FLOW SWITCH 10/11/15/20 EX

FLOW SWITCH 10/11/15/20 EX

It is a calorimetric flow switch so it is designed for monitoring of thermally conductive liquids. The big advantage of this type of flow switch is the fact that it is usable also in explosive atmosphere.

Key technical properties

Flow switch FS Ex 10/11/15/20 flow switch is certified for use in the following areas with explosive atmosphere:

I M1 Ex ia I Ma

II 1G Ex ia IIC T4..T6 Ga

II 1D Ex ia IIIC Txx°C Da

The flow switch for liquids is made in four versions. These are as follows:

FS 10Ex – 1× status output (depending on flow velocity)

FS 11Ex – 2× status output (depending on flow velocity)

FS 15Ex – 2× status output (1× depending on flow velocity and 1× on temperature)

FS 20Ex – 1× status output and 1× current output (depending on flow velocity)

The operational status is displayed using 10 LEDs. If the flow rate drops below the user specified limit (after exceeding in some case), the status output will be changed. The flow rate is indicated by ten LEDs within the measurement range and you can select the boundary for making/breaking the contact in the same graduation. The measuring cycle takes from 4sec to 8sec with recommended measurement range 4 ÷ 150 cm/sec (for default setting, the measurement range is 4 ÷ 400cm/sec). If the piping is empty, the sensor behaves identically as in the case of zero flow rate.

We offer two standard lengths of the bar type sensor according to piping ID at the installation site. The customer may select a bar type sensor 65 mm or 125 mm in length as needed. If the flow rate of medium is to be monitored in a pipe smaller than DN25 (or the flow velocity is below the sensor range for the given pipe diameter), it is advantageous to use an adapter block with the corresponding flow velocity and thereby ensure proper functioning and maintain the installation conditions. The adapters are designed for the short version of 65mm sensor with the use of direct neck with G½“ pipe thread. Individual designs of adapter blocks are as follows:

  • FS adapter block DN20/G3/4“ pro 5 ÷ 100 l/min. (rozměr 150×50×40 mm)
  • FS adapter block DN15/G1/2“ pro 2 ÷ 40 l/min. (rozměr 150×50×30 mm)
  • FS adapter block DN10/G1/4“ pro 0,4 ÷ 20 l/min. (rozměr 150×50×30 mm)
  • FS adapter block DN4,5/G1/4“ pro 0,1 ÷ 5 l/min. (rozměr 70×50×30 mm)
  • FS adapter block DN2,7/G1/4“ pro 0,075 ÷ 2 l/min. (rozměr 70×50×30 mm)


The designation of a switching point on the LED scale can be implemented in two colours (red and amber LEDs) that indicate simultaneously if the switching contact is closed or open:

In the case of FS15, the LED in the middle between the control buttons is used for temperature switching point indication. If the temperature of medium is above/below the set-point, the LED glows red and simultaneously indicates the open PIN2 (sensor delivered as a standard is set to be opened at a temperature above the set limit with the LED on).

When logics of the making/breaking points is changed by user, the logics of both outputs is changed at the same time (applies to versions FS 11 and FS 15).

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