled protection tubes where sagging is a problem at elevated temperatures.
• Note that metal tubes are somewhat porous above 1500°F or 815°C, so in some cases a ceramic inner tube is also used.

Back to Top

 

© Copyright 2005 Arklay S. Richards Co., Inc.