US2230717A - Pumping means - Google Patents

Description

Feb. 4, 1941. w, 35 LANCEY 2,230,717

PUMPING MEANS Filed 001:. 24, 1939 v3 Sheets-Sheet l INVENTOR ATTORNEYS Feb. 4, 1941. w. H. DE LANCEY 2,230,717

PUMP ING MEANS Filed Oct. 24, 1959 3 Sheets-Sheet 2 INVENTOR +m ATTO R N EYS Feb. 4, 1941.

W. H. DE LANCEY PUMPING MEANS a Sheets-Shee'd 3 Filed Oct. 24, 1939 5 l hnmuna Patented Feb. 4, 1941 PATENT OFFICE PUMPING MEANS Warren H. De Lancey, Springfield, Masa, assignor to Gilbert & Barker Manufacturing Company, West Springfield, Mass., a corporation of Massachusetts Application October 24, 1939, Serial No. 301,013

9 Claims.

This invention relates to an improved pumping unit, which while capable 013- other applications, is particularly suitable for use in oil burners.

The invention finds one advantageous use as a means for pumping the oil to an oil burner and it may, at the same time, be combined with a fan for supplying air to the burner.

The invention has for one object the provision in an oil burner of a motor-driven, air-supplying fan and an oil-supplying pump-the latter being coupled to the motor solely by electromagnetic meansthe arrangement being characterized in that the usual stuffing box, or other mechanical seal associated with the drive shaft of the pump, is eliminated and the oil pump with one element of the electromagnetic drive is sealed up, liquid tight, within a housing.

This arrangement has the advantage of delaying the starting of the pump until the fan has been started and of stopping the pump before the fan is stopped-thereby insuring, respectively, an adequate supply of air under proper pressure at the oil nozzle before emission of oil from the nozzle and a scavenging of all gases of-combustion from the burner after cessation of flow of oil from the nozzle. The arrangement also avoids the risk of leakage through a mechanical seal and the nuisance and expense of maintaining the same in adjustment. substantial saving in the power necessary to drive the pump because of the elimination of the heavy friction load of the mechanical seal.

Heretofore, it has been the practice in oil burners to employ a constant speed pump with a mechanical seal and to pump far more oil than is usually required for combustionthe excess oil being by-pas'sed around the pump or returned to the supply tank. The oil is pumped at relatively heavy pressure-say for example pounds per square inch-and if only a quarter or a fifth of the pumped oil is used at the burner as is frequently the case, then considerable power is wasted in useless work as will be evident. Oftentimes only three gallons an hour are consumed, while the pump'works at the rate of say sixteen gallons per hour.

This invention has for an object to provide a variable speed pump for delivering only as much oil as is requiredat the nozzle and to control the speed of the pump by the pressure of the pumped oil in such a manner that an increase in pressure of the pumped oil above a predetermined minimum results in a reduction in speed of the pump until the pressure falls to such minimum.

More particularly, the invention has for an ob- A further advantage is a ject the provision of a slip clutch in the drive between the motor and the oil pump and the provision of a control, responsive to the pressure of the pumped oil, for increasing the slip as such pressure increases, thereby reducing the speed of the pump until normal conditions are reestablished.

The invention also has for an object to provide an electromagnetic drive between the motor and pump-such drive constituting a slip clutch and enabling slippage without entailing wear and enabling also the pump and one element of said drive to be sealed up, liquid tight, within a casing and eliminating all necessity for a mechanical seal.

The invention has for a further object to provide a means responsive to pressure of the pumped oil for shifting one element of the electromagnetic drive more or less out of the field of the other to vary the torque therebetween and thereby vary the speed of the oil pump.

The invention has for a further object to provide adjacent one element of the magnetic drive, a stationary element of magnetic material which functions when the other element of the drive is shifted partially out of the field of the first element to shunt out some of the flux from the second element and increasethe rate of deceleration of the pump.

The invention will be disclosed with reference to the accompanying drawings, in which:

Fig. 1 is a sectional elevational view of a poweroperated fuel-pumping apparatus, embodm'ng the invention;

Figs. 2, 3, and 4 are cross sectional views taken on the lines 2-2, 33 and 4-4, respectively, of Fi 1;

Fig. 5 is a sectional elevational view of a modification of the invention; and

Fig. 6 is a diagrammatical view showing the arrangement of the pumping unit in an oil burner.

Referring to these, drawings, the invention contemplates an oil pump, of any suitable form, power-driven by any suitable means such for example as an electric motor, through means in the nature of a slip clutch, which will enable slip between the driving and driven members without entailing wear as a consequence, and preferably also, a control responsive to the pressure .of the pumped oil for varying the amount of slip between said members with the object of maintaining a constant pressure irrespective of variations in rate at which the oil is pumped.

In Fig. 1, the oil pump is mounted in a plate in Fig. l.

III between a plate II and a portion |2 of the end plate l3 of the casing of an electric motor. The motor includes a laminated iron stator l4 having windings l5 and being suitably fixed within a casing section l6. Another casing section II, alined with section l6 and secured thereto in any suitable way (not shown), affords a central bearing hub l8 for rotatably supporting the shaft l9 of the motor. The rotor 20, which may be of the squirrel cage type, as indicated, is suitably fixed to shaft IS. The clutch means is interposed between thr rotor 20 and the oil pump and is located in the space which is enclosed by the companion casing sections l1 and Hi.

The clutch means, referred to, preferably is of the electromagnetic type. In the one particular form herein shown, it includes a laminatediron member 2| fixed to an annular member 22, driven by the rotor 20 and suitably fixed thereto as by the cap screws 23. Such means also includes a multipolar permanent magnet 24 (see Fig. 3) fixed to a shaft 25 which drives the oil pump (shown in detail in Fig. 3). The shaft 25 is slidably keyed to the pump element--a gear 25 which it drives--and its outer end has fixed thereto a piston 27. This piston is slidable in a cylinder 28 formed in a hub 29 on end plate l3- such hub also affording a bearing for rotatably supporting shaft 25. The pump has inlet and outlet ports 30 and 3|, respectively, formed in the end plate l3, and the outlet port 3| is connected by a passage. 32 to the inner end of cylinder 28. Pressure of the pumped oil thus tends to push the piston 21 to the right, as viewed in Fig. 1, and to thereby move shaft 25 and carry the magnet 24 to the right.

Such movement of the shaft 25 is resisted by a spring 33 through the intermediary-of a bellcrank lever, having a depending arm 34 and a laterally-offset arm 35. The arm 35 pivotally supports a seat 36 for spring 33. This bellcrank lever is pivotally mounted on a pin 5?, having near one end a threaded part 38 screwed into the wall of a hollow cylindrical extension 39 of plate 53. This extension houses the spring 33, bellcrank 3l--35, piston 27, and cylinder 28, and has a removable cover 40 secured by a series of cap screws 4|. The pin 5'! also has a bearing at its inner end in a lug 42 on casing 39. A hexagonal head 43 is provided on the outer end of pin 31, whereby it may be unscrewed and removed whenever required. The spring 33 has a stationary seat 44 threaded on the upper screwthreaded part of a shaft 45, the lower part of which is rotatably mounted in the wall of extension 39 but not ordinarily axially movable therein. The seat 64 is held from turning by a web 45 on wall i2. This web engages in a notch" in seat 44. One may turn member 45 as with a screw driver to vary the tension of spring 53. Normally, the screw is concealed by a hollow nut 47 threaded into extension 39.

On starting up the motor, the magnetic rotor will be in the extreme left hand position shown It will be revolved by the revolving laminated iron member 2| because of the magnetic attraction therebetween. Initially, there will be some slip between these members because of the torque necessary to start up the oil pump but as the latter gets under way, the slip decreases and soon the pump element 25 and the rotor 20 are turning at substantially the same speed. Then, as the pressure of the pumped oil rises high enough to overcome the pressure exerted by Spring. ,.th piston 21 moves toward the right, drawing the permanent magnet 24 in the same direction so that part of the magnet projects beyond the outer end face of member 2|. Thereupon the magnetic pull between the members is decreased and the speed of the oil pump decreases. Oil will be pumped at a slower rate and the pressure will drop until it reaches the desired predetermined figure. With this arrangement, a constant pressure may be maintained regardless of the rate at which the oil is pumped.

A desirable adjunct to the arrangement described is a member 50 of magnetic material and mounted adjacent the laminated member 2|. This member 50 may take the form of an annular ring of soft steel, fixed by screws 5| to the end plate l3. As the magnetic rotor moves axially to the right, some of the flux will enter ring 50 and the latter, being stationary, tends by the magnetic drag to slow down the magnetic rotor and thus the oil pump. Also, the decrease in flux in member 2| is accelerated. The use of the member 50 increases the rate of deceleration of the oil pump for any given degree of axial shifting movement of the magnetic rotor 24.

Another desirable feature is a cup 52 of nonmagnetic material which encompasses the magnetic rotor. As shown, this cup is made of thin non-magnetic metal (stainless steel for example) and it is held in place by being suitably secured to member 5|. The cup renders unnecessary any seal between the oil pump and the motor. Any leakage from the pump, along its shaft or otherwise, is caught in the cup 52. The shaft 25 which not only revolves but also must slide axially, presents a difiicult sealing problem. If adequately sealed, as for example by a stufiing box, rapid wear will soon cause leakage and, in any event, the stufiing box imposes a substantial load on the motor. About one-third of the power is used in overcoming the load of the stufiing box in average cases. With the present arrangement, the pump can be driven with far less power and it starts up more easily because of the eliminationof the heavy resistance of the stuffing box.

Referring now to the details of the exemplary apparatus disclosed, the oil pump which may be of any suitable type, is preferably constructed as shown in Fig. 3. It includes in addition to the gear 25, an annular gear 58, gotating in a cylindrical recess in plate it about an axis 55 eccentric to that of shaft 25. The gear 26, turning in the direction of the arrow, rotates the annular gear 54 about axis 55. The inner gear has one less tooth than the outer gear 54. The two gears present a series of closed pockets 56 which gradually expand in volume as the rotors turn from the full mesh position 5'|'to the open mesh position 58. During part of the time, while these pockets are expanding in volume, they communicate with inlet port 30 and thus fluid is drawn into them by suction from an inlet passage 60. Then each pocket becomes cut ofl from port and, shortly after, moves into position where it can communicate with outlet port 3| at a time when the pockets are decreasing in volume, whereby liquid is expressed through the port 3| and into an outlet passage 59. This pump construction is more completely disclosed in Hill Patents Nos. 1,682,564 and 1,682,565, both dated Aug. 28, 1928.

The slip clutch preferably has the laminated member 2| constructed in much the same general manner as the squirrel cage rotor of an induction motor. It has a short-circuited winding made up of a plurality of copper rods 8|, extending through slots in the laminations 2|, and a pair of annular copper rings 62the ends of each rod 6! being connected one to one ring 62 and one to the other ring 62. The magnet 2 may conveniently be a permanent magnet made of some of the special alloy steels which afford exceedingly high coercive force. This magnet is cast in the form shown having a plurality (six as shown) of poles arranged in a circular series with alternate poles 63 of opposite polarity as indicated in Fig. 3. I

This magnet is secured to shaft 25 in any suitable way. For example, the magnet may have cast therein a hole Blof square or other noncircular shape, to receive a head 65 of hexagonal or other circular shape. The magnet and head 65 are assembled in a jig, by which they are positioned accurately in proper relation, and then the space between hole 64 and head 65 is filled with some suitable metal, such as zinc 6'! for example. The head 55, as shown, is part of a stud 66 screwed into shaft 25. The construction described is not important in itself and is merely illustrative of one of many available ways for mounting the magnet on shaft 25.

The motor usually also drives a fan especially when the pumping unit is used in connection with an oil burner. Thus, in Fig. l, a fan rotor 68 is shown as fixed by screws 88 to the shaft IQ of the motor. The rotor 68 revolves inside a suitable casing 69 as indicated.

When the pumping unit is used with an oil burner, it is arranged as shown diagrammatically in Fig. 6. The motor M, such as described above, drives the oil pump 10. This pump draws in oil through an inlet passage 60 and forces it through the outlet 59 into a pipe 10 and thence through a valve H and pipe 12 to the atomizing nozzle 13. This nozzle is arranged within a tube 14, connected to the outlet of the fan casing 69 described. The valve 11 has the function of preventing passage of oil to the nozzle until the oil has been placed under the desired predetermined pressure-say for example 100 pounds per square inch.

The invention may be used, with certain advantages, without the control device described which shifts the magnet axially to vary the torque between the driving and driven elements 2! and 24; Such an arrangement is shown in Fig. 5. The motor, the mounting of its parts, the electromagnetic transmission between the motor and oil pump, are the same as has been described and corresponding parts have been marked with the same reference numerals with the addition of a prime. Here, however, the oil pump Ill is mounted outside the end plate I3 which is of somewhat different form, and the pump shaft 25' and the magnet 24' fixed thereon are not' axially slidable. The oil inlet and outlet passages 59 and 60' are located differently but function as before. The oil pump I is, or may be, exactly the same as shown in Fig. 4 and the magnet 24 and its cooperating laminated member 2| are exactly as shown in Fig. 3.

That form of the invention shown in Fig. 5 has the advantage of a delayed starting of the oil pump and an earlier stopping of the same, as above pointed out. Also, the construction avoids the necessity for a stumng box or other equivalent form of mechanical seal. The elimination of a seal between relatively rotatable parts is very important. All likelihood of leakage is avoided. The frequent care necessary to maintain such aseal tight is avoided. Again, the heavy friction load of the seal is eliminated. In many oil burner pumps, this friction load represents one-third of the power consumed. Much easier and quicker starting results and actually a much smaller and less expensive driving motor can be used.

In the preferred form of the invention, all the advantages just enumerated are secured, with others. Thus the pump is driven by a variable speed transmission and the oil is maintained at constant pressure without pumping any more oil than is actually needed for combustion. The rate of pumping will vary as may be necessary to maintain the desired predetermined pressure. Actually, in the use of the invention in connec tion with oil burners, the pump, once it has built up-the desired pressure, will run at about uniform speed because oil is being consumed at a substantially uniform rate during burner operation. However, if the invention is used in such a way that the liquid is consumed at a variable rate, the pump will operate at variable speed under the described control.

a substantial saving in power is effected by this variable speed drive as against the pumping means heretofore employed in oil burners. The prior practice was to use a pump of large enough capacity to suit the conditions of any installation likely to be made. In most cases, the oil was consumed at a rate far less than that of the pump. As a common example, the pump has a capacity of 16 gallons per hour and about three gallons per hour is the rate of consumption. of oil by the burner. The result is that oil is pumped at the maximum rate and raised to the desired predetermined pressure-usually around 100 pounds per square inch-and two-thirds of the oil thus pumped is loy-passed around the pump or returned to the supply tank as the case may be. Two-thirds of the energy consumed in pumping the oil is thus wasted. With the present invention and under the same conditions, the pump would pump the three gallons per hour required by the burner and no more. .The use of a large capacity pump, such as that herein referred to as being capable of pumping 16 gallons an hours, has the advantage of enabling quick priming. Even though the normal rate of consumption of oil is usually somewhere around three gallons per hour, the high capacity pump is of great advantage, whenever it is necessary to pump all air out of the system, as after stoppage of the burner from exhaustion of oil. One usually opens a vent in the system somewhere on the pressure side of the pump to allow the air to escape. It is desired to rid the system of air as quickly as possible and under these conditions, the pump can and does operate at maximum capacity even though when pumping oil under normal conditions, the pump operates at a much lower capacity.

The invention thus offers an improved pumping unit which, while capable of general application, is especially suitable for use with oil burners and is characterized by a substantial saving in operating rotatable magnetic members one mechanically connected to said motor and the other mechanically connected to said pump; and a liquid-tight housing encasing said pump and the member connected thereto and including a nonmagnetic portion extending through the space between said rotatable members.

2. In combination, a pump, a motor, driving means therebetween including spaced-apart cooperating rotatable magnetic members one mechanically connected to said motor and the other mechanically connected to said pump, one of said members comprising a magnetized field element and the other member comprising a wound armature; and a liquid-tight housing encasing said pump and the member connected thereto and including a non-magnetic portion extending through the space between said rotatable members.

3. In combination, a pump, a motor, driving means therebetween including spaced-apart cooperating rotatable magnetic members one mechanically connected to said motor and the other mechanically connected to said pump, one of said members comprising a multipolar permanent magnet and the other a laminated-iron armature with a squirrel cage winding; and a liquid-tight housing 'encaslng said pump and the member connected thereto and including a non-magnetic portion extending through the space between said rotatable members.

4. In combination, a pump including a casing and a drive shaft projecting therefrom, a multipolar permanent magnet fixed to said shaft, a cup of thin non-magnetic material secured to said casing and with the latter entirely enclosing within it said shaft and magnet, a motor, and a wound inductor driven by the motor and surrounding said magnet and cup.

5. In combination, a pump having an outlet passage, a valve closing said passage until a predetermined pressure has been built up therein by said pump, a motor, driving means connecting said pump and motor and including cooperating elements in the nature of a slip clutch, and means controlling the slip between said elements and varying such slip substantially in direct proportion to variations in pressure of the pumped fluid above said predetermined pressure.

6. In combination, a pump, a motor, and driving means connecting the pump and motor and including cooperating rotatable elements one driven by the motor and the other driving the pump and the one driving the other magnetically, 'said elements being relatively shiftable in the direction of the axis of rotation of said elements, and means responsive to the pressure of the pumped fluid for axially shifting said elements.

7. In combination, a pump, a motor, and driving means interconnecting the pump and motor and including a magnetic field element connected to drive said pump, an armature element driven by said motor and cooperatively associated with said field element to drive the same through the force of magnetic attraction between said elements, a stationary member of magnetic material adjacent said armature element, said field element being shiftable from a position of full cooperative association with said armature to any of a plurality of positions in which part of its magnetic flux passes into said stationary member and is thereby shunted out of said armature element, and means responsive to the pressure of the pumped fluid for shifting the field element.

8. In combination, a pump having an outlet passage, a valve closing said passage until a predetermined pressure has been built up therein by said pump, a motor, and driving means interconnecting the pump and motor and including a magnetic field element connected to drive said pump,an armature element driven by said motor and cooperatively associated with said field element to drive the same through the force of magnetic attraction between said elements, a stationary member of magnetic material adjacent said armature element, said field element being shiftable from a position of full cooperative association with said armature to any of a plurality of positions in which part of its magnetic flux passes into said stationary member and is thereby shunted out of said armature element, and means responsive to increase in the pressure of the pumped fluid above said predetermined pressure for relatively shifting said elements in the axial direction necessary to decrease the magnetic pull therebetween and responsive to a subsequent decrease in such pressure of the pumped oil to relatively shift said elements in the opposite direction.

9. In combination, a pump having an outlet passage, a valve closing said passage until a predetermined pressure has been built up therein by said pump, a motor, and driving means interconnecting the pump and motor and including a magnetic field element connected to drive said pump, an armature element driven by said motor and cooperatively associated with said field element to drive the same through the force of magnetic attraction between said elements, a stationary member of magnetic material adjacent said armature element, said field element being shiftable from a position of full cooperative association with said armature to any of a plurality of positions in which part of its magnetic flux passes into said stationary member and is thereby shunted out of said armature element, and means responsive to increase in pressure of the pumped fluid above said predetermined pressure to shift said field element from the first-named to some one of the second-named ositions and responsive to a subsequent-decrease in pressure of the pumped oil to shift said field element back toward its first-named position.

WARREN H. DE LANCEY.

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