Betts Manhole Cover
Betts PAF manhole with integral 406-98 Surge Suppression Pressure Relief Valve is the proven leader for cargo tank longevity, protection and safety.
The 406-98 incorporates a 10” (254mm) reclosing pressure relief valve (PRV) that satisfies primary pressure relief for specification US DOT406 and TC406 cargo tanks. The PRV meets the dynamic pressure surge requirements of 49CFR§178.345-10(b)(3)(ii) with less than one liter leakage as tested per TTMA RP No. 81. The PRV cover also serves as a quick-open inspection hatch that incorporates a secondary safety catch. PPVL models include a 6496 P/V normal vent.
The 16” (406mm) clamp ring style manhole is certified and marked in accordance with 49CFR178.345-5 with a test pressure of 36 psig.
PAF 406-98 is also available in a self-latch model by designating part number L742 in place of L716. On self-latch models, a stop bracket holds the PRV at a 91° position; if the cover is inadvertently left open, movement of the tank will cause PRV cover to drop and catch to a semi-closed position.
Stainless versions of the PRV are available. For manhole replacement on MC306 cargo tanks, see Betts’ line of PAF306 surge manholes.
Betts Aluminum Pressure Vacuum Vent
A normal vent designed for use on MC306 & DOT406 cargo tanks. Model 6496 has a pressure setting per 178.346-3(b)(2) of “not less than 1 PSIG” and a vacuum setting per 178.346-3(c)(2) “no more than 6 ounces” which allows for efficient recovery of vapors during closed system loading and off-loading. Unique roll over protection retains product at any attitude of rollover. Vent is flow tested and marked
Betts Emergency Valves
Betts flat seat style emergency valves combine Betts quality with an economical design. Valves feature aluminum construction with a specially designed seat disc to provide positive sealing. Shear section tested per TTMA RP84 and meets 49CFR178.345-8.
Air operated valves are provided with an external air cylinder to help prevent gasoline or other products from contaminating the air supply. The air cylinder is hard-coated aluminum with a polished stainless steel shaft Cylinders have 1/8” NPT port for air connection and are supplied with a fusible plug installed.
Cable operated valves are supplied with a universal lever arm which provides up to 8 cable travel options to work with most operators. Lever arm is “E” Coated to provide exceptional corrosion resistance.