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Inverted Bucket

Inverted Bucket Traps

These traps use an inverted bucket as a float device to control the opening and closing of the plug and seat to discharge condensate. Body materials available are Cast Iron and Stainless for pressures up to 450 psig. The top-mounted discharge orifice makes them less susceptible to clogging from dirt and debris. Primarily used for drip applications but may be considered for process applications when air venting is not critical.

  • Rugged and simple design and service life often exceeds other style traps.
  • Top-mounted discharge orifice less susceptible to failure from dirt and debris

SIB Series Stainless Steel Body

IB Series Cast Iron Body

IB Series Cast Iron Body (with Strainer)

Drip Leg in a Steam Main

Condensate that forms in steam main is collected by the drip leg and discharged by the steam trap. Drip legs and traps are placed every few hundred feet in the piping system. Strainers are recommended prior to the steam trap as debris or pipe scale may enter the steam trap causing premature failures

Drip Leg before a Control Valve

Regulators or Control Valves are typically utilized to reduce high pressure steam into a more manageable pressure in a process. It is common to see drip legs installed directly ahead of regulators and control valves minimize erosion to valve trim and flooding of valve bodies.

Inverted Bucket Traps

The inverted bucket within the trap will rest on the bottom of the trap body keeping the valve open and allowing condensate to be discharged (Figure A). In the top of the bucket there is a small bleed hole which allows air to escape from inside the bucket and exit through the outlet port (Figure B). When steam arrives through the inlet of the trap, it fills the inverted bucket which makes it buoyant and rise to the top of the trap, closing the valve (Figure C). As steam condenses and/or is bled through the small bleed hole in the top of the bucket, the bucket loses buoyancy which causes it to sink to the bottom of the trap. The valve then opens allowing condensate to be discharged from the system (Figure A). The bucket trap must maintain a certain amount of water (prime) in order to operate. If the trap loses its prime, the bucket will not be able to float when steam enters; keeping the valve in the open position which allows steam to escape (Figure D). Due to the balance of forces required between the incoming pressure and internal trap components, several orifice sizes are required to accommodate various differential pressure ranges. For this reason care must be used to select a trap model with an equal or higher PMO rating than the steam pressure.

Discharging Condensate

With condensate completely filling the trap, the bucket is in the down position with the valve open, allowing condensate to be discharged.

Discharging Air

Small amounts of air will pass thru the bleed hole on top of the bucket and be discharged. (Note: Large amounts of air will lift the bucket and close off the trap, temporarily air locking the system.)

Closed (Trapping Steam)

When steam enters the trap, the inverted bucket fills with steam and floats to the surface, closing off the valve, preventing steam from escaping.

Potential Failure Mode (Loss of Prime)

Potential Failure Mode: Bucket traps must maintain a water prime to function properly. If the prime is lost, the bucket will remain in the down position with the valve open, and live steam will be discharged from the system.

Why use a Thermic Vent?

The Thermic Vent is used for discharging air from the steam system during start-up. The Thermic Vent option should be considered when using IB traps in process applications that go through frequent start-ups.

Why use a Check Valve Option?

The optional internal check valve allows the bucket trap to retain its prime even when exposed to superheated steam. The IB Trap must retain hot condensate inside the trap body to operate. Superheated steam or a sudden drop in inlet pressure can flash off the hot condensate inside the trap body causing the trap to lose its prime. If the steam pressure falls below the discharge pressure on the outlet side of the steam trap, the internal check valve will stop the back flow of condensate into the steam system. When discharging to a condensate return line, a check valve is always recommended.

Blowdown Valve Connection

A Blowdown Valve connection is available as an option on the 1041, 1042, 1044, and 1038S models. This simplifies maintenance by allowing the strainer to be cleaned without removal. User to supply blowdown valve.

Replacement Kits

A replacement kit containing the lever and seat assembly is a more economical option than replacing the entire steam trap. Also available are replacement screens, gaskets and buckets. When ordering replacement lever and seat assemblies specify model and operating pressure. See Replacement Parts and Kits Section for exact “cross-reference to Armstrong PCA (Pressure Change Assembly) Kits.

IB Series

DRIP, TRACING :  the IB1030 Series inverted bucket stream trap are used in drip application to remove condensate from steam mains and steam supply lines, For drip application, the smaller sized units have a adequate capacity. The discharge orifice of the inverted bucket trap is mounted at the top of the trap body which makes them less susceptible to clogging from dirt and debris when compared to other trap types. Since IB traps have poor air-handling capacity, they are only recommended for process applications such as united heaters and laundry equipment, where discharging air during system start-up is not a critical factor. F&T traps are the preferred choice for systems where air MUST be quickly discharged.

IB Series - with Strainer

DRIP, TRACING :  the IB1040 Series with built-in strainer and blowdown valve connection are used in drip application to remove condensate from steam mains and steam supply lines, For drip application, the smaller sized units have a adequate capacity. The discharge orifice of the inverted bucket trap is mounted at the top of the trap body which makes them less susceptible to clogging from dirt and debris when compared to other trap types. Since IB traps have poor air-handling capacity, they are only recommended for process applications such as united heaters and laundry equipment, where discharging air during system start-up is not a critical factor. F&T traps are the preferred choice for systems where air MUST be quickly discharged.

SIB / SIBH Series - Stainless Steel

DRIP, TRACING : the SIB & SIBH traps are suitable for removing condensate from steam mains and steam supply lines. They are also used on unite heaters, low capacity and less critical process applications where slow start-up can be tolerated. The discharge orifice of the inverted bucket trap is mounted at the top of the trap body, which makes them less susceptible to clogging from dirt and debris when compared to other trap types. The SIBH is physically larger and has a higher pressure capability for a particular orifice size then SIB.

Universal USIB450

DRIP, TRACING : the USIB450 & USIB450H Inverted Bucket Trap Modules must be mounted to a Universal Connector. They are typically used for drip applications such as draining condensated from steam main s or steam supply lined as well as for steam tracing applications. USIB450H has a higher capacity for a particular orifice size than USIB450.