Precision Orifices
Set-screw type, Series G
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Reference: 170-P-058000-EN-01
Issue: 08.2015
S high flow accuracy
S calibrated orifice diameter
S marked with orifice diameter
1 Description
Precision orifices from Bucher Hydraulics are manufac
tured with close tolerances (+0.02/-0.01) and thus guaran
tee high flow accuracy. Each orifice is marked with its re
spective orifice diameter. The orifices are used for throttling
and controlling oil flows in all hydraulic applications.
2 Symbol
3 Technical data
General characteristics Unit Description, value
Designation Orifice, type G
Material Free-cutting steel 11 SmnPb30+C (1.0718)
Thread size M3 … M6
Dimensions See table Dimensions in section 5
Mounting attitude unrestricted
Operating pressure range bar up to 420
Flow rate Q
max.
see Orifice table in section 4, Performance graphs
Fluid HL and HLP hydraulic oils to DIN 51524
(for other fluids please contact Bucher Hydraulics)
170-P-058000-EN-01/08.2015
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Description, valueUnitGeneral characteristics
Viscosity range mm
2
/s [cSt] 10 … 500
Minimum fluid cleanliness ISO 4406, code 20/18/15 or NAS 1638, class 9
(see section 8)
For applications outside these parameters, please contact BUCHER HYDRAULICS.
4 Performance graphs
4.1 Orifice table
Measured with oil viscosity 33 mm
2
/s [cSt]
0.06
0.1
0.3
0.5
0.8
2
0.2
0.4
0.6
1
3
4
5
6
8
10
20
30
40
50
60
80
100
200
300
400
500
600
300
250
200
150
100
80
70
60
50
40
30
25
20
15
10
8
7
6
5
4
3
2.5
2
1.5
1
Δp [bar]
Q [l/min]
1
1 Orifice diameter in mm
Pressure loss with turbulent flow in circular orifices as a
function of the orifice diameter and the flow rate.
170-P-058000-EN-01/08.2015
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5 Dimensions
SW
A
D
G
A
M3
[mm]
M4
[mm]
M5
[mm]
M6
[mm]
SW 1,5 2,0 2,5 3,0
G 3,5 4,0 5,0 6,0
Ø D 0,3 0,3 0,3 0,3
0,4 0,4 0,4 0,4
0,5 0,5 0,5 0,5
0,6 0,6 0,6 0,6
0,7 0,7 0,7 0,7
0,8 0,8 0,8 0,8
0,9 0,9 0,9 0,9
1,0 1,0 1,0 1,0
1,2 1,2 1,2 1,2
1,3 1,3 1,3
1,4 1,4 1,4
1,5 1,5 1,5
1,6 1,6 1,6
1,7 1,7
1,8 1,8
1,9 1,9
2,0 2,0
2,1 2,1
2,2 2,2
2,3
2,4
2,5
6 Ordering code
M6
D 0,8
Orifice type G
Thread type:
M3 M3
M4 M4
M5 M5
M6 M6
Orifice Ø (see table Dimensions in section 5)
Orifice type G
Supplied in packing units of 25 pieces.
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7 Hydraulic fluid
The oil for these orifices must have a minimum cleanliness
level of 20/18/15 to ISO 4406 or class 9 to NAS 1638.
We recommend the use of fluids that contain anti-wear addi
tives for operation with boundary lubrication. Fluids without
appropriate additives reduce the service life of the orifices.
The user is responsible for maintaining, and regularly
checking, the fluid quality. Bucher Hydraulics recommends
a DIN 51347-2 Brugger load capacity of >
30 N/mm
2
.
8 Cleanliness classification
Cleanliness class to ISO 4406 and NAS 1638
Code
ISO 4406
Number of particles / 100 ml
4 µm 6 µm 14 µm
NAS 1638
23/21/18 8000000 2000000 250000 12
22/20/18 4000000 1000000 250000 -
22/20/17 4000000 1000000 130000 11
22/20/16 4000000 1000000 64000 -
21/19/16 2000000 500000 64000 10
20/18/15 1000000 250000 32000 9
19/17/14 500000 130000 16000 8
18/16/13 250000 64000 8000 7
17/15/12 130000 32000 4000 6
16/14/12 64000 16000 4000 -
16/14/11 64000 16000 2000 5
15/13/10 32000 8000 1000 4
14/12/9 16000 4000 500 3
13/11/8 8000 2000 250 2
9 Application notes
Do not exceed the maximum operating pressure, and take
any pressure peaks into consideration. Do not exceed the
specified nominal flow rate.
Buyers bear the sole responsibility for ensuring that the se
lected orifices are suitable for their applications. Buyers ulti
mately establish this by undertaking qualification programs
on the test stands, or by evaluating the performance of pro
totype machines or systems.
E 2015 by Bucher Hydraulics Dachau GmbH, D- 85221 Dachau
www.bucherhydraulics.cominfo.dah@bucherhydraulics.com
All rights reserved.
Data is provided for the purpose of product description only, and must not be construed as warranted characteristics in the legal sense. The
information does not relieve users from the duty of conducting their own evaluations and tests. Because the products are subject to continual
improvement, we reserve the right to amend the product specifications contained in this catalogue.
Classification: 499.990.
