Oil & Gas
Process instrumentation — pressure, temperature, flow and level
CRS PLUS sources field instrumentation for oil and gas, utility and process plants — pressure, temperature, flow and level measurement, gas and flame detection, and the fittings, manifolds and tubing that connect them — against the project instrument datasheet. Each instrument is supplied with its calibration certificate and, where required, hazardous-area and SIL certification.
Product families
Sourced through the qualified supplier base. Listing does not indicate stock held by CRS PLUS — availability, origin and lead time are confirmed per enquiry, and every quotation states the certification that governs the supply.
Pressure
- —Bourdon tube and diaphragm gauges to EN 837-1 / ASME B40.100
- —Pressure and differential pressure transmitters, 4–20 mA HART
- —Pressure switches
- —Diaphragm seals and chemical seals for corrosive and viscous service
Specified by range, accuracy class, process connection and wetted material.
Temperature
- —Thermocouples type K, J, N, T to IEC 60584
- —Pt100 RTDs, 3- and 4-wire, class A and B to IEC 60751
- —Thermowells — bar stock, flanged and threaded, to ASME PTC 19.3
- —Temperature transmitters, head-mount and field-mount; bimetal gauges
Thermowell material and insertion length follow the line specification and wake-frequency calculation.
Flow
- —Orifice plates, orifice flanges and meter runs to ISO 5167
- —Turbine, positive-displacement and variable-area meters
- —Electromagnetic, Coriolis and ultrasonic flow meters
- —Rotameters and sight-flow indicators
Meter type follows fluid, accuracy requirement and custody-transfer status.
Level
- —Radar and guided-wave radar transmitters
- —Differential pressure and displacer level transmitters
- —Magnetic level gauges and reflex/transparent gauge glasses
- —Level switches — vibrating fork, float, capacitance
Selected on fluid, vessel geometry and process conditions.
Gas and flame detection
- —Fixed point gas detectors — catalytic, infrared, electrochemical
- —Open-path infrared gas detectors
- —Flame detectors — UV, IR, UV/IR and multi-spectrum IR
- —Portable multi-gas detectors and calibration gas
Certified for the hazardous-area zone in which they are installed.
Fittings, manifolds and tubing
- —Twin-ferrule tube fittings, 316 stainless, imperial and metric
- —Two-, three- and five-valve instrument manifolds
- —Instrument tubing 316L seamless, ASTM A269
- —Instrument valves, air headers and enclosures
The impulse-line bill of materials for each instrument installation.
How instruments are specified
An instrument enquiry is defined by the datasheet parameters below. Supplying the datasheet, or a tag list with these fields, allows an exact quotation.
| Parameter | What it defines | Common values |
|---|---|---|
| Measured variable and range | What is measured and over what span | e.g. 0–100 bar g; −50 to +400 °C; 0–500 m³/h |
| Accuracy class | Permitted error | Gauges class 1.0 or 1.6 to EN 837; transmitters ±0.075 % of span typical |
| Process connection | How the instrument mounts | ½" NPT; flanged ASME B16.5 class 150/300; thermowell thread or flange |
| Wetted materials | Parts in contact with the process | 316L stainless; Hastelloy C-276; Monel; PTFE-lined |
| Output and protocol | Signal to the control system | 4–20 mA with HART; Foundation Fieldbus; Profibus PA; switch contacts |
| Power supply | Loop or external | Loop-powered 24 V DC two-wire; four-wire |
| Ingress and hazardous-area rating | Enclosure and Ex certification | IP66/67; Ex ia or Ex d, ATEX and/or IECEx |
| Functional safety | SIL capability where used in a safety function | SIL 2 or SIL 3 per IEC 61508 |
| Calibration | Traceable calibration at supply | Certificate traceable to national standards |
Thermocouple vs RTD — which temperature sensor
The most common temperature-measurement question on an enquiry.
| Property | Thermocouple | RTD (Pt100) |
|---|---|---|
| Principle | Voltage from two dissimilar metals | Resistance change of platinum |
| Range | Wide: −200 to +1700 °C depending on type | −200 to +600 °C |
| Accuracy | Moderate: ±1.5 to ±2.5 °C class 1 | High: ±0.15 °C at 0 °C class A |
| Response | Fast | Slower |
| Stability and drift | Drifts with age and contamination | Very stable |
| Cost | Lower | Higher |
| Typical use | Furnaces, heaters, high temperature | Process temperatures below 600 °C where accuracy matters |
What the certificates state
No manufacturer-specific figures are published here: CRS PLUS sources from several mills and manufacturers and each issues its own certificate, which governs. These are the documents an instrumentation delivery will normally include.
| Document or test | Standard or method |
|---|---|
| Calibration certificate | Multi-point, traceable to national standards, per instrument |
| Material certificate for wetted parts | EN 10204 3.1 for pressure-retaining parts |
| Hydrostatic test | For thermowells, manifolds and pressure-retaining housings |
| Hazardous-area certificate | ATEX EU-type examination and/or IECEx certificate of conformity |
| Functional safety certificate | IEC 61508 SIL certificate and FMEDA data where specified |
| Thermowell wake-frequency calculation | ASME PTC 19.3 TW where specified |
| Flow meter calibration | Wet calibration on accredited rig for custody or fiscal meters |
| Gas detector bump-test and calibration | With certified calibration gas |
| Declaration of conformity | CE / PED where applicable |
| Instrument datasheet and manual | Per ISA or project format |
Supply terms
- Origin
- Sourced per enquiry from a qualified supplier base of mills and manufacturers in China, India, Europe and the Gulf. Origin and certifying body are stated on each quotation.
- Incoterms
- Ex-works and FOB as standard. CIF, CFR and DAP available to GCC, Levant, Red Sea, East and West African destinations.
- Documentation
- Mill test certificate to EN 10204 3.1 as standard, 3.2 with third-party witness on request; commercial invoice, packing list, bill of lading, certificate of origin.
- Inspection
- Third-party inspection at source available on request through recognised inspection agencies. Inspection scope agreed on the purchase order.
- Lead time
- Standard sizes and grades from stock to six weeks. Made-to-order items and large parcels eight to sixteen weeks. Confirmed per quotation.
- Enquiry detail
- The instrument datasheet, or per tag: measured variable and range, process connection, wetted material, output, power, hazardous-area and SIL requirements, and quantity.
Questions
Frequently asked questions
When should a transmitter be used rather than a gauge?
A gauge gives a local reading only. A transmitter converts the measurement to a 4–20 mA or digital signal for the control system, supports alarms and trending, and is required wherever the value is used in control or safety logic. Many installations fit both: a transmitter for the control room and a gauge for local indication during operation and maintenance.
What is HART?
HART is a digital communication protocol superimposed on the 4–20 mA analogue signal. It allows the control system or a handheld communicator to read diagnostics, configure range and tags, and retrieve secondary variables from the instrument without disturbing the analogue loop. Most modern transmitters are supplied with HART as standard.
What does SIL 2 mean for an instrument?
Safety Integrity Level, from IEC 61508 and 61511, expresses the risk reduction a safety instrumented function must achieve. An instrument used in a SIL 2 loop must have a certified failure-rate analysis and diagnostics that allow the loop to meet a probability of failure on demand between 10⁻³ and 10⁻². The instrument’s SIL certificate states its suitability; the loop design determines whether SIL 2 is achieved.
Why does a thermowell need a wake-frequency calculation?
Flowing fluid sheds vortices from the thermowell that can excite it at its natural frequency and cause fatigue failure. ASME PTC 19.3 TW sets the method for checking that the thermowell’s natural frequency is safely above the vortex-shedding frequency for the line conditions. The calculation needs the well dimensions, material, insertion length, fluid properties and velocity, and is normally supplied with the thermowell.
Which flow meter type is used for which service?
Orifice plates with DP transmitters remain the most common for gas and steam where moderate accuracy is acceptable. Coriolis meters give the highest accuracy and measure mass directly, and are specified for custody transfer and chemical injection. Electromagnetic meters suit conductive liquids such as water. Ultrasonic meters suit large-diameter gas and liquid lines without pressure loss. Turbine and positive-displacement meters are used for clean liquids and fiscal metering of products.
What is needed to quote an instrument?
The instrument datasheet, or for each tag: the measured variable and range, process fluid and conditions, process connection, wetted materials, output signal and protocol, power supply, enclosure and hazardous-area rating, any SIL requirement, and quantity. Accessories — manifolds, brackets, cable glands — should be listed if required.
Where is the equipment sourced from?
CRS PLUS sources instrumentation from its qualified supplier base of certified manufacturers in Europe, Asia and the Gulf. Origin and certification are stated on each quotation. Where an operator’s approved-vendor list restricts the make, CRS PLUS sources against that list. CRS PLUS does not name manufacturers on this page and holds no distribution or agency agreement with any of them.
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