The MODCO Figure 500 Hinged Closure is a mechanical device designed for secure and efficient sealing of vessels or barrels, primarily in industrial applications. It features a hinged cap mechanism that allows for easy opening and closing, facilitating access to the interior of the container. The closure is engineered to provide a reliable seal, preventing leakage and ensuring operational safety.

Function Description:

The primary function of the MODCO Figure 500 Hinged Closure is to provide a robust and accessible sealing solution for various industrial vessels. The hinged design allows the cap to swing open, providing full access to the vessel's interior for maintenance, inspection, or loading/unloading operations. The closure utilizes a threaded make-up system, where the cap screws onto a sub (the part welded to the vessel) to achieve a tight seal. An O-ring is crucial for the sealing mechanism, ensuring a leak-proof connection when the cap is fully engaged.

The closure incorporates a pressure warning device (PAV w/ Chain) as a safety feature. This device is designed to indicate the presence of pressure within the vessel before the cap can be fully opened, preventing accidental release of pressurized contents and potential injury.

Important Technical Specifications:

While specific dimensions and pressure ratings are not detailed in the provided document, the closure is designed for horizontal applications, with sizes ranging from 16" through 48". The construction involves several key components:

Sub: The part of the closure that is welded to the vessel or barrel. It features internal threads for the cap and a groove for the O-ring.
Cap: The movable part of the closure that screws onto the sub to seal the vessel. It is equipped with external threads, a sealing face, and cap ribs for structural integrity.
O-Ring: A critical sealing component, specially designed for MODCO closures. It is die-molded from a continuous mold to an exact cross-section dimension to fit the O-ring groove. Standard material is Buna N 70 Duro, with other compounds available upon consultation with the factory.
Hinge Arm: Connects the cap to the jib column, allowing the cap to swing open and close.
Cap Center Pin: A pin that the hinge arm pivots on, allowing for parallel adjustment of the cap to the sub.
Set Collars: Used to secure the hinge arm on the cap center pin and facilitate parallel alignment adjustments.
Vertical ADJ Nut: An adjusting nut on the vertical adjusting pin, used to balance the cap's weight on the hinge, preventing weight transfer onto the sub threads during make-up.
Jib Column: The main support structure for the hinge arm and cap assembly.
Jib Column Housing and Top Radial & Lower Thrust Bearing: Components that house the jib column and facilitate its movement, often incorporating bearings for smooth operation.
Trolley: A component that supports the cap and allows it to be pulled back and swung to the side of the sub during opening.
Actuator Device: An external tool used to tighten and loosen the cap onto the sub.

Usage Features:

Hinge Adjustment: Proper hinge adjustment is crucial for the closure's functionality. This ensures correct alignment of the cap and sub, balances the cap to eliminate thread drag during make-up, and allows for proper metal-to-metal contact between the cap sealing face and O-ring groove lands.
- Parallel Alignment: Adjusted by moving the hinge arm along the cap center pin, after loosening the set collars. This corrects for the cap tilting inward or outward at the top of the sub.
- Vertical Adjustment: Achieved by tightening or loosening the adjusting nut on the vertical adjusting pin. This balances the cap's weight on the hinge, preventing strain on the sub threads.
Marking for Closed Position: After fabrication, "arrows" should be marked on the back of the cap and sub to indicate the fully engaged, metal-to-metal closed position. These marks serve as a reference for future openings and closures.
Closing Procedure: The cap is tightened onto the sub using an actuator device. It is critical not to attempt to tighten the cap under pressure. Once the closure is completely made-up, the pressure warning device stem is screwed into the body on the sub and tightened.
Opening Procedure: First, the pressure warning device stem must be unscrewed from the body on the sub and screwed into the retainer on the cap. Warning: Do not unscrew the pressure warning device body from the sub while pressurized, as this could result in injury. After ensuring no pressure, the cap is loosened and unscrewed from the sub using the actuator device, then pulled back on the trolley and swung to the side.

Maintenance Features:

Preventative maintenance is essential for trouble-free operation.

At Every Closure Opening:
- Always clean cap and sub threads thoroughly and lubricate them.
- Always clean the O-ring, O-ring groove, sub face, and cap sealing face, and lubricate them thoroughly.
At Regular Intervals:
- Lubricate through grease zerks on the cap center pin bushing, jib column housing, and trolley wheels.
- Lubricate actuator device threads.
O-Ring Information: The O-ring is a custom-designed component. Standard material is Buna N 70 Duro, but other compounds are available. Consult the factory for specific needs.
Welding Instructions (for installation):
- The closure sub should be the last item welded to the vessel or barrel.
- Very Important: Wedging of the closure sub to the barrel or shell can cause warpage or out-of-roundness, preventing proper sealing.
- Unscrew the cap and remove the O-ring from the sub before welding.
- For horizontal hinged closures (16" thru 48" sizes), position the jib column housing at the 12 o'clock center on top of the sub, ensuring the sub face is perfectly vertical.
- Tack weld the sub every 4 to 6 inches around the circumference and re-check the vertical position of the sub face.
- The cap may optionally be screwed onto the sub to protect threads from welding splatter and foreign particles.
- As a precaution against sub distortion during welding, it is suggested that the sub be braced from 12 o'clock to 6 o'clock and 3 o'clock to 9 o'clock, especially important for thin-walled subs.
- A specific welding procedure is recommended by Lincoln Electric Company for "pipeline welding," involving stringer beads and hot passes with two men on opposite sides to equalize welding stresses. The sequence shown in a diagram should be followed, ensuring uninterrupted welding from 7:30 back to 4:30.
- Very Important: Careful attention to welding heat and procedure is recommended to avoid distortion of the sub face and threads.
Post-Welding Check for Warpage:
- Apply an even layer of non-drying Prussian blue to the cap sealing surface.
- Screw the cap onto the sub tightly using the actuator device.
- Remove the cap and check for a continuous trace of blueing on the O-ring lands of the sub face, indicating proper sealing surface contact.
Post Heat Treatment: For vessels or barrels requiring post heat treatment and stress relieving, it is important to remove the bearings in the jib column housing and hinge, as well as the trolley assembly and pressure warning device, before the heat treatment process.
Final Adjustment: After fabrication and any post-welding procedures, refer to the operation and maintenance instructions for hinge adjustments and lubrication procedures to ensure the closure is fully operational.

MODCO FIGURE 500 - MODCO FIG. 500 HORIZONTAL HINGE; Parts Identification

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