Instruction Manual for Pressure Maintaining Valve DHV05, ND05 NP350
HL Hydraulik GmbH www.HL-Hydraulik.de Page 1 of 14
BA00504270 E 09/2012
HL Hydraulik GmbH
Instruction Manual
Pressure Maintaining Valve DHV05
ND05 NP350
Item #00504270
SCHRUPP
Instruction Manual for Pressure Maintaining Valve DHV05, ND05 NP350
HL Hydraulik GmbH www.HL-Hydraulik.de Page 2 of 14
BA00504270 E 09/2012
0. Content
0. Content ................................................................................................................................................. 2
1. General Information ........................................................................................................................ 3
2. Safety Instructions ........................................................................................................................... 4
3. Functional Description..................................................................................................................... 5
4. Technical Data ................................................................................................................................... 7
5. Installation and Commissioning .................................................................................................. 9
6. Operating, Maintenance and Repair ........................................................................................ 11
7. Taking out of service ..................................................................................................................... 12
8. Warranty ............................................................................................................................................ 13
9. Manufacturers data ........................................................................................................................ 13
10. Appendix ............................................................................................................................................ 14
Instruction Manual for Pressure Maintaining Valve DHV05, ND05 NP350
HL Hydraulik GmbH www.HL-Hydraulik.de Page 3 of 14
BA00504270 E 09/2012
1. General Information
This document contains information that shall be paid
attention to during installation and commissioning!
The instruction manual is valid for the following valve type only:
Pressure maintaining valve type DHV05, ND05 NP350,
item #00504270.
The valve is solely intended for applications as described in this
document. Each contrary usage, the defiance of the instructions
made in this document or any unauthorized changes made to the
device are forbidden. In this case HL Hydraulik GmbH will reject
any guarantee or liability claims.
The valve must be operated only with compressed air or other non-
dangerous, gaseous fluids according to group 2 of paragraph 9,
section 2, number 2.2 of the pressure equipment directive
97/23/EG. In case other fluids than compressed air are used the
compatibility of the fluid with the materials of the seals has to be
considered.
Please pay attention to the technical data of the valve, cf. to
section 4 of this document.
Conformity with pressure equipment directive 97/23/EG:
For this valve paragraph 3, section 3 of the pressure
equipment directive is valid. The valve is designed in
accordance with the requirements mentioned there.
Instruction Manual for Pressure Maintaining Valve DHV05, ND05 NP350
HL Hydraulik GmbH www.HL-Hydraulik.de Page 4 of 14
BA00504270 E 09/2012
2. Safety Instructions
The plants owner has to ensure, that the staff entrusted
with the installation, commissioning or maintenance of the
valve is familiar with the information and instructions in
this manual. For damages or injuries caused due to
ignorance or disregard of the instructions herein, HL
Hydraulik GmbH will not accept responsibility.
When improper handling the valve the following risks may occur
during operation:
- Danger due to pressure!
Improper handling of the valve may
suddenly set free pressurized fluid. This
may cause severe injuries to persons or
damages to equipment, e.g. through
bursting parts or loud noises.
During operation it is forbidden to fasten
or loosen fittings or to remove parts of the
valve.
To avoid such dangers the plants owner has to comply with all
regulations, directives and laws concerning operation and
maintenance of pressure equipment valid in the respective
country of installation.
These may be for example, but not exclusive:
Legislative directives concerning the operation of
pressurized plants or parts of it.
Accident prevention regulations of liability insurance
companies
Regulations or directives of standardization commitees or
associations (e.g. DIN/EN/ISO-standards)
It shall be ensured that:
maintenance and repair duties are done by skilled and
authorized staff only.
Instruction Manual for Pressure Maintaining Valve DHV05, ND05 NP350
HL Hydraulik GmbH www.HL-Hydraulik.de Page 5 of 14
BA00504270 E 09/2012
3. Functional Description
Usage:
Typically this valve type will be applied in air compressor units. It is
installed in the pipeline running from the compressor discharge port
to the compressed air storage vessel. The valve maintains the
compressor outlet pressure nearly constant. By this, efficient work
of the compressor water separation and/or dryer is possible.
Features:
- seat-type valve
- simple design
- easy installation
- equipped with cutting-ring type pipe fittings
The pressure maintaining valve keeps the pressure p
1
at the
valve inlet nearly constant, independent of the valve flow or the
pressure p
2
at the valve outlet. To avoid backflow from the
compressed air storage vessel when the compressor is switched
off, a check valve installed between pressure maintaining valve
and vessel is necessary, cf. to diagram 1.
Diagr. 1
When the pressure in the compressor discharge line rises valve
piston “7” lifts from seat “17” as soon as the pressure force is
higher than the preset spring force “11”. Now air flows through the
valve to the vessel.
By adjusting the initial tension of spring “11” it is possible to fit the
valves operating point to the requested compressor output pressure
set-point p
1set
.
The compressor output pressure is kept nearly constant due to the
control action of the pressure maintaining valve. However due to its
proportional characteristic there is a small deviation of the actual
compressor output pressure p
1
from the set-point p
1set
, in case the
compressors operating point is different from the operating
conditions during adjustment.
Instruction Manual for Pressure Maintaining Valve DHV05, ND05 NP350
HL Hydraulik GmbH www.HL-Hydraulik.de Page 6 of 14
BA00504270 E 09/2012
If for example the vessel pressure p
2
rises, the compressor flow
would decrease and/or the compressor output pressure p
1
would
increase (strictly only when the flow is subsonic). But because the
pressure maintaining valve opens slightly in this situation to
increase its cross section, the pressure increase at the compressor
output is marginally. In case the pressure p
1
drops, the control
action of the pressure maintaining valve is vice versa.
Diagr. 2
Spring
Piston
Seat
17
Counter Nut
Set Screw /
S
p
rin
g
Dome
Instruction Manual for Pressure Maintaining Valve DHV05, ND05 NP350
HL Hydraulik GmbH www.HL-Hydraulik.de Page 7 of 14
BA00504270 E 09/2012
4. Technical Data
Fluids: Compressed air or other
nonhazardous, gaseous fluids acc. to
group 2 of paragraph 9, section 2,
number 2.2 of the pressure
equipment directive 97/23/EG.
(In case other fluids than
compressed air are used, the
compatibility of the fluid with the
materials of the seals has to be
considered)
Rated pressure: 350 bar
Test pressure: 500 bar
Size: ND05
Pressure set range : 60-350 bar
Control characteristic: Proportional controller
Flow rate: With compressed air and a pressure
drop of 10bar (difference between
inlet pressure p
1
and outlet (vessel)
pressure p
2
the following flow rates
are possible:
p1-p2=220bar Q=3.500l/min(ANR)
p1-p2= 10bar Q= 160l/min(ANR)
(ANR=Atmosphere normale de
reference; air volume at normal
conditions)
Instruction Manual for Pressure Maintaining Valve DHV05, ND05 NP350
HL Hydraulik GmbH www.HL-Hydraulik.de Page 8 of 14
BA00504270 E 09/2012
Max. operating temperature: 60°C
Min. fluid temperature: -20°C
Fluid content : < 0.1 liter
Installation length: 84mm (pipe to pipe)
120mm (incl. union nuts)
Pipe length necessary
for installation: : straight pipe section
of 150mm minimum length
Weight: 1,05kg
Materials:
Housing and threaded studs: brass
Disc and bolt: brass
Piston: POM
Seals: POM, NBR70
Fittings: steel, galvanized and chromated
Connections:
Ports P and A: cutting ring type fittings
(comprising cutting ring,
threaded adaptor and union nut)
Pipe size: OD12mm,
(fittings for other pipe sizes are
available on request
Pipe material: steel or copper
(but no stainless steel)
Instruction Manual for Pressure Maintaining Valve DHV05, ND05 NP350
HL Hydraulik GmbH www.HL-Hydraulik.de Page 9 of 14
BA00504270 E 09/2012
5. Installation and Commissioning
Danger due to pressure!
Always make sure the pipe section where
the valve shall be installed is depressurized
Be cautious during installation and ensure
the valve is installed properly to avoid any
risks of injury or damage during operation.
Shut-off valves separating the pipe section
worked on from other pressurized parts of
the compressed air system shall be secured
against intended or unintended opening
during the installation works.
The installation shall be done by qualified
staff using appropriate tools. Valve, fittings
and pipes must be suited for the operating
pressure of the plant.
Any damage to the valve, unauthorized
modifications or the usage of pipes/fittings
not rated for the plants operating pressure,
may cause severe injuries to persons,
damages to equipment or disturbances of the
plant operation.
To avoid contamination the valve is delivered with plastic plugs
inserted in both ports. Remove these plugs before installation.
Keep care that no dust or dirt gets into the valve.
Before installation visually inspect the valve. If any damages are
recognizable do not install the valve! Compare the technical data
of the valve with the plants operating data (pressure and
temperature).
Each pressure maintaining valve DHV05 is tested before leaving
the factory and is delivered ready for operation
For installation and commissioning proceed as follows:
1.) Installation of the valve
The valve shall be installed such that is not subject to
vibrations, shock or heavy loads neither during
installation nor during operation. Furthermore it shall be
installed such that is protected from being influenced by
external impact, dirt and high temperatures.
Most preferable it is to install the valve on a support. For
this purpose the valve is designed with two threaded
holes on the bottom side of the housing.
Instruction Manual for Pressure Maintaining Valve DHV05, ND05 NP350
HL Hydraulik GmbH www.HL-Hydraulik.de Page 10 of 14
BA00504270 E 09/2012
Installation without support is allowed only if the pipe is
capable of carrying the valves static (weight) and
dynamic loads.
The valve has to be installed free of tension or stress.
The installation length (pipe to pipe) is 84mm. Taking
into account the fittings and the necessary space to
remove the union nuts, a straight pipe section of at least
150mm length is necessary to integrate the valve.
2.) Connecting the pipes
The valve is delivered with screwed fittings for pipe with
outer diameter 12mm (fittings for other pipe sizes
available on request). Suited pipe materials are standard
steel (but no stainless steel) or copper alloys. Use only
pipe which is rated at least for the plants operating
pressure. The screwed fittings are of the Ermeto EO
cutting ring type (manufacturer: Parker Ermeto). Each
fitting comprises one cutting ring, one threaded adaptor
and one union nut.
The cutting ring shall be mounted in accordance with
Parkers assembly instructions for “EO”-type cutting rings!
3.) Adjusting the valve
After installation the valve has to be adapted to the
compressors flow rate.
First pre-fill the compressed air vessel until the pressure
p
2
in the vessel is approx. 80-100% of the switch-off
pressure. Now adjust the pressure maintaining valve until
the operating pressure p
1Set
of the compressor is reached.
For the adjustment of the valve two pressure gauges are
necessary: one for the compressor output pressure p
1
and one for the vessel pressure p
2
.
Instruction Manual for Pressure Maintaining Valve DHV05, ND05 NP350
HL Hydraulik GmbH www.HL-Hydraulik.de Page 11 of 14
BA00504270 E 09/2012
The valve is adjusted by lowering or increasing the spring
tension. Turn the set screw #3 (compare to diagram 2 or
data sheet TD504270 E) clockwise to increase the tension
or counter-clockwise to lower the tension. Increasing the
tension means increasing the set pressure and thus the
compressor output pressure p
1
and vice versa. After
adjusting the valve secure the set screw position by
tightening counter nut #4.
For proper working a pressure drop across the valve of at
least 10bar is necessary (difference between compressor
working pressure p
1Set
and max. vessel pressure p
2
)
6. Operating, Maintenance and Repair
Every four weeks the valve shall be inspected visually. In case of
any malfunction, leakage or visible damages take the valve out of
service for repair immediately.
Repairs must be done by the manufacturers personnel only or
staff authorized by the manufacturer.
For an undisturbed operation of the valve a regular maintenance
is vital. The frequency of maintenance depends on the valves
operating time. Maintenance is recommended at least every
3 years.
Maintenance comprises the following activities:
1.) Replacement all elastomer seals
2.) Replacement of valve piston
A list of all spare parts is included in document TD00504270-92 E
For maintenance or repair take the valve out of service acc. to the
instructions in section 7.
Instruction Manual for Pressure Maintaining Valve DHV05, ND05 NP350
HL Hydraulik GmbH www.HL-Hydraulik.de Page 12 of 14
BA00504270 E 09/2012
7. Taking out of service
Danger due to pressure!
Before dismantling the valve makes sure the
connected pipelines are pressureless.
Close the shut-off valves in the connected
pipelines and safeguard them against
intended or unintended reopening.
Unscrewing the fittings or removing other
parts of the valve under pressure may cause
severe injuries or damages due to explosive
decompression or bursting parts.
To dismantle the valve, unscrew the union nuts
on both valve ports. It may be necessary to
remove parts of the pipe or pipe clamps to take
the valve out of the pipeline.
Instruction Manual for Pressure Maintaining Valve DHV05, ND05 NP350
HL Hydraulik GmbH www.HL-Hydraulik.de Page 13 of 14
BA00504270 E 09/2012
8. Warranty
Warranty for the valve is granted for a period of 6 months after shipment
ex-works from the manufacturer workshop or, if applicable, after
installation and commissioning by one of the manufacturers employees.
Excluded from the warranty are all parts subject to wear, like e.g. seals.
HL Hydraulik GmbH is entitled to reject any warranty claims in case:
- the recommended maintenance interval is not observed
- the valve is handled improperly or instructions in this manual
are neglected.
9. Manufacturers data
Address: HL Hydraulik GmbH
Kupferhütte 5c
D57562 Herdorf
Germany
Phone: +49(0)2744 9324-0
Fax: +49(0)2744 9324-56
Website: www.hl-hydraulik.de
Instruction Manual for Pressure Maintaining Valve DHV05, ND05 NP350
HL Hydraulik GmbH www.HL-Hydraulik.de Page 14 of 14
BA00504270 E 09/2012
10. Appendix
- Technical data sheet
TD00504270 E Pressure maintaining/check valve ND05 NP350
- Spare parts
TD00504270-92 E Spare parts
pressure maintaining/check valve ND05 NP350
/
