Acragage diaphragm seals offer a solution to many difficult process applications. The function of the seal is to intercept the pressure of the process fluid, and by means of a fill fluid, transmit pressure variations directly to the pressure gauge, pressure switch, or other pressure instrument.
This optional Acragage® feature provides for completely purging all air from the Bourdon tube in sealed systems or in solid-filled gauges, (such as those with diaphragm-type chemical attachments). The removal of all air allows the gauge to function accurately, without spongy or sluggish action. This is extremely important on chemical gauges in low pressure ranges where diaphragm effect must be minimized, or in high pressure ranges where diaphragm travel is limited.
They also prevent or reduce the instances of clogging due to viscous fluids with suspended solids.
The connection between the instrument and diaphragm seal may be direct or remote by an unprotected capillary or by a flexible armor-sheathed capillary.
Materials may be selected which offer resistance to almost any corrosive process fluid.
Process fluid temperatures can range from -40 to 600° F. The determining factors are the fluid diaphragm material and the bottom housing material.
Acragage® offers a complete line of diaphragm seals for all applications. For more information about component materials, options, and other specifications, see below.
All above materials are standard. Other materials and options are available upon request. See the Model Selection Chart - Diaphragms for more information.
The fill fluid fills the void between the instrument and the diaphragm of the seal. Acting like a hydraulic system, pressure applied to the diaphragm displaces the fill fluid, which causes the instrument to measure pressure.
|Fill Fluid||Temperature Range:|
|Low Temperature DC-200 Silicone||-60 to 300° F|
|High Temerature DC-200 Silicone||-40 to 600° F|
|Instrument Oil||-30 to 300° F|
|Glycerin||-35 to 150° F|
|Fluorocarbon||-50 to 500° F|
Pressure limits are a function of the diaphragm seal type, materials being used, and actual temperature.
Depending on the diaphragm seal type, accuracy ranges from ±0.5 to ±2%. The accuracy is referenced at 68° F; changes in ambient or process temperatures will introduce temperature errors caused by expansion of the fill fluid.
Care must be taken in selecting components of diaphragm seals. Process fluids and conditions must be given careful consideration. Improper application of these components may result in failure of the seal and possible damage to property or injury to personnel. Any seal connected to a severe oxidizer such as, but not limited to, Oxygen, Nitric Acid, Sulfuric acid, etc., must be filled with fluorocarbon fluid.