Subsea Leak Monitor

The Non-intrusive ClampOn DSP Leak Monitor detects small and medium leaks or flow-throughs, even with low differential pressure over the measuring point on pipes and valves. The ClampOn DSP Leak Monitor has been developed with the aim of offering a product that can quantify a leak through a closed valve. The ClampOn DSP Leak Monitor is qualified as a subsea and topside monitor.

How it works

The basic theory is that a leak creates a very high-frequency noise that can be monitored by an ultrasonic sensor. In a «non-leak» situation the ultrasonic pattern will be stable, but when a leak occurs the signature will change drastically. ClampOn’s DSP technology distinguishes and eliminates background noise unrelated to leakages so that the hiss from the leaks can warn the operator. The system also includes a program or data-base that helps to monitor and indicate the volume of the leak.

The ClampOn DSP Leak Monitor is the result of a joint venture project involving several participants in the petroleum industry.

The ClampOn DSP Leak Monitor is designed to be installed at critical points such as valves, flanges, joints, etc., and can monitor very small leakages. A pressure differential of as little as 1 bar can be monitored in gases, and 3 bar in liquids.

The ClampOn subsea sensors are designed to meet these requirements:Subsea Leak Guitars

  • Designed for a service life of more than 25 years
  • Independent redundant electronics
  • Independent high and atmosphere pressure chambers
  • Electron beam (EB) welding of the chamber against external pressure (no rubber or mechanical seals)
  • Glass-metal penetrator as a barrier between high and atmosphere pressure chambers
  • Outstanding sensitivity, repeatability, accuracy and signal/noise ratio thanks to Digital Signal Processing (DSP)
Leak Monitor Subsea


A leak in an oil or gas flow line is a highly dangerous situation – upstream as well as downstream, so it is extremely important for the operator to be warned about any leak immediately should it occur.

A leak in a flow line, valve, flange or any other component can compromise safety and may also lead to a shutdown at the production stage or down-stream at a refinery or terminal.

A product leak normally has a very low flow-rate, which is determined by the size of the defect, the properties of the fluid and the pressure differential. There are a number of advantages in using the DSP Leak Monitor to monitor valves:

  • Reduced loss to flare
  • Gas leak to the sea
  • Reduced loss to the atmosphere
  • Reduced process loss
  • Maintenance planning

The ClampOn DSP Leak Monitor helps operators identify and quantify sources of gas/liquid leakages, thus enabling them to take appropriate action. Customers have successfully used the ClampOn Leak Monitor to identify cross-flow in valves connected to the manifold.


Our instruments can easily be integrated into any existing or new control system. A computer with our software is often used in-between our instruments and the control system. The computer will be used for calculations and all recorded data will be stored for analyzing and calibration purposes.

We always recommend using the digital interface due to following benefits:

  • Two way communication enabling instrument software update and configuration
  • Full signal range resolution
  • All sensor data can be transmitted
  • No signal loss


Subsea Leak Monitor

Principle of operation

Passive acoustics, intelligent sensor

Minimum minimum leakage

Gas: dP>1 bar, min. leakage rate 0.1 l/min
Liquid: dP>3 bar, min. leakage rate 0.1 l/min
(depending on delta pressure [dP] over the leakage point)



Method of installation

Clamped to pipe surface, non-intrusive

Sensor electronics

Intelligent DSP electronics with signal processing

Interface options

All sensors can be supplied with:
Digital RS485 (ASCII, binary, ModBus RTU), 4-20mA (active/passive). Relay (Other options on request).
Options: CANBus, Profibus

Two-way communication


Software upgrading


Pipe Surface Temperature

-40 °C to +225 °C (-40 °F to +437 °F)

High temperature fixture

Yes – up to 500 °C (932 °F)

Flow regimes

Intelligent health-test of electronic hardware


Minimum hardware

Pentium III (or equivalent) with 512 MB RAM

Software requirements (for ClampOn Software)

Windows 2000/2003/XP/Vista

Signal interface to Client system (typical)

RS232 / RS485 / Relay / ModBus / TCP I/P – Optional 4-20mA / Relay


Water depth


Max. operating pressure barA

300 (4351psi)

Max. test pressure barA

333 (4829psi)

Housing material


Dimensions excl.ROV handle

ø90 x 324mm (ø3.5” x 12.8”)

Dry weight, kg (lbs)

5.2 (11.5)

Hose/jumper interface

Bennex or ODI

Independent redundant electronics / single electronic


Gasket / sealing


EB welding


Glass-metal penetrator

Low pressure / high pressure chamber


ROV installation / retrieval


Retrofit clamp / funnel


Power Supply


Current draw

Approx. 70mA @ 24VDC

Design Lifetime (MTBF)

220 000 hours (25 years)