PT CouplingMD20D2 in MAXI-DRY Dry Disconnect Coupler, 316 Stainless Steel with Viton FKM Seals, 2 in Coupler x 2 in Female NPT, 150 PSI

Product Description

What this part is

A PT Coupling MD20D MAXI-DRY dry disconnect coupler, part number 44000200V. It is the coupler half — the female side — of a two-inch dry-break connection, built in 316 stainless steel with Viton FKM seals. The connection is 2 in coupler on one end and 2 in female NPT thread on the other, and the assembly is rated 150 psi.

Decoding the designation

PT Coupling gives this product both a numeric part number and a short designation. The number 44000200V identifies material and seal: the 44 series is stainless steel where the 40 series is aluminium, 0200 states the two-inch size, and the trailing V marks Viton FKM seals where E marks EPDM and T marks PTFE. The short designation MD20D reads as MAXI-DRY, 20 for the two-inch size, and D for the coupler in the MDD product type. Both forms describe the same item.

What these specs mean in practice

A dry disconnect coupling closes valves in both halves of the connection as the halves separate, so the line contents stay inside the pipe and the hose rather than draining onto the ground. That is the entire reason this class of fitting exists: on fuel, solvent, acid and chemical transfer, an ordinary cam-and-groove coupling releases whatever is standing in the line every time it is parted. A dry-break fitting brings that loss to a few drops, which matters for operator exposure, for environmental compliance and for product value.

The interlock is the safety feature that governs how the fitting is used. The male and female halves cannot be separated while the line is under pressure, so the sequence of operations is enforced by the hardware rather than by procedure. The coupler can also be drained deliberately, which relieves the pressure that builds when trapped product warms and expands.

Material selection decides chemical compatibility. A 316 stainless steel body with Viton FKM seals handles aggressive service that would attack aluminium and Buna: fuels and solvents, and many acids and oxidisers. Viton holds up against hydrocarbons and a broad range of chemicals at elevated temperature, which is why it is specified in place of nitrile on this variant.

Published specifications

Function: dry disconnect (dry-break) coupler
Product line: PT Coupling MAXI-DRY, type MDD
Half supplied: coupler (female half)
Size: 2 in
Connections: 2 in MAXI-DRY coupler x 2 in female NPT
Body material: 316 stainless steel
Seal material: Viton FKM
Pressure rating: 150 psi
Overall length: 7-1/2 in
Internal components: stainless steel
Handle: dual-purpose locking handle
Part number: 44000200V

Quantity and configuration

Sold as 1 Pc — one coupler half. The mating MAXI-DRY adapter, which is the male half of the connection, is not included. A complete dry-break connection requires both halves.

Installation and setup notes

The female NPT end threads onto pipe, a hose tail or a tank fitting, and the coupler end receives the mating MAXI-DRY adapter. The locking handle both draws the halves together and secures them, and the internal valves open only once the halves are fully engaged. Because the halves cannot be parted under pressure, the line is depressurised as part of the disconnection sequence. Viton seals set the chemical compatibility of the assembly, so the seal material is matched to the product being transferred.

Interchange guidance

Part 44000200E is the same 2 in stainless steel MAXI-DRY coupler with EPDM seals, and PTC-MD20D-ALT is the aluminium body with PTFE seals; those differ in body or seal material, which changes chemical compatibility, so they are related variants rather than equivalents. Part 40000200 is the aluminium and Buna version of the same coupler. Part 40000200SV, designation MD20DSW, is a 90° swivel elbow version in aluminium with Viton seals, so it differs in geometry as well. MAXI-DRY halves mate only with other MAXI-DRY halves of the same size; dry disconnect fittings from other manufacturers use different profiles and do not interchange. A direct replacement matches part number 44000200V.