Envent Engineering Ltd.
Located in Calgary, Canada, Envent Engineering is a world class developer of measurement devices for the natural gas processing industry. We produce H2S / Total Sulfur analyzers, Moisture monitors, O2 analyzers, CO2 analyzers, Gas Chromatographs and Low pressure flare vent / meters.
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Head Office
Bay E, 7060 Farrell Road SE
Calgary, Alberta T2H 0T2
Canada (+ see map)
H2S Analyzer
Model: 331 H2S / Total Sulfur Analyzer
This uniquely rugged and simple design by Envent utilizes a lead acetate based detection system that provides a linear and interference-free output of the H2S or optional Total Sulfur concentration.
Downloads
- Data Sheet: 331 H2S / Total Sulfur Analyzer

- User Manual: 331 H2S / Total Sulfur Analyzer

- Configuration Software Manual

- Total Sulfur Analyzer Manual

- Dilution System Manual

- Spare Parts Cross Reference

- H2S analyzer cleaning procedure

- Modbus communications guide

Software
- Analyzer Software (zipped file, 511 kb)
- Microsoft.net
- Adobe Reader
Certification
Tutorials
Support
Applications
An analyzer that measures H2S and/or Total Sulfur (optional) in natural gas, petrochemical streams, condensate, or LPG with optional integrated CO2 IR bench.
Features
- Ranges from 0–50 ppb to 0–100%
- 1.5% accuracy, 1% repeatability
- Modbus Serial communications,
- Displays up to 5 times full scale
- Dual Isolated 4–20 mA outputs
- less than 20-second response time to alarm
- Optional Total Sulfur and CO2
- Interference-free Lead acetate sensor
- 60–90 day tape (longest tape life in the market)
- Zero sensor drift
Value
The 331 measures H2S in natural gas or other process gases. The unit has dual 4–20 mA outputs, dual measurement alarms, plus trouble and fault alarm relays. The 331 displays H2S concentration in user specified units (ppb, ppm, grams, %, m/g3) and as well will auto range to 5 times the lower calibrated range. Calibration is performed manually via the operator interface or automatically when connected to a calibration bottle and optional auto calibration solenoid. The 331 is available with a number of sample systems and accessories to handle various applications such as high range H2S, Total Sulfur or H2S in liquids.
Lead Acetate Sensors: Lead acetate is essentially interference-free from other sulfur compounds. This is why it is used by the vast majority of industry users when accurate measurement is required. The linear output enables the user to perform a single-point calibration.
Longest Tape Life: Envent Tape is the strongest in the market, with the longest tape life by using a proprietary tape advance algorithm to make complete use of the 300-foot tape. The unit will accept up to a 350-foot roll.
Specifications
| Power | 12-24 vdc @ less than 3 watts or 100-240 VAC 50/60 HZ |
| Electrical classification | Class 1, Div1 Grps A, B, C & D certified to CSA standards |
| Ambient Temperature | 0–50 ˚C (std) consult factory for other requirements |
| Output Ranges | H2S 0–50 ppb to 0–100 ppm are standard. For higher concentrations, consult factory. |
| Response time | 20-sec alarm |
| Accuracy | 1.5% of full scale (H2S only); 3% (TS and Dilution) |
| Inputs | 24 bit A/D Microprocessor-based sensor block Low Tape Alarm Remote calibrate, Stream switch, or Low pressure |
| Outputs | Dual isolated 4–20 mA (loop power required) Modbus serial RS-232 & RS-485 Four 5 amp SPDT alarm relays (high reading, high high reading, low tape, failure) Four solid state solenoid drivers ( auto cal, total sulfur, stream switching, valve actuator) |
| Displays | 2 x 16 character LCD with backlighting Menu is scrolled by internal button |
Optional Equipment
| Total Sulfur | Total sulfur furnace—converts all sulfur compounds to H2S which allows analyzer to measure Total Sulfur. |
| CO2 | Dual-beam IR bench. CO2 concentration is displayed on second line of display and can be configured to output 4–20 mA CO2 from 0–2% up to 0–20% |
| Configuration Software |
A custom GUI for customer configuration, archive retrieval, Modbus mapping |
| Auto Calibration | Allows user to initiate a calibration based on time or external switch |
| Stream Switching | Allows switching of two input streams or from H2S to Total Sulfur measurement |
| Dilution | Allows measurements up to 100% H2S using permeable membrane dilution. |
| Liquid sampling | Liquid sample system to measure H2S from hydrocarbon liquids |
| Custom systems | Envent can design custom integrated systems to meet application requirements |
| Panels | 331 is 13”W x 15”H x 8”L fiberglass enclosure Standard system and 331 are mounted on a 24”W x 16”H x ¼” thick anodized panel |
