OPERATING DEVICE FOR A VALVE AND BELONGING MOTION AMPLIFIER

Abstract: An operating device (1) for a valve has a regulating unit (10), acting, via a motion amplifier (14), upon a connecting link (16), the motion amplifier (14) having elements with tapered surfaces (22 to 29). The motion amplifier comprises an inlet element (15) being displaceable by the regulating unit (10) along an axis (E), with at least one tapered inlet surface (22, 23), an outlet element (16), also displaceable along the axis (E), with at least one tapered outlet surface (24, 25), and between them at least one intermediary element (17, 18). The at least one intermediary element (17, 18) extends vertically to the axis (E) and carries to tapered intermediary surfaces (26 to 29) with different inclinations in relation to the axis (E), the influence of a transverse force causing the first one (26, 27) to bear on a tapered inlet surface (22, 23) and the second one (28, 29) to bear on a tapered outlet surface (24, 25). Thus, the motion of the regulating unit (10) can be exposed to an amplification substantially without suffering from the influence of skew forces.

Description: Operating device for a valve and belonging motion amplifier The invention concerns an operating device for a valve, with a regulating unit, acting, via a motion amplifier, upon a connecting link, which is connectable with the closure member of the valve, the motion amplifier comprising elements with tampered surfaces having different inclinations . From DE 43 19 814 CI a similar operating device with motion amplifier for thermostatically operable valves is known. The motion amplifier has an amplifying element with two tapered surfaces or ramps, which extend radially or in the circumferential direction, of which one co-operates with an inlet or outlet element, the other with a part fixed on the housing. Thus, the motion of the regulating unit can be converted to an increased or reduced motion. The invention is based on the task of providing an additional operating device of the kind described in the introduction. According to the invention, this task is solved in that the motion amplifier has: a) an inlet element, displaceable by means of the regulating unit along an axis, with at least one tapered inlet surface, b) an outlet element, also displaceable along the axis, with at least one tapered outlet surface, and c) at least one intermediary element, extending vertically to the axis, as well as two tapered intermediary surfaces with different inclinations in relation to the axis, the influence of a transverse force causing the first one to bear on a tapered inlet surface and the second one to bear on a tapered outlet surface. In this construction the outlet element performs neither a transversal nor a rotary movement. The motion amplification occurs, as the displacement of the inlet element in the closing direction of the valve causes at least one intermediary element to be laterally displaced, and the outlet element follows under the influence of the return spring acting upon the valve rod of the second tapered intermediary surface. It is recommendable that the inlet element has two symmet- rically arranged tapered inlet surfaces and the outlet element has two symmetrically arranged tapered outlet surfaces and that two symmetrically arranged intermediary elements are provided, which are pressed against each other by the transverse force. Thus, the inlet element, the intermediary elements and the outlet element are working substantially symmetrically in relation to each other, which permits a construction without fixed guides for the inlet element and the outlet element in the housing. In this connection, the valve rod is substantially loaded in the axial direction, which ensures a long lasting sealing. It is advantageous that the inclination angle in relation to the axis of the second tapered intermediary surface has the same direction, but is smaller than the inclination angle of the first tapered intermediary surface. This gives a amplification in the same direction. An alternative foresees that the inclination angle in relation to the axis of the second tapered intermediary surface has the opposite direction, but is smaller than the inclination angle of the first tapered intermediary surface. Here, the amplification effect is connected with a movement reversal, so that a heating valve closing at increasing temperature is converted to a refrigeration valve opening at increasing temperature and at the same time being submitted to an amplification factor through the fitting of the motion amplifier. Preferably, the transverse force is produced by at least one spring. For this purpose, several sorts of springs can be used, for example, helical springs, clip springs, annular springs and the like, but also simple O-rings or elastic ribbons are applicable. Most favourable are springs surrounding both intermediary elements, thus pressing them against each other, as this unit will then locate itself centrally in relation to the other parts. It is recommendable that the connecting link is formed by the outlet element and has a stop for a valve pin, which is spring loaded in the pressure direction. This gives a particularly small component height. It is also favourable that the guide for the intermediary elements is arranged on a head having means for fixing on a valve housing. Thus, the inverter is positioned correctly in relation to the valve pin. It is recommended that the head also carries the regulat ¬ ing unit. This gives an easily operable operating device. Another preferred alternative provides that the head has a holder on which an upper part containing the regulating unit can be fixed. Thus, the head can also be two-part. It is particularly recommendable that the holder of the head corresponds to that of the valve housing. The upper part can then optionally be mounted on the valve housing direct or by way of the head carrying the inverter. Preferably, the motion amplifier is also available as an independent component for an operating device. In the following the invention is described on the basis of preferred embodiments in connection with the drawings, showing: Fig. 1 a longitudinal section through an operating device according to the invention Fig. 2 a longitudinal section through a modified embodiment Fig. 3 a cross-section along the line A-A in Fig. 2 Fig. 4 a cross-section along the line B-B in Fig. 2 The operating device 1 in Fig. 1 has a head 2, which, by means of fixing means 3, can be fixed on a valve housing 4 having a corresponding holder 5. The valve housing 4 is only shown intermittently. It shows the usual parts, namely a closure element 6 with a return spring 7 normally holding the valve open, and a valve pin 8, which is led to the outside through a gland seal 9. The parts of the valve are neither true to scale nor shown in their correct position. The head 2 comprises a thermostatically operable regulating unit 10, which is connected with an external sensor element via a capillary tube 11. The ther ostatic system can, for example, work with a liquid-vapour charge or a liquid charge. The regulating unit 10 has a regulating surface 12 and a corrugated pipe 13. A motion amplifier 14 has an inlet element 15 and an outlet element 16, which are displaceable along an axis E corresponding to the movement track of the operating unit 10, and two intermediary elements 17 and 18, which are guided on guides 20 vertically to the axis E and thus vertically to the symmetry level extending between the two intermediary elements 17 and 18. The inlet element 15 is provided with a barrel-shaped extension 21 surrounding the corrugated pipe 13. Further, the inlet element 15 has two tapered surfaces 22 and 23 extending symmetrically to the axis E and thus to the symmetry level, said surfaces extending in this embodiment at an angle of 50° in relation to the symmetry level. The outlet element 16, which at the same time serves as connecting element for connection with the valve pin 8, also has two tapered surfaces 24 and 25, which have in this embodiment an angle of 35° in relation to the axis and thus also to the symmetry level, and which have an opposite inclination direction in relation to the tapered surfaces 22 and 23. The two intermediary elements 17 and 18 have first tapered surfaces 26 and 27 adapted to the tapered surfaces 22 and 23, and second tapered surfaces 28 and 29 adapted to the tapered surfaces 24 and 25. When the inlet element 15 is acted upon in the closing direction of the valve, the two intermediary elements 17 and 18 are pressed apart in the transversal direction. As the outlet element 16 is pressed in the direction of the inlet element 15 by the return spring 7, a displacement of the closure element 6 in a direction opposite to that of the regulating unit 10 takes place. At the same time an amplification caused by the angle relation 50° to 35° occurs, here by an amplification factor of 1.7. A spring 30, which surrounds both intermediary elements 17 and 18, ensures that these intermediary elements are pressed against and follow each other, when the regulating movement occurs opposite the closing direction of the valve. Instead of the annular springs shown, also helical springs, clip springs or the like can be used. Also rubber materials and the like can be used. The spring 30 must be so strong that the valve is not able to act upon the system in the opposite direction via the valve pin, and that it can keep the valve closed. The best performance is reached in that the spring force is the same in both directions. This gives an automatic orientation of the parts . In the embodiment according to Figs. 2 to 4 corresponding parts have reference numbers increased by 100 in relation to Fig. 1. The most essential difference is that the head 102 merely comprises the motion amplifier 114, but has a holder 131, which corresponds to the holder on the valve housing, so that the head 102 can be provided with an upper part containing the regulating unit 10. Thus, the upper part can be used optionally with or without inserted motion amplifier 114. Another difference is that the second tapered intermediary surfaces 128 and 129 together with the tapered outlet surfaces 124 and 125 have the same orientation than the first tapered intermediary surfaces 126 and 127 together with the tapered inlet surfaces 122 and 123, but form different angles in relation to the axis E and thus to the symmetry level, here again 50° on the inlet side and 35° on the outlet side. With this construction the amplification can be obtained without movement reversal. In both embodiments the tapered surfaces should be made of a material with low frictional resistance, so that the motion amplifier quickly follows the movements of the regulating unit. The tapered surfaces do not have to be plane. They can, for example have the shape of a channel or be grooved, which enables an additional guiding. To prevent the outlet element 16, 116 from falling out before the head is fixed on the valve housing, a suspen- sion with oblong holes can be foreseen, which is suspended on the guide 119, 120 or on the inlet element. Of course, the motion amplifier cannot only be dimensioned for amplification factors above zero, but also for those below zero. The embodiments show regulating units with external temperature sensors. However, it is also possible to arrange the sensor in the regulating unit. Instead of the thermo- static regulating unit also other regulating units, for example with a heatable expansion material, like an electrically heatable wax cartridge, can be used. According to the embodiment in Fig. 2, the motion ampli- fier is arranged in a head forming an independent unit 102. Optionally, this head can be built-in or not built- in. Instead of the shown screw fitting, other connection forms can be used, for example snap connections.

Claims: Patent claims 1. Operating device for a valve, with a regulating unit, acting, via a motion amplifier, upon a connecting link, which is connectable with a closure member, the motion amplifier comprising elements with tampered surfaces having different inclinations, characterised in that the motion amplifier (14; 114 comprises): a) an inlet element (15; 115) , displaceable by means of the regulating unit (10) along an axis (E) , with at least one tapered inlet surface (22, 23; 122,123), b) an outlet element (16; 116) , also displaceable along the axis (E) , with at least one tapered outlet surface (24, 25; 124, 125), and c) at least one intermediary element (17, 18; 117, 118) , extending vertically to the axis (E) , as well as each two tapered intermediary surfaces (26 to 29; 126 to 129) with different inclinations in relation to the axis, the influence of a transverse force causing the first one (26, 27, 126, 127) to bear on a tapered inlet surface (22, 23; 122, 123) and the second one (28, 29; 128, 129) to bear on a tapered outlet surface (24, 25; 124, 125) . 2. Device according to claim 1, characterised in that the inlet element (15; 115) has two symmetrically arranged tapered inlet surfaces (22, 23; 122, 123) and the outlet element (16; 116) has two symmetrically arranged tapered outlet surfaces (24, 25; 124, 125) and that two symmetrically arranged intermediary ele- ments (17, 18; 117, 118) are provided, which are pressed against each other by the transverse force. 3. Device according to claim 1 or 2, characterised in that the inclination angle in relation to the axis (E) of the second tapered intermediary surface (128, 129) has the same direction, but is smaller than the inclination angle of the first tapered intermediary surface (126, 127) . 4. Device according to claim 1 or 2, characterised in that the inclination angle in relation to the axis (E) of the second tapered intermediary surface (28, 29) has the opposite direction, but is smaller than the inclination angle of the first tapered intermedi- ary surface (26, 27) . 5. Device according to one of the claims 1 to 4, characterised in that the transverse force is produced by at least one spring (30) . 6. Device according to one of the claims 1 to 5, characterised in that the connecting link is formed by the outlet element (16) and has a stop for a valve pin (8) , which is spring loaded in the pressure direc- tion. 7. Device according to one of the claims 1 to 6, characterised in that that the guide (20; 119, 120) for the intermediary elements is arranged on a head (2; 102) having means (3; 103) for fixing on a valve housing (4) . 8. Device according to claim 7, characterised in that the head (2) also carries the regulating unit (10) . 9. Device according to claim 7, characterised in that the head (102) has a holder (131) on which an upper part containing the regulating unit can be fixed. 10. Device according to claim 9, characterised in that the holder (131) of the head (102) corresponds to that of the valve housing. 11. Motion amplifier (114) as an independent component of an operating device according to one of the claims 1

Inventors: FREDERIKSEN BJARNE, FREDERIKSEN, BJARNE
Applicants: DANFOSS AS, FREDERIKSEN BJARNE, DANFOSS A/S, FREDERIKSEN, BJARNE
Application year: 1999
Main classification: F16K31
IPC codes: F16K31, F24D19, G05D23