US2677417A

US2677417A - Time delay device and auxiliary cutoff valve for pressure-atomizing oil burners

Info

Publication number: US2677417A
Authority: US
Inventors: Joseph A Logan; George D Robinson
Original assignee: Gilbert and Barker Manufacturing Co Inc
Current assignee: Gilbarco Inc
Priority date: 1952-06-05
Filing date: 1952-06-05
Publication date: 1954-05-04
Anticipated expiration: 1971-05-04

Description

May 1954 J. A. LOGAN ETAL 2,577,417

TIME DELAY DEVICE AND AUXILIARY CUTOFF' VALVE FOR PRESSURE-ATOMIZING OIL BURNERS Filed June 5, 1952 INVENTOR JbdZJP/l A.l064/Y mm GIwwzJZHoa/wo/v W ATTORNEYS Patented May 4, 1954 TIME DELAY DEVICE AND AUXILIARY CUT- OFF VALVE FOR PRESSURE-ATOIWIZING OIL BURNERS Joseph A. Logan, Hadley, and George D. Robinson, Agawam, Mass., assignors to Gilbert &

Barker Manufacturing Company,

West Springfield, Mass., a corporation of Massachusetts Application une 5, 1952, Serial No. 292,004

2 Claims.

This invention relates to an impr'ovedfu'el control device for oil burn'ers' of the pressure-atomizing type, particularly those which are adapted for house-heating service and operate intermittently under automatic control, being started and stopped many times during each day of the heating season.

In a copending application Serial No. 262,954, filed December 22, 1951, now Patent No. 2,662.,- 542 issued December 15, 1953, we have disclosed a hydraulic control device for use with the highpressure liquid-fuel-supply pump of an oil burner of the above-named type. Such device has for its purpose the modification of the oil pressure conditions during the starting and stopping intervals of operation of the burner, when the moving part are respectively accelerating and decelerating. More particularly, this control device effects a delay in the building up of oil pressure during the starting interval and a speedier cutting-ofi' of oil flow during the stopping interval. This device is adapted to be connected to the inlet and outlet sides of the pump and includes a movable wall, the movement of which is controlled by the pressure of the pumped oil. The

connection to the outlet side of the pump is located between the pump outlet and the usual pressure-regulating valves, which include cutoil and by-pass valves respectively controlling the minimum and maximum pressures of the oil supplied to the pressure atomizing nozzle of the oil burner.

This invention has for its object the provision of an auxiliary valve, which may be interposed in the oil line between the usual cut-off valve and the nozzle, and preferably located as closely as feasible to the nozzle, and which is controlled by the movement of the movable wall of the control device, such as that disclosed in the aboveidentified application or one generally similar thereto; the auxiliary cut-offvalve' being initially closed, opening by the movement of the wall which occurs during the starting interval of operation, and closing by the movement of the wall which occurs during the stopping interval of operation of the burner.

The invention will be disclosed with reference to the illustrative embodiment of it shown in the accompanying drawings, in which,

Fig. l is a full-size sectional-elevational view showing the auxiliary cut-off valve embodied in the control device of the above-identified application, the parts being shown in the positions which they occupy when the burner is stopped. This view also shows on a small scale and dia- 2 grammatically, a fuel supply system for an oil burner of the class described and the manner in which the control device and auxiliary cut-off valve are connected into such system; and

Fig. 2 is a sectional-elevational view of the control device and auxiliary cut-off valve showing the parts in the positions which they occupy at the end of the time delay interval on starting the pump.

Referring to these drawings, the invention will be disclosed for illustrative purposes, as embodied. in a hydraulic control device for oil burners of the type disclosed in the aforesaid application. It will be clear that it may be embodied in other control devices of the same general type having a movable wall actuated by oil pressure.

This control device includes a chamber, such as the cylinder I, formed within a casing, such as a tubular barrel 2, having heads 3 and 4, suitably fixed as indicated in a leak-tight manner, one in each end of the barrel. Within the cylinder I is a movable wall, in this case a piston 5 slidably engaged in a leak-tight manner with the peripheral wall of the cylinder. A spring 6, partially telescoped in a cylindrical opening 7 in head 4, acts between the end wall of this opening and one face of piston 5 and tends to move the piston toward head 3 and yieldingly hold it in the position shown in Fig. 1. Inlet and outlet tapped openings 8 and 9 are provided in heads 3 and 4, respectively, for connection to suitable piping to be later described. The opening 8 connects by a passage I0, formed in head 3, with one end (the left as shown) of cylinder I. The opening 9 is connected by a radial passage II to an axial passage 12, which connects with one end of a smaller axial passage I 3, the other end of which opens into the opening I and thus into the right hand end of the cylinder I. The outer end of passage I2 is closed by a plug I' l. A ball valve I5 is yieldingly held by a spring I6, acting between it and plug I4, in position to close off communication between the axial passages I2 and H3 The piston 5 has a passage 'I'I therethrough, a portion 58 of which is of very small diameter, in the present example .024, The piston is adapted to be moved to the right by the pressure of the oil entering through passages 8 and I0 into the left hand end of cylinder I until it abuts the end face or" the annular part of the head 4.

The control device described is especially adapted for use in connection with the high-pressure positively-acting, fuel-supply pumps commonly used in oil burners of the mechanical or pressure-atomizing type, such as are adapted for the fuel-supply system of the burner.

house-heating service and are started and stopped many times each day under automatic thermostat control. One purpose of this control device is to delay the emission of oil from the atomi-zing nozzle of the burner untilthe motor, which drives the pump and also a non-positively-acting, air-supply fan, has acquired high speed, and preferably full speed, in order to secure the proper rate of air flow to result in good combustion. Another purpose to secure a quick cutting ofi of oil flow to the atomizing nozzle after the pump motor is deenergized.

Fig. 1 shows diagrammatically and on a. small scale, the fuel-supply means for a pressureatomizing oil burner of the class described. A pump I9, adapted for connection to a fuel-supply tank (not shown) by means of a suction pipe 20, forces oil through a conduit 2| to a casing 22, containing a by-pass valve 2 3, and from such casing through a, conduit 24 to a casing 25, containing a cut-off valve 26. The pump. in the present example, is designed to pump oil at the rate of 18 gallons per hour. The outlet of casing 25, which is controlled by valve 26.. is adapted to be connected to themechanical or pressureatomizing nozzle 21 of the oil burner. The outlet of casing 22, which is controlled by by-pass valve 23, is connected by a by-pass conduit 23 to the suction side of pump I9, as to pipe 25. The pump I9 has a screw plug 29, which may be loosened in order to rid the system of air, whenever necessary, as for example, when initially installing the burner or whenever the pump, after having stopped becausev of exhaustion of the oil supply, is subsequently started.

The cut-off valve 26 is held closed by a spring 30 until the pressure of pumped oil reaches a predetermined minimum value, say for example about 90 p. s. i. The lay-pass valve 23 is held closed by a spring 3I until the pressure of the pumped oil reaches a predetermined maximum value, say for example, 100 p. s. i., which is the normal operating pressure. The inlet opening 8 of the control device is adapted to be connected to the pressure side of the oil pump at a location between its outlet and the by-pass valve 23 and, as indicated by the dot-dash line 32, to the conduit 2 I. The outlet opening 8 of the control device is adapted for connection to the suction side of the oil pump, and, as indicated by the dot-dash line 33, to the pipe 20.

In an oil-supply system oi the type described, the pump I9 must be vented initially and each time after the fuel-supply has become exhausted. in order to rid the system of air. for the pump are usually closed by valves, such as 23 and 28 which open at relatively high pressures, greater than any that the pump can produce when pumping air alone. For example, in the present case, the greatest pressure which pump I9 can produce, when pumping air is around 20 p. s. i. Hence, the valve 26 will not open and allow air to escape from nozzle 21. Therefore, the plug 29 on the pump is provided and this plug, when loosened, will afford an outlet for the pumped air to escape. As soon as oil appears, the plug 29 is screwed in tightly and the system will then operate in the normal manner.

The control device provides by the passage l1, it through its pistona by-pass. between the inlet and outlet of the pump l9 that is continuously open during normal operation. This by-pass has to be closed before air can be eliminated from The check The only outlets valve I5 automatically closes this by-pass to en able elimination of air to be effected, when required, and yetenable the by-pass to be open during normal operation of the burner to accomplish its purpose. The spring I6 is designed so that the check valve I5" will open at 25 p. s. i. Thus, this valve I5 cannot open, when the pump I9 is pumping air alone. The same result might be effected by manual closure of a hand valve, such as 34, in the pipe 33, whereby the valve I5 might be eliminated but the latter is desirable and preferred because it takes care of the condition automatically without requiring any attention on thepart of the operator.

The spring 6 is designed to have sufiicient force to return the piston from the Fig. 2 to the Fig. 1 position, when the oil pump stops. This spring must have sufficient force to overcome the friction of the piston 5 sliding on the wall of cylinder I and also to force oil from the left hand to the right hand side of the piston through the restricted portion I8 of the passage IT in the piston. And the spring 8 must yield before the check valve I5 opens. In the present example, this spring 5, when fully stressed exerts a force to 23 p. s'. i on the piston.

This invention provides in a control valve of the general class described, an auxiliary nozzle cut-off valve which is related to and controlled the movable wall 5 of the control device. To this end. the head 3 is provided with two tapped holes 35 and 3-5. which are adapted to be respectively connected by pipes, indicated by the

dotdash lines

31 and 38, to the outlet of the cut-off valve 25 and to the atomizing nozzle 21.

Parallel passages

39 and 40,v formed in head 3, extend. inwardly from the respective holes 35 and 33 part way through the head and their inner portions are interconnected by a cross passage 4I, having intermediate its ends a seat 42 for the auxiliary cut-off valve, herein shown as a needle valve 43. This valve has a stem. 44 slidably mounted, in a suitable leak-tight manner in head 3 with its inner end extending into the cylinder I and terminating with a head 45. A spring 46 acting between heads 3 and tends to hold the auxiliary cut-oil valve 43 in open position. Movement of this valve in the opening direction is limited in any suitable way, as for example, by a pin 41 fixed in head 3 and extending through a diametrical slot in the stem 44. The head 45 is adapted to be engaged by the piston 5 to move valve 43 against the force of spring 45 into and hold it in closed position. as shown in Fig. 1, the pistonmoving-spring I5 being stronger than spring 46. When the piston 5 is moved by pressure of the liquid into its Fig. 2 position, the piston moves away from head 45, allowing spring 45 to move valve 43 to open position- In operation, with the parts positioned as shown in Fig. 1, the burner motor is started. thus driving the pump I9. Since the check valve I5 is then closed, the oil pressure builds up rapidly, as for example to 25 p. s. i. when the check valve opens the by-pass around the pump. The piston 5 will move slowly to the right under pressure of the pumped oil. Some oil may pass through the continuously-open by-pass I1, I8 but initially the rate of flow therethrough is only very small com pared to that at which oil is forced into cylinder l by the pump. The piston, as it moves toward the right, releases the abutment 45, allowing it to be moved by spring 48 to open the auxiliary cut-off valve 43. Continued movement of th piston in the same direction causes it to engage the end face of the annular part of head 4 as a stop. Pressure then builds up fast until the usual cutoil valve 29 opens to allow oil to flow to the nozzle. The auxiliary cut-oil valve 43 is then open so as not to impede such flow. More and more oil will then flow through the by-pass ll, I8 until at full operating pressure, a rate of about 4.5 gallons per hour is established. A delay of about 2.4 seconds is effected in the opening of the cut-oil valve 29 after the pump I9 is started. When the power to the pump is cut off, oil pressure drops rapidly because of the by-pass l1, l8. The bypass valve 23 immediately closes, followed soon after (say for example .7 of a second) by the closing of the usual cut-on. valve 26. Thereafter, the pressure drops still more rapidly to zero, say for example in .3 of a second. As the pressure drops, the spring 6 moves the piston to the left and eventually the piston engages the abutment 45 and moves it to close the auxiliary cut-ofi valve 43. The latter is then held closed until the burner is again started.

The auxiliary out-oi? valve 43 provides insurance against leakage of oil, which might occur.

Under a gravity head, oil can flow through the 1 pump 19, when idle, if the usual cut-off valve 26 should leak, as it may and frequently does, because it is subject to rapid wear due to the high pressure imposed on it. The auxiliary cut-ofi valve 43 also serves to prevent flow from the nozzle 21 due to expansion of the oil caused by heat reflected back from the combustion chamber after the burner has stopped. The nearer the auxiliary valve 43 is located to the atomizing nozzle 21, the more effective is its action in this respect. The expansion of the body of oil which is trapped between the usual cut-ofi valve 26 and the auxiliary cut-ofi valve 43 cannot act on the latter in a direction such as to open it.

The invention thus provides an auxiliary cutofi valve, which may be embodied in the casing of a control device of the general kind shown in the above-named application and operated by the movable wall thereof and which is adapted to prevent leakage of oil from the nozzle of an oil burner while the burner is stopped.

What is claimed is:

1. In an oil burner, of the type wherein a pressure atomizing nozzle is supplied with oil by a pump through a pressure regulating valve the outlet of which is connected by a conduit to the nozzle and which opens to admit oil to such conduit only after the pump has placed the oil under predetermined minimum atomizing pres-- sure and a second pressure regulating valve opens at a predetermined maximum atomizing pressure a by-pass around the pump; a time delay device comprising a casing having a chamber therein, an inlet at one end of the chamber connected to the discharge side of said pump between the outlet of the pump and the inlet to said regulating valves, an outlet at the other end of the chamber connected to the inlet side of said pump, a movable Wall in said chamber partitioning said inlet from said outlet, a continuously open by-pass conduit of restricted area interconnecting said ends of the chamber, a spring tending to move said wall from a first extreme position near said outlet to a second extreme position near said inlet, said spring yielding under pressure of the pumped oil that is much less than the atomizing pressures at which said regulating valves open and allowing the wall to move from said second to said first position, said casing having another and independent fuel passage interposed in the first-named conduit, said passage having intermediate its ends a valve seat and a cut-off valve mounted in said casing for movement toward and away from said seat, said movable wall controlling the movement of said cut-off valve and operable when moved into and out of said second position to respectively close and open the cutoff valve.

2. The combination, as claimed in claim 1, in which the cut-off valve has a spring biasing it to open position and a stem projecting into said chamber in the path of said movable wall to be moved thereby to close the cut-oil valve when said wall moves into said second position.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,032,886 Murphy et al. Mar. 3, 1936 2,257,702 Murphy Sept. 30, 1941 2,451,681 Logan Oct. 19, 1948 2,494,714 Lyman Jan. 17, 1950