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EP0805280A1 - Sicherheitsventil für eine durch Druckfluid getriebene Vorrichtung - Google Patents

Sicherheitsventil für eine durch Druckfluid getriebene Vorrichtung Download PDF

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Publication number
EP0805280A1
EP0805280A1 EP97106674A EP97106674A EP0805280A1 EP 0805280 A1 EP0805280 A1 EP 0805280A1 EP 97106674 A EP97106674 A EP 97106674A EP 97106674 A EP97106674 A EP 97106674A EP 0805280 A1 EP0805280 A1 EP 0805280A1
Authority
EP
European Patent Office
Prior art keywords
fluid
valve
channel
chambers
cursors
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97106674A
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English (en)
French (fr)
Inventor
Francisco Lopez Mota
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
G.P.A. ITALIANA S.P.A.
Original Assignee
Gpa Italia SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Gpa Italia SpA filed Critical Gpa Italia SpA
Publication of EP0805280A1 publication Critical patent/EP0805280A1/de
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
    • F15B20/001—Double valve requiring the use of both hands simultaneously

Definitions

  • the present invention relates to a safety valve for apparatus operating with fluid under pressure and, particularly, a valve of the double-body parallel-flow type used to control clutches and/or brakes of presses fed with compressed-air.
  • pneumatic presses are universally recognised as particularly dangerous machines and are therefore subject to very restrictive safety norms everywhere.
  • the safety valve constitutes an essential part of the organs of control of a press and must ensure that the supply of pressurised fluid in each phase of the operating cycle is stopped in the event of a malfunction of the same valve. For instance, if there is a leak in the valve, the supply of pressurised fluid to the apparatus must be stopped and provision must be made for venting the pressurised fluid in the apparatus to the atmosphere. Moreover, the resumption of the normal operation must only be possible after correct operation has been restored.
  • Safety valves of the double-body parallel-flow type generally comprise an inlet port for the pressurised fluid, an outlet port for the fluid going to the apparatus and an exhaust port to vent the fluid of the apparatus to the atmosphere.
  • Inside the body there are a pair of valve-sets, each of which is fitted with a working piston, a shutter for closing the vent port to the atmosphere and a shutter for blocking the passages connecting the inlet port to the outlet port towards the apparatus.
  • a pair of pilot electro-valves allows the fluid to be fed under pressure to both the pilot chambers when the press is required to be activated.
  • An object of the present invention is to produce a safety valve that allows the volume delivered to the apparatus to be increased.
  • Another object of the present invention is to produce a safety valve in parallel that allows the delivery to the apparatus to be controlled.
  • a further object of the present invention is to produce a valve to control the feed to pneumatic apparatus that ensures a higher degree of safety compared to the valves currently known.
  • a safety valve of the double-body, parallel-flow type for apparatus operating with fluid under pressure comprising at least a first inlet port for the pressurised fluid, at least an outlet port for the fluid going to the apparatus and at least a first exhaust port to vent the fluid of the apparatus to the atmosphere; a pair of valve-sets, the respective stems of which are fitted with respective working pistons which run in the respective pilot chambers, with respective shutters for closing the exhaust port venting to the atmosphere and with respective shutters for blocking the passages connecting the first inlet port and the outlet port towards the apparatus, the first inlet port comprising portions of duct with reduced cross-section connecting with the respective inlet chambers; and a pair of pilot electro-valves which enables or disables the fluid flow under pressure to both the pilot chambers through the respective ducts with its respective portions of reduced cross-section, characterised by comprising a second inlet port to feed fluid under pressure to the outlet port, as well as means to intercepting the flow between the second inlet
  • the additional feed allows an increase in the volume of pressurised fluid going to the apparatus when the valve is activated, reducing the time taken to reach the nominal operating pressure.
  • the means for intercepting the flow of fluid between the second inlet port and the outlet port to the apparatus comprise a pair of distribution cursors bound respectively to the valve stems opposite to the working pistons.
  • the distribution cursors are bound to the common valve-sets in a such way that they don't alter the principle of operation of the same valve.
  • the safety valve according to the invention can also be used, if necessary, in place of any valve of known type without necessarily causing modifications to the plant for feeding the pressurised-fluid or to the apparatus controlled.
  • the distribution cursors run inside respective antagonist chambers in fluid communication with the respective inlet chambers through passages drilled in the respective cursors.
  • the distribution cursors intercept a second channel in fluid communication with the second inlet port and with the said antagonist chambers in a such way that the additional feed operates as soon as the valve is activated.
  • means are provided to regulate the flow of fluid between the second inlet port and the second channel.
  • the volume of fluid of the additional feed can be regulated in a such way as to adapt to the most varied operational requirements.
  • the means for regulating the flow of fluid between the second inlet port and the second channel comprise a piston, running in a control chamber, that intercepts a passage between the control chamber and the second channel under the combined effect of a force caused by elastic means and of a pilot pressure applied in the same chamber through a device for regulating the pilot pressure.
  • Figures 1-3 show a valve according to the present invention, i.e. a valve of the double-body, parallel-flow type with dynamic control, in which a system of additional feeding has been inserted.
  • the valve comprises a body 100 in which are drilled a first inlet port P of the pressurised fluid, at least one outlet port A of the fluid to the apparatus (not shown) and at least one first exhaust port R for venting the pressurised fluid to the atmosphere.
  • valve body 100 Inside the valve body 100 there are fitted a freely moving pair of valve-sets 13 and 14 with their respective stems 113 and 114 to which are bound respective working pistons 109 and 110, running in their respective pilot chambers 9 and 10 (Fig. 2).
  • the inlet port P comprises portions of ducts 23 and 24 with reduced cross-section (flow reducers) communicating with respective inlet chambers 27 and 28 of the pressurised fluid.
  • pilot electro-valves 1 and 2 in the upper part which enable or block the feeding of the pressurised fluid to the pilot chambers 9 and 10 through the respective ducts 117 and 118.
  • the latter also comprise respective portions 17 and 18 having reduced cross-section (flow reducers) at the respective inlet chambers 27 and 28.
  • a pair of connections CP on each of the ducts 117 and 118 allows the pressure in each duct to be measured during the operation of the valve.
  • the pilot electro-valves 1 and 2 comprise respective cores 3 and 4 that move with clearance in the respective housings in such a way as to allow the evacuation of the residual fluid contained in the pilot chambers 9 and 10 through the vents 7 and 8 when the same cores are in the closed position shown in Figure 1.
  • the closed position of the cores 3 and 4 is maintained by a spring or other suitable elastic means.
  • a second inlet port PB (shown in more detail in the Figures 4A-4D) which allows further pressurised fluid to be fed to the outlet port A in addition to the fluid that passes through the flow reducers 23 and 24.
  • the feed deriving from PB is intercepted by a piston 31 (described in more detail below) and by a pair of distribution cursors 19 and 20 bound to the stems 113 and 114 opposite the working pistons 109 and 110.
  • the distribution cursors 19 and 20 move inside respective antagonist chambers 29 and 30, in which there are moreover antagonist springs 21 and 22 which act to return the valve sets 13 and 14 in their rest position.
  • the cursors 19 and 20 are provided internally with passages 35 and 36 respectively, which are in fluid communication with the antagonist chambers 29 and 30 with the respective inlet chambers 27 and 28.
  • the distribution cursors 19 and 20 intercept a first channel 25 which can be placed selectively in fluid communication with a pair of intermediate exhaust ports 33 and 34 (as in Figure 1), or with the inlet chambers 27 and 28 (as in Figure 2). Moreover, the distribution cursors 19 and 20 intercept a second channel 26 to either close it (as in Figure 1) or for put it in communication with the passages 35 and 36 inside the same cursors (as in Figure 2).
  • valve-sets 13 and 14 thus maintaining unchanged the original safety functions of these types of valve.
  • the valve is able to vent the feeding of one valve-set if the other valve-set is not commutated simultaneously.
  • valve-sets 13 and 14 are positioned to the top by the antagonist springs 21, 22 and by the pressure in the inlet chambers 27 and 28.
  • the shutters 15 and 16 close the passages 115 and 116 respectively preventing the passage of the pressurised fluid to the outlet port A to the apparatus.
  • the outlet port A is instead connected directly to the exhaust port R through the passages 11 and 12.
  • the inlet chambers 27 and 28 are connected respectively to the antagonist chambers 29 and 30 through the passages 35 and 36 inside the cursors 19 and 20, so as to balance the effect of the pressure on the cursors 19 and 20.
  • the valve-sets 13 and 14 With the valve-sets 13 and 14 in this position, the channel 25 is connected to the intermediate exhaust ports 33 and 34, while the channel 26, which could be connected to the port PB of additional feeding by acting on the piston 31, remains obstructed by both the cursors 19 and 20.
  • FIG. 2 shows the valve in an activated or excited condition.
  • both the pilot electro-valves 1 and 2 are fed electrically.
  • the cores 3 and 4 overcome the force of the springs opening the passages of feeding 5, 6 and closing the vents 7 and 8.
  • the existing resting pressure on the passages 5 and 6 reaches the pilot chambers 9, 10 and moves the valve-sets 13 and 14 to the lower part, by acting on the working pistons 109 and 110.
  • the piston 31 could be activated by applying for instance a suitable pilot pressure through the duct 32.
  • Figure 3 shows the valve in the unbalanced condition, a condition in which the feeding of air under pressure to the outlet port of A must be prevented.
  • the hypothesis is that only the pilot electro-valve 1 is excited or, in an equivalent way, that only pilot electro-valve 2 is not excited.
  • the core 4 closes the passage of inlet 6 and opens the vent 8 evacuating the fluid from the chamber 9.
  • valve-set 13 moves to the top under the pressure of the spring 21 and of the pressure on the shutter 15.
  • the passage 115 is obstructed while the passage 11 is opened to the exhaust port R.
  • the valve-set 14 holds instead, the excited position.
  • the pressurised fluid deriving from the flow-reducer 24 only is conveyed to the exhaust port R through the passage 11, therefore preventing the necessary pressure developing at the outlet port A to activate the apparatus connected to the valve.
  • the fluid deriving from the flow-reducer 24 is conveyed moreover to the intermediate exhaust port 33 through the channel 25, as well as the fluid deriving from the additional feeding port PB that flows through the channel 26, through the passage 36 and through the channel 25 up to the exhaust port 33.
  • valve remains therefore jammed in this position.
  • the unlocking of the valve from the unbalanced position is only possible after both the valve-sets are restored to the position rest (as in Fig. 1) to allow the inlet pressure in the inlet chamber 28 and in the duct 6 to stabilise again.
  • valve according to the invention is equipped with means for regulating the flow of fluid between the second inlet port PB and the second channel 26.
  • Figs. 4A and 4B show schematic views in section of the said means of regulation in the position of exclusion of the additional feeding deriving from the inlet port PB, while Figs. 4C and 4D show the same means in condition of activation of the additional feeding.
  • the means of regulation comprise a piston 31, moving in a control chamber 131, that opens and closes a passage of communication 126 between the chamber 131 and the channel 26.
  • the piston 31 is positioned inside the chamber 131 under the combined effect of the pressure of a force caused by the spring 231 and of a pilot pressure applied in the control chamber 131, through a duct 32, from a pilot pressure regulating device.
  • the volume of fluid deriving from the additional feeding port PB is regulated and directed to the channel 26. It is thus possible to modulate the volume sent by the additional feeding to allow a gentle approach of the actuator controlled by the valve.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Safety Valves (AREA)
  • Self-Closing Valves And Venting Or Aerating Valves (AREA)
  • Multiple-Way Valves (AREA)
EP97106674A 1996-05-02 1997-04-23 Sicherheitsventil für eine durch Druckfluid getriebene Vorrichtung Withdrawn EP0805280A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT96MI000858A IT1282395B1 (it) 1996-05-02 1996-05-02 Valvola di sicurezza per apparecchiature funzionanti con fluido in pressione
ITMI960858 1996-05-02

Publications (1)

Publication Number Publication Date
EP0805280A1 true EP0805280A1 (de) 1997-11-05

Family

ID=11374181

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97106674A Withdrawn EP0805280A1 (de) 1996-05-02 1997-04-23 Sicherheitsventil für eine durch Druckfluid getriebene Vorrichtung

Country Status (2)

Country Link
EP (1) EP0805280A1 (de)
IT (1) IT1282395B1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0848166B1 (de) * 1996-12-16 2003-01-22 Ross Operating Valve Company Ventil mit sich kreuzenden Leitungen und mit Sperrfunktion
EP1059460A3 (de) * 1999-06-11 2003-10-15 Ross Operating Valve Company doing business as Ross Controls Doppelventil mit Schutz gegen Missbrauch

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3283862A (en) * 1964-04-10 1966-11-08 Minster Machine Co Secondary pilot control valve
FR2388151A1 (fr) * 1977-12-16 1978-11-17 Technomatic Ag Soupape de surete
GB2137737A (en) * 1983-04-05 1984-10-10 Ross Operating Valve Co Improved monitor for double safety valves
DE9014789U1 (de) * 1990-10-25 1991-02-07 Herion-Werke Kg, 7012 Fellbach Sicherheitsventil

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3283862A (en) * 1964-04-10 1966-11-08 Minster Machine Co Secondary pilot control valve
FR2388151A1 (fr) * 1977-12-16 1978-11-17 Technomatic Ag Soupape de surete
GB2137737A (en) * 1983-04-05 1984-10-10 Ross Operating Valve Co Improved monitor for double safety valves
DE9014789U1 (de) * 1990-10-25 1991-02-07 Herion-Werke Kg, 7012 Fellbach Sicherheitsventil

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0848166B1 (de) * 1996-12-16 2003-01-22 Ross Operating Valve Company Ventil mit sich kreuzenden Leitungen und mit Sperrfunktion
EP1059460A3 (de) * 1999-06-11 2003-10-15 Ross Operating Valve Company doing business as Ross Controls Doppelventil mit Schutz gegen Missbrauch

Also Published As

Publication number Publication date
IT1282395B1 (it) 1998-03-20
ITMI960858A0 (de) 1996-05-02
ITMI960858A1 (it) 1997-11-02

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