Abstract:
There is provided a proportioner for the internal admixture, at a constant proportioning ratio, of an inflowing liquid additive to a liquid carrier, the proportioner including a first flow-attenuating means, and a second flow-attenuating means, wherein the first and second flow-attenuating means are mechanically coupled and biased by biasing means against the carrier inflow.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a proportioner.  
       BACKGROUND OF THE INVENTION  
       [0002]     Fluid systems frequently require the supplementation of an additive to a pressurized carrier liquid, with the additive/carrier ratio being constant, predetermined and independent of the instantaneous parameters of pressure and flow in the system.  
         [0003]     In systems with pipelines up to a diameter of 1″, this is achieved by means of proportional injection pumps of the hydraulic in-line type. In larger systems, use is made of electro-mechanical systems in which the injection rate of on-line hydraulic pumps is computer-controlled.  
       DISCLOSURE OF THE INVENTION  
       [0004]     It is thus an object of the present invention to provide a proportioner for the proportioning of fluid additives supplied at pressures equal to, or higher than line pressure, with the additive/carrier ratio remaining constant throughout the duration of flow, a component that is of the passive type, i.e., does not need external energy sources, and has no moving parts that would require servicing or undergoing amortization, and that is capable of operating under any pressure sources acting on the additive, such as electric or hydraulic pumps, pressure-equalizing vessels and the like.  
         [0005]     According to the invention, this is achieved by providing a proportioner for the internal admixture, at a constant proportioning ratio, of an inflowing liquid additive to a liquid carrier, said proportioner comprising a first flow-attenuating means, and a second flow-attenuating means, wherein said first and second flow-attenuating means are mechanically coupled and biased by biasing means against the carrier inflow. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]     The invention is herein described, by way of example only, with reference to the accompanying drawings.  
         [0007]     With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.  
         [0008]     In the drawings:  
         [0009]      FIG. 1  illustrates a cross-sectional view of a first embodiment of the proportioner according to the present invention;  
         [0010]      FIG. 2  illustrates a variant of the embodiment of  FIG. 1  with integral pressure equalizing valve;  
         [0011]      FIG. 3  represents a variable proportioner, and  
         [0012]      FIG. 4  illustrates variants of a variable proportioner with a pressure equalizing valve. 
     
    
     DETAILED DESCRIPTION  
       [0013]     Referring now to the drawings, there is seen in  FIG. 1 a  schematic representation of the proportioner according to the invention. Shown is the proportioner  2  in its outer shape, of a substantially T-like configuration and having an inlet port  4  and an outlet port  6 . Branch  8  of proportioner  2  is usually, although not necessarily, inclined and has an additive inlet  10 .  
         [0014]     Proportioner  2  according to the invention, requires no external energy for its mixing operation, the energy used up coming from the pressure drop ΔP between the inlet side P in  of proportioner  2  and its outlet side P out : hence, ΔP=P in -P out , e.g., an optional pressure drop of about 0.3 atm. This embodiment requires the additive to reach its inlet  10  at a pressure identical to the carrier&#39;s input pressure P in .  
         [0015]     There is seen a tapering valve head  12 , which is connected to a valve stem  14 . The valve head  12  is biased by a helical spring  16  to close a gate  18  that separates inlet space  20  from outlet space  22 . Spring  16  is calculated to start yielding only to a pressure of the predetermined ΔP. Beyond that, spring  16  gives gradually and valve head  12  slowly advances, and, because of its conical shape, gradually increases the size of the annular gap between valve head  12  and gate  18 , until the established gate opening is sufficient to drop the ΔP upon the inflow of the carrier liquid. Valve head  12  withdrawal is therefore an indicator of the instantaneous inflow of the proportioner. Tapering valve head  12  is provided with a number of ribs  24  for better guidance.  
         [0016]     Further seen in  FIG. 1  is a flow-attenuator  25  of the additive, having a sleeve  26  and a substantially axial groove  28  with a bottom slanting away from valve head  12 . For easy sliding of valve stem  14  with satisfactory sealing, a Teflon R  ring  30  may be used. For further sealing effect, the Teflon R  ring may be supported and biased by an elastic O-ring  32 . Peripheral openings  34  permit the additive to discharge into space  22 . The Teflon R  ring seals, at a state of rest, a part of the non-grooved portion of the stem  14 , and thereby, prevents additive leakage into the proportioner after the mains shut off.  
         [0017]     Attenuator  25  carrying groove  28  can be replaced by other attenuators with different groove cross-sections, to enable the user to choose from a selection of mixing ratios. Since the carrier liquid and the additive are entered to the proportioner at the same pressure, P in , since the liquid and the additive are meeting for mixing at the output carrier pressure P out  and since for any carrier liquid inflow there is only one specific axial displacement of stem  14 , it requires only to calibrate the resistance of the selected effective part of the additive&#39;s attenuator, sealed by the Teflon R  ring at this position, to impose on the additive inflow to keep the required proportion with the carrier instantaneous flow.  
         [0018]     While  FIG. 1  shows the groove made in the sleeve and sealed by the outside surface of the Teflon R  ring, the opposite is feasible just as well, i.e., the attenuator  25 , in the shape of an axial, slanting groove or thread-like variable-depth helical groove of a triangular or rectangular cross-section, can be placed or made along the outer surface of the stem  14  sealed by the inner surface of the Teflon R  ring, with or without  0 -ring  32  provided in the sleeve  26 .  
         [0019]      FIG. 2  represents a variant of the embodiment of  FIG. 1 . Since this embodiment incorporates a pressure equalizer  48  at the additive input, the additive can be entered into the proportioner at any pressure, namely, at a pressure ≧P in . Here, the second flow-attenuating feature is now produced by having a tapering skirt  36 , surrounding the inside part of inlet  4 . The tapered valve head  12  is substantially flat, while the gradually widening annular gap between gate  18  and valve head  12 , is formed when the valve head  12  moves inwards. Also provided are a number of guide ribs  38 .  
         [0020]     The stem  14  carries the head  12  on the inlet side  4  and a smaller head  40  on its other end, the end of the additive attenuator. The stem  14  serves as a mechanical link between the two heads and keeps them coaxial. Both attenuators similarly comprise moving disc-shaped heads inside a coaxially disposed tubular skirt  36  and sleeve  46 .  
         [0021]     In this embodiment, sleeve  46  is advantageously an integral component of a pressure equalizer  48 , the task of which is to equalize the ingoing additive pressure P add  to respective pressures of the carrier, P in , and of the additive, P add . The pressure equalizer  48  may be independent of, i.e., detached from, the proportioner. Pressure equalizer  48  consists of a housing  50 , which has three openings: inlet opening  52  to introduce the additive at the as yet under unequalized pressure P add , outlet opening  54  through which the now pressure-equalized additive exits the pressure equalizer  48  and enters space  56  in which there exists only additive at the equalized pressure P add =P in . The third opening is inlet opening  58  through which reference pressure P in  is introduced.  
         [0022]     When valve seat  60  and valve pad  62  touch, they prevent passage of additive, with the position of valve seat  60  being controlled by the movement of diaphragm  64 , the surfaces of which also include two rigid disks  66 . The upper outer side of diaphragm  64  is exposed to P in  entering through opening  58 , while the lower side is acted upon by the additive that passes through the gap between valve seat  60  and valve pad  62 . The moment additive pressure below the inside of diaphragm  64  becomes higher than P in , diaphragm  64  is pushed upwards, thereby shutting off further additive supply. Conversely, when additive pressure below the inside of diaphragm  64  falls below P in , diaphragm  64  will flex inwards, causing valve seat  60  and valve pad  62  to separate, until pressure is equalized.  
         [0023]     The stem movement produced, which is related in proportion to the carrier flow-attenuator&#39;s head thread or channel displacement, is largest when the device is at rest and flow rate or input sets the flow of the additive. Clearly, the resistance to flow of the flow-attenuating thread or channel is largest when the device is at rest and decreases the deeper valve head  12  is pushed in against spring  16 , and conversely. The total length and cross-section of the respective flow-attenuating paths at each point of their length is so calculated that at any instantaneous position of the compound: valve head  12  and valve stem  14 , the additive flow rate will be such that the predetermined proportioning ratio K will be constant, both fluids in their respective flow-attenuating means being driven by ΔP=P in -P out .  
         [0024]     The pressure equalizer  48  can also be remotely interposed between the additive pressure source and the proportioner.  
         [0025]      FIG. 3  illustrates a proportioner of the variable type. Shown is the proportioner  2  which, in this embodiment, uses a standard T-joint. Seen are three openings: mains inlet port  4 , mains plus additive outlet port  6  made in branch  8 , and additive inlet  10 . Additive arrives at inlet  10  from a pressure equalizer (not shown). Inlet  10  is part of a mixing-ratio setting element comprising a rotatable knob  70 , a shaft  72 , advantageously integral with knot  70 , and a Teflon R  sleeve  74  that is fixedly attached to shaft  72 . Knob  70  is provided with an index line cooperating with a scale (not shown).  
         [0026]     Shaft  72  is mounted in closure  76  sealing off the additive-side of T-joint  4  and is provided with a first circumferential groove  77 , into which reaches the end of a pin  80  thread-mounted in closure  76 . Pin  80  provides shaft  72  with one degree of freedom in rotation relative to closure  76 , i.e., permit it to rotate, but prevents any axial movement. Further provided in shaft  72  are groves for O-rings for sealing purposes, as well as a central bore  78  that ends at, and communicates with, a radial hole  82  that passes between two O-rings and registers with a radial hole  83  in Teflon R  sleeve  74 .  
         [0027]     Also seen is a valve head  84  to which is fixedly attached a hollow valve stem  86  that presents a sliding fit with respect to sleeve  74 . Valve stem  86  is also provided with a number of flow-attenuating, slanting, longitudinal grooves  88  each having different dimensions, and a hole  90  via which valve space  92  can communicate with P out -space  94 . The grooves  88 , which corresponds to the desired mixture ratio, is selected by turning knob  70 .  
         [0028]     In the drawing shown, mains inlet port  4 , which is actually constituted by a sleeve  89 , the inside end portion of which is provided with a tapering skirt  91 , is blocked by valve head  84  which is biased by hydraulic force, demonstrated in two alternative embodiments, one represented above the horizontal center line, and one below that line. In both of these embodiments, the biasing force constituted previously by spring  16  is replaced by hydraulic force acting axially within a special space made in the upper half of  FIG. 3  by a rolling diaphragm  120  defining an annular space  122  communicating with additive inlet  10  via an opening  124  in central bore  78 . As the additive comes from a pressure equalizer (not shown), pressure in space  122  equals P in .  
         [0029]     The variant in the lower half of the drawing comprises an annular space  126  defined by a wall section  128  and the edge  130  of valve stem  86 . As with space  122 , space  126  communicates with inlet  10  via opening  124 . In this variant, edge  130  forms an annular piston acted upon by the additive flow. The moving valve stem  86  is sealed off by Teflon R  ring  132 .  
         [0030]     While the embodiment incorporating a rolling diaphragm  120  is more complex, requiring additional components for the mounting of diaphragm  120  (the attachment of which is shown only schematically), it has the advantage of the total absence of friction, adding sensitivity to the proportioner, reacting to the smallest of changes in the mains flow.  
         [0031]     As with increasing mains flow the annular gap between valve head  84  and skirt  91  increases, to re-establish the predetermined value of ΔP. Therefore, every mains flowrate causes valve head  84  to assume a unique position, being a measure of the instantaneous mains flowrate. As the mains flowrate increases, the valve stem  86  is slid over sleeve  74  and the effective length of the active cross-section of the selected one of several flow-attenuation grooves  88  becomes shorter. A set of ribs  96  prevents valve head  84  from rotating and maintains concentricity between the moving valve head  84  and skirt  91 .  
         [0032]      FIG. 4  illustrates a proportioner according to the present invention of a variable type, including an integral pressure equalizer valve through which the additive is being admitted into the proportioner at the line P in .  
         [0033]     The pressure equalizing valve operates in the same manner as the valve according to the embodiment of  FIG. 2 , except that the stem  14  passes the pressure equalizing valve in its center and is hollow, in order to pass the additive entering inlet opening  52 . The additive is then admitted via the gap in the valve seat, into the opening  140 , to the hollow  142  in stem  14  and therefrom, it exits into space  144  and to the feeding channel  146 . On its way, the additive reaches the inner side of the diaphragm  148  via opening  150 . The pressure equalizer utilizes three  0 -ring seals  152  to separate between different pressure zones.  
         [0034]     The mains attenuator differs from the one in  FIG. 3  by forming the attenuation grooves  160  on the turn able part of stem  14 . The additive is directed to the chosen groove by the selecting/feeding channel  146  by means of turning knob  162 . The additive flows from the selected groove  160  via opening  164  and the channels  166  to P out  space  94 . The valve head  84  is coaxially guided and angularly restricted by a set of pins  168  freely sliding in grooves  170 . Pins  172  and  174  keep the angular positions during assembly, to ensure proper operation of knob  162  according to scale  176 . The two end portions of the device are sealed by O rings  178 .  
         [0035]     It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrated embodiments and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.