US 3560105 A
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Description (OCR text may contain errors)
Feb. 2,1911 F. .CILIFFIORD 3,560,105
IMPELLER' PUMP Filed Jan. 2, 1969 v 2 Sheets-Sheet 2 United States Patent Filed Jan. 2, 1969, Ser. No. 788,446 Claims priority, applicatign Great Britain, Jan. 2, 1968, 11/6 8 Int. Cl. F04d 29/40, 31/00; FOld 25/24 US. Cl. 415116 4 Claims ABSTRACT OF THE DISCLOSURE A reversible impeller pump comprising a casing defining a chamber in which is mounted a rotary impeller and which has two circumferentially spaced ports communicating with liquid flow conduits, and a reversing mechanism comprising a conduit substantially in the form of a pipe elbow which is mounted in the chamber with one limb thereof in communication with the eye of the impeller and which is turnable about the axis of the other limb to bring the latter selectively into register completely or partially with the ports, whereby the direction of liquid flow through the ports can be reversed and the rate of delivery can be varied.
This invention relates to pumps for propelling liquids through systems.
In particular, the invention is concerned with a pump of the kind comprising a casing in which is mounted a rotary impeller and which has ports connectible to liquid flow conduits, and a reversing mechanism operable to reverse the direction of liquid flow through the ports.
The invention is primarily, but not exclusively, concerned with reversible impeller pumps for use in dyeing systems in which dye liquor travels in a closed circuit.
Various forms of reversible impeller pumps of the kind concerned have previously been proposed, but these have several disadvantages.
In some prior pumps the reversing mechanism includes at least one component which is disposed very close to the rotary impeller; thus, in one example, this mechanism includes a valve shell which surrounds the impeller and is turnable to reverse the direction of liquid flow through the ports. The primary disadvantage of pumps having such a shell is that the forces exerted on the valve shell and the impeller by the liquid travelling through the pump tend to deflect these components so that the shell fouls the impeller and, as a result, may damage it. This problem is aggravated by the fact that the valve shell is supported by a mounting outside the pump casing and is therefore susceptible to deflection by the forces set up by the liquid. Moreover, the impeller and its mountings are subjected to unevenly balanced forces which act primarily in diametrically opposed directions.
Prior pumps having a reversing mechanism of the general form described above have the disadvantage that there is a tendency for any foreign matter in the liquid being pumped to become lodged between the impeller and the said component of the reversing mechanism.
Further disadvantages of prior pumps are that their reversing mechanisms are of complicated constructions and that the path of liquid fiow through them is uneven, resulting in a loss of efficiency.
With the object of eliminating the above disadvantages, the present invention provides an improved form of reversible impeller pump of the kind concerned wherein the rotary impeller is mounted in a chamber with which the two ports communicate, and the reversing mechanism includes a conduit which is mounted in the ice chamber, one end of which is in communication with the eye of the impeller, and which is turnable to bring the other end thereof into register with one or the other of the ports, whereby the direction of liquid flow through the ports is reversible.
Thus, the direction of liquid flow through the ports is determined by which of the ports is in register with the conduit, the other port communicating directly with the chamber surrounding the impeller. In operation the liquid enters the pump through the first-mentioned port and is drawn under the suction effect of the impeller through the conduit and the eye of the impeller; the liquid is then thrown out by the impeller into the chamber whence it passes through the second-mentioned port. Reversal of the direction of liquid flow, i.e. so that the liquid enters through the second-mentioned port and is discharged through the first-mentioned port, is effected by turning the conduit to bring it into register with the second-mentioned port. There is no need for any change in the direction of rotation of the impeller.
In implementing the invention, the chamber may be of circular cross section with the impeller mounted concentrically therein, the two ports may be arranged at circumferentially spaced locations around the chamber, and the conduit may be substantially in the form of a pipe elbow one limb of which is coaxial with the impeller and in communication with the eye thereof, and the other limb of which is arranged to be selectively brought into register with the ports by turning of the conduit about the axis of the first-mentioned limb.
A pump constructed in accordance with the invention has several advantages. Firstly, since the reversing mechanism, i.e. the conduit, is not intimately associated with the rotary impeller as heretofore, there is a greater freedom of design. The impeller can be of a quite conventional form, and the reversing mechanism can be freely made of a simple construction. Moreover, since the reversing mechanism need not be disposed close to the impeller with no intermediate fixed part between them, there is no danger of the impeller being fouled by the mechanism or the operation of the impeller being impaired by any foreign matter in the liquid being pumped. Furthermore, since the impeller throws out the liquid all round it, i.e. all round the aforesaid annular space, the forces set up by the liquid are not concentrated at any particular location, and accordingly any unevenly balanced forces applied to the impeller and the reversing mechanism are minimised. In addition, the path of the liquid flow through the pump, i.e. through the conduit and the chamber, is smoother than in previous pumps. The number of valve apertures is kept to a minimum and therefore the reversing mechanism is simple in construction and operation.
It is often required to add large quantities of liquid to the liquid travelling through a pump, particularly in a dyeing installation in which dye liquor is being circulated through a dyeing vessel by the pump. An important facility provided by the invention is that this can advantageously be effected at the suction zone of the pump. Previously the addition of liquid to the liquid being pumped could not be effected at the suction zone because the location of this zone was changed when the direction of liquid flow was reversed.
A preferred embodiment of a reversible impeller pump according to the invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a vertical longitudinal section through the pump of this example.
FIG. 2 is a cross section through the pump taken on the lines 11-11 of FIG. 1, and
FIGS. 3A, 3B and 3C are diagrammatic views, corresponding to the view shown in FIG. 2, showing the reversing mechanism of the pump in three different positions.
The pump illustrated in the drawings is primarily intended for use in a dyeing system in which it circulates dye liquor in a circuit including a dyeing vessel.
Referring to the drawings, the pump comprises a casing 1 generally of cylindrical form. This casing comprises a cylindrical part 1a, and a part 1b which is secured to one end of the cylindrical part and carries an end wall 10, an end wall 1d being secured to the other end of the cylindrical part. The casing defines a chamber 2, and mounted concentrically in this chamber is a rotary impeller 3 so that there is an annular space around the impeller. The latter is supported at one end thereof by an annular drive part 4 which extends through the end wall 1c of the casing and has secured therein the drive shaft 5 of a motor (not shown) for driving the impeller. This motor is mounted on a plate 6 carried by the pump casing. Thus, the drive to the impeller is direct, this avoiding the necessity for a belt drive as used in prior pumps.
A mechanical rotational seal 7 similar to that described and illustrated in our Pat. No. 3,360,968 is disposed around the drive part 4 at the location where it passes through the end wall 10.
Mounted in the chamber 2 is a fiow reversing conduit 8 substantially in the form of a pipe elbow one limb of which, the shorter, is coaxial with the impeller and in communication with the eye E thereof, and the longer limb of which extends radially outwards and is arranged to cooperate selectively with two ports 9 formed at circumferentially spaced locations in the cylindrical part 1a of the casing 1. These ports open into the chamber 2 and communicate respectively with two liquid flow conduits 10 which are adapted to have pipes of the circuit concerned connected thereto.
In order that the relevant end of the conduit 8 can be brought selectively into register with the ports 9 to reverse the direction of liquid flow through the latter, the conduit is turnable about the axis of the shorter limb thereof. Thus, the conduit is carried by a spindle 11, and this spindle is in turn supported at one end by the end wall In! of the casing and at the other end by a ring 12 inside the chamber 2. The spindle 11 projects through the end wall 1d and is provided outside the casing with means for turning the conduit; this means comprises a handle 13 in the embodiment shown but may be of other forms, for example a small motor. The ring 12 surrounds the free end of the impeller 3 and is fixed to the pump casing. Extending inwardly from the ring is a number of regularly spaced radial arms 14 which carry a central bearing bush 15 in which the inner end of the spindle 11 is located. This bush is coaxial with and close to the eye E of the impeller 3. Thus, one of the mountings of the conduit 8 is located at the point where any forces set up by the liquid being pumped act, i.e. adjacent the eye E of the impeller, and the conduit is therefore less susceptible to deflection than, for example, the valve shell in the above described prior arrangement. The relevant end of the conduit is provided with a ring 16 which bears through the medium of a sealing element 17 against the ring 12.
It will be observed that the ring 12 is formed to provide around the edge of the free end of the impeller 3 an annular space 18 which communicates with the gap between this end of the impeller, i.e. its eye E, on the one hand and the radial arms 14 and bush 15 on the other hand. Opening into this space 18 is an inlet conduit 19 provided in the casing, and this conduit can be used for the addition of large quantities of liquid to the liquid being pumped by the pump, this addition therefore being effected at the suction zone of the pump.
If desired, the pump may incorporate the features of the invention of our Pat. No. 3,360,968 whereby small 4 quantities of make-up liquid to be added to liquid being pumped by the pump are fed to the liquid inside the pump in the vicinity of the rotational seal 7. Thus, where the pump is to be used in a system, for example a dyeing system, comprising a circuit in which liquid at a high temperature is circulated by the pump and into which liquid at a lower temperature is fed to make up the hot liquid to the required amount or for other purposes (in addition to the large quantities mentioned above), the liquid at a lower temperature will be introduced into the circuit in the vicinity of the seal 7 thereby to isolate or protect the seal from the effect of the hot liquid. To facilitate this, the pump may be provided with a further inlet conduit 20 which is connected to an opening in the end wall 1c of the casing behind the impeller and which can be used to feed the small quantities of make-up liquid into the chamber 2 in the vicinity of the seal 7.
Referring to FIGS. 3A, 3B and 3C, operation of the pump is as follows:
The direction of liquid flow through the ports 9 is determined by which of the ports has the conduit 8 in register therewith. With the conduit in the position shown in FIG. 3A, the liquid enters the pump through the port A with which the conduit is in register, and is drawn under the suction effect of the impeller through the conduit 8 and the eye E of the impeller 3. The liquid is then thrown out by the impeller into the chamber 2 whence it passes through the other port B which communicates directly with the latter. Reversal of the direction of liquid flow is effected by turning the conduit 8 into the position shown in FIG. 3B (and also FIG. 2) so that the liquid enters the pump through the port B with which the conduit 8 is now in register, and is discharged through the port A which now communicates with the chamber 2.
The circumferential spacing of the two ports 9 is such that the conduit 8 can be positioned not only in two positions in which it is completely in register with the respective ports, but also in an infinite number of intermediate positions in which it is partially in register, to different extents, with both ports, this enabling the rate of delivery of the liquid to be varied, as desired, for either direction of liquid flow. Thus, each of the first two positions provides the maximum rate of delivery in the direction of liquid flow concerned. When the conduit 8 is in the central position as shown in FIG. 3C, the pump delivers no liquid whatsoever, since the liquid expelled from the chamber 2 is not delivered through one port to the associated liquid flow conduit, but passes in equal amounts through the two ports and flows back into the conduit 8 which conveys it back to the impeller, whence it is pumped into the chamber again. Thus, the liquid circulates continuously inside the pump, and this arrangement has the advantage that no high pressures are set up inside the pump as in prior arrangements in which the ports are completely closed to shut off the delivery of liquid. The rate of delivery of liquid from the pump can be varied by adjusting the conduit 8 between the central position and one of the outer, maximum flow positions depending on the direction of liquid flow required. Thus, in such a position, the liquid expelled from the chamber flows through the two portsa larger quantity through the port corresponding to the direction of liquid flow selected than through the other port. Most of the liquid from the first port is discharged and the remainder passes into the conduit for recirculation, whereas all the liquid from the second port passes with the incoming liquid into the conduit.
1. A reversible impeller pump comprising a casing defining a chamber of circular cross section which has ports arranged at circumferentially spaced locations around the chamber and connectible to liquid flow conduits, a rotary impeller mounted concentrically in the chamber and spaced therefrom to form an annular space around the impeller, and a reversing mechanism including a conduit mounted in the chamber and substantially in the form of a pipe elbow, one limb of this conduit being coaxial with the impeller and in communication with the eye thereof and the conduit being rotatable about the axis of the side one limb to bring the other limb thereof selectively into register with the ports so that the direction of liquid flow through the ports is reversible, said impeller being supported at one end by its drive shaft which extends through one end wall of the casing, and the other, eye end of the impeller being located within a fixed ring against which the relevant end of the conduit bears in sealing fashion, said ring having a number of regularly spaced, inwardly extending radial arms carrying a bearing bush which is coaxial with the adjacent to the eye of the impeller and which supports one end of a spindle carrying the conduit, the other end of said spindle being supported by the end wall of the casing remote from the end wall through which the drive shaft extends, projecting from the casing and being provided outside the casing with means for turning the conduit.
2. A reversible impeller pump according to claim 1 wherein said ports comprise two ports wherein the circumferential spacing of the two ports is such that the conduit can be positioned not only in two positions in which it is completely in register with the respective ports, but also in an infinite number of intermediate positions in which it is partiallywin register, to different extents, with both ports, whereby the rate of delivery can be varied for either direction of liquid fiow.
3. A reversible impeller pump according to claim 1, wherein the ring is formed to provide around the edge of the eye end of the impeller an annular space which communicates with the gap between this end of the impeller on the one hand and the radial arms and bearing bush on the other hand, and an inlet conduit leading to the said annular space is provided in the casing for facilitating the addition at the suction zone of large quantities of liquid to liquid being pumped by the pump.
4. A reversible impeller pump according to claim 1, wherein there is provided sealing means for forming a rotational seal between the drive shaft of the impeller and the relevant end wall of the casing, and the casing is provided adjacent the sealing means with an inlet conduit for supplying small quantities of make-up liquid for addition to liquid being pumped by the pump, whereby these quantities are fed to the liquid in the vicinity of the sealing means.
References Cited UNITED STATES PATENTS 1,548,247 8/1925 Bennett 103-3 3,360,968 1/1968 Swindall et a1. 68189 FOREIGN PATENTS 219,319 12/1958 Australia 1033 547,740 9/1956 Italy 1033 CARLTON R. CROYLE, Primary Examiner J. J. VRABLIK, Assistant Examiner US. Cl. X.R.