Chemtrol Australia Product - CR-301 High Temperature & Pressure Corrosion Rate Sensor

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CR-301 High Temperature & Pressure Corrosion Rate Sensor

Product Details
Specifications
High Temperature & Pressure
Installation
Video

CR-301 High Temperature & Pressure Corrosion Rate Sensor

The Pyxis CR-301 measures how fast metal is corroding inside a live process line. It uses linear polarisation resistance (LPR) between two replaceable test-metal electrodes to give the general corrosion rate, from 0.001 to 995 mpy (thousandths of an inch per year), and reads the electrochemical noise between them to give a localised (pitting) corrosion index from 0.001 to 100.

It is rated to 240 °C and 34.5 bar, for hot, pressurised water beyond the reach of ordinary corrosion probes. It measures the water’s conductivity itself and corrects the LPR reading for it. Powered at 24 V DC from a controller, PLC or DCS, it sends both readings over two 4–20 mA outputs and RS-485 Modbus.

Set-up is from the uPyxis^® app over Bluetooth^®, with the MA-CR adapter supplied. Choose the electrode metal and the app loads its alloy factor and output scales; both can be changed.

Titanium Body, Signal Processed in the Sensor

The liquid end is titanium and PEEK, and cooling fins keep process heat away from the electronics. The LPR signal is tiny, so the CR-301 amplifies and digitises it inside the sensor: a long cable run to the controller can’t add noise or weaken it, and the titanium body screens out electrical interference.

Specifications

Item	CR-301
Part Number	51021
Method	Linear polarisation resistance (general corrosion); electrochemical noise (localised corrosion)
General Corrosion Range	0.001 – 995 mpy (4–20 mA scale set in uPyxis®)
Resolution	0.001 mpy or 1% of reading
Localised Corrosion Index	0.001 – 100 (4–20 mA scale set in uPyxis®)
Conductivity Compensation	10 – 50,000 µS/cm
Reading Interval	3 – 1,440 minutes (more than 3 minutes for localised corrosion)
Alloy Factor	0 – 3; default set by the metal (UNS code) chosen in uPyxis®
Outputs	Two 4–20 mA (general and localised corrosion) and RS-485 Modbus
Wireless	Bluetooth® with the MA-CR adapter (supplied), uPyxis® app
Power Supply	24 V DC, 2 W
Process Connection	¾" NPT
Materials	Titanium and PEEK
Operating Pressure	Up to 34.5 bar (500 psi)
Operating Temperature	−10 – 240 °C (14 – 464 °F)
Storage Temperature	−20 – 70 °C (−4 – 158 °F)
Dimensions	280 mm long, 52 mm diameter
Weight	1,150 g
Cable	8-pin, 1.5 m (5 ft); extension cables available
Protection	IP68
Approvals	CE, RoHS; FCC Part 15 (US)
Electrodes	5 cm², 4-40 thread; mild steel pair (51002) and copper pair (51003) supplied
Supplied With	1.5 m extension cable, 0.6 m flying-lead cable, MA-CR Bluetooth® adapter, MA-NEB USB Bluetooth® adapter for a PC, 2.0 mpy (51010) and 0.1 mpy (51011) calibration check caps
Warranty	13 months

Test Metals and Default Settings

Metal	UNS	Alloy Factor	Default General Corrosion Scale (mpy)	Default Localised Corrosion Scale (index)
Aluminium AA1100	A91100	0.94	0 – 50	0 – 100
Aluminium AA6061	A96061	0.94	0 – 50	0 – 100
Aluminium AA2024	A92024	0.86	0 – 50	0 – 100
Cu/Ni 70/30	C71500	1.50	0 – 5	0 – 10
Copper 110 ETP	C11000	2.00	0 – 5	0 – 10
CDA 687 Aluminium Brass Arsenical	C68700	1.62	0 – 5	0 – 10
CDA 642 Aluminium Silicon Bronze	C64200	1.48	0 – 5	0 – 10
Arsenical Admiralty Brass CDA 443	C44300	1.67	0 – 5	0 – 10
Phosphorised Admiralty Brass CDA 445	C44500	1.68	0 – 5	0 – 10
Pipe Grade Carbon Steel	A135	1.00	0 – 50	0 – 100
Mild Steel C1010	G10100	1.00	0 – 50	0 – 100
Mild Steel C1015	G10150	1.00	0 – 50	0 – 100
Mild Steel C1018–C1020	G10180	1.00	0 – 50	0 – 100
Mild Steel C1080	G10800	1.00	0 – 50	0 – 100
Stainless Steel 304	S30400	0.89	0 – 2.5	0 – 10
Stainless Steel 304L	S30403	0.89	0 – 2.5	0 – 10
Stainless Steel 316	S31600	0.90	0 – 2.5	0 – 10
Stainless Steel 316L	S31603	0.90	0 – 2.5	0 – 10
Duplex Stainless 2205 (F51)	S31803	0.90	0 – 2.5	0 – 10
Duplex Stainless 2507 (F53)	S32750	0.90	0 – 2.5	0 – 10
Common Lead	L50045	2.57	0 – 2.5	0 – 1

The electrodes are 5 cm² with a 4-40 thread. With an electrode of a different surface area, the alloy factor must be recalculated in proportion to the area.

High Temperature & Pressure Systems

In hot, pressurised water, waiting weeks for a coupon to come out is too slow. The CR-301 screws straight into the line in geothermal process plant, district heating loops, oil and gas process and produced water, and other high-temperature, high-pressure systems, and reports corrosion continuously, so treatment can be adjusted while it still matters.

Key Features

General corrosion 0.001 – 995 mpy and localised (pitting) index 0.001 – 100
Rated to 240 °C and 34.5 bar
Titanium and PEEK liquid end with cooling fins
Signal amplified and digitised in the sensor; titanium body screens interference
Measures and corrects for conductivity, 10 – 50,000 µS/cm
Two 4–20 mA outputs (general and localised) and RS-485 Modbus
21 preset metals in the uPyxis^® app, with adjustable alloy factor and output scales
Bluetooth^® set-up with the MA-CR adapter, supplied
2.0 and 0.1 mpy calibration check caps supplied
24 V DC, 2 W, IP68

Fitting

The sensor ships without electrodes. Put an O-ring on each threaded rod and screw the electrodes on until the O-rings are just compressed. Wear gloves, and clean the electrodes with isopropanol before use.
Screw the sensor into a ¾” NPT tee. Both electrodes must be fully under water, lined up parallel to the flow, evenly placed and away from turbulence.

Wiring

Red: 24 V DC +
Brown: 0 V
White: general corrosion 4–20 mA +
Pink: localised corrosion 4–20 mA +
Grey: 4–20 mA − (joined to 0 V inside the sensor)
Blue: RS-485 A
Yellow: RS-485 B
Green: shield, earth

Setting Up

The sensor leaves the factory set for mild steel: 4 mA = 0, 20 mA = 50 mpy general corrosion and 100 on the localised index. To check the controller’s scaling, fit new electrodes, plug in a calibration check cap and allow 15 minutes; the controller should read the value marked on the cap.

LPR and Coupons

An LPR reading is a snapshot of corrosion now; a coupon is an average over the weeks it was in. The two follow each other but won’t match reading for reading. Trend the LPR figure, compare its average with your coupon results, and adjust the alloy factor if needed so the two agree.

Care

Replace electrodes once they are badly corroded, and clear scale or deposits from the electrodes and sensor body. A light film of corrosion product is fine. Don’t leave the sensor in stagnant water for long.