Diaphragm Chemical Seal Pressure Gauge

A diaphragm seal is a flexible membrane that seals and isolates an enclosure. The flexible nature of this seal allows pressure effects to cross the barrier but not the material being contained.

Common uses for diaphragm seals are to protect pressure sensors for example the bourdon or the bellow from the fluid whose pressure is being measured.

Diaphragm seal units manufactured at Goa Thermostatic Pressure gauge division are made from stainless steel (several grades example SS316, SS316L, SS316 + Ti stabilised), Hastelloy, Monel, Inconel, tantalum, titanium and several other metals.

Examples of use of the diaphragm seal Pressure gauges also known as Chemical seal Pressure Gauges are:

  • Sanitary processes (food, pharmaceuticals, etc.) where allowing process fluid to accumulate in the pressure port of the pressure gauge would compromise the purity of the fluid (such as milk getting into the pressure port of a pressure gauge and spoiling).
  • Very pure process fluids, where the metal surface of the pressure gauge sensor might contaminate the fluid (such as copper ions from brass leaching into ultra pure water).
  • Pneumatic systems where small changes in pressures must be eliminated, such as those controlling air bearings.
  • Saline water applications or applications which are viscous in nature.

Refer TABLES for ranges available, connection types and the various options available with the supply of Temperature gauges.

Diaphragm seal/ Chemical seal units are available in 2 constructions:

Diaphragm seal pressure gauge with flanged process connection: PG120 Series

Temperature Gauges Pressure Gauges Thermowells Thermostatic

  • All Stainless Steel construction.
  • Welded diaphragm design.
  • Weather-proof casing to IP:65, IS:13947.
  • Integral and remote seal designs.
  • Dry and Filled versions.
  • Seal fluid options to suit process fluids.
  • Process flange DN 25 and below.
Scope of supply : PG120# Series Pressure gauges with chemical seal unit and flanged process Connection, “Socket welded to case construction” with no external mounting screws.
Model Number(Typ) : PG120# Series P-B-B-1-4-S4-S6-S6-S4-0/10-SU12-2M-S6-S4-S6-1”150#-Op0.
Case : SS304, Weather-proof to IP:65, IS:13947, bayonet bezel ring.
Dial Size : 150mm (6”), white background with black markings.
Bourdon : SS316, TIG welded to socket and stress relieved.
Socket : SS316.
Movement : SS304.
Pointer : Micro-gear adjustment type for zero re-set.
Window : Shatter-proof Glass.
Range : As shown against tag nos in kg/cm2.
Overall inaccuracy : ± 1% FSD.
Overrange protection : 130% FSD.
Blow Out Disc : Neoprene rubber, provided at the back of the case.
Connection to process : 3N…½”NPT(M), bottom entry.
Chemical Seal Unit : SU12…Seal unit with flanged process connection.
SU12R…Seal unit with flanged process connection remote mounting by means of 5 metre long capillary in SS316 covered with SS304 armour.
Design : Welded diaphragm type.
Top Chamber : SS316.
Diaphragm : SS316, welded to top chamber.
Process Connection : ¾”flanged to ANSI B16.5, 150#RF in SS316.
Seal fill fluid : Silicon Oil, Dow Corning grade DC200, 1000cst.

Notes

1) Seal unit filling is carried out on “State-of-the art” automatic filling system imported by us from our Principals, M/s HNL Instruments and Controls Ltd, UK.

2) For high pressure applications, we can offer “Safety Pattern” gauges with “Solid Front” partition between sensing bourdon and dial and “Blow out back” for quick pressure relief in the unlikely event of bourdon failing due to sudden overpressure.This feature is a Safety feature and would prevent possible injury to operators.

*Please note the following parameters can be varied by referring to the model decoding sheet:
Model Number,Case Material, Dial Size, Mounting, Bourdon and Socket Material, Range and unit of measurement required, Accuracy required , the Connection to process, top chamber, bottom chamber material and diaphragm material and seal fill fluid for high temperatures.

Diaphragm seal pressure gauge with flanged process connection and flushed diaphragm design : PG180 Series

  • All Stainless Steel construction.
  • Welded diaphragm design.
  • Weather-proof casing to IP:65, IS:13947.
  • Integral and remote seal designs.
  • Dry and Filled versions.
  • Seal fluid options to suit process fluids.
Scope of supply : PG180# Series Pressure gauges with chemical seal unit and flanged process connection, “Socket welded to case construction” with no external mounting screws.
Model Number (Typ) : PG 180 Series P-B-B-1-4-S4-S6-S6-S4-0/10-SU14R-2M-S6-S6-1”150#-Op0
Case : SS316, Weather-proof to IP:65, IS:13947, bayonet bezel ring.
Dial Size : 150 mm(6”), white background with black markings.
Bourdon : SS316, TIG welded to socket and stress relieved.
Socket : SS316.
Movement : SS304.
Pointer : Micro-gear adjustment type for zero re-set.
Window : Shatter-proof Glass.
Range : As shown against tag nos in kg/cm2.
Overall inaccuracy : Within ± 1% FSD.
Over range protection : 130% FSD.
Blow Out Disc : Neoprene rubber, provided at the back of the case.
Connection to seal : 3N…½”NPT(M), bottom entry.
Chemical Seal Unit : SU14…Seal unit with flanged process connection, diaphragm flush with process flange.
SU14R…Seal unit with flanged process connection, diaphragm flush with process flange, remote mounting by means of 5 metre long capillary in SS316 covered with SS304 armour.
Design : Welded diaphragm type.
Diaphragm : SS316, flush and welded to process flange.
Process Connection : 2” flanged to ANSI B16.5, 150#RF in SS316.
Seal fill fluid : Silicon Oil, Dow Corning grade DC200, 1000cst.

Notes

1) Seal unit filling is carried out on “State-of-the art” automatic filling system imported by us from our Principals, M/s HNL Instruments and Controls Ltd, UK.

2) For high pressure applications, we can offer “Safety Pattern” gauges with “Solid Front” partition between sensing bourdon and dial and “Blow out back” for quick pressure relief in the unlikely event of bourdon failing due to sudden overpressure.This feature is a Safety feature and would prevent possible injury to operators.

*Please note the following parameters can be varied by referring to the model decoding sheet:
Model Number,Case Material, Dial Size, Mounting, Bourdon and Socket Material, Range and unit of measurement required, Accuracy required , the Connection to process, top chamber and diaphragm material and seal fill fluid for high temperatures.

 

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