Pressure-Relief Cartridge Valve, Size 4
Q
max
= 30l/min (7.5 gpm)p
max
= 420bar (6000 psi)
Seated design,direct acting,with mechanical operation
Series DDPC-1L…
1/5
Reference: 400-P-260111-EN-02
Issue: 09.2019
S Compact construction for
cavity type AL – 3/4-16 UNF
S High flow rates
S 7 pressure ranges available
S High-pressure damping ensures
very stable operation
S Also suitable for anti-shock
function (cross-line relief)
S Available with hand-knob or tamper-proof cap
S All exposed parts with zinc-nickel plating
S Can be fitted in a line-mounting body
1 Description
Series DDPC-1L… cartridges are screw-in pressure-relief
valves, nominal size 4 mm. They are direct-acting seat
valves. The mounting thread is the 3/4“-16 UNF pattern.
The straightforward design delivers an outstanding price/
performance ratio and good pressure drop - flow rate char
acteristics. In order to obtain a good pressure adjustment
over the entire pressure range, the total pressure range is
subdivided into 7 pressure stages. A pressure stage corres
ponds to a certain spring for a settable maximum operating
pressure. The cartridges can be fitted in the AL cavity and
also in some 3/4“-16 UNF cavities from other valve man
ufacturers. The pressure is set by means of an adjusting
screw or a hand-knob. To safeguard pressure settings, the
adjusting screw can be sealed with a tamper-proof cap.
These pressure-relief cartridges are used to limit the system
pressure in mobile and industrial applications. All external
parts of the cartridge are zinc-nickel plated to DIN 50979
and are thus suitable for use in the harshest operating envi
ronments. If you intend to manufacture your own cavities or
are designing a line-mounting installation, please refer to
the section “Related data sheets”.
2 Symbol
1
2
3 Technical data
General characteristics Description, value, unit
Designation pressure-relief cartridge valve
Design seated design, direct acting,
with mechanical operation
Mounting method screw-in cartridge 3/4-16 UNF
Tightening torque 50±10 % (35 ft-lbs±10 %)
Size nominal size 4 cavity type AL to Bucher standard
Weight 0.19 kg (0.42 lbs)
400-P-260111-EN-02/09.2019
Series DDPC-1L…
2/5
Description, value, unitGeneral characteristics
Mounting attitude unrestricted
Ambient temperature range -25°C … +80°C (-13°F … +176°F)
Hydraulic characteristics Description, value, unit
Maximum operating pressure - port 2
- port 1
420bar (6000 psi)
250bar
1)
(3600 psi)
Maximum flow rate 30l/min (7.5 gpm)
Nominal pressure ranges 20bar, 40bar, 100bar, 160bar, 250bar, 350bar, 420 bar
(285 psi, 570 psi, 1400 psi, 2300 psi, 3600 psi, 5000 psi,
6000 psi)
Pressure adjustment range 1 turn ≅ 80bar (1150 psi) = p
N
420 bar (6000 psi)
1 turn ≅ 70 bar (1000 psi) = p
N
350 bar (5000 psi)
1 turn ≅ 51 bar (700 psi) = p
N
250 bar (3600 psi)
1 turn ≅ 32bar (455 psi) = p
N
160 bar (2300 psi)
1 turn ≅ 21 bar (300 psi) = p
N
100 bar (1400 psi)
1 turn ≅ 8bar (120 psi) = p
N
40 bar (570 psi)
1 turn ≅ 4bar (60 psi) = p
N
20 bar (285 psi)
Flow direction 2 → 1, see symbols
Hydraulic fluid HL and HLP mineral oil to DIN 51 524;
for other fluids, please contact BUCHER
Hydraulic fluid temperature range -25°C … +80°C (-13°F … +176°F)
Viscosity range 10…650mm
2
/s (cSt), recommended 15...250mm
2
/s (cSt)
Minimum fluid cleanliness
Cleanliness class to ISO 4406:1999
class 20/18/15
ATTENTION!
1)
Any residual- or surge-pressure in port 1
(tank pressure) is additive to the pressure setting
in port 2.
4 Performance graphs measured with oil viscosity 33mm
2
/s (cSt)
Δp = f (Q) Pressure drop - Flow rate characteristic
p
N
=
420 bar (6000 psi)
Q [l/min (gpm)]
302520151050
P0539.ai
400 (5700)
100 (1400)
0
200 (2900)
500 (7100)
300 (4300)
p [bar (psi)]
(7.5)(6.5)(5)(3.75)(2.5)(1.25)
Δp = f (Q) Pressure drop - Flow rate characteristic
p
N
=
350 bar (5000 psi)
Q [l/min (gpm)]
302520151050
P0540.ai
100 (1400)
200 (2900)
400 (5700)
300 (4300)
p [bar (psi)]
(7.5)(6.5)(5)(3.75)(2.5)(1.25)
0
400-P-260111-EN-02/09.2019
Series DDPC-1L…
3/5
Δp = f (Q) Pressure drop - Flow rate characteristic
p
N
=
250 bar (3600 psi)
Q [l/min (gpm)]
302520151050
P0541.ai
50 (700)
100 (1400)
150 (2100)
200 (2900)
250 (3600)
300 (4300)
p [bar (psi)]
(7.5)(6.5)(5)(3.75)(2.5)(1.25)
0
Δp = f (Q) Pressure drop - Flow rate characteristic
p
N
=
160 bar (2300 psi)
Q [l/min (gpm)]
302520151050
P0542.ai
160 (2300)
40 (570)
0
80 ( 1150)
200 (2900)
120 (1700)
p [bar (psi)]
(7.5)(6.5)(5)(3.75)(2.5)(1.25)
Δp = f (Q) Pressure drop - Flow rate characteristic
p
N
=
100 bar (1400 psi)
Q [l/min (gpm)]
302520151050
P0543.ai
100 (1400)
25 (350)
0
50 (700)
125 (1800)
75 (1050)
p [bar (psi)]
(7.5)(6.5)(5)(3.75)(2.5)(1.25)
Δp = f (Q) Pressure drop - Flow rate characteristic
p
N
=
40 bar (570 psi)
Q [l/min (gpm)]
302520151050
P0544.ai
40 (570)
10 (140)
0
20 (285)
50 (700)
30 (430)
p [bar (psi)]
(7.5)(6.5)(5)(3.75)(2.5)(1.25)
Δp = f (Q) Pressure drop - Flow rate characteristic
p
N
=
20 bar (285 psi)
Q [l/min (gpm)]
302520151050
P0545.ai
10 (140)
20 (285)
40 (570)
30 (430)
p [bar (psi)]
(7.5)(6.5)(5)(3.75)(2.5)(1.25)
0
– · – · – p2 min. = application limit / minimum bypass pressure
400-P-260111-EN-02/09.2019
Series DDPC-1L…
4/5
5 Dimensions & sectional view
With adjusting screw “S”
M
A
= 50 [Nm] ± 10%
2
1
15...21
52
33.1
100...106
2)
13
22
Ø 24
3/4−16 UNF
1
2
3
3
s
1
4
(3.94...4.17)
(2.05)(1.3) (0.6...0.83)
(35 ft−lbs ± 10%)
(Ø 0.95)
With hand-knob adjuster “H”
27...33
Ø 32
(1.06...1.3)
(Ø 1.26)
26
(1.02)
Adjusting screw with tamper-proof cap
(order separately in plain language)
6 Installation information
IMPORTANT!
When fitting the cartridges, use the specified
tightening torque. Set the required pressure with
the adjusting screw (s
1
). After you have set the
valve, lock the adjusting screw with the lock nut.
ATTENTION!
The DDPC-1L-4… cartridge is also suitable for
anti-shock service (cross-line relief). Note, how
ever, that the pressure at port 1 must not exceed
250 bar.
ATTENTION!
Only qualified personnel with mechanical skills
may carry out any maintenance work. Generally,
the only work that should ever be undertaken is to
check, and possibly replace, the seals. When
changing seals, oil or grease the new seals tho
roughly before fitting them.
IMPORTANT!
Valve settings can be sealed by fitting the tamper-
proof cap. To fit the cap, the snap ring
2)
has to be
removed. Subsequent adjustment is only possi
ble by destroying the tamper-proof cap.
Seal kit NBR no. DS-350-N
3)
Item Qty. Description
1 1 O-ring no.017 ∅17,17x 1,78 N90
2 1 O-ring no.014 ∅12,42x 1,78 N90
3 2 Backup ring ∅10,70x1,45x1,00 FI0751
IMPORTANT!
3)
Seal kit with FKM (Viton) seals, no. DS-350-V
400-P-260111-EN-02/09.2019
Series DDPC-1L…
5/5
7 Ordering code
D = pressure-control valve
D = direct acting
P = cartridge design
A ... Q = standard model - see relevant data sheets
Z ... R = special features - please consult BUCHER
1 = pressure function 1 (pressure-relief)
L = cavity type AL
4 = nominal size 4
42 = pressure range …420 bar
35 = pressure range …350 bar
25 = pressure range …250 bar
16 = pressure range …160 bar
10 = pressure range …100 bar
04 = pressure range … 40 bar
02 = pressure range … 20 bar
S = screw adjuster (standard)
H = hand-knob adjuster
(blank) = NBR (Nitrile) seals (standard)
V = FKM (Viton) seals
(special seals - please contact BUCHER)
1 ... 9 = design stage (omit when ordering new units)
-1
_
Ex.
42 -L1C --PDD-4 S
IMPORTANT!
When required, the tamper-proof cap (the adjustment seal) must be ordered separately in plain language.
8 Related data sheets
Reference Description
400-P-040011 The form-tool hire programme
400-P-040171 Cavity type AL
400-P-720101 Line-mounting body, type GALA (G 3/8”)
E 2019 by Bucher Hydraulics AG Frutigen, CH-3714 Frutigen
www.bucherhydraulics.cominfo.ch@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: 430.305.300.305.305.355