Ring Joint Gaskets are metallic ring-shaped PALMFOX sealing systems that can be used in work environments with elevated pressure and temperature. The main applications of these metallic rings are oil and gas and petrochemical industries, power plant technologies, valves, pumps, compressors, boilers, heat exchangers, and pipe and flange connections.

 

 

 

 

 

 

These gaskets (also known as RTJ gaskets) are generally produced in two different cross sections namely octagonal and oval. The working mechanism of RTJ gaskets is as the following:

To form a vigorous sealing between two flanges, the gaskets are connected with RTJ flanges. By the time flanges are fastened by bolts, the gasket is compressed into the groove of the flange and therefore provides a tight seal between two mating flanges. It should be mentioned that to prevent the destruction of the flanges the material of them should be harder than that of the gaskets.

RTJ gaskets are manufactured in three basic types namely style R (consisting of octagonal and oval cross sections), style RX and BX that has separately been clarified below.

BX	RX	R (octagonal)	R (Oval)

 

Style R: This style consisted of two different oval and octagonal cross sections that are applicable in work pressures up to 5,000 psi. To make this style of RTJ gaskets suitable to be used in connection with flange designations including API 6A, ASME / ANSI B16.5, and ASME 16.47 SERIES A, they are standardized with all relevant criteria.

 

Oval-shaped style R: These gaskets’ cross-sectional areas are manufactured with an oval geometrical shape. When the oval ring is fixed in the round and flat bottom of the ring groove flange and the compressive forces are applied, the sealing function is performed by an initial line contact or an edging action. It’s worth mentioning that despite the similar sealing performance of oval and octagonal RTJ gaskets, the former one’s sealing efficiency is lower than the latter one.

 

 

 

 

Octagonal-shaped style R: the geometrical shape of these gaskets is octagonal. The average diameter of this style is marginally higher than that of the gasket’s groove. The angle between the ring gasket and the bevel face of the gasket’s groove is approximately 23˚.

 

 

 

 

Style RX: Style RX of PALMFOX RTJ gaskets is a specific type of octagonal-shaped gasket that is modified based on the R-style gasket. To make these gaskets suitable for API 6B and ASME/ANSI B 16.5 flanges, they comply with API 6A and ASME B 16.20 standards. Due to contact between the gasket and ring joint faces, particularly the outside face, the sealing is efficient. This style is also applicable for pressures up to 5,000 psi.

 

Style BX: this style is also a special type of octagonal gasket that is applicable for pressures up to 20,000 psi. These sealing equipment are standardized with API 6A criterion and can be appropriately applied for API 6BX flanges. For the sake of equalizing pressure across sealing faces, all dimensions of style BX gaskets have a pressure relief hole.

 

Technical specifications of RTJ gaskets:
The surface finish of styles R and RX must not be rougher than 1.6 µm (63 µin). the surface finishing of style BX must have a roughness lower than 0.8µm (32µin).
As can be observed in the table below, based on the required hardness of the gasket’s material it can be selected from a wide variety of options.

MATERIAL	MAXIMUM HARDNESS
	Brinell HB	Rockwell HRB
Soft Iron	90	56
Mild Carbon Steel	120	68
Low Alloy (CR-Mo)	130	72
SS 304	160	83
SS 304L	160	83
SS 309	160	83
SS 316	160	83
SS 316L	160	83
SS 321	160	83
SS 347	160	83
SS 904	160	83
SS 410	170	86
Duplex SS	232	99
Super Duplex SS	232	99
Aluminium	30	-
Copper	81	-
Brass	62	-
Nickel 200	110	62
Monel 400	150	80
Inconel 600	150	80
Inconel 625	150	80
Incoloy 800	150	80
Incoloy 825	195	92
Hastelloy B2	230	99
Hastelloy C276	210	95
Titanium Grade 2	-	-