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Coupling Housings
Casing:
Stainless Steel: It is made of stainless steel with good mechanical properties (such as high strength, toughness and ductility) and the material has tensile strength not below 600 MPa (N/mm2) and elongation not below 15%, withstands high-pressure and high-impact of pipeline generated by several disadvantageous factors, highly resists and absorbs vibration.It is able to normally run under conditions requiring good mechanical properties.The housings material standard is according to Materials Engineering Association of the United States Standard ASTM A351.
Ductile Iron:Coupling Housing is cast of ductile iron to ASTM A536 Grade 65-45-12which refers to t he 65,000 PSI (448,110KPa) minimum tensile strength, 45,000 PSI (310,230 KPa) minimum yield strength and 12% minimum elongation. This compares favorably with A53ERW steel pipe having minimum tensile of 60,000PSI (413,640KPa), 35,000PSI (241, 290KPa ) yield and 25% elongation.
The housing is designed to provid the optimum combination of pressure, stress relief and end load conditions while maintaining reasonable weight and manufacturing characteris-tics,
Every grooved pipe coupling, be it a flange adaper, reducing coupling,outlet, rigid or flexible coupling has a similar key section.This engages fully into the groove tying the joint integ-rally to the pipe.
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Coatings
Coatings may be applied to various couplings, fittings and accessory products. To maintain the published performance levels with respect to maximum rated working pressure and end load, the maximum coating thickness on our couplings should not exceed 0.010 .If additional protection is required, the coating thickness may be increased on the external surfaces of the coupling only. |
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Gaskets
The unique, C-shape,pressure responsive gaskets design has been the heart of the grooved systems since its inception.Relying on compound compression set and the initially flared design, the gasket seals on the dimension of the pipe move-ment noted,while sealing under both pressure and vacuum.The manufacture and test is to ASTM D2000 and UL157 quality controlled with test of hardness strength, strength at break, elonga-tion at break change in hardness,change in strength at break,change in elongation at break, and low temperature compression set available rubber compounds now include the standard gasket EPDM for water ( +230H/ + 110 ) and nitrile compound gasket for oil services ( to +180H/
+ 82).Special gasket includes fluoroelastomer,neoprene, silicone, white nitrile and epichlorohydrin.Each gasket is traceable by being marked with manufac-turing date, formula code and operators code.
During assembly, the gasket is slightly stretched over the pipe ends, applying the natural compression of the angles lips as well as the resiliency of the entire gasket body. It is important to note that grooved coupling gaskets always should be lubricated on the lips and the outside back before assembly. Assembly of the coupling housing over the gasket mates it closely to the gasket back, fully encasing the gasket with a backbone of ductile iron, with the bolt
pads fully tightened this adds additional compressive force without full compression, leaving the natural resiliency as an active sealing force within the joint.The full encasement of the gasket prevents any extrusion of the rubber under high pressure.
ANSI / NSF Standard 61 is a National Standard that
was developed to establish minimum requirements for the control of potentia adverse human health effect form products which contact drinking water. Its primary focus on contaminants or impurities which may be imparted indirectly to potable water. Please note that material do not come indirect contact with potable water do not require evaluation. The sealing material as establish-ed by ANSI/NSF 61are Cold which is limited to -29.2H(-34) Maximum and Hot which is limited to +230H+110棩Maximum.
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Bolts and Nuts
The bots and nuts secure the entire joint together.The bolts are not taking the primary load,nor are they functional in the sealing process. The bolts hold the coupling housings into the grooves and contain the gasket, once tightened; the bolts require no
further tightening.There are no torque specifications for most grooved coupling as with flange bolts. The plated bolt head is an oval neck track bolt configuration conforming to openings in the housing bolt pads, which permits tightening the nuts from one side without a backup wrench.
The standard stainless steel bolts are Type 316 Grade B8M Class 2 stainless steel to ASTM A-193. Stainless steels are susceptible to galling, which occurs when two of the same metals are rubbed together under a load, such as in the area of the thread contact between the bolt and nut at high torque. It is common practice that when using stainless steel hard-ware to apply and anti-seize lubricant to the bolt to prevent galling. The carbon steel bolts conform to ASTM A-183 minimum tensile 110,000PSI providing identifiable strength.
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Lubricant
PASS lubricant is a lubricating material for non-toxic,non-polluting for drinking water and non corrosion to gasket. Thorough lubrication of the gasket exterior including
the lips and housing interior, is essential
to prevent pinching the gasket during steel pipe
installed. Lubrication assists proper gasket installation, use PASS Lubricant for installation, other compatible material such as silicone and others may be used on E or L shaped gaskets.
Note: PASS lubricant is not recommended for used with polyethylene pipe.
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