US2403688A - Pump control - Google Patents

Description

9, 1946. 4 J B s r r 2,403,688

PUMP CONTROL I Filed April 2; 1945 to um su line iopumpdischorgeline Yaw. a

INVENTOR. JOSEPH 5.5mm

ATTORNEYS Patented July 9, 1946 PUMP CONTROL V m Joseph BL, Smith, Elida, Ohio; assignor toflheiy V 1 mew 11 This invention relates topump control}. and it is'amon'g the=objects oftheinventi'on top'rovide mechanism'which althougnssensitive' is rugged and powerful. :Tothe accomplishment of'the foregoing and related ends, the invention, then, comprises the'features hereinafter fully described,

and particularly pointed outi the claims, the

following description and 'the annexed. drawing setting forth indetail certain illustrative embodiments of the. invention, these-being indicative change being of magnitudeaspredetermined and adjusted. form any .desired instance, and thelever and trip-system serving'to control the power driving the pump. I Thusas-in the embodiment illustrated, there is a =leverL, fulcrumed on a pivot bar rorbolt 2 '=and operating a trip rod 3 to control the power driving the pump, the lever in turn being controlled by the pressure inthe pump feedline. upperor full line. position as shown in'Fig. 2, by

a plunger 4-which is seated ona diaphragm 5.

The diaphragm is of any suitable material, depending upon the liquid being-pumped, and it may be of copper or.other metaL or natural or synthetic rubber, etc. 7 The diaphragm is in compartly sche- Normally, the lever issupported in member 25. The latch26 at its'lower end rests Standard Oil Company, Cleveland, Ohio a cor- ADDlicatiomApril 2, 1943, -seria1'nai isnsls 1; l iblai nsf (01.103 25) to the far'end of the lever andadds its thrust to the upward: movement of the trip rod. 3which serves. to cut off the power driving the pump. A bufieror shock absorber I2 of resilient material may be providedtocushion the'weight'W. The

rear end of the levermay be formed by arr-extension I3 of the endpiece' II to coact with the trip rod 3, the latter being guidedin suitable bracket means. I4. The trip rod operates the power cutoff IE, whose detail varies, depending upon the character. of the driving power in any given instance, whether current to an electric motor, current to theignition system of an internal combustion engine, or steam supply driving the pump, etc. For example, with thecut-ofi I6 controlling the supply current to an electric motor I! driving the rotary pump l8, having a supply line I9 and discharge 20, the cut-off may be a switchof any usual or preferred detail, and it may be operated by trip rod 3through a lever 22 fulcrumed at 23, andhaving connections 24, 25 and 26, the latter element being a, latch pivoted at 21 on member 28 whichforms an extension handle and together with the member25 is pivoted at 29 on a suitable supportbracket. The two members 25 and 28 are normally held together by the latch 26 whose upper arm 3I-engagesashou1der or ledge of the on a flap which is pivoted at 32to a suitable bracket, and the latch 26 .thus normally rests passively in support on top of the trip rod 3 as in its lower or. inactive position, and thereby the weight of the latch 26 allows its engaging end 3| to rest in'the shoulder or ledge of the end of the member 25 and hold the two members 25 and V 28 together in alignment as one lever. -A hand municationthrough a pipe 6 with the pump supply line. Preferably, the lever L is ofcomposite form such as to provide a suitable guideway or track for a movable weight W. -In the form shown, this conveniently is cylindrical, and has grooves 8 near each end, which ride along the rods or bolts 9 secured in pair'sin the assembly by the end pieces I0, I I. As seen'in Fig; 2 thus, wh'enthe pressure through the communicating pipe 6 from the pump supply line is'sufiicient to support the diaphragm 5 and plunger 4 and hold the lever L in itsupper or full lineposition;-theweight W isat the endof its path of movement adjacent thefulcrum 2,.and the trip rod 3 is in:

its lower or inactive position, but with a pressure drop in line 6 which allows the plunger and the lever L to fall to thelower or dottedline position, the movable weight W rolls down on; its guideway latch 35 normally is set into position against a bracketon. the general. support panel. In such arrangement, it is readily seen that the trip latch 26 rests passively'at the top of the trip rod 3 under normal conditions and the cut-oil I6 is link 24 downwardly to throw the switch at Ita'nd cut off the power driving the pump. The limits between which the pump may be thus stopped or started depend uponthe desired'pressures at whichsuch actions are tooccur, andmay-be ade justed in any given case as desired by the proportion of the Weight and lever. The discharge pressure from the pump is controlled through the same mechanism, with association of a pressure responsive means 40 connected by a pipe 4| to the pump discharge line, and which may for convenience also involve an indicating pressure gauge, and have contacts settable for desired pressure levels between which operation is to be efiected. Connected in circuit with the pressure responsive device 40 is a secondary valve control comprising a normally open valve 43 and a normally closed valve 44. The valve 43 is in a bypass around a one-way check valve 45 which is in the pipe 6 communicating with the pump supply line, the check valve 45 permitting communication from the pump through the pipe 6; to the. diaphragm 5 one way, but closing the other way on pressure unbalance. The valve 44 connects from the pipe 5 on the diaphragm side of the check valve 45 to any suitable point of venting or discharge. fhe valves 43 and 44 conveniently may be electro-magnetically orlso-lenoid operated valves such asof any well-known or preferred construction. With this arrangement, it is readily seen that. as long as the pressure communicated to the pressure responsive device 48 from the pump discharge line is within the limits between minimum and maximum for which the control has been set, the pressure operating also on the diaphragm- 5 through the pipe. 6 from the pump supply line is freely operating through the valves .3 and 45, the vent valve 44 being closed, but in the event of pressure change in the pump discharge line being such as to close the circuit in the pressure responsive device 40, the valves 43 and 44 are reversed, the former being closed and the latter being opened to vent, and theone-way valve 45 prevents communication of pressure from the pump supply line, and the result is therelease of pressure supporting the diaphragm5 and the putting in operation of the controllever and the shutting off of the power driving the-pump.

In the control system also a thermal responsive element or thermostat 41 is again connected. in circuit to the valves 43 and 44,: suchthat these may also be operated to release pressure on the diaphragm lever and trip the powercut-ofiin event of an undue rise in temperature at a critical point. ,For instance, heavy duty pump bearings may. be provided with such, or with an internal combustion engine drivin the pump its cooling systemv may be provided with such temperature control,and as many such thermally-responsive elements may be provided in circuit as are desirable at any given instance.

The operation of the control is apparent from.

the foregoing. As long as the pump is operating under normal and predetermined conditions, the pressure communicated through the pipe 6 to the diaphragm 5 from the pump supply line maintains the lever L in supported position and the.

power driving the pump .is maintained. Suppose the predetermined minimum limit for which the control is desired to operate is 5 pounds per square inch for example. If the feed to the pump falls below this, the diaphragm-supported plunger 4 drops and. the lever L drops and the Weight W rolls to the long end of the lever, and the trip rod 3 is thrown up and releases the latch26 which holds the members and 28 together,-

Whereupon the spring 37 pulls the member 25 and link 24 down and operates the cut-out l6 and stops the pump. Or, ifthe pressure in the pump discharge lineas communicated through shut off the power.

pipe 4| to the pressure responsive element 40 goes out of bounds for which setting has been made, the electric circuit is closed and this operates the valves 43 and 44 to vent the pressure in the diaphragm chamber, and again the diaphragm-supported plunger 4 drops and the lever L drops and the trip rod 3 operates to shut off the power. Or, if the thermally-responsive element 41 is heated in eXcess of a predetermined safe temperature in bearings or cooling water system at a critical point which is being guarded, again the electric circuit is closed and the valves 43 and 44 operate to vent the diaphragm chamber and allow the diaphragm-supported plunger 4 and the weight L to drop and actuate the trip rod 3 to Suppose the adjustment be suchthat twenty pounds per square inch pressure in the pump feed line, as communicated therefrom through the pipe 6, is required to raise the lever to the height where theweight W can roll back to normal positiomwhen the pressure in the pump feed line is up to atlea'st 20 pounds then the lever L is raised and the pump may be started again. This differential between the shut-off and the startingpressures is an important practical advantage, and .if. for any reason the feed is in-v adequate or does not continue, there is an ample safety factor.. The pressures aforementioned are of course illustrative, and may be adjusted to the precise amounts desired in any given case. This control is always in operation, and thereby is especially advantageous over controls which must be cut out while starting and then be set when the normal speed is reached. Owing to the design which allows the diaphragm to be supported against a large surface of metal when pressure is applied, operation on very high pressure lines is possible, and operating pressures on the order of several hundred pounds to 1500 pounds or more per. square inch are feasible, and the setting may be such that a variation of a fraction.

of a pound will operate the control.

Other modes of applying the principle of the,

invention may be employed, change being made as regards the details described, provided the fea-.

. ways on said lever, a weight adapted to run on said guideways, a trip rod operated by said lever to shut off the power driving the pump, a oneway check valve between said diaphragm and the pump suction line, a valve normally open by.- passing said check valve, a valve normally closed positioned between said check valve and saiddiaphragm to a point of discharge, means responsive to pressure change in the pump dischargeline for reversing said last two valves, and a thermally-controlled element also having connections to reverse the same.

2. In pump control means, a lever, a plunger normally supporting said lever at an incline above a horizontal position, a diaphragm actuatingsaid plunger and being controlled by pressure com-- municated from the pump suction line, guideways on said lever, a weight adapted-to run on said guideways, a trip rod operated by said lever to shut off thepower driving the pump, a one-way check valve between said diaphragm and the pump suction line, a valve normally open bypassin said check valve, a valve normally closed positioned between said check valve and said diaphragm to a point of discharge, and means responsive to pressure change in the pump discharge line for reversing said last two valves.

3. In pump control means, a lever, a plunger normally supporting said lever at an incline above a horizontal position, a diaphragm actuating said plunger and being controlled by pressure communicated from the pump suctionline, guideways on said lever, a weight adapted to run on said guideways, a trip rod operated by said lever to shut off the power driving the pump, a one-way check valve between said diaphragm and the actuating said plunger said lever to open said switch.

and being controlled by pressure communicated from the pump suction line, guideways on said lever, a weight un-connected to the lever and normally balanced in alignment over said plunger and adapted to run on said guideways, a switch controlling the power drivingthe pump, and a trip rod operated by 9. In pump control means for a pump having a suction line and a discharge line, a lever, a plunger normally supporting said lever at an incline above ahorizontal position, a diaphragm pump suction line, a valve normally open bypassing said check valve, a valve normally closed positioned between said check valve and said diaphragm to a point of discharge, and a thermally-' controlled element having connections to reverse the same.

4. In pump control means, a lever, a plun ger sure on said diaphragm, and a thermally-conactuating" said plunger and being controlled by pressure communicated from the pump suction line, guideways on said lever, a Weight un-connected to the lever and normally balanced in alignment over said plunger and adapted to run on saidguideways, and a trip rod operated by said lever to'shut off the power driving the pump. 10. In pump control means for a pump having a suction line and a discharge line,-a lever, a

plunger normally supporting said lever at an incline above a horizontal position, a diaphragm V actuating said plunger and being controlled by 7 pressure communicated from the pump suction =line,.guideways on said lever, a rolling weight on trolled elementalso independently releasing the 7 pressure on said diaphragm.v

5. In pump control means, a lever, a plunger normally supporting said lever at an incline above a horizontal position, a diaphragmactuating said plunger and being controlled by pressure communicated from the pump suction line, guideways on said lever, a weight adapted to run'on said guideways, a trip rod operated by said lever to shut off the power driving the pump, and means responsive to pressure change in the pump discharge line for independently releasing the pressure on said diaphragm.

6. In pump control means, a lever, a plunger normally supporting said lever at an incline above a horizontal position, a diaphragm actuatingsaid plunger and being controlled by pressure communicated from the pump suction line, guideways on said lever, a weight adapted to run on said guideways, a trip rod operated by said lever to shut off the power driving thepump, and a thermally-controlled element for independently releasing the pressure on said diaphragm.

'7. In pump control means, a lever, a plunger normally supporting said lever at an incline above a horizontal position, a diaphragm actuating said plunger and being controlled by pressure communicated from the pump suction line, two pairs of parallel rods embodied with said lever, a cylindrical weight normally balanced in alignment over said plunger and having a circumferential groove near each end to ride between the pairs of rods in rolling motion, and a trip rod operated by said lever to shut off the power driving said pump.

8. In pump control means for a pump having a suction line and a discharge line, a lever, a

plunger normally supporting said lever at an incline above a horizontal position, a diaphragm the pump. I

said guideways normally balanced in alignment over said plunger and. gravitationally changing position relative to the lever, and a trip rod operated by said lever to shut ofi the power driving 11. In pumpcontrol means for a pump having a suction line and a discharge line, a lever normally maintained in inactive position by pressure 'in predetermined amount communicated from the pump suction line, a weight un-connected to the lever and normally balanced in alignment over said plunger and movable on said lever to over-balance on failure of the predetermined supporting pressure, and a trip rod actuated by said lever to thereupon shut off the power driving the pump.

12. In pump control means for a pump having a suction line and a discharge line, means in both said lines to control the operation, the means on the suction line including a lever normally maintained in inactive position by pressure in predetermined amount communicated from the pump suction line, an over-balancing weight on said lever gravitationally moving relative to the lever, and a trip rodactuated by said lever when moved from inactive position to shut ofi the power driving the pump.

13. In pump control means for a pump having a suction line and a discharge line, a normally connected cut out for the power driving the pump, a trip normally held inactive by pressure communicated from the pump suction line but operating said out out on pressure drop in such line, and means responsive to pressure change in the pump discharge line for independently operating said trip.

14. In pump control means for a pump having a suction line and a discharge line, a cut out for the power driving the pump, a lever and a weight gravitationally changing its position on the lever to operate the cut out, and control means therefor normally held inactive by pressure commu nicated from the pump suction line. I

' JOSEPH B. SMITH.

Images