A pump incorporated in a textile package dyeing machine

Abstract: A pump has a bearing stand (3) in which a pump shaft (1) is mounted to be driven by an electric motor. The shaft (1) mounts an impeller (9) having blades (10) which cause fluid entering through an axial inlet nozzle (11) to flow, by rotation of the impeller in one direction through a centrifugal exit nozzle (12) formed by a suitably located quarter toroid (13 a ), and a half toroid (14), formed as sheet metal pressings. When the impeller (9) is rotated in the opposite direction the centrifugal nozzle (12) acts as an entry nozzle and the axial nozzle (11) acts as an axial discharge. The pump is particularly suitable for treating textile yarns since said one direction of rotation can be used for out-to-in treatment liquor flow where relatively high resistance is encountered and said opposite direction of rotation can be used for in-to-out treatment liquor flow where resistance is relatively lower.

Description: The invention relates to a pump incorporated in a textile package dyeing machine. Yarn for textile manufacturing purposes is commonly wound on perforated tubular cores to form permeable packages through which liquor may be circulated for wet processes such as bleaching or dyeing. Both centrifugal pumps and axial flow pumps have been used for circulating dye liquor through textile material in machines for dyeing yarn and other textile products. The characteristics of the two types of pumps are dissimilar. Yarn packages are supported on perforated tubular or fluted spindles on package carriers which may be submersed in liquor for treatment. The dyeing process involves the circulation of dye liquor through the yarn, via these supporting spindles, in a machine having provision for adding dyes and chemicals, and raising the temperature of the liquor while periodically reversing the direction of liquor flow. The most level dyeings are obtained by passing the entire volume of dye liquor through the load at least once while increasing the temperature by a fixed increment before repeating the sequence in the opposite direction. Flow from inside to out tends to open up the package and to make it easier to penetrate, and flow from outside to in tends to compress the package and so increase its resistance to flow. It follows therefore that applying the same pressure in both cases does not produce the same rate of bath turnover. For applications which offer low resistance to flow, axial flow pumps can deliver higher flow rates than centrifugal pumps, and have been used instead of centrifugal pumps in textile package dyeing machines, the flow being reversed by reversing the direction of rotation of the axial flow impeller. GB-989832 and EP-A-0138726 disclose such axial flow pumps. Because the axial flow pump performs best against low resistance, system resistance must be reduced to a minimum, as for example by mounting the axial flow impeller vertically inside the machine, directly underneath the package carrier. However, as conventional direct drive with the electric motor in line with the pump would greatly increase the height of the machine and put the motor directly under the vessel in a location vulnerable to leaks, the motor can be mounted with its axis vertical, with the impeller being driven by belts. Attempts to incorporate an axial flow pump into an external circulating system introduce system resistance and restrict the designer to the alternatives of using double seals and bearings so as properly to support the impeller, or of having to accept a greater than desirable impeller overhang, as well as a sharp change of direction in system pipework if supported only from one end. This sharp change of direction introduces yet more resistance to which the axial flow pump is not suited. The softer the package, the greater is the difference in density when flow is changed from inside-out to outside-in, and in some circumstances in machines with axial flow pumps, it has been known for the outside-in flow rate to fall to zero, and for reversal to be discontinued as it served no purpose. Similarly, in machines for dyeing softly wound packages in open vessels, in which the temperature is raised as closely as possible to the boiling point of water while the direction of flow is periodically reversed, the characteristics of the centrifugal pump favour the maintenance of outside-in flow at the higher temperatures. The centrifugal pump has been favoured in machines for dyeing relatively tight packages, or which have external circulating systems offering resistance to liquor flow. The axial flow pump has been favoured in systems for dyeing soft packages, which offer little resistance to flow. It thus follows that in principle the centrifugal pump is better able to deal with the outside-in flow condition, and the axial flow pump is more suited to the inside-out flow condition. It would not be practical or economical to equip such a machine with two pumps, two circulating systems and two motors to exploit the different characteristics for the above purposes. Accordingly, the present invention provides a pump for incorporation in a textile package dyeing machine, including a cylindrical housing, an axial flow impeller concentrically rotatably disposed in the housing to pump treatment liquor through the machine, a first nozzle at one end and a second nozzle at the other end, wherein the first nozzle is an axial nozzle through which a liquor flow having a flow and pressure performance characteristic typical for an axial flow pump is obtained when the impeller is rotated in one direction and the second nozzle is a centrifugal nozzle through which a liquor flow having a flow and pressure performance characteristic typical for a centrifugal pump is obtained when the impeller is rotated in the opposite direction characterised in that, in use, axial flow operation is provided in an inside-out direction through a textile package in the dyeing machine and a centrifugal flow operation is provided in an outside in direction through the textile package. The present invention enables the characteristics of both types of pumps to be used to best advantage by mounting a conventional axial flow impeller inside the vessel with a suitably shaped discharge nozzle to permit liquor to exit in a partly radial direction on outside-in flow in order to retain a radial component of velocity in the discharged liquor, and by means of a divergent discharge passage utilise centrifugal force to augment the head potential of the conventional axial flow impeller, and for the same nozzle also to provide an easy path to guide liquor smoothly into the impeller eye by means of partly toroid deflectors so that conventional axial flow operation can be provided in the inside-out condition. In addition to providing performance characteristics not otherwise available, the invention permits the axial flow pump to be used with a traditional bearing stand and horizontal driveshaft, using an in-line drive motor as is commonly used with centrifugal pumps. The invention enables this centrifugal force to be used in one direction of rotation, instead of being cancelled out. The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figure 1 is a sectional view through a pump incorporated in a textile package dyeing machine according to the invention; and Figures 2a and 2b show, respectively, use of the pump of Figure 1 for inside-out treatment of textile yarns and for outside-in treatment of textile yarns, by treatment liquor. Referring to the drawings, a pump shaft 1 has a first key 2, whereby it can be coupled to drive means such as an electric motor (not shown), and extends through a bearing stand 3 in which bearings 4, 5 are provided. The pump shaft further extends through a simple pump backplate 6 which is secured by bolts 7 to the bearing stand 3 and which mounts shaft seals 8. An impeller 9 is keyed by a second key 15 to the other end of the pump shaft 1 to that end having the first key 2 and has a cylindrical boss 9a in which are set blades 10 at an angle to its axis. The impeller 9 may be generally similar to the propellers used in jet-ski or similar aquatic equipment. On the left-hand side as viewed in Figure 1 that is at one end of a concentrically mounted impeller housing 13, is an axial nozzle 11 and on the right-hand side of the concentrically mounted impeller housing 13, that is at the other end, is a quarter toroid pressing 13a. The pump backplate 6 is, as on conventional centrifugal pumps, equipped with a half torus pressing 14 to form, with the quarter toroid pressing 13a, a centrifugal nozzle 12. When the rotation of the pump shaft 1 is as shown in Figure 2a, liquor flows from right to left, liquor in the region of a vessel 16 underneath a package carrier 17 having unrestricted access to the impeller 9, and delivers a liquor flow into a conduit 18 joined by the axial nozzle 11 to the impeller housing 13 in the manner of a conventional axial flow pump. The conduit 18 leads to the perforated cores 19 of textile packages 20 so that liquor can pass through the packages 20 in inside-out flow to return to the vessel 16. In the opposite direction of flow shown in Figure 2b, the liquor leaving the impeller 9 is free to exit radially, as it would in a centrifugal pump, so that the pressure developed in the rotating liquor by centrifugal force and amplified by the divergent centrifugal exit nozzle 12, formed by the pressing 13a and the pressing 14, augments the limited pressure available to give a characteristic typical for a centrifugal pump. The liquor passes to the vessel 16 to enter the packages 20 for outside-in flow and through the perforated cores 19 before returning to the impeller 9 via the conduit 18, the axial nozzle 1and the housing 13.

Claims: A pump for incorporation in a textile package dyeing machine, including a cylindrical housing (13), an axial flow impeller (9) concentrically rotatably disposed in the housing (13) to pump treatment liquor through the machine, a first nozzle (11) at one end and a second nozzle (12) at the other end, wherein the first nozzle (11) is an axial nozzle through which a liquor flow having a flow and pressure performance characteristic typical for an axial flow pump is obtained when the impeller (9) is rotated in one direction and the second nozzle (12) is a centrifugal nozzle through which a liquor flow having a flow and pressure performance characteristic typical for a centrifugal pump is obtained when the impeller (9) is rotated in the opposite direction characterised in that , in use, axial flow operation is provided in an inside-out direction through a textile package (20) in the dyeing machine and a centrifugal flow operation is provided in an outside-in direction through the textile package (20). A pump according to claim 1, further including a conduit (18) connected to the first nozzle (11) for connecting the inside of a textile package (20) of a package carrier (17) in the machine to the pump. A pump according to claim 1 or 2, including a bearing stand (3) with a horizontal axis. A pump according to claim 3, wherein the centrifugal nozzle (12) includes deflectors (13a, 14) of partial toroid shape for providing a smooth flow path of decreasing area to guide liquor flow to the impeller (9) when rotated in the one direction, and an unrestricted exit of increasing area radially outwards for liquor flow from the impeller (9) when rotated in the opposite direction.

Inventors: CLIFFORD FRANK GRAHAM, TSUI WILLIAM TAK MING, CLIFFORD, FRANK GRAHAM, TSUI, WILLIAM TAK MING
Applicants: FALMER INVESTMENT LTD, FALMER INVESTMENTS LIMITED
Application year: 1997
Main classification: D06B5
IPC codes: D06B23, D06B5, F04D29, F04D3