WO1979000350A1

WO1979000350A1 - Deaerator device

Info

Publication number: WO1979000350A1
Application number: PCT/US1978/000122
Authority: WO
Inventors: D Krohn; J Wellauer
Original assignee: Caterpillar Tractor Co
Priority date: 1977-12-07
Filing date: 1978-10-20
Publication date: 1979-06-28
Also published as: CA1109808A; GB2035852A; GB2035852B; JPS54500110A

Abstract

A deaerator device (10) has a tubular casing (36) and an internal helical blade (38) defines an axial opening (60) through the center thereof toward which entrained gas bubbles will converge as a fluid travels through the casing (36). A vent pipe (40) collects the gas bubbles at the opening (60) and communicates them away from the casing (36).

Description

Deaerator Device

Technical Field

This invention relates generally to a deae- rator device, and more particularly to a compact deaerator device for effectively separating gas from a fluid by centrifugal action.

Background Art

It is common to circulate a cooling fluid through an engine and an associated heat exchanger or radiator core, but freauently gas is entrained in the fluid. This decreases the volume of fluid circulated by the pump and decreases the efficiency of the closed loop cooling system as the fluid and entrained air recirculated therethrough. This can cause undesirable heating of the engine and can lead to such a diverse and undesirable side effect as pitting of the internal surfaces of certain engine components.

While various radiator top tank constructions have been employed to separate air and gas bubbles from the fluid coolant by utilizing baffles and swirl chambers, such constructions have not been satisfac¬ tory from the standpoint that they have increased the size and expense of the radiator system to an ex- cessive degree.

Exemplifying the prior art in the field of devices for separating gas from a fluid are U.S. Patent Nos. 1,279,859 issued September 24, 1918 to J. K. Putnam; 2,316,729 issued April 13, 1943 to H. C. Tryon; 2,494,427 issued January 10, 1950 to

J. B. Bidwell, et al; and 3,028,716 issued April 10, 1962 to R. W. Sanderson, et al. However, such prior constructions are excessively long, complex and

0MP1 yfy. wipo costly, or have been relatively ineffective in separa¬ ting the gas bubbles from the fluid at a desirably low pressure drop. More specifically, some prior art de- aerators have had centrally located plugs or pipes which have interfered with the desired straight- through fluid flow path. Other deaerators have had restrictive passages for the gas bubbles to go through. These major disadvantages contribute to excessive pres¬ sure drop or ineffectiveness. In view of the above, it would be advanta¬ geous to provide merely the addition of a simple and compact device to any existing engine cooling system. Preferably, such a device should be capable of con¬ venient insertion in series with the existing hoses or conduits, of the engine cooling system and should not create an excessive pressure drop by incorporating bends or walls which require a substantial change in direction of the cooling fluid.

Disclosure of Invention The present invention is directed to over¬ coming one or more of the problems as set forth above. In one aspect of the present invention this is accomplished by providing a deaerator device includ¬ ing a single tubular casing having a substantially un- interrupted cylindrical inner wall, and a helical blade connected to the inner wall which defines an unob¬ structed central opening on the axis of the casing. The helical blade moves entrained gas bubbles converg- ingly inwardly toward the axis as fluid flows through the casing, and a vent pipe having an entry end located adjacent the exit end of the helical blade collects gas bubbles emenating from the central opening and communicates them outwardly of the casing. Advantageously, the instant deaerator device provides a substantially straight-through flow path for a relatively low pressure drop across it, and is constructed so that it can be conveniently connected in series with a hose line of an engine cooling system or the like. Moreover, it not only is axially and radially compact, but also has a high degree of effec¬ tiveness.

Other advantages of the present invention will become more readily apparent upon reference to the accompanying drawings and the following descrip¬ tion.

Brief Description of Drawings FIG. 1 is a diagrammatic side elevational view of an engine cooling system incorporating one embodiment of the deaerator device of the present invention thereon.

FIG. 2 is a diagrammatic and enlarged view of the deaerator device shown in FIG. 1 with a portion broken open to better illustrate details of its in¬ ternal construction.

Best Mode for Carrying Out the Invention

Referring to FIGS. 1 and 2 there is shown a deaerator device 10 constructed in accordance with the present invention in series with a pressurized engine cooling system 12. The engine cooling system generally includes a fluid-cooled engine 14, a heat exchanger or radiator 16, and motor means 17 such as a conventional engine driven pump for circulating fluid in a substantially closed loop therebetween. More particularly, the radiatdr has a dual compartment top or inlet tank 18 with a conventional filler and pressure relief cap 19 releasably connected to the top -4-

thereof, a bottom or outlet tank 20, and a core 21 interposed between the tanks with a plurality of fluid passages of the usual type therein. The top tank is divided into an upper section 22 and a lower section 23 by a horizontal partition 24, and a venting stand- pipe 25 extends through the partition toward the top of the upper section. A shunt line 26 extends from th bottom of the upper section to the bottom tank for filling purposes. A flexible conduit or hose 28 is releasably connected to the radiator bottom tank 20 and to the engine 14 adjacent the pump 17 for communicating fluid from the radiator 16 to the pump and subsequentl through various internal passages in the engine, not shown, as representatively shown by the flow indicatin arrows. After passing through the engine and being heated thereby, the fluid passes outwardly to a flex¬ ible outlet conduit or hose 30 releasably connected to the engine. The deaerating device 10 is releasably coupled in series between this outlet hose and another conduit or hose 32 releasably coupled to the lower section 23 of the top tank 18 to generally complete the closed loop recirculating cooling system 12.

Preferably, the hoses 28, 30 and 32 are of rubber or elastomeric material and telescopically over¬ lap their respectively associated and preferably rigid metal parts so that a plurality of encircling hose clamps 34 can be utilized therewith. Particularly, in a well known manner, such clamps are individually adjustable by a screwdriver or wrench to tightly and sealingly couple the ends of the hoses thereto.

Turning now to FIG. 2, it may be noted that the deaerator device 10 generally includes a single tubular casing 36, a single helical blade 38 within the casing, and a vent pipe 40. The axially compact tubular casing is generally cylindrical in construction with an inlet end 42, an outlet end 44, and an annular hose engaging coupling or ridge 46 at each of these ends. Preferably, the tubular casing is made of metal and the annular ridges are integrally formed therein. The hose clamps 34 encircle and tightly clamp the res¬ pective hoses 30 and 32 to the exterior surface of the tubular casing immediately adjacent and axially in¬ wardly of these ridges to provide a more positive seal thereat. Moreover, the tubular casing also has a sub¬ stantially uninterrupted cylindrical internal wall 48 having a preselected diameter A arranged along a cen¬ tral axis 50, and a radial opening 52 is provided therethrough. The helical blade 38 is preferably constructed of either metal or plastic material having an. inlet edge 56 and outlet edge 58, and preferably at least one and not more than about three revolutions there¬ between. In accordance with one aspect of the inven- tion the helical blade has turns of constant slope between the opposite edges 56 and 58, a substantially constant external diameter so that it can make sealed engagement with the internal wall 48 of the tubular casing 36, and a substantially constant internal diameter serving to define in unobstructed cylindrical axial opening 60 for the free passage of fluid centrally therethrough along the axis 50. The axial or central opening 60 preferably has a preselected diameter B having a range of from 10% to 25% of the preselected diameter A of the internal wall 48. Preferably also, the inlet edge 56 of the blade is located adjacent to the inlet end 42 of the tubular casing, and the out¬ let edge 58 is located between 50% and 75% of the over¬ all length L of the casing from the inlet end.

OMPI

< WIPO Referring now to the vent pipe 40,.it may be noted to extend through the opening 52 in the tubular casing 36. The pipe has a right angle radius bend so that it is substantially normal to the casing at the opening 52 and is substantially parallel to and concen¬ tric with the axis 50 at an entry end 64. The entry end of the intake pipe has a preselected inside diamete C and is located adjacent the outlet edge 58 of the blade. Preferably, the entry end is stabilizingly se- cured to the helical blade substantially at the outlet edge. A flexible conduit or hose 66 is releasably con¬ nected to the vent pipe exteriorly of the tubular casing and is in communication with the top of the uppe section 22 of the top tank 18 as is shown in FIG. 1. Two embodiments of the deaerator device 10 have the following parameters:

Example 1 Example 2 I.D. casing 36 (A) 59.3 mm (2.33") 59.3 mm (2.3 I.D. of opening 60 (B) 11.1 mm (0.44") 11.1 mm (0.4 I.D. of pipe 62 (C) 6.2 mm (0.25") 6.2 mm (0.2 Overall axial length(L) 152.4 mm (6.00") 152.4 mm (6.0 Helix lead (D) 42.0 mm (1.65") 57.2 mm (2.2

Revolutions of blade 2 1.5

In each of the above noted examples, the tubu lar casing 36 is substantially an uninterrupted cylin¬ drical tube with the overall length L being preferably limited to less than about three times the inside diameter A of the casing. This provides an extremely compact deaerator device while simultaneously having maximum effectiveness. While a tubular casing having an overall length greater than three times the inside diameter of the internal wall 48 could be constructed, it would either be more difficult or impossible to in¬ stall between the engine 14 and radiator 16 in the extremely limited space normally provided on a vehicle, for example.

Industrial Applicability

In operation, a fluid such as heated water with entrained gas bubbles therein is delivered upwardly to the deaerator device 10 by the pressurized engine cooling system 12. The helical blade 38 thereby imparts a swirling motion to the water so that the water is forced radially outwardly by centrifugal action and the lighter gas bubbles are displaced and converge radially inwardly toward the axis 50 as the water moves axially through the tubular casing 36. Subsequently, the gas bubbles congregate in a converging manner within the axial opening 60, whereupon the water and gas bubbles are collected at the entry end 64 of the vent pipe 40. In this way the major portion of the recirculating water flow, for example more than 70%, without excessive aera¬ tion is directed to the lower section 23 or liquid part of the top tank 18, while the remainder is directed from the vent pipe 40 to the top of the upper section 22 or gaseous part of the top tank via the hose 66.

It is contemplated that the entry end 64 of the vent pipe 40 may be divergingly flared as shown in FIG. 2, or may be otherwise presented with a compact conical intake collector, not shown, to better funnel the gas bubbles emanating from the juxtaposed opening 60 within the helical blade 38 into the vent pipe. It being understood that the facing cross sectional areas of the opening 60 and the vent pipe can be tailored to match the parameters of the cooling system 12.

Other aspects, objects and advantages will become apparent from a study of the specification, drawings and appended claims.

OMPI

Claims

1. A deaerator device comprising: a single tubular casing having an inlet end, an outlet end, a substantially uninterrupted cylindrical inner wall and an axis; a helical blade connected to said inner wall, having an outlet edge and defining an unobstructed cen¬ tral opening on the axis, said helical blade being of a construction sufficient for moving entrained gas bubbles relatively freely and convergingly toward the axis and said central opening as fluid to be treated flows into said inlet end along said axis, through said tubular casing and to said outlet end along said-axis; and a vent pipe having an entry end located ad- jacent said outlet edge of said helical blade on the axis, said vent pipe being of a construction sufficient for collecting the gas bubbles emanating from said cen¬ tral opening and communicating the gas bubbles outwardly of the tubular casing,

2. The deaerator device of claim 1 wherein said inner wall has a first preselected diameter, said central opening has a second preselected diameter, and said second preselected diameter is between about 10 and 25 percent of said first preselected diameter.

3. The deaerator device of claim 1 wherein said tubular casing has a preselected overall length, said inner wall has a preselected diameter, and said preselected overall length is less than about three times said preselected diameter.

4. The deaerator device of claim 1 wherein said helical blade is a single blade having less than about three revolutions.

5. The deaerator device of claim 4 wherein said helical blade preferably has at least one revo¬ lution.

6. The deaerator device of claim 1 wherein said tubular casing has an annular hose engaging coupling at each of said inlet and outlet ends.

7. The deaerator device of claim 1 wherein said entry end of said vent pipe is connected to said helical blade.

8. The deaerator device of claim 1 wherein said tubular casing has a preselected overall length between said inlet and outlet ends, said entry end of said vent pipe being located between 50 and 75 percent of said overall length from said inlet end of said tubular casing.

OMPI