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Danfoss introduced the PVG 32 pressure control (PC) spools to the market in the 1990s to overcome
instability problems on applications and to control the opening of counterbalance (CB) valves. Typically, a
main boom on a crane could be applied with a CB valve for safety reasons. Inertia in the system could
lead to oscillations which will be damped when using PC spools.

In this document you can read about the hydraulic functionality and behavior of a PC spool compared to
our standard flow control (FC) spools. These hydraulic principles make it easier to know when to apply PC
spools instead of FC spools in different applications.

Application Guide

Using flow or pressure control spools

Application overview

 

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©

 Danfoss | Feb 2017

AB00000079en-US0101

Содержание PVG 32

Страница 1: ...Application Guide PVG 32 Using flow or pressure control spools powersolutions danfoss com...

Страница 2: ...Revision history Table of revisions Date Changed Rev Feb 2017 First edition 0101 Application Guide Using flow or pressure control spools 2 Danfoss Feb 2017 AB00000079en US0101...

Страница 3: ...uction of whole or part of the contents of this manual is prohibited The following notes are used to raise awareness of safety considerations W Warning Xxxxx Identifies information about practices or...

Страница 4: ...ns Inertia in the system could lead to oscillations which will be damped when using PC spools In this document you can read about the hydraulic functionality and behavior of a PC spool compared to our...

Страница 5: ...f the compensator The other side of the compensator is connected to the Pc pressure The Pc pressure will remain 7 bar higher than Pl This also means that flow out of the valve is always directly propo...

Страница 6: ...y to keep the pressure drop across the main spool at the same level and follow the pressure oscillations from the actuator attached to the valve When the load pressure is changing the compensator will...

Страница 7: ...manipulates the LS signal A pc Pl physical opening area of the spool as a function of its position Pl load pressure Pc manipulated LS pressure spring pressure Ql flow out of the valve The example in...

Страница 8: ...e of the load and with variable deadband PC control to B port on page 8 illustrates a cut through PVB with PC control to one port PC control to B port Application Guide Using flow or pressure control...

Страница 9: ...a constant pressure Pc The load pressure Pl is oscillating Over time the pressure drop across the main spool Pc minus Pl varies which leads to a variable flow The flow out Ql is also shown on the grap...

Страница 10: ...lot pressure to open the CB valve on the B port The load is held by the CB valve and with the pressure build up on A port the opening of the CB valve is controlled PC is proportional to spool position...

Страница 11: ...rk port while allowing a variable flow depending on changes in the work port load A situation in which PC spools are of great value is when you are lowering a load in an application that uses counterb...

Страница 12: ...er Solutions ApS Nordborgvej 81 DK 6430 Nordborg Denmark Phone 45 7488 2222 Danfoss Power Solutions US Company 2800 East 13th Street Ames IA 50010 USA Phone 1 515 239 6000 Danfoss Power Solutions Trad...

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