Spirax Sarco BPS32 Stainless Steel Balanced Pressure Steam Trap

The Spirax Sarco BPS32 is the stainless steel member of the same balanced pressure thermostatic trap family as the carbon steel BPC32, and the model to pick where corrosion, low ambient temperature or process cleanliness rule out carbon steel. Its body and cover are austenitic stainless steel, it carries an integral flat strainer screen, and it is available with screwed, socket weld, butt weld and flanged ends from 1/2 in. to 1 in. (DN15 to DN25).

Technical specifications

Why stainless

The BPS32 has the same working principle as the BPC32: a balanced capsule that opens on cold condensate and closes at steam temperature, discharging condensate about 12 C below saturation with the STD capsule (SUB, 24 C below, and NTS, 6 C below, are optional). The difference is the body. Where wet steam is aggressive, where condensate is acidic from dissolved carbon dioxide, or where the trap is outdoors at low temperature, the stainless body gives a longer life; the data sheet gives a minimum allowable temperature of -200 C for the body, against -60 C for carbon steel.

The trap is described as unaffected by waterhammer and as safe for full vacuum.

Sizes, ends and dimensions

The BPS32 is built to a compact 95 mm face-to-face length with screwed, socket weld and butt weld ends, and 150 to 160 mm when flanged. The same body is used for all connections; flanged units weigh 2.9 kg at DN15 against 1.4 kg screwed. The pressure-temperature chart in the data sheet draws separate curves for screwed, socket weld, butt weld and ASME 300 ends, for EN 1092 PN40, for JIS/KS 20K, for ASME 150 and for JIS/KS 10K, so read the limit for the connection you choose and state the standard and rating with the size.

Capacity charts in the data sheet give condensate flow in kg/h against differential pressure for cold water and hot water, which is the basis for sizing.

Ordering and installation

An order should name the size, model, end connection and capsule fill, for example a DN15 BPS32 with an STD capsule and BSP screwed ends. The Y-strainer version BPS32Y, check valve versions BPS32CV and BPS32YCV, and EN 10204 3.1 certification are available; any certification has to be requested when ordering. Install in line with the arrow, with isolation valves either side for maintenance and a non-return valve where condensate is discharged to a return line that may carry back pressure.

Where the trap discharges to atmosphere, a diffuser is a sensible precaution. Check that a balanced pressure trap, which discharges slightly sub-cooled condensate, is the right trap type for the application.

Selection checks for a balanced pressure trap

Balanced pressure traps hold back a small amount of condensate until it cools below steam temperature. That behaviour is useful on tracer lines, instrument heating and small process equipment, where using some sensible heat from the condensate is acceptable, but it is not ideal where condensate must leave the moment it forms, such as on heat exchangers with tight temperature control. Before choosing the BPS32, confirm the steam pressure, the expected condensate load at start-up and in running conditions, and the back pressure in the return line, then size the trap with the capacity charts rather than simply matching the pipe size.

Installation practice

Fit the trap below the equipment it drains, with a short drop leg so condensate can reach it by gravity. Keep the trap accessible for inspection, because a maintainable trap only pays off if technicians can reach it with the line isolated. Support adjacent pipework so that its weight is not carried by the trap connections, and flush the line before the trap is fitted so that weld debris does not collect in the strainer screen. On welded versions, follow the data sheet guidance on welding so that the internals are not damaged by heat.

Commissioning the trap

Open the upstream isolation valve slowly so that the line warms gradually and air and cold condensate are discharged first. Watch the discharge where it can be observed safely to confirm that the trap opens on condensate and closes as steam arrives. Check the trap temperature with a contact thermometer or infrared gun; a trap that stays cold may be blocked or isolated, while a trap that blows live steam needs investigation before the system is handed over.

Steam systems in Oman and the GCC

Many steam systems in the region serve food, beverage, pharmaceutical and hospital plants, as well as process heating at refineries and petrochemical sites. High ambient temperature does not change the steam conditions, but it makes steam leaks and hot surfaces a bigger safety and comfort issue in plant rooms, so trap discharges to atmosphere should be directed safely. Outdoor traps near the coast are exposed to salty, humid air, which is one of the conditions where a stainless steel body is often preferred. Dust and sand can enter open pipe ends during construction, which is another reason to blow lines through before final installation.

Routine maintenance

Add the trap to the site steam trap survey, check it at regular intervals, clean the strainer screen as needed and replace the capsule or seat using the spares listed in the data sheet when testing shows the trap is no longer working correctly.

Documents and quotation

The official Spirax Sarco technical information sheet TI-P005-03 is attached to this page; it contains the pressure-temperature limits, materials, dimensions, capacity data and spares referred to above. Seven Star LLC is an independent supplier in Muscat. To request a quotation for BPS32, send the model, size, end connection, any certification you need under EN 10204 and the quantity so the request can be matched to the data sheet before we reply.

Before ordering, please confirm the part number, tube size and thread type against the attached catalog, as nearby codes differ by one character. Related items: product category.