Spirax Sarco B Series Inverted Bucket Steam Traps

The Spirax Sarco B Series Inverted Bucket Steam Trap are Cast Iron steam traps with a Stainless Steel inverted bucket. The inverted bucket controls the discharge cycle of these traps as its mechanism responds to the difference in density between steam and condensate. The cycle starts with bucket floating in condensate water and a closed valve that is connected to the bucket by a lever.  When steam is first turned on, air enters, escapes through vent holes at the top of the bucket and collects at the top of the trap. The condensate water that surrounds the bucket also fills the bucket, causing it to sink. This forces the closed valve to lift off its seat and open so the collected air can be discharged. As steam begins to fill the bucket, it regains its buoyancy, closes the valve, and remains shut until the steam condenses or vents. The bucket then sinks again, reopening the valve to release the condensate, and the cycle repeats.

B Series Bucket Steam Traps are available from ½" to 2" in nominal size with FNPT end connections. They are designed with Cast Iron bodies and Stainless Steel internals and inverted bucket. An available option for these traps is a 20 mesh or 1/16" perforated integral strainer screen. which is indicated by an "S" in the model name. Another option is a bimetal air vent which is indicated by a "2" in the model name. The integral strainer becomes standard when a B Series Trap includes this air vent. The maximum operating temperature is 450˚F at all operating pressures. 

The model number of each Spirax B Series Inverted Bucket Steam Trap represents the size and maximum operating temperature of the trap. Every size group has a maximum operating pressure range from 15 PSIG to 250 PSIG and pressure is explicitly indicated in each model name after the size group. These are the various size groups: 

• B1H Inverted Bucket Steam Traps are ½” and ¾" in size (including B1HS Inverted Bucket Steam Traps with strainer and B12HS Traps with air vent and strainer)
• B2 Inverted Bucket Steam Traps are ¾” in size (including B2S Inverted Bucket Steam Traps with strainer and B22S Traps with air vent and strainer)
• B3 Inverted Bucket Steam Traps are 1” in size (including B3S Inverted Bucket Steam Traps with strainer and B32S Traps with air vent and strainer and)
• B4 Inverted Bucket Steam Traps are 1-1/4” in size (including B4S Inverted Bucket Steam Traps and B42S Traps with air vent and strainer)
• B5 Inverted Bucket Steam Traps are 2” in size (including B5S Inverted Bucket Steam Traps and B52S Traps with air vent and strainer)

There are 7 steam trap spare parts for Spirax Sarco B Series Bucket Traps:

1. Replacement Cover & Mechanism Kit (includes Cover, Cover Gasket, and Complete Mechanism)
2. Replacement Mechanism Kit (includes Cover Gasket, Complete Mechanism, and Bucket)
3. Replacement Cover Gasket Set (set of 3)
4. Replacement Air Vent Assembly
5. Replacement Complete Mechanism
6. Replacement Bucket 
7. Replacement Strainer

Visit any of our B Series Inverted Bucket Trap product pages to view the complete listing of the available spare parts.    

Typical applications of Spirax B Series Bucket Traps include steam main drip stations, laundry equipment, industrial dryers, and storage tanks. The biggest advantage of inverted bucket traps is their high-pressure capabilities and resistance to waterhammer damage. The B Series Traps should be installed in a horizontal position below the equipment drainage connection.  To protect the trap internals and allow servicing, a pipeline strainer should be installed ahead of the trap and suitable full-port isolation valves should be placed around the trap. 

Cooney Brothers is proud to be an authorized distributor for Spirax Sarco, with one of the largest inventories in the country. Contact us and explore Spirax Sarco B Series Inverted Bucket Steam Traps, spare parts, and more.