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Sealed Diaphragm Pressure Gauges

Category: .

Product Description

Diaphragm sealed gauge commonly known as “chemical seal” gauge are designed and recommended to isolate the measuring system of a pressure gauge from corrosive, pasty or dangerous fluid depending on the viceosity, pressure, temperature, solidification of a particular process medium.

The diaphragm seal has been filled under vacuum with the transmitting liquid, the pressure gauge/diaphragm seal assembly must never be dismantled.

A carefully designed corrogated diaphragm is used to achieve maximum flexibility and linearity with sufficient stroke to provide the displacement needed to produce full deflection of the sensing element.

The diaphragm is argon arc welded to the top chamber to ensure a perfect selling “No LEAK”. In some cases the diaphragm is coated OR lined with a second membrane (teflon). The welded construction facilitates removal of the gauge for repair/service without process shut down.

The displacement of the diaphragm is transmitted to the bourdon sensing element, through solidly filled liquid having low cubical expansion with greater temperature stability.

The gauge indicator is either directly fitted with the sealed chamber OR by means of capillary tube, thus permitting easier mounting OR the remote reading of the pressure.

These Gauges are recommended where fluid is highly corrosive, contaminated, viscous or liable to crystallize inside measuring system. The gauge above the diaphragm seal is filled with silicon oil that transmits the pressure acting on the diaphragm to bourdon tube Diaphragm is welded to the upper part of sealed unit and therefore it is possible to seperate the upper and lower parts to clean the diaphragm without removing the gauge. Diaphragm can be ANSI 316. Tantalum, Hastelloy C and Monel. Pressure gauge can be of type 1, 3 and 5 and process connection with Standard threads or flanged connection confirming to ANSI, BS or DIN Specifications. Available in dial size 100 mm and 150 mm, Accuracy ±1percentage in all standard ranges.

Applications

  • Chemical process industry
  • Petrochemical industry
  • For aggressive, highly viscous, crystallising or hot media

Special Features

  • Flange with a flush welded diaphragm
  • Available for all common standards and nominal diameters
  • When special materials are selected, all wetted parts (diaphragm and sealing face) are made of the selected material

 Description

Diaphragm seals are used to protect the pressure measuring instrument from aggressive, adhesive, crystallising, corrosive, highly viscous, environmentally hazardous or toxic media. A diaphragm made of the appropriate material provides for the separation from the medium to be measured. Thus even the most difficult measuring requirements can be met by combining measuring instruments with diaphragm seals.

A fluid inside the system, which can be chosen to suit the particular application, hydraulically transmits the pressure to the measuring instrument.

Almost limitless application possibilities exist due to the large number of available variants, such as diaphragm seal designs or materials. The type of process connection (flange, threaded and sterile connection) and the basic method of manufacture are important design differentiation criteria.

Assembly of the diaphragm seal and measuring instrument is made via a direct assembly as standard or optionally via a cooling element or a flexible capillary

TECHNICAL SPECIFICATIONS :

TYPEDIAGHRAM SEALEDSTANDARD FITMENTBlow out disc
ACCURACY+/- 1% of range span
DIAL SIZE100 & 150 mmSTANDARD RANGESPressure : 0 –1,1.6,2,2.5,4,6,10,16,25,
40,60,100,160,250,400 & 600 kg/cm2
WINDOWClear glass-standard shatter proof glass-optionalVacuum: 0 to 760 mm
Hg Vac
Compound: (-)1 to (+)3, 5, 9, 15 & 24 kg/cm2
BOURDON TUBE MATERIALAISI 316 ss
MOVEMENT MATERIALAISI 316 SSSEALED UNIT
CONSTRUCTION
Diaphragm welded with SS chamber
SHANK MATERIALAISI 316 SSDiaphragm Loosely placed in between Top & Bottom chamber
ENCLOSUREDie cast aluminium weather proof Stove enamelled black-Standard

Pressed AISI 304 ss-Optional

SENSING ELEMENT

DIAPHRAGM MATERIAL

Diaphragm
AISI 316 ss
ENCLOSURE TYPEIP65
MOUNTINGLocal (Direct) Local (Surface/Wall Projection) Flush Panel (remote sensing)SEALING LIQUID

TOP CHAMBER

Silicone oil

AISI 304 SS

CONNECTION LOCATIONBottom for direct & surface / Wall / Projection mounting

Back for flush panel mounting

BOTTOM CHAMBER & CONNECTION MATERIALAISI 316 SS

 

CONNECTION½ BSP (M) ½” NPT (M) M20 x 1.5mm (M) – Standard
CAPILLARY PROTECTIONSpiral / SheathFlanged as per BS, ASA & DIN
LENGTH OF CAPILLARYStandard-2 Metres

Available upto 10 Metres

 

 

CAPILLARY MATERIALAISI 316 ss
CAPILLARY PROTECTION MATERIALAISI 304 ss