Pressure-relief valves, indirectly pilot-controlled

Series DVI

Range of application The pressure-relief valves of Series DVI can be applied for maximum operating temperatures up to 150°C (higher temperatures on request).

The pressure-relief valves can be applied for mineral and synthetic hydraulic oils, lube oils and fuel oils. They are not to be used for corrosive, abrasive and con-taminated fluids.

The exact operating data of the pressure-relief valve such as pressures, maximum rate of flow and viscosity range can be taken from the data sheet.

Types/Structural Design Together with the valve casing, the pressure-relief valve forms a control block.

Structural design of the main control valve The valve casing (1) has a pressure-side connection (A) and a suction-side connection (B) or connection (T) to the tank. The valve cone (8) with nozzle (19) is guided in the valve seat bush (3). The O-rings (15) and (34) seal the spaces (A) and (L) off from space (B) or (T) in the valve casing (1). Sealing of the valve cone (8) with nozzle (19) is ef-fected via the valve spring (30) through the valve seat (i) in the valve seat bush (3).

Structural design of the pilot control unit The pilot control unit consists of the control bush (10), the control cone (11), the nozzle (57), the valve spring plates (6) and (7), the O-rings (16) and (20) and the valve spring (29). The control cone (11) is guided in the control bush (10) and, via the valve spring (29), pressed onto the valve seat (e), thus sealing it. The control casing (2) with screw plug (5) doses the hydraulic pilot control unit via the gasket (14) and the O-ring (20), sealing it off from the outside. By means of the adjusting screw (17) and the valve spring (29), the opening pressure is adjusted. The ad-justing screw (17) is fixed in its position, checked by the hexagon nut (31).

Mode of operation The fluid to be pumped enters space (A) of the valve casing (1), where it is under a specific operating pres-sure pressing against the valve cone (8). In pressure-relief valves without control liquid filter, the fluid to be pumped flows through the bore hole (H) in nozzle (19), transferring the operating pressure onto both the space (L) in the valve cone (8) and the control cone (11).

As the guide diameter of the valve cone (8) is greater than the effective diameter of the valve seat (i), the valve cone (8) is kept closed hydraulically. In addition the valve spring (30), at zero pressure, presses the valve cone (8) in any mounting position onto the valve seat (i). The closing force of the valve spring (30) corresponds to the relief pressure. By means of the adjusting screw (17) the valve spring (29) is set to the required opening pressure, pressing the control cone (11) onto the valve seat (e).

If the operating pressure increases above the set open-ing pressure, the control cone (11) overcomes the spring tension of the valve spring (29) and opens the valve seat (e). As a result, the space (L) in the valve cone (8) is connected with the space (B) or (T) via the valve seat (e) through the space (K), the bore hole (F). The fluid to be pumped which is in space (L) in the valve cone (8) commences to flow off through the space (B) or (T).

As a result of the throttling effect of the bore hole (H) in the nozzle (19) or (104) as appropriate, the pressure in the space (L) of the valve cone (8) is reduced. The hydraulic closing force decreases so that the valve cone (8) is lifted off its valve seat (i). Now the fluid to be pumped commences to flow from space (A) into space (B) or (T).

If the operating pressure falls below the set opening pressure, the control cone (11) doses the valve seat (e). No more fluid can escape from the space (L). In space (L) of the valve cone (8) the operating pressure is built up again as in space (A). The valve cone (8) is hydrauli-cally kept closed.

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ALLWEILER

Series DVI ALLWEILER

Pressure-relief valves which are equipped with an addi-tional valve spindle (52) and a spindle nut (50) serve for pressureless starting of the pump. It is moreover poss-ible, during operation, to constantly branch off a certain delivery quantity from space (A) to space (B) or (T) with valve seat (i) open.

Switching diagram according to DIN/ISO 1219

Operation Operation with adjusting screw By means of the adjusting screw (17), the respective opening pressure is adjusted. Clockwise rotation: Pressure build-up Counterclockwise rotation: Pressure reduction.

Operation with spindle nut (only size 38) With turning clockwise of the spindle nut (50), the valve spindle is pressed against the valve cone (8) lifting same from valve seat (i).

Thus, a rated current can be carried off with the adjust-ment of the valve spring (29) not being changed.

Actuation of the hand relief system (HE) By opening the relief valve via the regulating screw (13), the pressure-relief valve can be depressurized by hand.

For these purposes, turn regulating screw by 1 to 2 counterclockwise rotations. Thus, an almost pressure-less circulation is possible, for example when starting the pump or during a short-time standstill of the plant.

The relief valve being closed via the regulating screw, the pressure in space (L) increases. At the same time, the valve cone (8) closes and the system and/or open-ing pressure set at the adjusting screw (17) is built up again. For these purposes, turn regulating screw (13) clockwise against the stop.

Actuation of the external control (FS) Instead of the screw plug (42), a piped 2/2 way solenoid valve can be connected to the control casing (2) for pressure relief. By actuating the solenoid valve, the pressure-relief valve can be released for pressure relief. Thus, an al-most pressureless circulation is possible, for example when starting the pump or during a short-time standstill of the plant.

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Series DVI ALLWEILER

Abbreviation

* max. flow with pipeline valves

Characteristics

Type of construction Cone seat valve

Flow range [l/min] 10 to 3600

Fluids Lube, hydraulic, fuel oils, oil-in-water emulsions

Temperature range [°C] -20 to +150

Viscosity range [mm2/s] 10 to 1000

Casing: GG/GGG/GS/ST

Valve cone: ST

Standard materials:

O-rings: NBR/Viton

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Series DVI ALLWEILER

Types

Type A Type B

Type C Type D

Type E Type F

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Series DVI ALLWEILER

Valve characteristic

Increase of pressure depending on rate of flow Graphs refer to average values for viscosities of 10 to 150 mm2/s

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Series DVI ALLWEILER

Valve characteristic

Increase of pressure depending on rate of flow Graphs refer to average values for viscosities of 10 to 150 mm2/s

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Series DVI ALLWEILER

Sectional drawing with parts list Pressure-relief valve Series DVI, type C (built-on, return to tank).

Pressure relief by hand (HE) from size 44

Pressure relief by external control from size 44

Pressure relief by spindle nut Size 38

This sectional drawing only relates to a specific size and type of construction. Sectional drawings for further sizes and types of construction on request.

Part No. Denomination Part No. Denomination Part No. Denomination 1 Valve casing 17 Adjusting screw 44 Socket-head cap screw 2 Control casing 19 Nozzle 48 � O-ring 3 � Valve seat bush 20 � O-ring 50 Spindle nut 5 Cover 21 � Joint ring 51 Guide bush 6 Valve spring plate 22 � Joint ring 52 Valve spindle 7 Valve spring plate 24 Spring dowel 53 � O-ring 8 � Valve cone 25 � Joint ring 54 Key

10 � Control bush 29 � Valve spring 57 Nozzle or grub screw 11 � Control cone 30 � Valve spring 90 � Name plate 12 � O-ring 31 Hexagon nut 91 � Rivet 13 Regulating screw 33 Socket-head cap screw 14 � Gasket 39 Screw plug 15 � O-ring 42 Screw plug � Spare parts/Replacement parts 16 � O-ring 43 Socket-head cap screw � not represented

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(A) Space with inlet opening (F) Bore hole from space (K) to (T) (H) Bore hole in the nozzle (K) Space in control casing (L) Space in valve cone (T) Space with outlet opening (e) Valve seat (i) Valve seat

Series DVI ALLWEILER

Valve dimensions and connections Type F, casing material GG/GGG/GS

Design with DVI 44

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Size Inlet- Flange Outlet- Flange Dimensions

DN1 PN D1 K1 J1 d1 z1 b1 DN2 PN D2 K2 J2 d2 z2 b2 a1 a2 r l

DVI44F 50 40 165 125 - 18 4 22 R2" - - - - - - 78 70 112 275

DVI47F 65 40 185 145 122 18 8 24 80 16 200 160 138 18 8 24 140 130 142 335

DVI50F 80 40 200 160 138 18 8 26 100 16 220 180 158 18 8 24 150 140 165 320

Series DVI ALLWEILER

Valve dimensions and connections Type F, casing material welded steel

Size Inlet- Flange Outlet- Flange Dimensions

DN1 PN D1 K1 J1 d1 z1 b1 DN2 PN D2 K2 J2 d2 z2 b2 a1 a2 r l h

DVK4F 50 40 165 125 - 18 4 22 R2" - - - - - - - 78 70 112 275 85

DVK7F 65 40 185 145 122 18 8 24 80 16 200 160 138 18 8 24 140 130 142 335 100

DVI50F 80 40 200 160 138 18 8 26 100 16 220 180 158 18 8 24 150 140 165 320 105

DVI56F 100 40 235 190 162 23 8 24 125 16 250 210 188 18 8 22 220 200 194 400 115

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Series DVI ALLWEILER

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Series DVI ALLWEILER 11

Series DVI ALLWEILER

The stated performance data are to be understood oniy as an outl ine of performance of our products. For exact limits of application please refer to the quotation and acceptance of oder.

VM 774 GB/02.99 - Ident-Nr. 795 733 12

Subject to technical alterations.

ALLWEILER AG Postfach 1140 ���� 78301 Radolfzell Allweilerstr. 1 ���� 78315 Radolfzell Germany Tel. +49 (0)7732 86-0 Fax. + 49 (0)7732 86-436 E-Mail: service@allweiler.de Internet: http://www.allweiler.com