US3375032A - Fluid actuated locomotive sanding system - Google Patents

Description

FLUID ACTUATED LOCOMOTIVE SANDING SYSTEM March 26, 1968 Filed NOV. 27. 1963 I n v e n t o r Virgil L. Frantz his Attorney FIG. A

March 26, 1968 v. L. FRANTZ FLUID ACTUATED LOCOMOTIVE SANDING SYSTEM Filed Nov. 27, 1963 3 Sheets-Sheet 2 his Attorney March 26, 1968 v. FRANTZ FLUID ACTUATED LOCOMOTIVE;SANDING SYSTEM 3 Sheets-Sheet 5 Filed Nov. 27. 1963 FIG. 5

FIG. 6

In v e n t o r Virgil L. Frantz wdzwm;

his Attorney United States Patent fiFice 3,375,032 Patented Mar. 26, 1968 3,375,032 FLUID ACTUATED LOCOMOTIVE SANDING SYSTEM Virgil L. Frantz, Salem, Va., assignor to Graham-White Sales Corporation, Salem, Va., a corporation of'Virgima Filed Nov. 27, 1963, Ser. No. 326,449 10 Claims. (Cl. 291-12) This invention relates to locomotive sanding systems and has for its primary object the provision of an improved sanding system wherein any clogging condition in the sand delivery pipe is automatically sensed and removed to restore the system to normal condition.

Another object of the invention is to provide a sanding system wherein, when a clogging condition occurs in a sand delivery pipe, high pressure air is automatically applied to the pipe to remove the condition and delivery of sand to the pipe is simultaneously cut off.

A further object of the invention is to provide a locomotive sanding system of the character above described, wherein the high pressure air used to remove the clogging condition in the sand delivery pipe is limited in duration to prevent exhaustion of the supply of reservoir air.

An additional object of the invention is to provide a sanding system of such construction and arrangement as, in a sanding operation with the discharge pipe in clogging condition, to override the normal setting of the operating valve and apply to the pipe through the valve a blast of high pressure air of limited duration to remove the condition.

Another object of the invention is to provide a sanding system wherein high pressure air is employed both to remove a clogging condition in the sand delivery pipe and to prevent sand from flowing into the pipe during such removal.

Other objects and advantages of the invention will appear hereinafter in the detailed description, be particularly pointed out in the appended claims and be illustrated in the accompanying drawings, in which:

FIGURE 1' is a side elevational view, partly in section, of an embodiment of the improved locomotive sanding system of the present invention;

FIGURE 2 is a side elevational view, partly in section, of another embodiment of the sanding system of the present invention having a different means for cutting off flow of saind into the delivery pipe during removal of a clogging condition therein;

FIGURE 3 is a fragmentary side elevational view on a reduced scale of the discharge pipe of the system with portions broken away to more clearly illustrate certain details of the construction;

FIGURE 4 is a fragmentary vertical sectional view of the control valve of the system taken along lines 44 of FIGURE 1;

FIGURE 5 is a schematic view of the system of FIG- URE 1 showing the interrelation between the parts of the system in a normal sanding operation; and

FIGURE 6 is a view similar to FIGURE 5, but with the parts responding to a clogging condition in the delivery pipe.

Referring now in detail to the drawings, in which like reference characters designate like parts, the improved locomotive sanding system of the present invention is designed particularly for use on diesel locomotives. The system is comprised of a sander, sand trap or sand conveyor 1 for delivering sand from a sand box or other source (not shown) through a discharge pipe 2 to the rails beneath the driving wheels (not shown) of a locomotive, control valve 3 for operating the sander by air pressure, a sensing device for applying air under high pressure to the discharge pipe and means for cutting off the flow of sand from the sander to the discharge pipe during application of the high pressure air. To prevent excessive consumption of reservoir air, there also is the preferred system means for limiting the duration of application of the high pressure air.

As in both of the illustrated embodiments, the sander 1 of the system preferably is generally similar to the sander of my Patent No. 3,088,764, issued May 7, 1963. Thus, as in the sander of that patent, the preferred sander 1 has the flow of sand through it to the discharge pipe 2, regulatable by a blade 4, which is swingable or adjustable to vary the opening between the inlet and outlet legs 5 and 6, respectively, of its sand chamber 7, and air for carrying, transporting or moving sand through the discharge pipe to the rails, is introduced into the discharge pipe through a fixed passage or nozzle 8 built into the body 9 of the sander below the sand chamber and extending beneath the floor 10 of the outlet leg to the bodys outlet end 11. To facilitate cleaning, the preferred sander 1 has attached to its inlet end 12 a sand cut-off 13 such as shown in my Patent No. 3,024,797 issued Mar. 13, 1962, for manually cutting off the sander from the sand box or other source of supply of sand (not shown) and the clean out opening 14 in the body 9 below the inlet leg 5 is normally closed by a clean-out plug 15 such as shown in my copending application No. 224,010, filed Sept. 17, 1962, now Patent No. 3,207,540, issued Sept. 21, 1965.

The control valve 3 preferred in the system for controlling the operation of the sander 1 is generally of the type disclosed in my Patent No. 2,589,794, issued Mar. 16, 1952, in which a differential piston 16, normally held closed by a return spring 17, is openable by the pressure of actuating air from an operating valve (not shown) on its larger head 18 to admit air under reservoir pressure, introduced into the body 19 below the piston, initially and momentarily to a clean-out orifice 20 and normally dur ing a sanding operation, to a sanding orifice 21. Opening onto a valve chamber 22 in the body 19, respectively above and between upper and lower valve seats 23 and 24 which are alternately closable by upper and lower valve elements 25 and 26 on the piston 16, the clean-out and sanding orifices 20 and 21 are connected through a single outlet port 27 and air line 28 to the inlet 29 of the air passage or nozzle 8 in the body of the sander 9, conventionally, the clean-outorifice 20 is of a size to pass the air without substantial reduction in its pressure, while the sanding orifice 21 is relatively restricted so as to pass only the low pressure air used in the actual sanding.

The sander 1 has removably attached to its outlet end 11 an extension 30 in which is contained an expansion chamber 31 which is normally open to the outlets of both the sand chamber 7 and the air passage 8 and connects to and forms part of the sand discharge or delivery pipe 2 leading to the rails. Conveniently mounted on the extension 30 is a pressure sensitive switch 32, preferably in the form of a micro-switch closable by a diaphragm 33 on exposure of the latter to a pressure above a predetermined minimum. The diaphragm 33 is exposed to the air pressure in the expansion or mixing chamber 31 in the extension 30, suitably through an opening 34 in the base 35 of the micro-switch 32 and a connecting port or drilling 36 in the extension which desirably is inclined away from the sander to prevent entry of sand, and the predetermined minimum closing pressure of the switch is above the low pressure existing in the expansion chamber during actual sanding. So arranged, the switch under normal conditions will not have time to close in the brief interval in which the initial clean-out blast is applied and will remain open during the actual sanding stage of the operation in which the sanding air is applied or supplied through the restricted sanding orifice 21 in the control valve 3. However, if instead, the discharge pipe 2 is in a clogging condition during the sanding stage of the operation, the air, blocked from discharge by the wet sand or other material causing the clogging, will build up in pressure in the expansion chamber 31 above the predetermined minimum of the sensing switch 32 and cause the latter to close.

The automatic sensing or recognition by the sensing switch 32 of a clogging condition in the discharge pipe 2, in the preferred system, is applied to the control valve 3 to override the action of the actuating air upon the differential piston 16 and cause the piston to shift to the position in which the clean-out orifice- 20 is open to reservoir air. This in turn causes the air under sanding pressure in the expansion chamber 31 to be replaced by air under high or reservoir pressure, which under most conditions is sufficient to dislodge or remove the matter in the discharge pipe causing the clogging. The dislodging action of the air preferably is facilitated by using a rubber hose as the main part of the discharge pipe or by providing at the discharge end of the pipe a rubber nozzle 37, either of which will expand under such pressure.

The preferred overriding of the control valve 3, in response to sensing by the sensing switch 32 of a clogging condition in the discharge pipe 2, is obtained in the illustrated embodiments by mounting on the body 19 of the control valve 3 below the differential piston 16 a housing 38 containing in axial alignment with the piston an override piston 39 having a head 40 opposing the head 18 of the differential piston. The head 40 of the override piston 39 has fixed or attached to and upstanding or extending from it toward the differential piston 16, a coaxial or concentric stem or push pin 41 which extends through a cap 42 closing the lower end of the body 19 and attaching the housing 38 thereto and normally is spaced from the adjoining or confronting lower end of the differential piston. The push pin or pusher 41 normally is spaced from the adjoining end of the differential piston 16 but, within a range of reciprocable movement of the override piston 39 in the housing 38, is adapted to engage that end and push, move or displace the differential piston 16 upwardly from sanding position to clean-out position at which air at reservoir pressure is free to pass through the clean-out orifice 20 to the expansion chamber 31 in the discharge pipe 2.

For moving the override piston 39 to displace the differential piston 16 from sanding to clean-out position, the cylinder 43 in the housing 38 in which it slides, is connected below the head 40 of the override piston 39, to air at reservoir pressure, conveniently through'a T 44 in the air line 45 for operating air leading to the control valve 3 and an inlet passage 46 in the housing with the passage normally closed by a plunger 47 of a solenoid valve 48. Suspended from the housing 38, the solenoid valve 45 is electrically connected in circuit to the sensing switch 32 so as to be energized on closing of the switch and, by retracting its plunger 47, to open the inlet passage 46 and expose or present the underside of the head 40 of the override piston 39 to reservoir pressure. Since the air for actuating the differential piston 16 ordinarily will be at reservoir pressure, the relative areas of the two heads 18 and 14 presentable to that pressure must be such that the combined force on the override piston 39 and of the return spring 17 is greater than the opposing force on the differential piston. With this requirement fulfilled, energizing of the solenoid valve 48 by closing of the sensing switch 32 enables the override piston 39 to displace or shift the differential piston 16 to clean-out position.

Usually, a clean-out blast of a few seconds duration will suffice to dislodge the material clogging the discharge pipe 2. However, in the exceptional case in which the nature of the clogging or blockage is such as not to be relieved by a high pressure air blast of a duration of the order of 10-12 seconds, the only effect of further application of the high pressure air would be to deplete, dangerously, the air pressure in the main reservoir. To prevent such depletion, there is provided in the electrical circuit between" the sensing switch 32 and the solenoid 49 of the solenoid valve 48, a thermal overload unit 50 having a temperature responsive or thermal switch 51 and a heater 52 connected respectively in series and in parallel with the solenoid and of such operative characteristics as to break the circuit after a predetermined interval which in the usual installation will be on the order of 10-12 seconds. The preferred thermal overload unit 50, once it breaks the circuit, requires manual resetting by a reset button 53 as an indicator and reminder of the clogging condition in the discharge pipe 2. The thermal overload unit 50 effectively prevents depletion or reduction of the pressure in the main reservoir below a safe operating level during the unclogging operation, but there remains the problem of preventing the heavy draw on the sand supply which the high pressure air would cause were the sand free to flow through the sander 1 to the expansion chamber 31 at this time. For this problem two solutions are illustrated, one in each of the embodiments. In the embodiment of FIGURE 1 the floor 10- of the outlet leg 6 of the sand chamber 7 is interrupted inwardly of its outward end by a transverse slot 54 opening downwardly onto the air passage 8. The slot 54 in the floor 10 normally is covered by a rubber or like flap or flap valve 55, the free outer end of which at that time rests on the floor above the outer portion of the air passage. Sufficiently resilient to remain in slot-covering position during the application of low pressure sanding air, the flap 55, under the relatively high air pressure applied to its underside through the slot 54 during an unclogging operation, is deflected or displaced to and held in a position in which it closes the outlet leg 6 of the sand chamber 7 with its free end resting against the legs top wall 56. Thus, during an unclogging operation the sand in the sand chamber 7 is cut, shut off or blocked from the suction action of the high pressure air and cannot flow into the expansion chamber 31 until that pressure is removed.

In the alternative arrangement shown in FIGURE 2, there is provided in the line leading from the sand supply to the sander 1 a nipple 57 in which is mounted or contained a rubber or like resilent boot or sleeve 58 clamped at its ends to or against the wall 59 of the nipple, as by clamps 60. An air line 61, conveniently connected to an outlet 62 in the side of the housing 38 below the head 40 of the override piston 39 so as to be charged only when the solenoid valve 45 is opened by closing of the sensing switch 32, leads through an aperture 63 in the wall of the nipple 59 intermediate and preferably substantially midway of the latters end. Consequently, when the sensing switch 32 senses a clogging condition in the discharge pipe 2, high pressure air will be applied to the side of the boot 58 between the clamps 60 and cause the boot to collapse or squeeze shut. As in the ease of the flap 55 of the first embodiment, the response of the sensing switch to a clogging condition will shut or cut off the flow of sand to the expansion chamber 31, in this case by the blocking by the collapsed boot 58 of the normal gravity flow of sand from the sand supply to the sander 1.

Not only does the sand-ing system of this invention provide for automatic elimination of a clogging condition in the discharge pipe 2 without dangerous reduction in the air pressure in the main reservoir or waste of sand, but if for any reason the automatic unclogging action should fail to occur, the system will fail safe and still be capable of performing a normal sanding operation. Consequently, even under the most adverse conditions the sanding capability of the system is independent of the sensing switch 32 and other components of the assembly responsible for automatic unclogging and can be restored in the manner of a conventional system by manual unclogging of the discharge pipe 2. Correction of any failure of the unclogging assembly therefore is postponable until such time as a locomotive equipped with the system is sent to the repair shop for some other reason.

From the above detailed description it will be apparent that there has been an improved locomotive sanding system which has the capabilities of a conventional sanding system and in addition can eliminate a clogging condition in a discharge pipe except under the most adverse conditions and without waste of sand or over-reduction of the pressure in the main reservoir. It should be understood that the described and disclosed embodiments are merely of the invention and that all modifications are intended to be included that do not depart from the spirit of the invention or the scope of the appended claims.

Having described my invention, I claim:

1. A sanding system comprising a sander, a discharge pipe connected to said sander for receiving sand therefrom, means for sensing a clogging condition in said pipe, means responsive to said sensing means for applying air under high pressure to said pipe to remove said condition, and means for cutting off said air after a predetermined interval.

2. A sanding system comprising a sander, a discharge pipe connected to said sander for receiving sand there from, means for sensing a clogging condition in said pipe, means responsive to said sensing means for applying air under high pressure to said pipe to remove said condition, and thermal means connected to said sensing means and acting on said air-applying means for limiting the application of said air to a predetermined interval.

3. A sanding system comprising a sander, a discharge pipe connected to said sander for receiving sand therefrom, valve means for successively applying high pres sure clean-out and low pressure sanding air to said discharge pipe, sensing means for sensing a clogging condition in said pipe, means responsive to said sensing means and acting on said valve for causing said valve to apply said clean-out in place of said sanding air to said pipe to remove said condition, means for blocking sand flow to said pipe during said last-named air application, and means for limiting the duration of said last-named air application.

4. A sanding system comprising a sander, a discharge pipe connected to said sander for, receiving sand therefrom, a control valve, a differential piston in said valve shiftable from a position to out 01f air to said pipe alternately to positions to apply high pressure clean-out and low pressure sanding air to said pipe, an override piston connected to said valve and operable to override the setting of and shift said differential piston from sanding to clean-out position, sensing means for sensing a clogging condition in said pipe, and valve means responsive to said sensing means for operating said override piston and by shifting thereby of said differential piston to clean-out position applying clean-out air to said discharge pipe to remove said condition.-

5. A sanding system comprising a sander, a discharge pipe connected to said sander for receiving sand therefrom, a control valve, a difierential piston in said valve shiftable from a position to cut off air to said pipe alternately to positions to apply high pressure clean-out and low pressure sanding air to said pipe, an override piston connected to said valve and operable to override the setting of and shift said ditferential piston from sanding to clean-out position, a pressure sensitive switch for sensing a clogging condition in said pipe, and a solenoid valve in circuit with and responsive to said sensing switch for operating said override piston and by shifting thereby of said differential piston to clean-out position applying clean-out air to said discharge pipe to remove said condition.

6. A sanding system comprising a sander, a discharge pipe connected to said sander for receiving sand therefrom, a control valve, a differential piston in said valve shiftable from a position to cut off air to said pipe alternately to positions to apply high pressure clean-out and low pressure sanding air to said pipe, an override piston connected to said valve and operable to override the setting of and shift said differential piston from sanding to clean-out position, a pressure sensitive switch for sensing a clogging condition .in said pipe, a solenoid valve in circuit with and responsive to said sensing switch for operating said override piston, and by shifting thereby of said dilferential piston to clean-out position applying clean-out air to said discharge pipe to remove said condition, and thermal switch means in the circuit of said switch and solenoid valve for breaking said circuit after a predetermined interval and thereby cutting off said clean-out air application to remove said condition.

7. A sanding system comprising a sander, a discharge pipe connected to said sander for receiving sand therefrom, a control valve, a differential piston in said valve shiftab'le from a position to cut olf air to said pipe alternately to positions to apply high pressure clean-out and low pressure sanding air to said pipe, an override piston connected to said valve and operable to override the setting of and shift said differential piston from sanding to clean-out position, a pressure sensitive switch for sensing a clogging condition in said pipe, a solenoid valve in circuit with and responsive to said sensing switch for operating said override piston and by shifting thereby of said differential piston to clean-out position applying clean-out air to said discharge pipe to remove said condition, thermal switch means in the circuit of said sensing switch and solenoid valve for breaking said circuit after a predetermined interval and thereby cutting ofi said clean-out air application, and means for cutting oif flow of sand to said discharge pipe during said clean-out air application to remove said condition.

8. A sanding system comprising a sander, a sand chamber in said sander and having inlet and outlet legs, an air passage in said sander below said chamber, a discharge pipe connected to said sander for receiving sand from said outlet leg and air from said passage, valve means for alternately applying high pressure clean-out and low pressure sanding air through said passage to said pipe, means for sensing a clogging condition in said pipe, means responsive to said sensing means for causing said valve means to apply said clean-out air to said pipe to remove said condition, and a flap valve in said sander and normally covering a floor of said outlet leg, said flap valve being shiftable under the force of high pressure air in said passage for closing said outlet leg and blocking flow of sand to said discharge pipe during application thereto of said clean-out air to remove said condition.

9. A sanding system comprising a sander, a sand chamber in said sander and having inlet and outlet legs, an air passage in said sander for receiving sand from said outlet leg and air from said passage, valve means for alternately applying high pressure clean-out and low pressure sanding air through said passage to said pipe, means for sensing a clogging condition in said pipe, means responsive to said sensing means and acting through said valve means for applying high pressure clean-out air to said pipe to remove said condition, and valve means in a sand line leading to said inlet leg and operative on sensing of said condition by said sensing means for blocking flow of sand to said sander during application of said high pressure clean-out air to remove said condition.

10. A sanding system comprising a sander, a sand chamber in said sander and having inlet and outlet legs, an air passage in said sander below said chamber, a discharge pipe for receiving sand from said outlet leg and air from said passage, valve means for alternately applying high pressure clean-out and low pressure sanding air through said passage to said pipe, means for sensing a 7 8' clogging condition in said pipe, means responsive to said References Cited llfiifig i i22122133352133? iii 3? s aii ii gefi iii ii UNITED STATES PATENTS y 7 said condition, a nipple in a sand line leading to said inlet 2,196,977 4/1940 Campbell et 291"3 leg, a rubber sleeve in and clamped at ends to said nipple, 5 2,953,248 9/1960 Tfulalld 210-451 and an air line charged on sensing of'said condition by 2,324,274 7/1943 Baldwm 291-4 said sensing means for applying air under pressure be- 21589794 3/1952} Framz tween said nipple and said sleeve intermediate said ends i r of said sleeve and thereby squeezing said sleeve shut and ARTHUR LA POINT Prlmary Examiner blocking flow of sand to said sander. 10 LEO QUACKENBUSH, B. FAUST, Examiners.

Claims (2)

1. A SANDING SYSTEM COMPRISING A SANDER, A DISCHARGE PIPE CONNECTED TO SAID SANDER FOR RECEIVING SAND THEREFROM, MEANS FOR SENSING A CLOGGING CONDITION IN SAID PIPE, MEANS RESPONSIVE TO SAID SENSING MEANS FOR APPLYING AIR UNDER HIGH PRESSURE TO SAID PIPE TO REMOVE SAID CONDITION, AND MEANS FOR CUTTING OFF SAID AIR AFTER A PREDETERMINED INTERVAL.

6. A SANDING SYSTEM COMPRISING A SANDER, A DISCHARGE PIPE CONNECTED TO SAID SANDER FOR RECEIVING AND THEREFROM, A CONTROL VALVE, A DIFFERENTIAL PISTON IN SAID VALVE SHIFTABLE FROM A POSITION TO CUT OFF AIR TO SAID PIPE ALTERNATELY TO POSITIONS TO APPLY HIGH PRESSURE CLEAN-OUT AND LOW PRESSURE SANDING AIR TO SAID PIPE, AN OVERRIDE PISTON CONNECTED TO SAID VALVE AND OPERABLE TO OVERRIDE THE SETTING OF AND SHIFT SAID DIFFERENTIAL PISTON FROM SANDING TO CLEAN-OUT POSITION, A PRESSURE SENSITIVE SWITCH FOR SENSING A CLOGGING CONDITION IN SAID PIPE, A SOLENOID VALVE IN CIRCUIT WITH AND RESPONSIVE TO SAID SENSING SWITCH FOR OPERATING SAID OVERRIDE PISTON, AND BY SHIFTING THEREBY OF SAID DIFFERENTIAL PISTON TO CLEAN-OUT POSITION APPLYING CLEAN-OUT AIR TO SAID DISCHARGE PIPE TO REMOVE SAID CONDITION, AND THERMAL SWITCH MEANS IN THE CIRCUIT OF SAID SWITCH AND SOLENOID VALVE FOR BREAKING SAID CIRCUIT AFTER A PREDETERMINED INTERVAL AND THEREBY CUTTING OFF SAID CLEAN-OUT AIR APPLICATION TO REMOVE SAID CONDITION.

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