EP2047108A1

EP2047108A1 - Soft start valve device

Info

Publication number: EP2047108A1
Application number: EP06829284A
Authority: EP
Inventors: Grzegorz Bogdanowicz; Jakob Brenner; Andreas Decker
Original assignee: Festo SE and Co KG
Current assignee: Festo SE and Co KG
Priority date: 2006-12-05
Filing date: 2006-12-05
Publication date: 2009-04-15
Anticipated expiration: 2026-12-05
Also published as: EP2047108B1; TW200900613A; DE502006005894D1; WO2008067828A1; TWI403656B

Abstract

A soft start valve device (21) is proposed which has a main valve (24) which controls the fluid connection between a primary channel (1) and a secondary channel (2). In order to switch over the main valve (24) into the open position, an opening force is exerted on the valve. In an operating mode that is controlled by a secondary pressure, said force is derived from the secondary pressure which prevails in the secondary channel (2) and, in a time-controlled operating mode, is derived from a pressure medium which flows through a throttling device (39). A particular advantage results from the fact that the two operating modes are carried out simultaneously in a superimposed manner.

Description

FESTO AG & Co, 73734 Esslingen

Soft start valve device

The invention relates to a soft-start valve device, with a between a primary pressure under a primary pressure-carrying primary channel and a secondary channel switched main valve, which is switchable from a connection separating the primary channel and secondary channel closed position into a compound for maximum flow releasing open position, wherein the opening force responsible for this switching is derived in a secondary pressure-controlled operating mode of the valve device from the secondary pressure of the pressure medium gradually building up in the secondary channel, which flows from the primary channel into the secondary channel via a first throttle device.

Such a soft-start valve device designed for secondary-pressure-controlled operation goes from the textbook

"Pneumatic Controls", Werner Deppert, Kurt Stoll, Vogel Verlag, 10th edition 1994, pages 160 and 161, forth. The main valve is turned on there in the connection between a connected to a pressure source primary channel and connected to the consumers to be supplied secondary channel and can optionally shut off the connection (closed position) or release (open position). Normally, the main valve is biased by a closing pressure based on the primary pressure in the closed position. After switching on the valve device, the pressure medium can flow past the closed main valve past a first throttle device into the secondary channel. The secondary pressure prevailing in the secondary duct is returned to the main valve to generate a control force and switches it to the open position when the secondary pressure has reached a predetermined opening force. This ensures that the soft start valve device only permits an unthrottled fluid passage when the secondary pressure has risen to a certain pressure level. This overall achieves a relatively slow pressure build-up in the connected consumers, and avoids the occurrence of pressure surges which could lead to damage or unintentionally fast movements in the connected i5 consumers.

However, there are applications in which with such, depending on the secondary pressure controlled soft-start valve device only an insufficient operation is possible. Occurs, for example, on the secondary side

20 relatively high fluid consumption, it may take a very long time until the secondary pressure required to generate the opening force is built up, which can greatly delay the commissioning times of a system. Under unfavorable conditions you may find switching over

25 main valve in the open position does not take place at all.

In order to counteract such shortcomings, also purely time-dependent controlled soft-start valve devices are known in which the main valve switches independently of the actually prevailing secondary pressure after a certain period of time 3o in the open position. As an example of such a soft-start valve device that in the product catalog "The Pneumatic Catalog", 1997/1998 edition, FESTO AG & Co., Page 9.1 / 42-1, referred to as the so-called pressure build-up valve. Since such a purely time-controlled valve does not query the secondary pressure and thus the pressure prevailing at the connected consumers, there is the risk that improper use will cause the main valve to open too early, possibly resulting in damage too strong pressure pulse.

In many cases, a specific selection of the type of soft-start

Valve device be taken into account. In changing operating conditions, however, this proves to be impracticable. As a rule, there is no realistic possibility of retrofitting a plant from application to application.

The present invention has for its object to propose measures that allow in a simple and cost-effective manner in the most cases a specific graded to the requirements gradual pressure build-up.

To achieve this object, the soft-start valve device is constructed such that it can be operated at the same time as the secondary-pressure-controlled operating mode in a timed operating mode that switches the main valve independently of the secondary pressure into the open position independently of the secondary pressure Switching responsible opening force is derived from a pressure medium flowing through a second throttle device.

The soft-start valve device can thus be operated at the same time in two operating modes which functionally overlap one another are. Thereby, the main valve is switched in response to the conditions present on the secondary side individually either on the basis of reaching a predetermined secondary pressure or on the basis of an elapsed since the switch-on time in the maximum flow releasing open position. The soft-start valve device can thus be designed, for example, such that the secondary-pressure-controlled switching represents the normal case, but at the latest at a predetermined time switching takes place by the superimposed time control, even if the secondary pressure has not yet reached the pressure threshold at which it is able to switch the main valve. Decisive for the switching to the open position is thus the time at which either the secondary pressure or the downstream of the second throttle device prevailing pressure has reached a level sufficient to generate the associated opening force. Since the selection of the operating mode ultimately responsible for the switching operation takes place automatically, no external intervention is required during operation of the soft-start valve device, and in particular it is not necessary to convert or even replace the soft-start valve device for adaptation to different applications.

The soft-start valve device can be used wherever one or more of them are being used during commissioning

Consumer, for example, a pneumatically controlled system or machine, a slow pressure build-up is sought. For example, the soft-start valve device may be part of a valve battery combined with a plurality of multi-way valves to form a module. An insert is considered to be particularly advantageous as a component of a preferably modular compressed-air maintenance device. which is used for the treatment of compressed air in compressed air networks. There, the soft-start valve device, in particular if it is designed as a compact valve unit, take over the function of a so-called on-off valve.

Advantageous developments of the invention will become apparent from the dependent claims.

If the first throttle device is designed to be adjustable, the time duration that is normally required can be varied without difficulty until the secondary pressure causing the changeover to the open position has built up.

With an adjustable second throttle device, the absolute time duration can be set variably, after which the switchover to the open position takes place, unless a switchover by the secondary pressure has already been initiated beforehand.

The majority of the applications of soft-start valve devices usually only require a secondary-pressure-controlled mode of operation. If the channel containing the second throttle device and designated as a timing channel is equipped with shut-off means which, if required, permit shutting off the fluid passage, the soft-start valve device according to the invention can be switched to an exclusively secondary-pressure-controlled operating mode if required. The time-controlled operating mode is then shut down.

The blocking means can be designed, for example, in the form of a separate shut-off valve. However, a design in which the adjustable second throttle device directly itself defines the shut-off means is simpler and less expensive. Disabling the timed Operation mode can be effected in this case, that the second throttle device is adjusted so far that it no longer lets fluid through.

In a particularly advantageous design variant, the soft-start valve device is characterized as follows: the main valve is switchable between the closed position, the open position and a soft start position, wherein in the soft start position, the secondary channel connects to the primary channel via a pressure control channel containing the first throttle device and in the Open position, the first throttle device immediate, direct connection between the primary channel and secondary channel unlocks, there is a for influencing the switching position of the main valve serving pilot valve, upon actuation of a fluid pilot signal is generated, which acts on a first actuating surface of the main valve to the main valve of the a basic position forming closed position to switch to the soft start position, - it is also vorh actuatable by the prevailing secondary pressure in the secondary channel switching valve anden, at a predetermined level of the secondary pressure, a second actuating surface of the main valve beaufschl- the pilot valve generated by the fluid pilot signal to switch the main valve from the soft start position to the open position, and the second throttle device is arranged so that at its input the fluid supply pilot signal of the pilot valve is present, while its output is connected to the second actuating surface of the main valve.

The main valve of the soft-start valve device is thus formed at least as a three-position valve, in addition to the functioning as a basic position closing position and the maximum open position can also take a responsible for the soft start phase SoftstartStellung. In the prior art, which is documented, for example, by DE 9105458 U1, the soft-start fluid flow mostly flows through the pilot valve and around the main valve. Now it can pass through the main valve and does not require immediate control by the pilot valve. Responsible for the various switching positions of the main valve is the preferably electrically actuated pilot valve in cooperation with the additional changeover valve. The fluidic pilot signal generated by the pilot valve first switches the main valve from the closed position to the soft start position. If, after a certain period of time, the secondary pressure has reached the desired switching threshold, it causes the switching valve to actuate the fluidic pilot signal of another actuating surface, so that the main valve is then switched from the soft start position into the open position ensuring the maximum flow , Regardless of the pressure build-up in the secondary channel, the second actuation surface of the main valve is constantly acted upon by the flow restricting second throttle device of the fluidic pilot signal and can thereby cause a usually gradual switching to the maximum open position even if the secondary pressure the required switching threshold not reached within a desired time frame.

The switching valve is expediently fluid-actuated bar, wherein the secondary pressure can be switched on directly as a control pressure. Here, the switching valve, for example, work in the manner of a pressure compensator. Alternative would be but also an only indirect activation of the switching valve by the secondary pressure possible by, for example, an electrically activated switching valve is used, the switching signal is generated with the cooperation of a pressure sensor or s pressure switch, which detects the secondary pressure. The latter allows a particularly simple variation of the switching threshold.

Since the secondary pressure does not act directly on itself as the actuating pressure on the main valve, there is a lo decoupling from the switching signal for the main valve supplying pilot signal. As a result, an interconnection is possible in which occurring during the open position in the primary channel and / or in the secondary channel pressure fluctuations do not affect the switching position of the main valve. This i5 allows undisturbed, continuous operation until the pilot valve is switched off.

It is expedient to design the main valve in such a way that, in its closed position, it relieves the secondary channel in terms of pressure, which means that the secondary channel is vented when it is used pneumatically. Relief through the main valve eliminates the use of a separate relief valve or relief through the pilot valve.

One or both throttle devices expediently include an adjustable throttle screw for specifying the respective desired throttling intensity.

The various components of the soft-start valve device are expediently combined to form an assembly. This simplifies handling during installation and deinstalla- tion. The pilot valve is in particular a solenoid valve. However, other electrically activatable valve types can also be used, for example piezo valves or electrostatic valves.

It is expedient if the two actuating surfaces of the main valve point in the same direction. Switching from the closed position to the soft start position and from the soft start position to the open position takes place here with rectified switching movements, which are in particular of a linear type.

The main valve expediently contains a main valve member that can be positioned to predefine its switching positions in a corresponding number of switching positions, in particular in the form of a valve slide. For switching first, the first and then the second actuating surface act in each case drivingly together with the main valve member.

While the responsible for switching to the open position second actuating surface is preferably arranged stationary on the main valve member, which is responsible for switching to the soft start position first actuating surface is conveniently located on a respect to the main valve member separate actuator. This actuator is decoupled from the main valve member such that the latter can be switched without entrainment of the actuating element from the soft start position into the open position. Thus, while switching over from the closed position to the soft start position expediently both actuating surfaces are moved together, the first actuating surface remains when switching to the open position, and the second actuating surface moves away from it. Reason for the aforementioned movement is expediently the presence of a arranged in the adjustment of the actuating element stop surface, which defines the Softstartstel- ment.

The actuating element is preferably designed as an actuating piston. Alternatively, however, would be conceivable, for example, a realization as an actuating diaphragm.

Advantageously, the main valve member is subject to a permanent closing force caused by spring means in the direction of its closed position. After switching to the

Softstart position, the spring means are compressed by a certain amount, whereby the degree of compression increases even further until the open position. After deactivation of the pilot valve, the spring means provide for a provision of the main valve member in the closed position.

The loading of the first actuating surface with the pilot pressure is expediently carried out directly via a control channel controlled by the pilot valve. The actuation of the second actuating surface is expediently carried out via a switching channel branched off from the pilot control channel, in the course of which, in the manner of a parallel connection, the switching valve and the second throttle device are switched on.

The changeover valve expediently contains a movable changeover valve member. This is controlled and actuated on the basis of the secondary pressure. Direct pressurization by the secondary pressure, if required, can be effected, for example, by means of a tapping channel which leads to the secondary channel or to the channel between the secondary channel and the first channel. seleinrichtung extending channel branch of the pressure control channel is connected.

There are applications in which the full primary pressure is needed during the soft start phase parallel to the gradually building secondary pressure. This applies, for example, to the provision of an actuating pressure required for switching valves. In such cases, it is advantageous if an upstream, so lying in front of the first throttle device fluid space is present, which is separated in the closed position of the main valve from the primary channel and connected at least in the soft start position with the primary channel, so that in him during the soft start position of the Primary pressure prevails. A fluid tap channel connected to the fluid chamber then allows an unthrottled fluid tap in the soft start position and expediently also in the subsequent open position.

The invention will be explained in more detail with reference to the accompanying drawings. In this show:

1-3 a preferred embodiment of the softstart

Valve device in a setting for mixed operation with simultaneously activated secondary pressure-controlled operating mode and time-controlled operating mode during different operating phases, wherein the left part of the figure represents a longitudinal section of the valve device in a first plane and wherein the right part of the figure, the upper portion of the valve device in a order 90 ° twisted section plane around the different planes placed on different planes Make components of the valve device more visible,

Fig. 4-6, the same soft-start valve device with deactivated timed mode of operation, again in s several operating phases, and

Fig. 7 is a schematic circuit diagram of the soft start valve device.

In FIGS. 1 to 6, the channels running within the soft-start valve device are shown for the sake of better clarity, partly only as dotted, dashed and solid lines. The dotted lines represent unpressurized channels, while the solid lines represent channels that are currently under pressure. Dotted lines indicate channels are under pressure build-up.

i5 Denoted in its entirety by reference numeral 21

Soft-start valve device is expediently designed as a valve unit, in which all components are summarized in the manner of an assembly. This favors on-site installation and, in particular, integration.

20 on in a modular built, usable for the treatment of compressed air compressed air maintenance device. As an example, the soft-start valve device is designed as a module (maintenance module) of such a compressed air maintenance device and can be combined with other maintenance modules, for example

25 se with a pressure regulator module and / or a filter module. Within a compressed-air maintenance device, the soft-start valve device is used in particular as a so-called switch-on valve, which optionally achieves a complete shut-off or a complete release of a fluid passage.

30 allows, with the release of the fluid passage gradually takes place, so that on the output side, ie on the secondary side, no sudden, but a gradual increase in pressure occurs, which allows easy commissioning of secondary consumers connected.

The soft-start valve device 21, which for the sake of simplicity is also referred to as "soft start valve" below, contains a housing 28, on which a fluidic inlet connection 22 and a fluidic outlet connection 12 are formed. The inlet connection belongs to a primary channel 1 running in the housing 28 and makes it possible to connect one

Pressure source P, which supplies a fluid under pressure under a primary pressure fluid, which is in particular compressed air. Alternatively, the soft start valve 21 can also be operated with another gas or with a liquid pressure medium.

The outlet connection 12 belongs to a secondary channel 2 extending in the housing 28, via which the pressure medium fed in via the primary channel 1 leaves the soft-start valve 21, standing at a secondary pressure, in order to be supplied to one or more consumers (not shown). The at least one consumer is, for example, a drive operated by fluid power, a valve device or other components operated with a fluid.

In a non-illustrated embodiment, the soft start valve 21 is designed as a component of a valve battery. The valve battery includes a one-piece or multi-part fluid distributor, which is equipped with a plurality of electrically operable control valves and which is additionally equipped with the soft start valve 21. The fluid distributor is used to control the control valves. fed pressure medium. The soft-start valve 21 is functionally connected upstream of the control valves in such a way that, when the valve battery is put into operation, a gentle fluid admission of the control valves takes place, so that damage or malfunctions are avoided. The soft-start valve can be mounted on the outside of the fluid distributor, but integration is also possible.

The exemplary soft start valve 21 is functionally divided into a plurality of individual valves, which, however, are expediently combined to form a uniformly manageable assembly. Here, the soft start valve 21 includes a main valve 24, a pilot valve 25 and a switching valve 26th

As further essential components, the soft-start valve 21 includes a first throttle device 38, which is responsible for a secondary pressure-controlled operating mode, and a second throttle device 39, which is primarily responsible for a purely timed operating mode. These throttle devices 38, 39 are also conveniently housed in the housing 28.

The soft-start valve 21 is activated by the pilot control valve 25, which can act on the main valve 24 indirectly and indirectly, with the interposition of the switching valve 26 and the second throttle device connected in parallel therewith, by one of a total of three possible switching positions of the Main valve 24 pretend.

The pilot valve 25 is in particular of the electrically actuated type and has an electrical interface 27, via which it can be supplied with the required electrical actuation signals. In the housing 28 of the soft start valve 21 is an elongated, exemplary vertically aligned cavity defining a valve member receptacle 32. The valve member receptacle 32 includes an elongated, in the direction of its longitudinal axis 31 linearly displaceable main valve member 33. In the context of one of the longitudinal axis 31 following, indicated by a double arrow switching movement 34, the main valve member 33 and thus the main valve 24 can be switched between a total of three switching positions to be explained in more detail , The main valve member 33 is designed in particular in the manner of a valve spool.

By means arranged in the valve member receptacle 32 fixed to the housing sealing means 35, which consist for example of a plurality of axially spaced apart annular sealing elements which coaxially surround the main valve member 33, the valve member receptacle 32 is divided into a plurality of axially successive sections 36a, 36b, 36c, of which in each case a valve channel passing through the valve housing 28 goes off. These valve channels are the primary channel 1, the secondary channel 2 and a further channel, which is connected within the housing 28 with the secondary channel 2 and which is designated as a pressure control channel 3.

The communicating with the primary channel 1 first portion 36a of the valve member receptacle 32 is located axially between the communicating with the secondary channel 2 second portion 36b and communicating with the pressure control channel 3 third portion 36c.

In the course of the pressure control channel 3, the first throttle means 38 are turned on. They limit the fluid flow through the pressure control channel 3 according to the predetermined throttling intensity. By the first throttle device 38 With regard to the throttling intensity which can be predetermined by it, the flow rate for the pressure control channel 3 can be set variably as required. By way of example, the first throttle device 38 includes a throttling screw 38a accessible from an outer surface of the housing 28.

The longitudinal section of the main valve member 33 located within the sections 36a, 36b, 36c forms a control section 42 cooperating with the sealing means 35. It is graduated in its longitudinal direction and contains alternately arranged regions of larger and smaller diameter. Depending on whether a region of larger diameter or a region of smaller diameter is arranged at the same axial height with one of the sealing elements of the sealing means 35, the sections of the valve member receptacle 32 arranged axially on either side of the corresponding sealing element are separated from one another or fluidly connected to one another.

On the control section 42, on the side of the third section 36c of the valve member receptacle 32 connects to an An¬ 2o drive section 43 of the main valve member 33 at. At this grip spring means 44, which bias the main valve member 33 in the direction of one of Figures 1 and 4 apparent closed position. This closed position is the basic position of the soft-start valve 21.

The spring means 44 are preferably designed as a compression spring device, which expediently encloses the drive section 43 coaxially. It is supported at one end - in the drawing with its lower end - on the housing 28 and at the other end - with its end lying in the drawing - at the main

30 valve member 33. Thus, the main valve member 33 by the spring force of the spring means 44 constantly - in the drawing directed above - acted upon in the direction of its closed position.

By executing the switching movement 34, the main valve member 33 can optionally be positioned in the closed position shown in FIGS. 1 and 4, in the soft start position shown in FIGS. 2 and 5, or in the maximum open position shown in FIGS. 3 and 6. These positions differ in a different interconnection of the valve channels 1, 2, 3 through the Steuerab- lo cut 42. If the timed mode of operation is effective, intermediate positions of the main valve member 33 between the soft start position and the maximum open position are possible (indicated by dash-dotted lines in Figure 2) ,

In the closed position apparent from FIGS. 1 and 4, the secondary channel 2 is completely separated from the primary channel 1.

Also, the fluid passage through the pressure control channel 3 is shut off here. Conveniently, the secondary channel 2 is in the closed position, however, connected to a discharge channel 4 of the main valve 24, so that a pressure relief of the 2o secondary channel 2 takes place. If compressed air is used as the pressure medium, the relief channel 4 forms a venting channel, to which a silencer not shown in the drawing can be connected if required.

It is useful if the discharge channel 4 opens into coaxial extension 25 of the valve member receptacle 32 at one end face of the housing 28.

If the soft-start valve 21 is operated in the purely secondary-pressure-dependent operating mode according to FIGS. 4 to 6, the secondary channel 2 is in the soft-start position shown in FIG. 5 exclusively via the pressure control channel 3, and thus across the first throttle device 38, with the primary channel 1 in conjunction. The connection is here released between the first and third sections 36a, 36c of the valve member receptacle 32. A direct connection between primary channel 1 and secondary channel 2, bypassing the pressure control channel 3, does not exist.

If both operating modes are active, in addition to the connection via the pressure control channel 3, a direct connection between the secondary channel 2 and the primary channel 1 via the first and second sections 36a, 36b of the valve member receptacle 32 can also be present in the soft start position shown in FIG. In this last-mentioned direct connection, however, the maximum flow cross-section is not yet released, so that only throttled overflow of the pressure medium takes place, which is illustrated by the dashed arrow flow arrow 30.

In the soft start position, the secondary channel 2 is separated from the discharge channel 4.

Finally, in the open position shown in FIGS. 3 and 6, via the two directly interconnected first and second sections 36a, 36b of the valve member receptacle 32 there is a direct connection between primary channel 1 and secondary channel 2 permitting the maximum flow, bypassing the pressure control channel 3 and this Associated first throttle device 38. Thus results in the secondary channel 2, a secondary pressure corresponding in height to the primary pressure.

In the open position, the connection between primary channel 1 and secondary channel 2 via the pressure control channel 3 expediently additionally remains as a parallel connection. Due to the throttling that takes place, however, the associated flow rate is substantially lower than that of the direct main flow bypassing the pressure control channel 3.

Even in the open position of the discharge channel 4 is still separated from all other valve channels.

The main valve 24 includes a first (46) and a second (47) actuating surface, each drivingly cooperating with the main valve member 33.

The first actuating surface 46 is located on an independent with respect to the main valve member 33 actuating element 48 which is exemplified in the manner of an actuating piston and which is received axially after the drive portion 43 of the main valve member 33 in the Ventilgliedauf- receiving 32. The first actuating surface 46 has axially away from the main valve member 33, in the drawing upwards.

The actuating element 48 is slidably mounted in the direction of the longitudinal axis 31 of the main valve member 33 in a receiving chamber 52 formed by the end portion of the valve member receptacle 32. With its peripheral wall, it is in sealing contact. The end faces of the receiving chamber 52 form a main stopper 33 facing the first stop surface 53 and an oppositely oriented second stop surface 54 for the actuator 48, which limit the adjustment.

Instead of actuating piston 48, the actuating element 48 could for example be designed as an actuating diaphragm. The second actuating surface 47 is axially fixed to the main valve member 33. It therefore makes every linear movement of the main valve member 33 with. It points in the same direction as the first actuating surface 46, in the present case, therefore, away from the control section 42.

Preferably, the second actuating surface 47 is located on the end face of the main valve member 33 facing the actuating element 48.

Moves the main valve member 33 in the direction of the lo closed position, it dives with its second actuating surface 47 having end portion in the receiving chamber 52 (Figures 1 and 4). In addition, the main valve member can take the other apparent from the drawing positions in which it is completely moved out of the receiving chamber 52 i5 and the second actuating surface 47 having end portion in a subsequent to the receiving chamber 52 longitudinal portion 55 of the valve member receptacle 32 is the Cross section is smaller than that of the receiving chamber 52. Accordingly, the second 20 actuating surface 47 is advantageously smaller than the first actuating surface 46th

As long as the main valve member 33 protrudes into the receiving chamber 52, oriented in the direction of the switching movement 34 power transmission between the main valve member 33 and Be

25 actuating element 48 possible. However, these two parts are only loosely against each other, so that only oppressive restoring forces are transferable. On the other hand, this makes it possible for the main valve member 33 to lift off the actuator 48 and to move away from it, and then

At the same time the distance between the two actuating surfaces 46, 47 changed. The above-mentioned spring means 44 are arranged locally between on the one hand the two actuating surfaces and on the other hand the control section 42 on the drive section 43 of the main valve member 33.

By way of example, the spring means 44 are based on the main valve member 33 on a preferably sleeve-shaped head piece 57, on which the second actuating surface 47 is expediently formed.

The actuating element 48 subdivides the receiving chamber 52 into a first actuating chamber 62 lying on the side opposite the main valve element 33 and a second actuating chamber 63 lying on the side facing the main valve element 33. The first actuating chamber 62 is opposite the actuating element 48 through the first stop surface 53 limited. The second actuating chamber 63 has, axially opposite the actuating element 48, via a rigid boundary wall formed by the second stop surface 54 and also via an axially movable boundary wall, which is formed by the main valve member 33 and the second actuating surface 47. With a corresponding position of the main valve member 33, thus, the second actuating chamber 63 may extend a little way into the adjoining the receiving chamber 52 longitudinal portion 55 of the valve member receptacle 32 in, as can be seen from Figures 3 and 6.

A fluidic pilot channel 64 branches off from the primary channel 1 and ends in the first actuating chamber 62. In the course of this pilot channel 64, the pilot valve 25 is switched on, so that the pilot channel 64 is connected to a pilot valve communicating with the primary channel 1. Supply channel 64a and a communicating with the first actuating chamber 62 pilot working channel 64b is divided.

If necessary, an auxiliary valve 69 enabling manual activation of the soft-start valve can be switched on in the course of the pilot-control working channel 64b, allowing the fluid passage through the pilot-control working channel 64b to be unrestricted in the basic position shown in the drawing.

Specifically, the pilot valve 25 is a 3/2-way valve capable of connecting the pilot working passage 64b to either the pilot feed passage 64a or to a pilot relief vent passage serving to relieve the pressure in the interior of the pilot valve 25 extends and is not shown in the drawing. When operated with compressed air, the pilot exhaust passage opens expediently directly to the atmosphere.

The switching valve 26 includes a preferably linear, according to double arrow 66 movable Umschaltventilglied 67. A preferred mechanical spring means 68 generates a spring force by which the switching valve member 67 is biased in the direction of one of Figures 1 to 5 apparent starting position. The starting position is predetermined by the installation of the changeover valve member 67 on a stop section 72 fixed to the housing. In addition or as an alternative to the mechanical spring device 68, a gas spring device, in particular an air spring device, could also be used.

Together with the housing portion surrounding it, the switching valve member 67 axially delimits a control chamber 73 which is constantly connected to the secondary channel 2 via a tap channel 74. This connection can take place directly as shown, but also by connecting the tap channel 74 to the channel branch of the pressure control channel 3 extending between the first throttle device 38 and the secondary channel 2.

Thus prevails in the control chamber 73 constantly the current secondary pressure. This exerts on the changeover valve member 67 a switching force which is opposite to the spring force of the spring means 68.

A switching channel 75 is connected at one end to the pilot control working channel 64 and at the other end to the second actuating chamber 63. The switching valve 26 and the second throttle device 39 are integrated in parallel in the Ver i run the Umschaltkanals 75. More specifically, the switching channel 75 branches between its input portion 75a connected to the pilot working channel 64b and its output portion 75b connected to the second actuating chamber 63 into two parallel-connected ones

20 first and second branch portions 75c, 75d, wherein in the first branch portion 75c, the switching valve 26 and in the second branch portion 75d, the second throttle device 39 is turned on.

Since the second branch section 75d includes the second throttling device 39 responsible for the timed operating mode, it is also referred to below as the "timing channel".

The switching valve 26 is capable of controlling the fluid passage through the first branch portion 75c. In the off-30gangstellung of Umschaltventilgliedes 67 is the connection interrupted. If the changeover valve member 67 is displaced by a sufficiently high switching force into the switching position shown in FIG. 6, the fluid passage through the switching channel 75 is released. In the exemplary embodiment, the switching force also has to overcome the pressure force resulting from the fluidic precontrol signal, which acts in the same direction as the spring device 68 on the changeover valve member 67.

The second throttle device 39 is expediently designed to be adjustable with respect to the throttling intensity which can be predetermined by it. As an example, it contains as an adjustable throttle element an externally accessible throttle screw 39a.

The pressure medium diverted from the pilot-control working channel 64b into the switching channel 75 can flow over into the second actuating chamber 63, irrespective of the switching position of the switching valve 26, via the second throttle device 39. The flow rate depends on the set throttling intensity. Accordingly, the set duration of the pressure build-up in the second actuation chamber 63 is predetermined by the set throttling intensity.

In the preferred embodiment, the second throttle device 39 also takes over the additional function of shut-off means 70, through which the fluid passage through the timing channel 75d can be completely shut off. By way of example, this happens simply in that the throttle screw 39a is screwed into a closed position. In an exemplary embodiment which is not shown in more detail, the shut-off means are formed by a shut-off valve, which is provided in addition to the second throttle device 39, and which is provided in one Series connection with the second throttle device 39 is incorporated into the timing channel 75d.

One possible mode of operation of the soft-start valve device 21 is explained below with reference to FIGS. 4 to 6, wherein the second throttle device 39 assumes a shut-off position, so that the fluid passage through the timing channel 75d is blocked. The soft-start valve device 21 is in this way exclusively in a secondary-pressure-controlled operating mode. The time-controlled operating mode has been shut down.

It is assumed that the pilot valve 25 is deactivated and the main valve member 33 is in the closed position shown in FIG. As a result, the secondary channel 2 is depressurized, as well as the consumers possibly connected thereto. Via the inlet connection 22, a pressure medium which is under a primary pressure is fed in, which thus also rests in the pilot-control feed channel 64a. The two actuating chambers 62, 63 are vented via the pilot valve 25.

To switch on the soft-start valve 21, the pilot valve 25 is actuated via a supplied electrical control signal. The pilot valve 25 opens the passage through the pilot channel 64, so that a primary pressure corresponding fluid pilot signal is fed via the pilot working channel 64b away in the first actuating chamber 62 and there applied to the first actuating surface 46. The actuating force resulting therefrom displaces the actuating element 48 until it abuts against the second stop surface 54, whereby it acts on the main valve element 33 on its second actuating surface 47 and carries the spring means 44 while overcoming the spring force. Does the actuation element 48 reaches the second stop surface 54, the main valve member 33 is in the apparent from Figure 5 soft start position.

In this case, the switching valve member 67, which still occupies the initial position, keeps the second actuating chamber 63 separated from the pilot control channel 64.

Starting with the switching of the main valve 24 to the soft start position, a soft start phase lasting a certain time begins. This is characterized in that flows over the enabled pressure control channel 3 away with throttled flow pressure medium in the secondary channel 2, so that the prevailing secondary pressure gradually increases. The gradient of the pressure increase can be varied via the setting of the first throttle device 38.

About the tap channel 74 is the current secondary pressure in the control chamber 73 of the switching valve 26 at. Accordingly, as the secondary pressure increases, the switching force applied to the change-over valve member 67 increases, but this has no effect as long as a threshold value defined by the spring means 68 and the fluid pressure applied via the input portion 75a is not reached.

When this threshold is reached, the soft start phase ends. The switching force is now sufficiently large to displace the switching valve member 67 into the switchover position shown in FIG. 6, with the result that the fluidic pilot signal passes through the now opened first branch section 75c of the switching channel 75 also in the second actuating chamber 63 and thus pending on the second actuation surface 47. As a result, this shifts Main valve member 33 continues into the apparent from Figure 6 open position, wherein the actuator 48 remains in place. Since the cross section of the longitudinal section 55 is smaller than that of the first actuating chamber 62, s acts on the actuating element 48 a differential force, which holds it in abutment against the second stop surface 54.

By switching to the open position, the secondary channel 2 is supplied with pressure medium from the primary channel 1 via the large flow cross-section, which is now maximally released by the main valve member 33, that is to say with the first throttle device 38. As a result, the secondary pressure increases in the shortest possible time up to the level of the primary pressure.

In order to return to the basic position, only the pilot valve 25 is to be switched off, so that the pilot control working channel 64b is pressure-relieved. The spring means 44 then displace the main valve member 33 back into the closed position.

The spring means 68 of the switching valve 26 may be formed adjustable in terms of their spring force. This allows a variation of the switching threshold. In general, the switching valve 26 will be designed so that the switching threshold is at a secondary pressure which corresponds to half of the primary pressure.

The particular advantage of the soft-start valve 21 is that it can be operated according to FIGS. 1 to 3 in a manner in which a time-controlled operating mode is superimposed on the second-pressure-controlled operating mode just described with reference to FIGS. 4 to 6. The timed mode of operation is active in addition to the secondary pressure controlled mode of operation 30 when fluid flow through the timing channel 75d through is possible. For this purpose, in the exemplary embodiment, only the second throttle device 39 is to be adjusted so that it no longer completely shuts off the timing channel 75d, but allows flow with a flow rate corresponding to the selected on position.

In the combined time and secondary pressure-controlled operation according to FIGS. 1 to 3, on the one hand, the processes described above with reference to FIGS. 4 to 6 take place. The further description can therefore be limited to the time-dependent factor.

In the closed position according to FIG. 1, there is no functional difference to the state of FIG. 4, since the fluidic pilot channel 64 is depressurized.

After switching to the soft start position according to FIG. 2, pressure medium flows from the inlet section 75a of the switching channel 75 through the timing channel 75d into the outlet section 75b and from there into the second actuating chamber 63. In accordance with the flow rate permitted by the second throttle device 39, a gradual pressure increase occurs the second actuating chamber 63, so that the main valve member 33 is continuously displaced in the direction of its maximum open position, which is indicated by dash-dotted lines at 33a by way of example with reference to some intermediate positions. In this gradual displacement into the open position, the flow cross section between the two sections 36a, 36b of the valve member receptacle 32 is increasingly released, so that in this way a throttled overflow into the secondary channel 2 takes place, in addition to the flow taking place in parallel through the pressure control channel 3 through. It is understood that the movement of the main valve member 33 in the direction of the open position only begins after the pressure in the second actuating chamber 63 is sufficiently high to overcome the restoring force of the spring means 44.

If the secondary pressure does not reach the switching threshold required to actuate the switching valve 26 even after a relatively long time, the main valve member 33, after only a certain time, arrives at the maximum flow between the pressure medium via the second throttle device 39 both sections 36a, 36b releasing open position. The actual switching time depends on the throttling intensity of the second throttle device 39.

However, if the secondary pressure increases within the time window prescribed by the two-fifth throttle device 39 to the level of the switching threshold for the switching valve 26, the latter is switched to the working position in the manner described above with reference to FIGS. 4 to 6, regardless of the time elapsed so far. As a result, the flow through the first branch section 75c is released, so that the pressure medium from the pilot control working channel 64b, in addition to the fluid flowing through the timing channel 75d, can also, but now unthrottled, flow into the second actuating chamber 63 via the first branch section 75c. This then leads to a virtually sudden changeover to the open position of the main valve 24 which releases the maximum flow.

In the mode of operation with superimposed operating modes, the switching of the main valve 24 into the open position which opens the maximum flow rate is ultimately determined by the pressure which first causes the switching over. has reached the threshold, either the tapped over the tap channel 74 secondary pressure or in the second actuating chamber 63 constituting actuation pressure.

In the exemplary embodiment, the pressure prevailing in the secondary duct 2 pressure is the switching valve 26 switched directly as the switching force supplying control pressure. Alternatively, however, it would also be possible to form the changeover valve 26 in an electrically operable manner, wherein the electrical changeover signal is generated with the assistance of a pressure sensor or pressure switch which detects the secondary pressure.

Finally, let us briefly discuss the optional auxiliary valve 69. This has an auxiliary valve member 77, which is turned on in the course of the pilot control working channel 64b and allows in the normally occupied, from the drawing i-apparent unactuated basic position a free passage through the pilot control working channel 64b and at the same time a continuous connection between This pilot-control working channel 64b and the input portion 75a of the switching channel 75th

The auxiliary valve 69 is connected to the primary channel 1 or the section 36a of the valve member receptacle 32 via one auxiliary control channel 78 indicated only by dot-dash lines, whereby this auxiliary control channel 78 is shut off in the normal position by the auxiliary valve 695.

The auxiliary valve 69 enables activation of the soft-start valve 21 when the pilot valve 25 is not actuated, that is to say when the pilot-control working channel 64b is depressurized. By means of arrow 79, manual switching of the auxiliary valve 69 3o into an actuated working position becomes a fluid connection between the auxiliary control channel 78 and the input portion 75a of the switching channel 75, which allows operation as well as if the fluidic pilot signal would be present.

5 The auxiliary valve 69 is suitably self-resetting. It returns automatically to the normal position when the liquid-phase pilot control signal is applied by operation of the pilot control valve 25 in the channel branch of the pilot control working duct 64b extending between the auxiliary valve 69 and the pilot control valve 25. This acts on the

Auxiliary valve member 77 opposite to the arrow 79 and moves it back to the normal position. Thus, a manual reset of the auxiliary valve 69 is unnecessary in the unactuated Grundste1lung.

An advantage of the described valve assembly is also in the insensitivity of the soft-start valve 21 to pressure fluctuations in the primary channel 1 or secondary channel 2. Should because of a pressure drop acting on the switching valve 26 switching force so far drop that the switching valve 26 in

20, the initial position switches back, this does not affect the open position of the main valve member 33, because the pilot chamber located in the second actuating 63 remains imprisoned and can not escape. If the time-controlled operating mode is active at the same time, it is also available

25 constantly on the second throttle device 39 pressure medium in the second actuating chamber 63, which maintains the open position of the main valve member 33.

Finally, reference should be made to an advantageous equipment variant of the soft-start valve device 21, which is merely indicated in FIG. This variant provides a Fluidabgriffskanal 80, the one end in an upstream the first throttle device 38 opens existing fluid space, which is exemplified by the upstream of the first throttle device 38 lying input side channel portion 3a of the pressure control channel 3. Alternatively, this fluid space could also be the section 36c of the valve member receptacle 32. In any case, it is a fluid space which is separated in the closed position of the main valve from the primary channel 1, but immediately with the beginning of the soft start phase directly, via the portion 36 a, is connected to the primary channel 1.

With its opposite end, the fluid tapping channel 80 leads to the outer surface of the housing 28, where connecting means (not shown in greater detail) are associated with it, which make it possible to connect a fluid line leading to a consumer. The consumer is, for example, the pilot valve of a pilot operated multiway valve.

The effect of this optional design is that immediately above the fluid tap channel 80, the full primary pressure can be tapped when the main valve 24 is switched to the soft start position. Regardless of the gradual pressure build-up in the secondary channel 2, a consumer connected to the fluid pick-up channel 80 can then be supplied with the uncommon primary pressure immediately. The soft-start valve device 21 then outputs a throttled and an unthrottled pressure medium simultaneously and independently of one another.

Claims

claims

1. Soft-start valve device, having a primary channel (1) leading between a pressure medium under a primary pressure and a secondary channel (2) connected to the main valve (24).

5 opening channel (1) and secondary channel (2) separating the closed position in this connection for maximum flow releasing open position is switchable, the responsible for this switching opening force in a secondary pressure-controlled operating mode of the valve device of the lo in the secondary channel (2) gradually building Secondary pressure of the pressure medium is derived, which flows through a first throttle device (38) away from the primary channel (1) in the secondary channel (2), characterized in that the valve device at the same time superimposed on the Sekundärdruckgesteuer- i5 th operating mode in a mode of operation, the Main valve (24) independent of the secondary pressure purely time-dependent in the open position switching time-controlled operating mode is operable, wherein the responsible for this time-dependent switching opening force of a through

20, a second throttle device (39) is flowed through the pressure medium.

2. Soft-start valve device according to claim 1, characterized in that the second throttle device (39) in a timing channel (75d) is arranged, wherein blocking means

25 (70) are present, which is a shut-off of the fluid passage through this timing channel (75d) to turn off the timed operation mode.

3. soft-start valve device according to claim 2, characterized in that the blocking means (70) of the in a Ab-

5 blocking position adjustable second throttle device (39) are formed.

4. soft-start valve device according to one of claims 1 to 3, characterized in that the first throttle device (38) is formed in terms of adjustable by them choke o intensity.

5. soft-start valve device according to one of claims 1 to 4, characterized in that the second throttle device (39) is designed to be adjustable with respect to the choke intensity predetermined by them. s

6. soft-start valve device according to one of claims 1 to 5, characterized in that the main valve (24) is biased by a spring means (44) caused closing force in the closed position or prestressed.

7. soft-start valve device according to one of claims 1o to 6, characterized in that the secondary channel (2) in the closed position of the main valve (24) is connected to a discharge channel (4).

8. soft-start valve device according to one of claims 1 to 7, characterized by the following features: 5 - the main valve is switchable between the closed position, the open position and a soft start position, wherein it in the soft start position the secondary channel (2) via a first throttle device ( 38) containing pressure control 3) with the primary channel (1) connects and in the open position a first throttle device (38) immediate, direct connection between the primary channel (1) and secondary channel (2) unlocks,

5 - there is a pilot valve (25) serving to influence the switching position of the main valve (24), upon actuation of which a fluid pilot signal is generated, which acts on a first actuating surface (46) of the main valve (24) to move the main valve (24). It is also possible to switch from the closed position to the soft start position; a secondary valve (26), which can be actuated by the secondary pressure prevailing in the secondary channel (2), generates the fluid pilot signal generated by the pilot valve (25) at a predetermined level of the secondary pressure a second actuating surface (47) of the main valve (24) switches to switch the main valve (24) from the soft start position to the open position, the second throttle device (39) is connected so that at its input the fluid pilot signal is applied

20 and its output is connected to the second actuating surface (47).

9. soft-start valve device according to claim 8, characterized in that the main valve (24), the pilot valve (25), the switching valve (26) and the two Drosseleinrich-

25 lines (38, 39) are combined to form an assembly.

10. soft-start valve device according to claim 8 or 9, characterized in that the pilot valve (25) is an electrically actuated valve, in particular a solenoid valve.

11. Soft-start valve device according to one of claims 8 to 10, characterized in that the two actuating surfaces (46, 47) point in the same direction.

12. Soft-start valve device according to one of claims 8

5 to 11, characterized in that the three switching positions of the main valve (24) are predetermined by corresponding switching positions of a movable main valve member (33), wherein the first and the second actuating surface (46, 47) is each designed to be drivably connected to the main lo valve member (33) cooperate.

13. Soft-start valve device according to claim 12, characterized in that the first actuating surface (46) is formed on a relative to the main valve member (33) separate actuating element (48) which upon application of i5 by the fluidic pilot signal with entrainment of the main valve member (33). until it rests against a stop surface (54) which predetermines the soft start position, with the main valve element (33) being removed from the actuating element (48) when it subsequently passes through the stop element (54)

20 fluid loading of the second actuating surface (47) is moved further in the direction of the open position.

14. Soft-start valve device according to claim 13, characterized in that the actuating element (48) is axially connected following the linearly displaceable main valve member (33).

25 is arranged and loosely applied to the main valve member (33) in a manner permitting only the transmission of pressing actuating forces.

15. soft-start valve device according to claim 13 or 14, characterized in that the actuating element (48) kol-

30 benartig formed.

16. soft-start valve device according to one of claims 12 to 15, characterized in that the second actuating surface (47) fixed to the main valve member (33) is arranged.

17. Soft-start valve device according to claim 16, characterized in that the second actuating surface (47) moves away from the first actuating surface (46) when the main valve (24) is switched from the soft start position to the open position.

18. Soft-start valve device according to one of claims 12 to 17, characterized in that the first actuating surface (46) delimits a first actuating chamber (62) which is provided with a pilot control channel (64) which supplies the fluidic pilot signal and is controlled by the pilot valve (25) ) communicates.

19 19. Soft-start valve device according to one of claims 8 to 18, characterized in that a to the second actuating surface (47) leading switching channel (75) is present, which communicates with the fluidic pilot signal supplying pilot channel (64) and in its course , in

Parallel connection, the switching valve (26) and the second throttle device (39) are turned on.

20. Soft-start valve device according to claim 19, characterized in that the second actuating surface (47) delimits a second actuating chamber (63) connected to the switching

25 channel (75) communicates.

21. soft-start valve device according to one of claims 8 to 20, characterized in that the switching valve (26) has a biased by a holding force in an initial position switching valve member (67), the opposite sets to the holding force of one of the in the secondary channel (2) prevailing secondary pressure dependent switching force is applied.

22. soft start valve device according to claim 21, characterized

5 characterized in that the switching valve member (67) controls the passage of fluid through a switching channel (75), which at one and the same time can be acted upon by the pilot fluidic signal of the pilot valve (25) and at the other end leads to the second actuating surface (47), such that the fluid passage lo is shut off in the initial position of the changeover valve member (67) and is released when a changeover valve member (67) deflected due to the reaching of a secondary pressure of a predetermined level into a changeover position.

23. soft start valve device according to claim 21 or 22, i5 characterized in that the holding force is supplied by a spring means (68).

24. Soft-start valve device according to one of claims 8 to 23, characterized in that in the secondary channel (2) prevailing secondary pressure the changeover valve (26) directly

20 is itself connected as serving to bring about the switching force control pressure.

25. Soft-start valve device according to one of claims 8 to 24, characterized in that an upstream of the first throttle device (38) lying fluid space (3a) is present 5, separated in the closed position of the primary channel (1) and at least in the soft start position with is connected to the primary channel (1) and which is in communication with a Fluidabgriffska- channel (80), which allows during the soft start phase, an unthrottled fluid tap.

26. soft-start valve device according to one of claims l to 24, characterized in that it is part of a compressed air maintenance device.