THT Injection Systems


THT Injection Systems

The odorization is a system applied to odorise natural gases which are itself odourless. Therefore, the gas odorization is an indispensable safety measure to protect the users, guarantee a safe network, and thus an efficient means to eliminate risks and wastage.
SESPI qualified personnel and the right equipment ensure maximum safety during all the phases of the odorization procedure.
The odorizing substance is based on tetrahydrothiophene (99% THT).


THT odorizing injection system is specifically designed to guarantee a constant odorization rate regardless of the gas flow rate, the type of odorizer employed, and the required odorization rate.

The odorizing systems used up until now have several disadvantages from the point of view of operation as well as safety, as summarized below:

  •  Very low precision.
  •  Difficulties regarding calibration and regulation.
  •  Low operational flexibility
  •  Difficulties in communications between man and machine.

SESPI system solves all of these problems and permits gas to be easily and safely odorized:

  •  The lack of precision inherent to the other past systems is compensated for by our system’s  Automatic operating principle.
  •  The electronic regulator receives the amount of gas dispensed and the amount of odorizer injected and, based on its programming parameters, it sets the number of impulses to be sent to the metering pump to guarantee the set odorization rate.
  •  The system is easily calibrated and regulated. The startup operations are simple and intuitive and are completely guided by interactive software menus. The operator just need to program the system’s typical data, the type of odorizer liquid, and the required odorization rate.
  •  System safety: The size of all the components is established to be able to withstand the system’s maximum operating pressure.


  •  The control unit’s job is to control the metering pumps according to the amount of gas and odorizer measured by its sensors, so as to maintain a constant network odorization rate that matches the set value. It is also able to record in an internal database the alarms and logged data that can be read by the appropriate software.
  •  The equipment can be queried in the field or by a remote system. A display with keyboard that makes it possible to view and modify all the quantities, is available for use in the field.
  •  The remote system is comprised of a Windows PC on which is installed the communications software that can dialogue with the peripheral via direct serial connection (RS232) or via analogue modem or GSM.
  •  An (optional) printer is available. If it is connected to the control unit via the RS232 serial port, it will generate a printout of the hourly data recorded at the end of the day and at the end of the month.
  •  The amount of the gas to be odorized can be received from fiscal calibrators with a 4-20 analog signal or impulse signal, or directly from sensors in the field such as meters or DELTA p transmitters.
  •  The control unit is able to control the automatic actions of the emergency systems.


Our THT odorizing Packages can be supplied fully certified according to ATEX requisites for Hazardous Areas as well as according to the standards of PED.