Brass
Fluid Level Sight Glasses
With Natural Glass, BSPT or NPT Threads
GN 743.7

GN 743


RoHS Compliant

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Specification
Information

Sight glass body: Brass, CuZn40PbZ
Sight glass: Natural glass
Reflector: Heat resistant technopolymer plastic (Polysulfon)
O-ring: NBR Rubber (Perbunan)

The conical thread of GN 743.7 fluid level sight glasses makes a metallic seal possible. When the male thread is tightened, it wedges itself within the appropriate female thread.
At the reference level "a," the male thread has the same thread diameter as the female thread, so that it can be fastened in by hand. The secure tightening by means of a tool increases the length of engagement and seals the screw connection. Additionally a sealant (fibrous or teflon band) is usually used. The thread is "roughened," so that the sealant does not shift during fastening.
Fluid level sight glasses GN 743.7 can be used on pressurized oil tanks.
Temperature resistant to 230°F (110°C).

See our Technical Section for pipe thread size details and pressure ratings.
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NPT Threads Table

Dimensions in:

inches
(millimeters)

Part Number
d1
d2
Male
Thread Tapered
a
Datum Plane
d3
at a
d4
Female Thread Tapered
e
l1
l2
l3
Usable Thread Length
s
p
Thread
Pitch
Wrench Flats
With
Reflector
Without
Reflector
.43
(11)
3/8" NPT
.24
(6.1)
.97
(17.1)
3/8" NPT
.87
(22)
.59
(15)
.24
(6)
.40
(10.1)
.75
(19.05)
.053
(1.337)
3/4"
.55
(14)
1/2" NPT
.32
(8.1)
.83
(21.2)
1/2" NPT
1.08
(27.5)
.63
(16)
.28
(7)
.52
(13.2)
.94
(23.8)
.071
(1.814)
15/16"
.71
(18)
3/4" NPT
.34
(8.6)
1.05
(26.6)
3/4" NPT
1.30
(33)
.71
(18)
.31
(8)
.57
(14.5)
1.13
(28.6)
.071
(1.814)
1 1/8"
.94
(24)
1" NPT
.40
(10.2)
1.33
(33.7)
1" NPT
1.59
(40.3)
.87
(22)
.31
(8)
.66
(16.8)
1.37
(34.9)
.091
(2.309)
1 3/8"
1.26
(32)
1 1/4" NPT
.42
(10.7)
1.66
(42.2)
1 1/4" NPT
2.02
(51.3)
.91
(23)
.35
(9)
.75
(19.1)
1.75
(44.5)
.091
(2.309)
1 3/4"
BSPT Threads Table

Dimensions in:

inches
(millimeters)

Part Number
d1
d2
Male
Thread Conical
a
Datum Plane
d3
at a
d4
Female Thread Cylindrical
e
l1
l2
l3 Usable Thread Length
s
p
Thread
Pitch
Wrench Flats
With
Reflector
Without
Reflector
.43
(11)
R 3/8"
.25
(6.4)
.66
(16.7)
Rp 3/8"
.87
(22)
.59
(15)
.24
(6)
.40
(10.1)
.75
(19)
.053
(1.337)
3/4"
.55
(14)
R 1/2"
.32
(8.2)
.82
(21)
Rp 1/2"
1.08
(27.5)
.63
(16)
.28
(7)
.52
(13.2)
.94
(24)
.071
(1.814)
15/16"
.71
(18)
R 3/4"
.37
(9.5)
1.04
(26.4)
Rp 3/4"
1.30
(33)
.71
(18)
.31
(8)
.57
(14.5)
1.06
(27)
.071
(1.814)
1 1/8"
.94
(24)
R 1"
.41
(10.4)
1.31
(33.2)
Rp 1"
1.60
(40.5)
.87
(22)
.31
(8)
.66
(16.8)
1.37
(35)
.091
(2.309)
1 3/8"
1.26
(32)
R 1 1/4"
.50
(12.7)
1.65
(42)
Rp 1 1/4"
2.03
(51.5)
.91
(23)
.35
(9)
.75
(19.1)
1.75
(44.5)
.091
(2.309)
1 3/4"