Inverted Bucket
Steam Traps
for efficient condensate
drainage of industrial
and HVAC equipment
Inverted Bucket steam traps
The proper drainage of condensate is essential to efficient steam system
operation. Condensate, if allowed to collect in the steam system, creates several
problems:
• Build-up of condensate in steam mains and headers can eventually
lead to water hammer which can seriously damage the steam
system and create safety problems.
• Condensate which is not removed may eventually back up into the
steam space of process equipment, consequently reducing
efficiency.
Inverted Bucket steam traps rely on the difference in density between steam
and condensate to drain condensate as it forms. This keeps the steam space
free of condensate to provide maximum system efficiency.
These durable traps are designed to withstand corrosion, dirt, and water
hammer to provide long lasting service. On applications where air and non-condensible gases are present, an external air vent can be fitted to assist the normal
operation.
Spirax Sarco offers a full range of Inverted Bucket steam traps to handle
steam pressures up to 900 psig.
How it works
As condensate reaches the trap, it forms a
water seal inside the body. The weight of the
bucket keeps the valve off its seat so condensate
can flow around the bottom of the bucket and out
of the trap. Under low load or superheat conditions, the trap may need to be “primed” with
water before system startup (1).
When steam enters the underside of the
bucket, the bucket becomes buoyant and rises.
This positions the lever mechanism such that the
main valve “snaps” shut (2).
The bucket will lose its buoyancy as the
enclosed steam condenses due to radiation
losses, and steam escapes through the vent
hole. Once this happens, the weight of the bucket will pull the valve off its seat and the cycle is
then repeated (3).
1
2
2
Any air reaching the trap
will also give the bucket buoyancy and close the valve,
preventing condensate flow. The
small vent hole in the bucket will bleed
air into the top of the trap. The vent
hole is of small diameter to reduce
steam loss and thus will vent air very
slowly. Under startup conditions, this is
further compounded by the low differential pressures present. This can lead to
waterlogging of the plant and subsequent
poor heat transfer. A separate external air vent
is normally required to ensure speedy and efficient
startup of a steam plant. A bimetal air vent assist
can be added to some models to help with cold
startup air.
3
User benefits
Venting of non-condensibles
through the vent hole in the
top of the bucket provides
continuous operation.
✓
Resists water hammer with durable design.
✓
Flexible choice of connections:
screwed, socket weld or flanged.
✓
Simple installation and maintenance with
in-line horizontal piping connections.
✓
Compatible with a wide array of systems
with pressure ranges up to 900 psig.
All working parts are
stainless steel providing
good resistance
to corrosion and wear.
Bodies available in cast iron,
steel and stainless steel to
meet specific requirements.
Available with either
horizontal or vertical
flow patterns for piping
convenience.
Because condensate flows
under the bucket, dirt is
kept away from the orifice
until the valve is fully open.
Inverted Bucket steam trap overview
Model
Sizes (inches)
1/2 3/4 1 1-1/4 1-1/2 2
x
200 Series
x
x
x
HM34
x
x
x
600 Series
x
x
x
x
x
x
x
x
Standard
2.402
900 Series
x
x
x
x
x
x
x
x
Standard
2.403
SIB30
x
x
x
x
Air Vent Check Valve
x
x
x
x
TIS
#
x
UIB30
x
Options
x
x
x
Pipe Configuration
Body Material
In-line
Cast Cast Stn.
Horiz. Vert.
Iron Steel Steel Strainer
B Series
SIB45
x
Connections
NPT SW FLG
x
x
x
Optional Optional
x
2.401
x
Standard
x
x
x
x
x
x
x
x
x
x
x
x
x
x
Swivel Connector
2.407
x
2.404
2.410
Standard
2.411
2.412
3
Typical applications for Inverted Bucket steam traps
High Pressure Steam Mains
Steam Separator
Instant removal of condensate prevents water hammer
and improves steam quality.
“Wet” steam can damage equipment and
reduce process efficiency. A Spirax Sarco
separator
efficiently
“knocks
out”
condensate droplets in the steam flow. This
condensate must be continuously drained
from the separator to prevent it from becoming re-entrained in the steam flow. Spirax
Sarco Inverted Bucket steam traps discharge
condensate as it forms to prevent this from
happening.
Laundry Equipment
Laundry equipment uses steam for cleaning and
pressing garments. Inefficient condensate drainage
will not allow the proper
cleaning drying and pressing temperatures to be
achieved. Spirax Sarco
Inverted Bucket
steam traps keep the
equipment operating
smoothly by draining
condensate as it forms.
Steam trap selection and sizing
Need to know
How to size
1. The steam pressure at the trap after any pressure drop through
the control valve or equipment.
2. The distance the condensate must be lifted after the trap.
Rule of thumb: 2 feet of lift equals 1 psi back pressure (approximately).
3. Any other possible sources of back pressure in the condensate
return system. For example:
• Condensate taken to a pressurized deaerator tank or flash
recovery vessel.
• Local back pressure due to discharge of numerous traps
close together into an undersized return.
4. Quantity of condensate handled. Obtained from:
• Measurement
• Calculation
• Manufacturer’s data
5. Safety Factor that is dependent upon particular application,
typical examples as follows:
Steam Mains
2:1
Tracers
2:1
Non-Modulating
2:1
Modulating over 30 psi
3:1
Modulating under 30 psi
Size trap at full load and
1/2 psi differential
The difference between the steam pressure at the trap inlet and
the total back pressure, including that due to lift after the trap, is
the differential pressure. The quantity of condensate should be
multiplied by the appropriate safety factor to produce the sizing
load. The trap may now be selected using the differential
pressure and the sizing load.
Note: The inlet pressure to the steam trap should never exceed the
Maximum Operating Pressure (PMO) of the selected trap,
regardless of differential pressure.
Example
A steam trap is required to drain 2,000 lb/h of condensate from a
Unit Heater receiving steam at 100 psig.
There is a lift after the trap of 10 ft.
Inlet Pressure
100 psig
Lift
10 ft. = 5 psi (approximately)
Therefore,
Differential Pressure
Quantity 2,000 lb/h
Safety Factor
2:1
Sizing Load
Rule of thumb: Use a factor of 2 on everything except Temperature
Controlled Air Heater Coils and Converters, and Siphon Applications
4
100 psi - 5 psi = 95 psi
4,000 lb/h
A 1-1/4" B4-125 will handle 7,590 lb/h at 95 psi differential
pressure.
Inverted Bucket steam trap range
B Series
200 Series
The B Series Inverted
Bucket steam traps are
traditional
cast
iron,
horizontal flow products. The
stainless steel bucket and
valve are resistant to corrosion and water hammer.
Operating pressures are
available up to 250 psig with
capacities to 20,000 lb/hr.
Another traditional cast iron
product, the 200 Series
utilizes the popular bottom
in/top out flow pattern. The
stainless steel bucket and
valve are resistant to
corrosion and water hammer.
Operating pressures are available up to 250 psig with
capacities to 20,000 lb/hr.
B Series
Model
Size
200 Series
B1H
B2
B3
B4
B5
Model
211
212
213
215
216
1/2", 3/4"
3/4"
1"
1-1/4"
2"
Size
1/2"
3/4"
1"
1-1/2"
2"
Body Material
Cast Iron
Body Material
Cast Iron
Connections
NPT
Connections
NPT
Piping Configuration
In-Line Horizontal
Piping Configuration
In-Line Vertical
Options
Strainer, Air Vent
Options
N/A
TIS#
2.407
TIS#
2.401
250 psig
Maximum
Operating
Pressure (PMO)
250 psig
Maximum
Operating
Pressure (PMO)
B
Top plug not
provided on
B1H, B12H,
B2, B22,
B5, B52.
B
C
200 Series Dimensions (nominal) in inches
Size
1/2"
3/4"
1"
1-1/2"
2"
C,C1
A
D
A
E
E
Size
Type
A
B
C
C1*
D
E
Weight
1/2", 3/4"
B1H
5
4
3.3
3.8
3
1.4
6.2 lb
3/4"
B2
6.6
5.3
3.5
4.0
4.1
1.9
12.5 lb
20,000
15,000
6
, 22
216
5
, 22
215
B3
7.9
5.9
4.4
4.4
4.8
2.2
19.5 lb
1-1/4"
B4
9.3
7
5.6
5.4
7.4
2.3
40 lb
10,000
2"
B5
11.2
8.8
6.3
6.6
10.7
3.4
75 lb
7,000
*C1 Dimension for traps supplied with bi-metal air vents (B12H, B22, B32, B42, B52)
-30
-75
Condensate, lb/h
10,000
5,000
B4-15
3,000
2,000
B3-15
B2-15
-125
-180 -250
-180 -250
-30
-75
-30
-30
-75
-125
-180 -250
-75
-125
0
-180 -25
-75
-125
-180
5,000
Condensate, lb/h
B Series Capacities
B5-15
C
7.0
9.0
11.0
15.0
18.5
D
2.6
3.7
4.5
5.5
7.2
Weight
6.25 lb
11.5 lb
27.0 lb
59.0 lb
96.0 lb
200 Series Capacities
1"
-125
B
4.3
5.3
7.4
9.4
11.3
D
B Series Dimensions (nominal) in inches
20,000
A
6.4
7.9
10.6
14.4
17.0
3,000
2,000
48
32
28 24
22
20 18
20
16
14 12
12
10
40
36
3
, 22
213
24
2
, 22
212
16
28
8
1,500
1,000
1,
21
700
1
22
7
12
10
8
7 6
500
300
1,000
-30
B1H-15
-250
200
150
100
100
1
10
Differential Pressure, psig
100125 180 250
8 10
15 20
30
50
70 100
150 200 250
Differential Pressure, psig
5
Inverted Bucket s
HM34
UIB30/UIB30H
The steel construction of the
HM34 makes it a logical
choice for systems up to 465
psig. Available in 1/2"
through 1" with threaded or
socket weld connections.
The stainless steel bucket
and valve are resistant to
corrosion
and
water
hammer.
The UIB30 is a sealed
inverted bucket steam trap
complete with Spirax
Sarco’s versatile swivel
connector for installations
requiring horizontal or vertical flow. The swivel
connector is ideal for maintaining the proper trap
operation. The two-bolt
connector design simplifies
maintenance and reduces
downtime.
HM34
Size
Body Material
Connections
Piping Configuration
Options
TIS#
Maximum
Operating
Pressure (PMO)
1/2", 3/4", 1"
Steel
NPT, SW
In-Line Horizontal
Strainer is Standard
2.404
(Connector of choice
sold separately)
B
A
D
A
C
464 psig
E
UIB30 / UIB30H Dimensions
A
B
HM34 Dimensions (nominal) in inches
Size
1/2"
3/4"
1"
A
4.7
4.7
7.1
B
4.1
4.1
6.3
C
4.0
4.0
6.3
F
2.6
3.5
5.7
G
3.5
4.2
4.7
H
2.6
2.6
3.4
Weight
5.8 lb
8.9 lb
22.9lb
G
H
HM34 Capacities
2,000
Condensate, lb/h
1,000
800
1
600
1
500
HM
HM
M
1H
/10
34
HM
3/4
HM
1/2
200
2
1/
M
1H
6
34/
7
34/
HM
4/7
3/4
3
6
HM
34/
1/2
HM
3/4
/8
34
34/5
HM
3/4
/8
34
HM
/8
34
0
/1
34
HM
3/4
400
300
2
/1
34
/5
34
M
1 H /5
34
M
H
1/2
/4
34
HM
2
/
1
/6
34
110
100
8 10
20
30
40 50 60 80 100 120 170 200 290300 400
Differential Pressure, psig
6
B
3.4
3.3
3.4
C
4.9
4.9
4.9
Size
Body Material
Connections
Piping Configuration
Options
TIS#
Model
Maximum
Operating
Pressure (PMO)
Model
Maximum
Operating
Pressure (PMO)
Withdrawal
Distance
HM34
A
2.4
2.9
3.5
600
(nominal) in inches
D
1.3
1.3
1.3
E
3.1
3.1
3.1
Weight
4.8 lb
4.9 lb
5.2 lb
UIB30 / UIB30H
Condensate, lb/h
F
Size
1/2"
3/4"
1"
1,000
900
800
700
600
500
1/2", 3/4", 1"
Stainless Steel
NPT, SW
In-Line , Swivel Connector
Check Valve is Standard
2.412
30/8
30/7
30/6
30/5
30/4
58
psig
435
psig
123
psig
174
psig
290
psig
30H/10
30H/8
30H/6
30H/5
58
psig
123
psig
290
psig
435
psig
UIB30 / UIB30H Capacities
/8
/10
30H
UIB
/6
/7
30
UIB
/6
30
UIB
8
30/
UIB
400
/5
30/5
UIB
300
200
30/4
UIB
8 10
20
30 40
58 60 80 100 125 175 200
Differential Pressure, psig
290300 400
steam trap range
SIB45 Capacities
SIB30 / SIB30H / SIB45
0.5
The SIB30 and SIB45
Inverted Bucket steam traps
are sealed for tamper-proof
operation. The all stainless
steel construction is highly
resistant to corrosion and
water hammer. Operating
pressures up to 652 psig are
available with sizes ranging
from 1/2" through 1" and
either threaded or socket weld
end connections.
0.8 1
2
Differential Pressure barg
4 5 6
8 10
3
20
30
45
400
1000
800
/8
45
/10
45
700
300
/6
45
600
200
/5
45
400
Condensate kg/hr
Condensate lb/hr
500
300
100
200
80
70
60
50
SIB30 / SIB30H / SIB45
∆PMX
SIB30/12
SIB30 / SIB30H
SIB45
1/2", 3/4"
3/4", 1"
Stainless Steel
NPT, SW
In-Line Horizontal
Check Valve is Standard (SIB45 only)
2.410
2.411
770
662
0.5
1
Differential Pressure barg
∆PMX
∆PMX
∆PMX ∆PMX ∆PMX
∆PMX
SIB30/7 SIB30/6 SIB30/5 SIB30/4
SIB30/10 SIB30/8
2
4
/12
/8
/10
30
30
B
30
I
S
SIB
SIB
5
8
10
20
30
30/7
SIB
350
300
0/6
B3
SI
221
100
188
90
176
80
SIB30 Dimensions (nominal) in inches
154
70
Size
1/2"
3/4"
132
60
435
psig
652
psig
A
4.3
4.3
B
3.0
3.0
C
4.9
4.9
D Weight
5.6 3.3 lb
5.6 3.3 lb
110
7
15
29
SIB30H
Size
1/2"
3/4"
A
4.3
4.3
B
3.0
3.0
C
6.3
6.3
D Weight
7.0 3.9 lb
7.0 3.9 lb
0.5
770
662
44
1
2
/12
0H
3
B
SI
Differential Pressure barg
∆PMX ∆PMX ∆PMX
SIB30/10 SIB30/8 SIB30/7
3
50
435
290
∆PMX ∆PMX
SIB30/6 SIB30/5
4
5
8 10
20
8
/
6
0
/
H
H/1
30H
30
30
SIB
SIB
SIB
7
H/
30
B
SI
441
SIB45
58 73
116 145
Differential Pressure psig
∆PMX
SIB30/12
SIB30H Dimensions (nominal) in inches
30
450
400
5
H/
30
B
I
S
Size
3/4"
1"
C D
A
4.3
4.3
B
3.3
3.3
C
6.9
6.9
D Weight
7.8 6.5 lb
7.8 6.5 lb
221
100
188
90
176
80
154
70
132
60
110
7
15
29
44
58 73
116 145
Differential Pressure psig
290
Condensate kg/hr.
SIB45 Dimensions (nominal) in inches
Condensate lb/hr
200
A
B
3
200
/5
30
B
I
S
0/4
SIB3
C D
B
300 400 500600
441
SIB30
A
30 40 50 60 80 100
200
Differential Pressure psig
SIB30
Condensate lb/hr
Model
Size
Body Material
Connections
Piping Configuration
Options
TIS#
Maximum
Operating
Pressure (PMO)
20
Condensate kg/hr.
8 10
50
435
7
Inverted Bucket steam trap range
600/900 Series
E
C
Withdrawal
Distance
600 Series Dimensions (nominal) in inches
The 600 and 900 Series
of Inverted Bucket steam
traps are designed for
high pressure steam
systems with operating
pressures available up to
900 psig. The robust
forged steel construction
with stainless steel internals are resistant to
corrosion and water
hammer.
Size
1/2"
3/4"
1"
1-1/2"
2"
A
D
B
A
10.6
10.6
12.0
15.8
17.4
B
7.3
7.3
8.0
9.8
11.9
C
8.0
8.0
9.0
12.0
13.0
D
4.7
4.7
5.1
6.6
8.4
E
1.1
1.1
1.4
1.8
2.1
Weight
40 lb
40 lb
65 lb
110 lb
175 lb
600 Series
Withdrawal
E
C Distance
900 Series Dimensions (nominal) in inches
Size
1/2"
3/4"
1"
1-1/2"
2"
A
D
B
A
12.1
12.1
16.1
16.1
17.7
B
8.0
8.0
9.8
9.8
11.9
C
9.0
9.0
12.0
12.0
13.0
D
5.1
5.1
6.6
6.6
8.4
E
1.4
1.4
1.8
1.8
2.1
Weight
65 lb
65 lb
110 lb
110 lb
175 lb
900 Series
900 Series
600 Series
Model
Size
Body Material
Connections
Piping Configuration
Options
TIS#
Maximum
Operating
Pressure (PMO)
621
622
623
625
1/2"
3/4"
1"
1-1/2"
Steel
Flanged
In-Line Vertical
Check Valve is Standard
2.402
626
2"
600 psig
Model
Size
Body Material
Connections
Piping Configuration
Options
TIS#
Maximum
Operating
Pressure (PMO)
600 Series Capacities
921
922
923
925
1/2"
3/4"
1"
1-1/2"
Steel
Flanged
In-Line Vertical
Check Valve is Standard
2.403
926
2"
900 psig
900 Series Capacities
10,000
8,000
6,000
4,000
3,000
2,000
1,000
800
600
400
300
200
100
/32
626
0
626/2
8
625/1
/22
625
623/16
/14
625
625/12
3
62 /12
623/8
623/10
12
22/
NORTHEAST
26
1/1
0
62 Sewell
/1
Nigel
622
/10
Columbus,
Ohio
621
8
/
Hub Office
622
8
/
7760
River
621Olentangy
2/7
62
Suite 120
/7
1
62
Columbus,
OH 43235
Road
Phone: (614) 436-8055
10 (614)
20 436-8479
30 40 50 60 80 100120 200 300 400 600
8 Fax:
450
Differential Pressure, psig
10,000
8,000
626/18
Condensate, lb/h
Condensate, lb/h
626/24
/18
926
/16
926
6,000
4,000
2
5/1
/92
923
0
5/1
/92
923
3,000
2,000
2/8
/92
921
1,000
800
600
400
8 10
20
30 40
60 80 100
200 300 400
600 800
Differential Pressure, psig
Spirax Sarco, Inc. • 1150 Northpoint Blvd. • Blythewood, SC 29016 • Phone: (803) 714-2000 • Fax: (803) 714-2222 • www.spiraxsarco.com/us
Printed in USA 11/04. Copyright 2004 Spirax Sarco, Inc.
8