Ullage Temperature Interface -UTI
UTI (Ullage Temperature Interface) is a detector used to measure the ullage, temperature, and the oil-water interface onboard tankers. In this blog post, we examine the UTI functions, principles of working and the importance of its annual calibration.
What is Ullage Temperature Interface (UTI)?
The UTI detector is a portable liquid level gauge that is commonly used in the shipping industry to measure the amount of hydrocarbons and chemicals in a ship’s tank. This device includes a sensor probe, measurement tape, display unit, and winding drum. Its primary purpose is to determine the temperature and oil-water interface on tankers by attaching the sensor probe to the measurement tape, which can vary in length from 15m to 40m. Manufacturers offer a temperature range between -40°C and 110°C. All UTI meters have earth grounding capabilities for safety purposes.
Note: It is very important that the Ullage Temperature Interface system is grounded to the tank before the probe is introduced into the tank and remains grounded until after complete withdrawal from the tank.
How does Ullage Temperature Interface (UTI) work?
In the following paragraphs, we will introduce how the ullage, temperature and oil-water interface are detected onboard:
Ullage Detection
The ullage detector of the UTI integrates two elements (1) electronic circuits and (2) two piezoceramic plates. When the sensor head reaches the oil or petroleum, an ultrasonic sound is emitted. The receiver processes and sends this sound to the instrument unit that emits a continuous beep sound.
Temperature Detection
The sensing component of the UTI detector is a Platinum Resistance Temperature Detector (RTD). This element is situated in the temperature electrode that is filled with a heat transfer compound paste to hasten the latency. After digitizing the RTD element signal, the micro-controller in the sensor probe corrects and compensates for any errors. The RTD element’s attributes are saved in the sensor memory and are exclusively for that sensor, so a new calibration is not required when replacing the sensor. The micro-controller sends the data to the Display Unit that can be read by the technician.
Interface Detectiom
The operating principle for oil-water interface level detection of the UTI detector involves measuring conductivity between an active electrode and a grounded electrode. When the liquid measured is conductive (e.g., water), the ullage sensor detects its existence. Afterwards, the conductivity electrodes and their related electronic circuits modify the coded signal generating an intermittent beep sound.
What types of Ullage Temperature Interface (UTI) exist?
UTI meters can be either open or closed types, with the latter having a gas-tight body to prevent hazardous gases from escaping the measurement tank.
Closed Gauging Tape
The Portable Closed Flexi-Dip measuring tapes are battery-operated electronic units that are totally gas-tight. When installed in a vapour-control valve mounted on a storage (cargo) tank, it forms a tightly sealed system that prevents toxic vapors from escaping and creates a closed gauging system for that tank. This tight environment reduces the diffusion risk of any (inert) gas. The tape is marked in metric or English units and is anti-static coated (as is the sensor). In addition, the tape is color marked to make tape direction and motion easily seen and to ensure full rewind position. A coiled grounding cable with a large alligator clip is standard. This closed system is recognized by many worldwide regulatory bodies as equivalent to a fixed gauging system as long as the tape remains in the valve from the beginning until the end of loading or discharging of the (cargo) tank.
Open (and Restricted) Gauging Tape
Restricted and Open Gauging Tapes provide a convenient and accurate means for measuring ullage, product temperature and the oil-water interface. The units are configured to operate in the trimode, bimode, interface or temperature mode. Each instrument is designed to maximize ease of use. A single penetration of each tank can provide comprehensive data about internal tank conditions. When the electronic probe senses hydrocarbon, a steady tone is heard; when sensing water, it emits an intermittent tone. Temperature is shown on an LED display in the hub of the instrument.
How often should you calibrate the Ullage Temperature Interface (UTI)?
To ensure the UTI detector’s accurate measurements and function, it should be calibrated once a year by a specialized maker service company. Express Dock Instruments & Controls repairs and calibrates all types of UTI detectors and has a large stock of spare parts in our warehouses.
As specialized partners for MMC and Honeywell, we also have a stock of new and refurbished UTI systems available for fast delivery. Please feel free to contact us for more information about Ullage Temperature Interface.
About Express Dock Instruments & Controls
Express Dock Instruments & Controls is your reliable partner to install, calibrate, certify, repair and maintain the following group of products:
- UTI (Ullage Temperature Interface)
- Fixed gas detectors
- Portable gas detectors
- Fire detectors
- Tank level monitoring
- 15 ppm oily water separators 15ppm
- ODME
- Pressure calibrators
Our technicians are available in 150+ global ports 24/4 to ensure the safety and compliance of your vessel. Contact our team to book your next service or have your service reserved by filling the form on this page.
Express Dock can also service your marine elevator and Ballast Water Treatment System. Our engineers can perform the annual safety inspection, modernization, and repair of your marine elevators. You can also book your IMO D2 Commissioning Sampling, VGP Compliance Sampling, and additional water testing services to ensure compliance with applicable safety requirements.
