FR2561798A1 - Pressure reducing valve with progressive pressurising - Google Patents

Abstract

Pressure reducing valve with progressive pressurising for a pneumatic installation comprising actuators, especially jacks. The spring 30 of a pressure reducing valve 25 is slowly compressed by the increasing force of the piston 2 of the jack which is supplied with pressure from the network through a flow rate reducer 5 and a microvalve 13. The deflection given to the spring, its force and consequently the downstream pressure, result from the adjustment on the stem 9 of the control wheel 8 limiting by abutment the working stroke of the piston. A pressure leak sampled downstream is then shut off and a signal appears at 7. Removing the control of the microvalve 13 gives rise to the return of the piston 2 to the rest position and, by opening the discharge channel 31, emptying the installation to the atmosphere. Application to pneumatics technology.

Description

the devices called soft starters are used in pneumatic technology for the gradual re-pressure of instations comprising jacks, which, having been moved during the air cut-off, then very slowly return to their end-of-travel position. These devices include a valve or a distributor with 2 orifices-2 positions, normally closed, and a flow reduction nozzle mounted in bypass; this allows to fill gradually by the low flow, the downstream installation until the value of the pressure y prevailing is sufficient to open the valve and allow full flow: this pressure threshold is generally close to half of the pressure upstream and determined by the force of the return spring when closing the valve or by the coefficient of internal amplification of a YES cell used for its opening control. A distributor q 30rifices-apositions called disconnector and placed between the pressure regulator and the start soft ripper, allows the installation to be emptied into the atmosphere; the soft starter then moves to the reduced flow position for future filling.

It is understood that this process has drawbacks, the capacities of the installations being extremely variable, different passage nozzles are offered to the user. This choice remains very difficult for an installation comprising cylinders of very different volumes and loads, each of '' between them resuming its position with a speed dependent on a predetermined flow. It often happens that jacks carrying vertical loads cannot take their place during the progressive pressurization, the pressure which is necessary for them being higher than the threshold of full opening of the soft starter; they then resume their position very abruptly. On the other hand, no indication is given, other than by reading pressure gauges, that the pressure set at the regulator is well established in the installation and a premature start is always possible.

The present invention combines in the same device the functions of pressure regulator, progressive pressurization device, and disconnector. It allows pressurization in a progressive and continuous manner in a time independent of the capacity of the installation, without abrupt threshold of the zero pressure at the set pressure, and the emission of a pneumatic signal indicating that this set pressure is reached downstream.

The progressive pressure regulator according to the invention consists of a conventional regulator with automatic decompression, the spring of which is gradually put under stress by a jack. pneumatic single acting, supplied through a flow restrictor adjustable or not, by the pressure taken upstream or downstream of the device. Your device allows by an adjustment to limit at will the deflection of the spring and consequently its force and the value of the pressure admitted downstream which depends directly on it.

The pressure admitted into the cylinder of the device can be established or emptied into the atmosphere by a micro-valve 3 orifices-2 positions, monostable or bistable, manual, pneumatic or electric control placed between the flow restrictor and the cylinder, or any other component such as a logic cell or a time delay, capable of canceling the spring force of the regulator, causing the emptying of the installation through the device's automatic discharge device, network pressure being able to be present at its entry the other characteristics and advantages of the invention will be better understood on reading the description which follows of several embodiments and with reference to the accompanying drawings.

Fig Ia, IbiIc are sections of a pressure reducer with progressive pressurization shown in Fig Ia during operation, in Fig Ib in the end of work position, the set pressure being reached downstream, and on the Fig Ic in the installation emptying position.

According to Fig I, the progressive pressure regulator com takes the conventional elements of a regulator contained in its body 25, a membrane 28 subjected on one side to the force of a spring 30, and on the other side to that of the pressure passing through the device or admitted downstream; the fluid flow is controlled by a valve 29 which follows the changes in the membrane as a function of the balance of these two forces. network is permanently applied to the inlet port 26 and its flow is interrupted by closing the valve 29 when the force of the downstream pressure exiting at the port 27 balances that of the spring 30;
According to the present invention, the device comprises a pneumatic cylinder I with a single effect, the piston 2, of a section close to that of the membrane 28, slides in its cylinder 3 closed by the bottom 4 by transmitting its force to the spring 30 .The network pressure taken from inlet 26 is directed through an adjustable flow restrictor 5, towards the inlet of a micro-valve I3 with 3 orifices - 2 positions, and of the outlet of the micro-valve at I5 practiced in the bottom 4 of the cylinder I. Following Fig Ia, the microvalve I3 being on, the low flow rate of the network pressure controlled by the reducer 5 penetrates by the input I5 cyans the cylinder whose piston2 performs its stroke at a speed which depends on the adjustment of the gearbox 5. The spring 30 is gradually compressed and the valve 29 opens to admit a flow of fluid towards the instation as a function of the force of the spring. cOurse end position causes downstream pressure drop recorded by the membrane which tends to reduce the flow, while the continuous increase in the force of the spring tends to the opposite effect, the result leading to a certain stability of the driving pressure of the jack. According to Fig Ib, the piston 2 is arrived at its work limit stop. In this position, the deflection and the force of the spring 30 is determined by the distance between this stop and the body 25 of the device, which is adjusted using the nut 6 pressure adjustment, which, retained in the guide tube 32 of the piston 2 by a clip and free in rotation, is screwed on the cylinder 3. The cylinder 3 is immobilized in rotation during the adjustment of the nut 6 by a guide light 23 formed in its wall along a generator, into which a lug 24 integral with the tube 32 penetrates. The piston 2 carries two lip seals 21 and 22 and in its end-of-travel position as shown, the active seal 21 having exceeded the entire section of the orifice 7 formed in the wall d u cylinder 3, the fluid admitted into the jack is withdrawn from this orifice as a signal indicating that the pressure adjusted by the nut 6 is reached at the downstream outlet 27.

This signal authorizes for example the start of the pneumatic cycle of the installation. The seal 22 of the piston prevents the pressure in the cylinder I from being lost to the atmosphere during the movement of the seal 21 in front of the orifice 7. According to Fig Ic, an emptying order has opened the micro-valve I3 in purge and the fluid contained in the jack I instantly empties into the atmosphere: its piston 2, under the action of the spring 30 returns to its rest position and the orifice 7 is connected to the atmosphere. The pressure admitted into the installation lifts the diaphragm 28 in the absence of spring force 30 it escapes to the atmosphere through the axial channel 31 of the diaphragm plunger 28 and the lumen 23 of the cylinder 3 of the jack. network pressure being always present at the inlet 26 of the device, the valve 29 pressed against its seat by this pressure does not open.

Fig 2 is the sectional view of a variant of the model previously described according to Fig I shown in purge of the installation, in which the adjustable flow regulator is replaced by a fixed calibration nozzle 5. The working stroke speed of the piston 2 is regulated by the position in the cylinder 3 of a piston 34 equipped with a seal 37 and modifying the capacity of the chamber of the jack I. A screw 35 secured to the piston 34 screwed into the fixed base 4 allows the with the aid of an external control 36 to ensure movement.

Fig 3 is the sectional view of a variant of the model previously described according to Fig I and shown in the position where a partial purge of the installation has been carried out. A screw I4 screwing from the inside and at will into the bottom 4 of the jack I makes it possible to limit the stroke of the piston 2 when it returns to the rest position and to avoid a total emptying of the installation; the pressure which is kept there is a function of the force left by the spring 30 by the stop screw 14.

 Fig 4 is the sectional view of a variant of the previous model described in Fig I and shown during the pressurization of the installation. The jack I comprises a chamber 38 adding a capacity to its driving chamber; a rod 40 provided with an external rotation control 39 passes through the bottom 41 in a leaktight manner via the seal 43, then the bottom 4 to be screwed into the movable member 2, immobilized in rotation by a finger 24 secured to the guide tube 32 and penetrating into a groove 44 formed according to a generator.

The rod 40 has two different diameters connected by a conical part and such that in its first working stroke part the driving chamber of the jack and the chamber 38 both receive the fluid coming from the flow limiter 5, and only in the second part determined by the screwing of the rod 40 in the piston 2, these chambers are isolated from one another by the conical part of the rod having penetrated into a seal 42 carried by the idler 4 of the jack.

Under these conditions, the piston 2 then undergoes an acceleration, the flow of the fluid entirely benefiting only the driving chamber of the jack. Far the adjustment of the position of the connection of the two diameters of the rod 40 relative to the piston, it is therefore possible to obtain for a same flow rate of the limiter 5, two different speeds of progressive pressurization, being located in pressure chosen according to the characteristics of the installation.

Figs 5b and 5c are sectional views of another model of pressure reducing valve. Fig 5b shows the device in the position where the set pressure is reached in the installation; the die 5c represents the device in the position where the emptying of the installation completes its effect. As in the models previously described, the progressive pressure regulator comprises a body 25 a balanced valve 29, a membrane 28 pushed by a spring 30, a discharge channel 31, an inlet 26 and an outlet 27, all elements specific to the conventional pressure regulator. According to the invention, it further comprises an actuator I supplied by the network pressure taken from 11 orifice 26 and passing through a flow limiter 5 and a micro-valve I3 with 3 orivices - 2 positions. The piston 2 sliding in the cylinder 3 in a leaktight manner by a seal 21 transmits its force to the spring 30 of the apparatus; it is immobilized in rotation by a finger 24 which is integral with it and slides in a slot 23 formed along a generator in the wall of the cylinder 3. The piston 2 receives axially a screw 9, the non-threaded part of which crosses the bottom 4 of the jack which carries two seals 10 and It ensuring in all positions of the piston the tightness of the cylinder chamber. The rod 9 has a groove I2 where a groove whose length along the generatrix is substantially equal to the maximum possible stroke of the piston 2. The space between the seals IO and II, separated by a substantial distance: ent equal to the maximum possible stroke of the piston 2 dice or che outside the bottom 4 by an orifice 7 of pressure tap.

The outer end of the rod 9 is equipped with an adjustment wheel 8 which, by its rotation, modifies the distance separating it from the bottom 4 of the jack; by stop on this bottom 4, the flywheel 8 limits the working stroke of the piston and, by de-consequenoe, the force of the spring 30 and the pressure admitted downstream of the device.

In this end of stroke working position of the piston 2, the relative position of the groove I2 and of the seals IO and II is such that the space between these seals is open to the pressure prevailing in the jack and which appears at the 'ofifice 7, and closed to the atmosphere by the IO seal. Conversely, the cylinder having been purged of its pressure and its piston having then returned to its rest position by the force of the spring 90, the space between the seals IO and II is isolated from the cylinder chamber by the seal II and the pressure which was there emptied to the atmosphere through the annular space between the groove I2 and the joint IO. the pressure signal appearing at 7 at the end of the piston working stroke is advantageously used to authorize the start of a pneumatic cycle, the pressure adjusted by the handwheel 8 being then reached in the installation. the purge of the jack by the control of the micro-valve I3 causes the cancellation of the force of the spring 30 and the emptying of the installation by the opening of the discharge channel 31 and the light 23; the valve 29 remaining closed by the presence at input 25 of the network pressure.

Pig 6 is a sectional view of a variant of the model previously described according to FIGS. 5b and 5c, and shown in the position where the set pressure is reached downstream. A micro-distributor I3a, of the type 3 orifices-2 positions , spring return is-; connected by its output to the jack I. The network pressure taken from the orifice 5a having passed through the control microvalve I3, applies both to the pass-through input and to the control of inversion of the micro-distributor 13a, so that this pressure having reached a sufficient value, the micro-distributor I3a is inverted: the jack I is then supplied by the pressure downstream of the device passing through a flow restrictor 5.L inversion of the micro-distributor I3a, takes place for a sufficient pressure value determined by its return spring so that the displacement of the piston 2 causes blockage of the discharge channel 31 and a slight opening to the valve 29. The setting process in progressive pressure is then started, with the advantage that the expansion caused downstream by a cylinder returning to its end of travel position, stops or slows down, by the pressure drop, the progression of the piston 2; the pressure stabilizing during this stroke to a value equal to or less than that which was sufficient to start it. In this same embodiment according to FIG. 6, the micro-dis tributor1l3a can be advantageously replaced by a logic function cell TEST "I3b, unbalanced by a spring, such that at the progressive pressurization control, it is open at one inlet to the pressure of the upstream network and closed at the other inlet to the downstream pressure; this arrangement reverses when the pressure of the network at its corresponding input reaches a value sufficient to overcome the force of its spring.

Fig 7 is a sectional view of another embodiment of a pressure reducer with progressive pressure, according to the invention.

In the latter, a rod 9 integral with the piston 2 passes through the bottom 4 of the jack 1 in a sealed manner. On the threaded external end of the rod 9 is screwed a flywheel 8 which by abutment on the bottom 4 limits the working stroke piston 2. A washer 46 made of plastic, integral with the steering wheel 8 then closes a leak, the pressure of which appears at an orifice 7 for taking the signal. In the progressive pressurization command, the network pressure is directed both to a valve 47 which closes, opposing its own passage in the jack I, and to a space delimited by two seals Il and IIa in which slide the rod 9 in a leaktight manner. It has at its junction with the piston 2, a circular groove 48 formed over a length of its generatrix, such that the piston 2 being on its rest stop, the sealing defect of the seal It dà this groove, allows the passage of the network pressure in the cylinder and thus the start of the piston 2 on a stroke corresponding to the length of the groove 48 and sufficient to close the discharge channel 31, open the valve 29 and admit downstream a low pressure. The flow coming from the network is interrupted and the piston 2 then receives the downstream pressure. The diameter of the piston 2 being slightly larger than that of the diaphragm 28, and the same pressure being applied to these two elements, the result of the forces antagonists is always favorable to the progression of the piston Be flow restrictor 5 controls the arrival of the Brovenant fluid from downstream on the piston 2. the seal
It guarantees the tightness of the cylinder chamber with respect to the atmosphere in all positions of the piston. A purge order at control 13 opens the valve 47 and causes the udder 2 to return to rest and emptying pressure downstream of the device. A finger 24 secured to the piston 2, perpendicular to its section, eccentric, and penetrating into a corresponding hole 23 in the bottom 4, prevents rotation of the piston during adjustment of the device.

Of course, the invention is not limiting and those skilled in the art can withstand modifications without departing from the scope of the invention.

Claims (8)

REVENDICATI O. NS IO Pressure regulator with progressive pressurization of a pneumatic installation comprising in particular jacks, allowing the regulation of the pressure and rapid spurge, characterized in that the compression of spn spring is done at controlled speed, in a progressive way and continues, until reaching a force determined by regulation and thus the value of the desired pressure in the downstream installation, and in that the purging of the installation towards the atmosphere takes place through the apparatus, the upstream pressure being present or not at its inlet.  20 Expansion valve according to claim I characterized in that the means for ensuring the progressive compression of the spring 30 of the expansion valve, is a single-acting pneumatic cylinder I receiving pressure from upstream or downstream of the 'device through a flow restrictor and whose movable member gradually compresses the spring 30 until it gives a force determined by adjustment. The disappearance of the pressure keeping the movable member 2 in the end-of-travel position, causing it to be rested by the force of the spring 30 and thus purging the installation downstream by opening the relief valve discharge channel 31 .  30 Expansion valve according to claims I and 2 characterized in that the stroke of the movable member 2 of the cylinder I is invariable by the fixed position of its extreme stops and that the cylinder 3 secured to the bottom 4 can occupy variable positions, by adjustment the distance separating it from the body 25 of the device, using a threaded nut 6 bearing on the body and screwing onto the cylinder 3 to determine the deflection to be given to the spring 30. The guide tube 32 of the movable member 2 includes lights 23 in which slide fingers 24 integral with the cylinder 3 and immobilizing it in rotation.  40 Expansion valve according to claims I 2 and 3 characterized in that the piston 2 of the cylinder I comprises 2 seals 21 and 22 O-rings or lip oriented in the same active direction and that the wall of the cylinder 3 is pierced with an orifice 7 of pressure tap, located so that the piston 2 having arrived on its end-of-travel working stop secured to the cylinder 3, the active seal 21 of the piston 2 frees the passage of the fluid admitted into the jack I towards this orifice 7, pneumatic signal indicating that the set pressure is reached downstream of the device. the seal 22 prohibits any loss of fluid to the atmosphere during the running of the seal 21 in front of the orifice 7.  50 Regulator according to claims I 2 3 and 4 characterized in that the jack I comprises a movable bottom 34 equipped with a seal 37 modifying its capacity by an external control 36 of rotation of a S5 screw secured to the movable bottom 34 and Xe screwing into the bottom fixed 4.  60 Expansion valve according to claims I 2 3 and 4 characterized in that a screw I4 is screwed tightly into the bottom 4 of the cylinder I, limits the return stroke at rest of the movable member 2 to keep the spring 30 a residual force after emptying the cylinder pressure I.  70 Expansion valve according to claims I 2 3 and 4 characterized in that the cylinder I comprises an additional chamber 38; an external adjustment control 39 rotates a rod 40 sealingly passing through the bottom 41 of the chamber 38 and screwing into the movable member 2. The rod 40 has two different diameters with conical connection, such as during the first part of the working stroke of the movable member 2, the chamber 38 is open to you on the drive shaft of the jack, and that in the second part of the stroke determined by the screwing of the rod 40, the chambers are isolated from one the other by the penetration of the conical connection of the rod 40 into a seal 42 carried by the bottom 4 separating the cheabres.  8 Regulator according to claims I 2 6 and 7 characterized in that the working stroke of the movable member 2 of the cylinder I is variable and regulated by an external control 8 driven by this movable member abutting on the bottom 4 of the cylinder I. The control 8 rotates a rod 9 passing through the bottom 4 and screwing into the movable member 2 to determine the deflection to be given to the spring 30. The bottom 4 of the jack I carries 2 seals IO and II in which slides tightly the rod 9, separated from each other by a diameter substantially equal to the maximum possible stroke of the piston 2 and delimiting a space open to the outside by a pressure tap 7.The rod 9 has a groove I2 or a groove whose length on the generator and the position are such that, the piston 2 being stopped in its working stroke by the control 8 in abutment on the bottom 4, it allows the passage of the pressure from the jack I towards the orifice 7, and that in outside this position of the piston, this pressure tap 7 s isolated from the cylinder chamber and open to the atmosphere.  90 regulator according to claims I, 2,3,4,5,6,7, and 8 characterized in that it comprises a micro-valve I3 of the type 3 orifices-2 pcsitions, with drawer or with valve, with manual control, pneumatic or electrical, or any other pneumatic component such as logic or timer cell, capable of ensuring the connection between the pressure tap upstream of the apparatus and the jack I and of emptying the latter to the atmosphere and that in this case, total emptying of the installation a1 operates through the automatic relief valve discharge channel 31.  100 Regulator according to claims I, 2,3,4,5,6,7,8, et9 characterized in that it comprises a pneumatic element placed between the micro-valve I3 and the jack I succeptible to allow, from the com progressive pressurization command2 the passage of the upstream pressure towards the jack I, and the latter having reached there a level sufficient to cause the blocking of the discharge channel 31 and a slight opening of the valve 29 of the apparatus, of the '' interrupt and then allow the passage of the downstream pressure to the cylinder I, as soon as there is the upstream pressure at the corresponding inlet.This Element is a micro-distributor I3a of the type 3 orifices-2 positions with zlargpel by spring and pilot by the upstream pressure, or a cell 13b of logic AND function, unbalanced by a spring and has both an inlet normally open to the passage of the upstream pressure.  11 Expansion valve according to claims I, 2.8 and 9 characterized in that a rod 9 secured to the piston 2 passes through the bottom 4 of the oylindre in a sealed manner. On its external end is screwed an adjustment wheel 8 limiting the working stroke of the piston 2 by abutment on the bottom 4; a washer 46 secured to the flywheel 8 then plugs a leak, the pressure of which appears at the orifice 7 for taking the signal.  I20 Pressure regulator according to claims I, 2, 8.9 and II characterized in that, when the progressive pressurization command is given, the network pressure is directed both to a valve 47 which closes, opposing its own passage in the jack I, and towards a space delimited by two seals II and IIa in which the watertight hawk strainer the rod 9. This presents at its junction with the piston 2, a circular groove 48 formed over a length of generator, such that the piston 2 being on its rest stop, the lack of tightness of the seal II, dt at this groove, allows the passage of the network pressure in the jack I and thus the starting of the piston on a sufficient stroke to close the channel discharge valve 31, or screw the valve 29 and allow a slight pressure downstream. The flow coming from the network is then interrupted by the sealing of the joint II, and the piston 2 continues to progress by the downstream pressure arriving in the jack by the flow restrictor 5.A purge order at the control 13 opens the valve 47 and causes the piston 2 to return to rest and the emptying of the pressure downstream of the device.