The INVALCO Series 424 is a diaphragm-operated non-freeze liquid dump valve for high-pressure separators and other vessels where freeze-ups are a problem. It screws into the vessel so the plug and seat are fully immersed in the process fluid, preventing freeze-up at the trim. Hammer union construction reduces repair downtime and the trim is replaceable. A typical hook-up pairs it with a Flextube level control on a separator.
Key specifications
- Body: Low carbon steel; steel union body cover
- Connections: Vessel 2" MNPT; inlet tube 1" FNPT; outlet 1" FNPT
- Diaphragm operator: Steel, 65 sq. in., nylon-reinforced Buna-N diaphragm; 70 psi max recommended operating, 100 psi max containment; standard topworks direct action (normally closed)
- Maximum working pressure: 3000 psi
- Temperature: -20 to 250 °F
- Stem: 303 SS; packing non-lubricated Buna-N
- Trim: 1/4" (Cv 1.7) or 1/2" (Cv 6), taper; 416 hardened SS, 316 SS or carbide
- Weight: 45 lb
How to specify / order (model NFDSA-130-424, 2" x 1", 3000 psi)
- 1/4" trim: 416 SS 80005708; carbide 80005703
- 1/2" trim: 80005704 and 80005702 (see note)
- Specify model number, part number and trim description
Bulletin notes: in the 1/2" trim row the two part numbers are not clearly aligned to the 416 SS / 316 SS / carbide columns, so confirm which material each covers; the notes refer to Cg values although only Cv is given.
Pricing and lead time are quoted per configuration. Send the model code (or your application details), product, flow range, and pressure/temperature to Flow Measurement Services for a quote. Specifications summarized from Smith Meter (INVALCO) bulletin SSIN048 Rev 0.1 (12/18), pages 1-2; confirm current data with the factory before ordering.
Smith Meter (formerly FMC Technologies / TechnipFMC Measurement Solutions), now manufactured by Guidant. Flow Measurement Services supplies and services Smith Meter equipment.

