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LSE-HD Back Purging Unit

Back purging unit for safe cleaning of measurement taps and ports of differential pressure flow sensors in gas applications with dust and particles



Even robust flow measurement systems such as averaging pitot tubes reach their limits in applications with high amounts of dust and particles. To ensure safe and stable flow measurement at high dust concentrations of up to 50 g/m³, we have developed the LSE-HD back purging unit. Considering the poor experiences users have had with solenoid valve-based purging systems we offer an improved solution for real long-term reliability and stability.

The back purging unit is fully automated and enables maintenance-free operation even under challenging conditions. The LSE-HD is compatible and tested with all differential pressure based flow measurement methods and can typically be easily retrofitted in most cases. Due to the robust construction and the use of stainless steel for all wetted parts, it is particularly suitable for rough industrial applications. It can be equipped for use in hazardous Ex zones or in harsh outdoor conditions. To protect the differential pressure transmitter, it is typically integrated into the enclosure of the LSE-HD.

Its unique operating principle sets the LSE-HD apart from conventional purging units by cleaning positive and negative pressure side separately to avoid cross contamination and ensure proper removal of blockages.

The LSE-HD offers practical advantages wherever

  • Differential pressure based flow measurements (with averaging pitot tube, venturi tubes, etc.) are used in applications for air, exhaust gas, or other gases with high dust or particle concentration of up to 50 g/m ,
  • The measurement system must be robust and well proven,
  • Highest possible availability of the measurement system is required,
  • The purging parameters need to be adjusted to the specific application.


Further information

Product brochure




Installation and operating manual


Our WebApps

The following WebApps offer helpful calculations for selecting and sizing our differential pressure sensors.

Technical specification

Working principle: Back purging of measurement ports and taps of averaging pitot tubes and other differential pressure based flow meters
Purging medium: Pressurized air or nitrogen
Purge pressure: 3 to 12 bar
Purge cycle: 1 … 6000 min (adjustable)
Purge duration: 5 … 60 sec (adjustable)
ATEX Certification: ATEX Ex d drive (optional)
Wetted parts: 1.4571/1.4404
(AISI 316Ti/AISI 316L)
Supply Voltage: 24 V DC or 100 … 240 V AC
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