Spirax Sarco SMC32Y Carbon Steel Bimetallic Steam Trap

The Spirax Sarco SMC32Y is a maintainable carbon steel bimetallic steam trap with straight connections and an integral cylindrical Y-type strainer. The SMC32 version has a flat strainer screen. A stack of bimetallic discs bends as the condensate temperature rises and closes the valve, so the trap holds back steam and lets condensate leave a little below saturation temperature. It is a rugged choice for steam tracing, main drainage and drip legs where water hammer or vibration can upset other trap types.

Technical specifications

How a bimetallic trap behaves

As a general principle, a bimetallic element bends progressively with temperature, so the valve tracks the steam saturation curve at a fixed offset and opens as condensate cools below that line. The result is that a bimetallic trap holds back some condensate and discharges sub-cooled water, which is useful in tracing and in lines where the sensible heat of the condensate can be used. The elements are also tolerant of water hammer and superheat, but the discharge temperature moves with backpressure, and the data sheet warns that increased backpressure lowers the condensate discharge temperature.

The SMC32Y matches the carbon steel BPC32 family on pressure rating, while using a different operating principle.

Ratings, sizes and dimensions

The body design conditions are 50 bar g at 50 C for the ASME 300 rating, 400 C at 35 bar g allowable temperature, and a saturated steam operating limit of 32 bar g with 350 C maximum operating temperature. The minimum allowable temperature is -60 C and the trap is safe under full vacuum. Flange standards cover EN 1092 PN40, ASME 150 and 300 and JIS or KS 10K and 20K, and the data sheet gives different usable regions on the chart for each one. Face-to-face length is 95 mm screwed and 150 mm flanged.

The trap installs in any position, horizontal or vertical, and the cover and strainer cap come off without disturbing the pipe.

Installation and selection

Spirax Sarco recommends isolation valves upstream and downstream for maintenance, a non-return valve where condensate discharges into a return line with backpressure, and a diffuser when discharging to atmosphere. The Y-strainer screen is cleaned by removing the cap. Choose the connection standard to match your pipe class, and ask for EN 10204 3.1 certification at the time of order when you need it. The photograph shows a cutaway of the SMC32Y from the manufacturer.

Quote the model, size and connection exactly, for example 3/4 in. flanged ASME 300 SMC32Y.

Documents and quotation

Official reference attached: Spirax Sarco SMC32 and SMC32Y bimetallic steam traps technical information sheet TI-P076-10 (Issue 9). Send us SMC32Y with the quantity and any certification or option you need, and a quotation follows once the request is matched to the document. We supply as an independent company in Muscat.

Confirm the full order code, including any suffix, with your drawing before you order; similar codes are easy to mix up. Related items: product category.