Device for dispensing fluid jets without a rotating joint

Abstract

The disclosure relates to a device for dispensing one or more jets of cryogenic fluid, particularly liquid nitrogen, comprising a fluid conveying pipeline feeding one or more fluid dispensing nozzles arranged at the downstream end of said pipeline, and a motor collaborating with the fluid conveying pipeline via a rotary transmission shaft and a transmission mechanism.

Claims

1. A device for dispensing one or more jets of fluid (6) comprising a fluid conveying pipeline (7) configured to feed a fluid to one or more fluid dispensing nozzles (5) arranged at the downstream end of said pipeline (7), and a motor (1) collaborating with the fluid conveying pipeline (7) via a rotary transmission shaft (2) and a transmission mechanism (4a, 4b), in which device: the fluid conveying pipeline (7) comprises an upstream portion (7a) of first axis (XX) and a downstream portion (7b) of second axis (YY), the first and second axes (XX, YY) between them making an angle () of between 5 and 50, the downstream portion (7b) of second axis (YY) comprising the downstream end of the pipeline (7) with said fluid dispensing nozzle or nozzles, and wherein the transmission mechanism (4a, 4b) comprises motion-inducing elements capable of acting on said downstream portion (7b) of pipeline to impart a determined movement to it, further wherein the transmission mechanism (4a, 4b) comprises: a support pinion (4b) capable of rotational movement about a rotation axis situated at the center of said support pinion (4b), the fluid conveying pipeline (7) being positioned eccentrically and running freely through said support pinion (4b), and a pinion drive (4a) collaborating with the support pinion (4b), and the fluid conveying pipeline collaborates with an anchor (8) arranged on the pipeline upstream of the support pinion (4b), said anchor (8) forming all or part of a setting system configured to allow adjustment the length of fluid conveying pipeline between the anchor (8) and the downstream end of said pipeline (7).

2. The device as claimed in claim 1, wherein the anchor (8) is designed and able to be attached to or detached from said pipeline (7) so as to hold said pipeline (7) when the anchor is attached to the pipeline (7) or free said pipeline when the anchor is detached from the pipeline (7) and thus allow the length of pipeline (7) to be set, said length being measured between the anchor means (8) and the downstream end of the pipeline (7).

3. The device of claim 1, wherein the first and second axes (XX, YY) between them make an angle () of between 10 and 40.

4. The device of claim 1, wherein a transmission shaft (2) collaborates with the pinion drive (4a), and the pinion drive (4a) collaborates with said support pinion (4b) in such a way as to be capable of transmitting, via the pinion drive (4a), the rotational movement of the transmission shaft (2) to the support pinion (4b) and thus obtain a circular movement of the fluid dispensing nozzle or nozzles arranged at the downstream end of said pipeline (7).

5. The device of claim 1, wherein the support pinion (4b) is held by pinion-holding elements comprising one or more slippers or rolling bearings.

6. The device of claim 1, wherein the pipeline (7) is arranged in a passage (10) formed through the body of the support pinion (4b), which passage (10) is situated within a disk formed by the support pinion (4b), but not at the center of said disk.

7. The device of claim 1, wherein holding elements (9) are provided to hold the support pinion (4b), the holding elements (9) being positioned on the support pinion (4b) at a distance R from the axis of rotation of the support pinion (4b) which distance is greater than the distance r between the rotation axis and an orifice of a passage (10).

8. The device of claim 7, wherein the holding elements (9) are slippers, radial rolling bearings or spigots and/or the pinion drive (4a) is a pinion or a belt.

9. The device of claim 1, wherein the anchor (8) comprises a clamping device, a gland, a split nut, an elastic taper or a rack-pinion system.

10. The device of claim 1, wherein the pipeline (7) is a stainless steel tube.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For a further understanding of the nature and objects for the present invention, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements are given the same or analogous reference numbers and wherein:

(2) FIG. 1 is a schematic (side) view of a high-pressure fluid jet dispensing device according to the present invention,

(3) FIG. 2 is a schematic (front) view of the support and drive pinions of a device according to FIG. 1,

(4) FIG. 3 is a schematic (side) view of the support pinion and of the high-pressure tube of a device according to FIG. 1,

(5) FIG. 4 depicts details of the pinion-holding means,

(6) FIG. 5 depicts an embodiment with a pigtail system,

(7) FIG. 6 depicts a nozzle-holding tool with the path of the jets for a tool of the prior art,

(8) FIG. 7 depicts a nozzle-holding tool with the path of the jets for a tool according to the present invention,

(9) FIG. 8 depicts a manual tool according to the present invention, and

(10) FIG. 9 depicts an automatic tool according to the present invention incorporated into a robot.

DESCRIPTION OF PREFERRED EMBODIMENTS

(11) FIG. 1 illustrates the principle of a device for dispensing jets of fluid, preferably a fluid at cryogenic temperature and at high pressure according to the present invention. This device comprises a fluid conveying pipeline 7, such as a stainless steel tube, supplying one or more fluid dispensing nozzles arranged at the downstream end of said pipeline 7. In general, the nozzles are carried by a nozzle-holding tool 5.

(12) According to one embodiment, the fluid that is to be dispensed is a fluid at cryogenic temperature and at high pressure, particularly liquid nitrogen at a pressure of between 1000 and 4000 bar and at a temperature of between 140 and 200 C. The fluid being taken from a fluid source (not shown) such as a compressor, a tank, a heat exchanger, a supply line, one or more gas cylinders or the like, supplying the upstream end of the fluid pipeline 7.

(13) As illustrated in FIG. 3, the fluid conveying pipeline 7 of the fluid dispensing device collaborates with a motor 1 via a rotary transmission shaft 2 and a transmission mechanism 4a, 4b which will be detailed hereinafter.

(14) The fluid conveying pipeline 7 for its part comprises an upstream portion 7a of first axis XX and a downstream portion 7b of second axis YY between them making an angle of between 5 and 50, typically of between 10 and 40 and preferably of the order of 20 to 30.

(15) The downstream portion 7b carries the downstream end of the pipeline 7 where the fluid dispensing nozzle or nozzles is or are arranged, for example on a nozzle-holding tool.

(16) Moreover, the transmission mechanism 4a, 4b comprises motion-inducing means acting on the downstream portion 7b of pipeline so as to impart to it a determined movement, of whatever kind it might be, particularly a rotational or oscillatory movement. What should be understood by rotational movement is a movement which describes a circle or an ellipse, for example. The choice of the design of the component 4b will determine the type of movement chosen.

(17) The motor 1 collaborating with the fluid conveying pipeline 7 via its rotary transmission shaft 2 and the transmission mechanism 4a, 4b to which the transmission shaft 2 transmits its rotational movement. The motor is a pneumatic motor, an electric motor, a gasoline engine or any other type of motor.

(18) According to the invention, as visible in FIG. 2, the transmission mechanism 4a, 4b comprises a support pinion 4b capable of a rotational movement about an axis of rotation located at the center of said support pinion 4b, and the cryogenic fluid conveying pipeline 7 being positioned eccentrically through said support pinion 4b. In other words, the axis of the pipeline 7 and the axis of the support pinion 4b are non-coincident.

(19) The pipeline 7 is therefore arranged in a passage or orifice 10 formed through the body of the support pinion 4b, which passage is situated within the disk that the support pinion 4b forms, but not at the center of said disk.

(20) For preference, the passage for the pipeline 7 is situated at least 1 mm away from the center of the pinion, which means to say from the axis of said support pinion 4b.

(21) Moreover, a pinion drive means 4a, such as a drive pinion or a belt, collaborates with the support pinion 4b to drive the rotational movement of said support pinion 4b. More specifically, the transmission shaft 2, driven by the motor 1, collaborates with the pinion drive means 4a and the pinion drive means 4a itself collaborates with said support pinion 4b in order, via the pinion drive means 4a, to transmit the rotational movement of the transmission shaft 2 to the support pinion 4b and thus obtain a movement, preferably a circular movement, of the fluid dispensing nozzle or nozzles arranged at the downstream end of said pipeline 7, that is to say arranged on the nozzle-holding tool 5 used for dispensing the jets 6 of high-pressure fluid.

(22) As illustrated in FIG. 1, a transmission box 3 that forms a protective casing and that the transmission shaft enters and that houses the transmission mechanism 4a, 4b. In this transmission box 3 the pinion 4b is held in place by a set of slippers or by rolling bearings of any type, for example needle bearings or ball bearings, preferably ball bearings.

(23) The support pinion 4b is held by pinion-holding means 9 comprising one or more slippers or rolling bearings, notably a ball bearing as schematically illustrated in FIG. 4.

(24) It should be noted that elements 9, such as slippers, radial rolling bearings or spigots, are provided to maintain good rotation of the support pinion 4b. In fact, the support pinion 4b is grooved to accept the elements 9. The support pinion 4b is not held on its shaft. The pinion 4b is held by devices 9 which are positioned on the pinion 4b at a distance R from the axis of rotation of the pinion 4b which distance is greater than the distance r between the axis of rotation and the orifice 10, as illustrated in FIG. 3.

(25) Moreover, the fluid conveying pipeline 7 collaborates with anchor means 8, such as a gland, a clamp, a split nut, an elastic taper, a rack-pinion system or any other suitable mechanical device allowing the pipeline 7 to be held in position with respect to the rest of the jet dispensing device, said anchor means 8 being arranged on the pipeline 7 upstream of the support pinion 4b, i.e. the support pinion 4b is situated between the anchor means 8 and the end of the pipeline 7 bearing the nozzle or nozzles. In other words, the pipeline 7 is, on the one hand, kept stationary or approximately stationary in the region and because of the anchor means 8 and, on the other hand, comprises a downstream end 7b fitted with the nozzle or nozzles which is able to move and describes a given movement, preferably a circular movement, when the motor 1 drives the transmission shaft 2, the drive pinion 4a connected to the shaft 2, and the support pinion 4b which itself drives the tube 7 in a determined path, for example a circular path or the like.

(26) The anchor point 8 is a mechanical element that allows the sliding of the pipeline 7 though the device and ultimately through the passage 10 to be blocked or unblocked.

(27) The anchor point therefore makes it possible, for the time that the method is being implemented, to fix the length Lo, and therefore the diameter or the like of the circular path or the like described by the nozzle, in the knowledge that the distance between the anchor point 8 and the pinion 4b is fixed. Stated differently, modifying the length Lo is particularly advantageous for varying the radius of the circular path Ro described by the nozzle or nozzles for dispensing jets of high-pressure fluid as illustrated in FIG. 3.

(28) The mechanical element of the anchor point can be slackened off easily by the user, for example using an appropriate tool, if the user wishes to set or adjust the length Lo.

(29) If the pipeline 7 is positioned on a movement machine or on a robot, it may prove difficult or impractical to slide the tube 7 through the device. It is therefore beneficial for the pipeline 7 to be split into two parts connected by a very-high-pressure static coupling 7c positioned upstream of the anchor point 8. This allows this part of the tube between 7c and the nozzle-holding tool 5 to be changed easily for a tube of suitable length allowing Lo to be adjusted to the desired length without the entirety of the tube 7 having to be moved or modified.

(30) Furthermore, because this part of the pipeline is subject to deformation, it is preferable for it to be readily interchangeable for maintenance purposes.

(31) In order to obtain sufficient pipeline 7 elastic deformation (flexibility), the properties of said pipeline 7, or at least of the part 7b of pipeline 7 situated between the anchor means 8 and the end carrying the nozzle-holding tool 5, are chosen with care, particularly the nature of the material of which the tube 7 is made, and its sizing, i.e. the inside and outside diameters of said tube.

(32) For example, if it is a cryogenic fluid such as liquid nitrogen under high pressure that is being conveyed, use is preferably made of a stainless steel tube by way of pipeline 7, with inside and outside diameters as given in table II below.

(33) TABLE-US-00002 TABLE II Tube diameter outside 6.4 mm () 9.5 mm () 14.8 mm ( 9/16) inside 2.1 mm 3.2 mm 4.8 mm Rcmin = minimum 1 to 1.5 m 2 to 2.5 m R to great to bend radius in conceive of any meters without flexibility plastic deformation

(34) As can be seen from table II, the 14.8 mm diameter tube is too rigid to be used to effect. Hence, typically, use is made of a tube in 316 grade stainless steel able to withstand high pressures (up to around 4000 bar) with an outside diameter of around 6.4 mm.

(35) In order to make the tube still more flexible, it is possible to give said tube the form of a loop or pigtail, as shown in FIG. 5, or to use a bellows system.

(36) Likewise, in order to ensure freedom of movement between the pinion 4b and the tube 7 at the orifice 10, a ball bearing or similar system may advantageously be positioned at 10 around the flexible tube 7.

(37) A device according to the invention comprising a stainless steel tube with an external radius of 6.4 mm, supplied with liquid nitrogen at a temperature of 155 C. and at a pressure of 3500 bar, was tested without fatigue rupture over 2 000 000 cycles at a very high rotational speed of around 1100 rpm. Thus, according to the person skilled in the art of fatigue mechanics, the tube will not rupture through fatigue, whatever the number of cycles performed, particularly in excess of 2 000 000 cycles. The results obtained are therefore entirely satisfactory and the device works perfectly.

(38) It is to be noted that a device according to the invention will not exactly reproduce the path of the jets followed by the systems used previously. A nozzle holder equipped with two nozzles used with the system described in U.S. Pat. No. 7,316,363 gives the two nozzles concentric circular paths with different radii, as illustrated in FIG. 6, whereas the same nozzle holder equipped with the same two nozzles gives the nozzles circular paths with identical radii Ro but which are offset, as schematically illustrated in FIG. 7.

(39) The circles (FIG. 7) described by the liquid nitrogen jets will have a diameter that increases with increasing Lo and increasing . Thus, for a surface treatment or scalping of concrete for example, the output will therefore be greater because the surface area described will be greater.

(40) The device of the invention can be used for a manual application, as shown in FIG. 8, or an automatic or robotic application as shown in FIG. 9.

(41) More specifically, FIG. 8 schematically illustrates an example of a manual tool comprising a pneumatic motor 1 fitted with a handle 11, a trigger 12 and a compressed air inlet hose 13, whereas FIG. 9 shows an example of an automatic tool with an electric motor 1, mounted on a robot 14. The automatic tool can also be used with a mobile device having one or more axes of movement.

(42) The device of the present invention can be applied to any heat treatment operation or process that involves rotating jets of fluid, particularly cryogenic fluids, such as surface treatment, stripping or scalping of a material, such as metals, concrete, stone, plastics, wood, ceramic, etc.