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.
- Chemical process industry
- Petrochemical industry
- For aggressive, highly viscous, crystallising or hot media
- 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
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 :
|TYPE||DIAGHRAM SEALED||STANDARD FITMENT||Blow out disc|
|ACCURACY||+/- 1% of range span|
|DIAL SIZE||100 & 150 mm||STANDARD RANGES||Pressure : 0 –1,1.6,2,2.5,4,6,10,16,25,|
40,60,100,160,250,400 & 600 kg/cm2
|WINDOW||Clear glass-standard shatter proof glass-optional||Vacuum: 0 to 760 mm|
Compound: (-)1 to (+)3, 5, 9, 15 & 24 kg/cm2
|BOURDON TUBE MATERIAL||AISI 316 ss|
|MOVEMENT MATERIAL||AISI 316 SS||SEALED UNIT|
|Diaphragm welded with SS chamber|
|SHANK MATERIAL||AISI 316 SS||Diaphragm Loosely placed in between Top & Bottom chamber|
|ENCLOSURE||Die cast aluminium weather proof Stove enamelled black-Standard|
Pressed AISI 304 ss-Optional
AISI 316 ss
|MOUNTING||Local (Direct) Local (Surface/Wall Projection) Flush Panel (remote sensing)||SEALING LIQUID|
AISI 304 SS
|CONNECTION LOCATION||Bottom for direct & surface / Wall / Projection mounting|
Back for flush panel mounting
|BOTTOM CHAMBER & CONNECTION MATERIAL||AISI 316 SS|
|CONNECTION||½ BSP (M) ½” NPT (M) M20 x 1.5mm (M) – Standard|
|CAPILLARY PROTECTION||Spiral / Sheath||Flanged as per BS, ASA & DIN|
|LENGTH OF CAPILLARY||Standard-2 Metres|
Available upto 10 Metres
|CAPILLARY MATERIAL||AISI 316 ss|
|CAPILLARY PROTECTION MATERIAL||AISI 304 ss|