US2705457A - Air volume regulator - Google Patents

Description

April 1955 A. E. LE VAN 2,705,457

AIR VOLUME REGULATOR Filed June 6, 1949 2 Shets-Sheet 1 INVENTOR. I AME/P055 E. LE VAN 1.

AT TOR/V5) April 5, 1955 A. E. LE VAN 2,705,457

AIR VOLUME REGULATOR Filed June 6, 1949 2 Sheets5heet 2 IN VEN TOR.

AMBROSE E. LE I/A/V A T TORNE Y United States Patent AIR VOLUME REGULATOR Ambrose E. Le Van, Sellersville, Pa., assignor to American Machine and Metals, Inc., New York, N. Y., a corporation of Delaware Application June 6, 1949, Serial No. 97,397

4 Claims. (Cl. 103-6) This invention relates to air volume regulators and particularly to one for admitting air to a tank by passage of water through a venturi.

It is general practice in independent water systems to pump water from a well into a closed tank so that the water entering near the bottom of the tank compresses the air already in the tank. The system is usually provided with a means to automatically shut off the pump when the pressure in the tank reaches a pre-set value. The air thus compressed provides a cushion and permits the loss of a small amount of water either by leakage or by withdrawal without starting the pump again. The expanding air will deliver a substantial part of the contents of the tank, with an accompanying drop in pressure, before the pump again starts up. This means fewer starts of the pump and a substantial delivery of water each time the pump is started.

A variety of means are available for supplying air to make up air in the tank that is lost by absorption in the water. Many of these draw a small amount of air into the pump on the suction side together with the water and thus use the one pump to deliver both air and water to the tank.

When a centrifugal pump is used, and in the case of deep-well systems it is almost unavoidable that a centrifugal pump be used, the amount of air that is drawn in through an orifice of a given size will vary greatly with the pressure conditions within the system. When the pump first starts up, an excessive amount of air may be drawn in, and if this fills the pump chamber, the pump will not draw water.

It has been proposed to supply the air to the tank by utilizing the energy of a single pump without having the air pass through the pump. This is accomplished by passing the stream of water under pressure delivered by the pump into the tank against the tank pressure through a passage which contains a venturi. This venturi is so proportioned that the dynamic pressure in passing through the throat of the venturi is so increased at the expense of the static pressure that the static pressure in the throat falls below the atmospheric pressure. It is then possible to draw air into the throat of the venturi and as the water now carrying air bubbles passes on through the expanding portion of the venturi, the kinetic energy is lost and the static pressure is again built up. Upon entering the tank, the air separates from the water and rises to the top.

The invention is particularly adapted for use with shallow Well pumping systems in which a centrifugal pump at the top of the well draws water up by suction not more than 25 feet or with deep well systems in which a pipe from the discharge side of the pump is carried down into the well and there leads to a nozzle pointing upward. This nozzle is located inside a chamber which has at its lower side screened openings that are immersed in the pool within the well. A foot valve closed by the pressure of the water extending upwards in the system prevents the system from draining out into the well when the pump is not in use. The jet referred to discharges into a throat of a venturi which is connected to the suction side of the pump. When the pump is in operation, a portion of the water which it discharges is forced down into the well and there discharges through the nozzle in the chamber creating a vacuum which causes more water to flow from the well into the chamber. This additional water is carried along up into the suction side of the pump. Since more water is carried up into the pump than goes 2,705,457 Patented Apr. 5, 1955 down, there will be a surplus on the discharge side of the pump which is led to the tank.

To operate satisfactorily, the water filowing through the nozzle in the chamber must have a minimum pressure. To maintain this pressure regardless of the pressure in the tank, the pressure regulator is placed in the line leading from the pump to the water tank so that no water can flow to the tank until the pressure on the discharge side of the centrifugal pump is filled up to a given value.

In the practice of this invention, the venturi which draws in the air is not placed in the main passage from the discharge side of the pump to the tank but in a bypass of small cross-section. This permits the control of the amount of air drawn in without regard to the total quantity of water which passes into the tank. The air drawn into the by-pass is controlled by a float in the tank in such manner that an excessive amount of air is not drawn into the tank. It is obvious that when the air in the tank has expanded enough to drop the pressure to the point where the pump starts, that the pressure of the pump discharge is much higher than the pressure in the tank, and therefore a considerable amount of air would be drawn in each time the pump operates regradless of whether the air is needed or not.

One of the features of the invention is that no air is drawn into the tank until the water level reaches an intermediate level short of the final level for which the control equipment is set. When the water rising in the tank reaches this point, it elevates a float and this float permits air to be drawn through the by-pass until the pump shuts down. This may be accomplished in several ways. The float may prevent the passage of water through the by-pass until the level in the tank is suflicient to elevate the float. On the other hand, the float may permit water to pass through the by-pass at all times, and it may merely prevent the valve known and referred to hereafter as the snifter'valve, that is placed in the path of the atmosphere to the throat of the venturi from opening until the water level has reached the desired value.

The object is to provide an improved air supply unit in which water flows through a venturi during the entire time the pump is in operation, and a float in the tank prevents a snifter valve from allowing ambient air to enter the system until the water level in the tank being filled has reached a preset level.

Fig. 1 indicates diagrammatically a pump installation equipped with the invention partly in section.

Fig. 2 shows an elevation of the control device shown in Fig. 1 in enlarged scale.

Fig. 3 shows an elevation of a preferred form of the control device to an enlarged scale.

Fig. 4 shows an elevation of an alternate form of the control device to an enlarged scale.

In Fig. 1, a well is indicated in section at 1. This well may have a casing 2, and a pump 3, mounted on a stand 4 driven by a motor 5, draws water from the well through line 6. A part of this water passes through line 7 to a control device generally indicated at 8 mounted in the side of a tank 9. A part of the water delivered by the pump passes down into the well through. a line 10 into a chamber 11. The bottom of the chamber is closed by a check valve 12 that permits water from the well to pass into chamber 11 through a screen 13 but not to pass out of the chamber into the well. At the upper end of the chamber is a venturi 14 and the line 10 leads to a jet 15 which is directed into the venturi. This forces water from the well up to the riser 16 to the pump 3.

In addition to the Water flowing from the pump 3 down into the well through pipe 10 and through by-pass 7, the major part of the discharge is delivered through a regulator 17 which, similar to a pressure relief valve, allows water to flow into line 18 to the lower part of tank 9 only when a given pressure is reached. When the pressure in tank 9 reaches a given value, it acts on a pressure controlled switch 19 which interrupts the current flowing to the motor 5.

Water is delivered from the tank 9 through a delivery system 20. When the air in the upper part 21 of tank 9 has expanded to some point such as 22, the pressure will have dropped to the point where switch 19 cuts in and the pump starts again.

Referring to Fig. 2, it will be noted that the control device generally indicated at 8 comprises a body threaded at 26 screwed into a threaded opening 27 in the tank. The body 25 carries lugs 28 which support the bell crank 29 on a pivot 30. Connected to one end of the bell crank is a float rod 31 which leads to the float 32. Customarily, the float is so designed that the entire assembly shown in Fig. 2 may be inserted through the sides of the tank through the opening. A passage 33 extends through the body 25. This passage has a contraction at 34 and a venturi-like expanded section 35 toward the inside of the tank. A sliding plug 36 is adapted to bear against a seat 37 in this passage. The plug 36 is connected to a rod 38 which is connected at 39 to the bell crank 29. The one end of the passage is closed by a plate 40 fastened to body 25 by studs 41 or the like. A passage 42 leads into the passage 33 to the right of the seat and another passage 43 to the left of the seat. The passage 42 1s connected by a fitting 44 to line 7.

A snifter valve 45, is which may take the form of a tire valve, is seated in passage 43. This permits air to be drawn into the contracted portion of 34 of passage 33 but does not permit a flow from the passage to the atmosphere through passage 43.

When the level in the tank is below some point such as 23, the float will be hanging down and the weight of the float will draw the plug 36 against its seat thus preventing the flow of any water through the by-pass 7.

Whenever the rising level of water in the tank reaches 23, the float is lifted and this pushes the plug 36 off its seat. Immediately water flows through the by-pass 7, through the venturi throat 34, drawing air through the valve 43 and delivering the mixture of air and water through the venturi 35 into the tank. This continues until the pressure in the tank cuts out the switch 19. The water level will then be at some position such as 24, some distance above the level 23. Air will have been drawn into the tank only during the period that the water level was rising from 23 to 24.

In the form shown in Fig. 3, the body 25 has a similar passage 33 contracted at 34 and leading into a conical discharge passage 35. Air from the atmosphere passes in through a tire valve 45 in a passage 43.

The float rod 31 is attached to a bell crank 29 pivoted on ears 28 attached to the body 25 as before.

In the form of Fig. 3, no air is drawn into the tank until the rising water level reaches 23 and lifts a float and then air is continuously drawn in until the level 24 is reached when the pressure-actuated switch 19 cuts off the power to the motor.

The difference between this form and that shown in Fig. 2 is that while in Fig. 2 the introduction of air was prevented by shutting otf the flow of water through the by-pass until the float reached level 23, in the present form water is always flowing through the by-pass 7 when the pump is running. The float does not obstruct the flow of water. The two fingers carried by the bell crank 29 pass under the head 51 of the pin 52. The fingers engage a contracted portion 53 of the pin so that when the float is unsupported the pin 52 is forced to the right. The conical end 54 of the pin engages the end of the passage 43 preventing any air from being drawn in through the valve and thence through the passage 55 to join the water flowing through the throat 34. Thus, pin 52 positively prevents passage of air through 55. 56 is a permanent closure of the hole through which passage 55 was drilled.

In the form of the invention shown in Fig. 4, the body 25 is provided with the same passage 33, the throat 34, and conical discharge outlet 35 as in the other modifications. Here, as in the form shown in Fig. 3, water flows through the by-pass unobstructed while the pump is running. Here, as in the form shown in Fig. 3, the float serves to control the admission of air through valve 45 placed in passage 43 that leads into the venturi.

In the present form of the invention, the float rod 31 18 supported in a rubber grommet having a flange 60 and a body 61.

'bore 63. A metal ring 64 which may be staked in place after assembly, bears against the flange 60. The float rod 31 is fitted into a hole passing through the grommet. The material of which the grommet is composed is flexible enough, such as rubber or the like, to allow the float to transmit to the stem 31 movement to the portion 66 of the float rod. This engages the stem 67 of the snifter valve which may be a tire type valve. The weight of the float, when unsupported, holds the valve closed against the suction created by the liquid flowing through the venturi. Tire valve assembly 45 is of the usual type which is screwed into the passage 43 to seat on a shoulder in the passage. The valve inside of the valve assembly is attached to a stem 67 that is forced upwards in Fig. 4 by a light spring not shown. When the weight of the float causes the fork 66 to pull upwards on stem 67 the suction in passage 34 is insuflicient to open the valve. When the level of the water in the tank rises and supports the float, the suction is suflicient to overcome the light spring and draw air in through the passage 43- into the stream of water passing through the venturi 35.

I claim:

1. An air control having, in combination, a body adapted to be screwed into an opening in a tank wall, a passage through the body leading into the tank, a venturi throat in said passage, a second passage in the body leading from the atmosphere to the venturi, a snifter valve in said second passage permitting air to be drawn in but not to escape to the atmosphere, a third opening extending from the tank through said body, a flexible diaphragm closing said third opening, a float stem passing through said diaphragm and engaging the stem of said snifter valve, and a float in the tank attached to said stem and holding said snifter valve closed by its weight unless the water level in the tank supports the float.

2. In an air charging unit adapted to be inserted into the wall of a storage tank, the combination comprising a body having a first passage through which water flows into said tank, said passage having a venturi contraction, a second passage joining said first passage at the throat of the venturi and through which air can be drawn as water passes through said venturi into said tank, a normally closed snifter valve in said second passage in said body controlling passage of air through said second passage, said valve being openable to pass air through said second passage by drop in pressure therein when water is flowing through the venturi, float means projecting into said tank and supported on said body, shaft means connected to said float means and projecting into said body adjacent said snifter valve, said float connected means and said snifter valve being so constructed and arranged to jointly cooperate to control passage of air in said second passage and to positively close said second passageway until the water reaches a predetermined level in said tank, said float means then rising to cause movement of said float connected means to allow air to enter the stream of water flowing into said tank through said venturi.

3. The device as in claim 2, wherein said float connected shaft means includes a second valve operably disposed in said second passage.

4. The device as in claim 2, wherein said float connected shaft means includes a lost motion connection with the snifter valve.

References Cited in the file of this patent UNITED STATES PATENTS 2,279,948 Kent Apr. 14, 1942 2,291,746 Nelson et al. Aug. 4, 1942 2,319,554 Penn et a1. May 18, 1943 2,347,472 Dorward, Jr. Apr. 25, 1944 2,354,811 Jacuzzi Aug. 1, 1944 2,381,640 Brandstrom Aug. 7, 1945 2,642,747 Le Van Jan. 23, 1953

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