The inverted bucket is the most reliable steam trap operating principle known. The heart of its simple design is a unique leverage system that multiplies the force provided by the bucket to open the valve against pressure.
Since the bucket is open at the bottom, it resists damage from water hammer, and wear points are heavily reinforced for long life. The inverted bucket has only two moving parts—the valve lever assembly and the bucket. That means no fixed points, no complicated linkage. Nothing to stick, bind or clog.
Conserves energy even in the presence of wear
Armstrong inverted bucket steam traps open and close based on the difference in density between condensate and steam—the inverted bucket principle. They open and close gently, minimizing wear. This simple fact means that inverted buckets are subject to less wear than some other types of traps.
In fact, as an Armstrong inverted bucket trap wears, its tight seal actually improves. The valve and seat of the Armstrong trap provide essentially line contact—resulting in a tight seal because the entire closing force is concentrated on one narrow seating ring.
An Armstrong inverted bucket steam trap continues to operate efficiently with use. Gradual wear slightly increases the diameter of the seat and alters the shape and diameter of the valve. But, as this occurs, a tight seal is still preserved—the ball merely seats itself more deeply.
Corrosion-resistant parts
The stainless steel valve and seat of the Armstrong inverted bucket steam trap are individually ground and lapped together in matched sets. All other working parts are wear- and corrosion-resistant stainless steel.
Venting of air and CO2
The Armstrong inverted bucket provides continuous automatic air and CO2 venting with no cooling lag or threat of air binding.
Operation against back pressure
The Armstrong inverted bucket has excellent performance against back pressure. It has no adverse effect on inverted bucket operation other than to reduce its capacity by the low differential. The bucket simply requires less force to pull the valve open and cycle the trap.
Freedom from dirt problems
Armstrong designed its inverted bucket to be virtually free of dirt problems. The valve and seat are at the top of the trap, far away from the larger particles of dirt, which fall to the bottom. Here, the up-and-down action of the bucket pulverizes them.
Since the valve of an inverted bucket is either fully closed or open, dirt particles pass freely. And the swift flow of condensate from under the bucket's edge creates a unique self-scrubbing action that sweeps dirt out of the trap. To review a specific inverted bucket steam trap, select a series and go to the menu above.
200 Series—Cast iron for vertical installation
For pressures to 250 psig (17 bar) . . . Capacities to 20,000 lb/hr (9072 kg/hr)
800-813 Series—Cast iron for horizontal installation
For pressures to 250 psig (17 bar) . . . Capacities to 4,400 lb/hr (2000 kg/hr)
814-816 Series—Cast iron for horizontal installation
For pressures to 250 psig (17 bar) . . . Capacities to 20,000 lb/hr (9072 kg/hr)
880 Series—Cast iron for horizontal installation with integral strainer
For pressures to 250 psig (17 bar) . . . Capacities to 4,400 lb/hr (2000 kg/hr)
980 Series—Cast steel for horizontal installation with integral strainer
For pressures to 600 psig (41 bar) . . . Capacities to 4,400 lb/hr (2000 kg/hr)
300 Series—Forged carbon steel for vertical installation
For pressures to 650 psig (45 bar) . . . Capacities to 20,000 lb/hr (9072 kg/hr)
411G/421 Series—Forged carbon steel for vertical and horizontal installation
For pressures to 1,000 psig (69 bar) . . . Capacities to 1,300 lb/hr (590 kg/hr)
400 Series—Forged chrome-moly steel for vertical installation
For pressures to 1,000 psig (69 bar) . . . Capacities to 20,000 lb/hr (9072 kg/hr)
401-SH/501-SH Series—Carbon steel or stainless steel for vertical installation – superheat service
For pressures to 1,540 psig (105 bar) . . . Capacities to 1,300 lb/hr (590 kg/hr)
5000 Series—Forged chrome-moly steel for vertical installation
For pressures to 1,800 psig (124 bar) . . . Capacities to 5,150 lb/hr (2336 kg/hr)
6000 Series—Forged chrome-moly steel for vertical installation
For pressures to 2,700 psig (186 bar) . . . Capacities to 6,500 lb/hr (2948 kg/hr)
1000 & U1000 Series—All stainless steel for vertical installation (except U-1000 with strainer)
For pressures to 650 psig (45 bar) . . . Capacities to 4,400 lb/hr (2000 kg/hr)
1800 Series—All stainless steel for horizontal installation
For pressures to 650 psig (45 bar) . . . Capacities to 1,802 lb/hr (817 kg/hr)
2000 Series—All stainless steel with 360° connector
For pressures to 650 psig (45 bar) . . . Capacities to 1,300 lb/hr (590 kg/hr)
