US2532182A - Safety switch for engine cooling systems - Google Patents

Description

Nov. 28, 1950 F. w. MURPHY 2,532,182

SAFETY swrrcu FOR ENGINE coouuc; SYSTEMS Filed Oct. 11, 1948 2 Sheets-Sheet 1 9 r r Z i ii 0 6 IN V EN TOR.

F. W. MURPHY SAFETY SWITCH FOR ENGINE COOLING SYSTEMS Nov. 28, 1950 2 Sheets-Sheet 2 Filed Oct. 11, 1948 INVENTOR. g; WMw/rp'fiy 7'0. IGNITION Patented Nov. 28, 1950 SAFETY SWITCH FOE ENGINE COOLING SYSTEMS Frank W. Murphy, Tulsa, Okla.

Application October 11, 1948, Serial No. 53,943

3 Claims.

This invention relates to a safety means for pumps or engines.

In the embodiment of the invention herein disclosed, the device is constructed in the form of an attachment which can be secured to engines or pumps and will permit the unattended operation thereof for stated periods with the assurance that if the engine or pump should become overheated it will be automatically stopped, and can be subsequently started up again when the overheated condition has been corrected.

In the embodiment of this invention herein disclosed, a conventional temperature indicating meter employing a Bourdon tube, thermal or temperature responsive bulb is modified to form a switch which is open when the operating temperature of the engine or pump is normal, but is closed when the temperature is excessive, the switch being interposed in the ignition system so that the ignition system will be grounded and the engine stopped.

A further object is to provide a safety cut-off switch adapted for gas or internal combustion engines having a vapor cooling system with a condensing radiator cooled by a fan driven from the engine by a belt and in which the cooling water around the engine jacket is maintained at the boiling point of water, namely 212 F. at all times and the hot vapor or steam rising therefrom is condensed in the radiator instead of boiling away and the condensation returns to the jacket for normal operation of the engine. However, failure of the cooling system caused by a broken fan belt of the radiator cooling and condensing fan or leakage of water below nor mal running level will not raise the temperature above 212 F. so that it is impossible to use a conventional temperature safety switch. Instead, the engine continues to run with the cyiinder wall getting hotter, while the water jacket area gets cooler with lack of vapors until the piston scores the cylinder walls and seizes causing serious damage.

With the present invention, the enginewill operate normally when the water level ismaintained, and the water maintained around the Bourdon tube to control the temperature indicator, and switch for cutting on or groundingthe ignition system to stop the engine when exces sively hot, will not boil being maintained by its distance from the engine cylinders and sur-- rounding cooler ambient atmospheres sufi'iciently cool to prevent boiling or overheating. However, breaking of the fan belt causes the vapors to crowd the radiator in which the vapors are normally condensed to maintain the proper operating temperature at or below 212 F., faster than it can condense them and slight pressure thus caused forces the water at such temperature to seek escape through a vent adjacent or above the Bourdon tube in such a manner that the escaping hot water acting on the tube causes the indicator pointer to move across the dial indicating excessive heat and close the switch to cut oif the ignition system as by grounding the magneto ignition circuit of the engine to stop the same until the defect is corrected and the engine again started, to prevent damage. Also, should the water in the cooling system be lost or fall below normal level by leakage or otherwise, the moment the level falls too low below the Bourdon tube, the steam escapes from the overheated cooling system past or around the tube and operates the indicator hand and switch as described, thereby supplying a dependable contrcl device for the safe operation of engines or pumps to protect them from damage.

With the above and other objects in view, my invention consists in the arrangement, combination and details of construction disclosed in the drawings and specification, and then more particularly pointed out in the appended claims.

In the drawings, 7

Figure 1 is an elevation of an engine having ,-g a vapor cooling system equipped with a safety switch or control system embodying the present invention,

Figure 2 is an enlarged sectional view of the operating and control element, taken on the line 2--2 of Figure 1,

Figure 3 is a detached perspective elevation partly broken away of the safety switch or control device; and

Figure 4 is a diagrammatic view showing the manner of installing the device in the ignition system of an engine.

Referring to the drawings in detail, It desig nates a conventional gas or internal combustion engine or pump having the usual vapor cooling system including a water jacket H around the cylinder through which the water is circulated by a conventional pump 92 ,or from which the hot vapors or steam rising from the jacket is circulated or passed into a condenser or radiator l3 having the usual cores, .to be cooled andcondensed by a cooling fan driven inthe usual manner from the engine, as by a fan belt (not shown) as is customary. In a vapor cooling system, the cooling water in the jacket around the motor or cylinders thereof is maintained at a tempera- 3 ture of 212 F. at all times during the normal running of the engine. It is impossible to use a conventional temperature safety switch to stop the engine because failure of the cooling system caused by inoperation of the cooling fan as by a broken fan belt of the radiator or condenser, or leakage of the water will not raise the temperature above 212 to operate the switch and stop the engine as the engine will continue to run with the cylinder wall getting hotter while the water jacket area gets cooler with lack of hot vapors until serious or irreparable damage results such as by the piston scoring the cylinder walls and seizing, cracking or other damage caused ther by.

The present invention is designed to reliably and dependably protect the engine by stopping the engine. For this purpose, an upright or vertical riser or stand pipe it is attached to the jacket l! through a tapped hole is as by an L-fitting or elbow it coupled or threaded into said hole and to which the lower end of pipe I4 is coupled or threaded as shown. The riser i2 is spaced far enough away from the cylinder or cylinder head and surrounded by cooler ambient atmospheres so that the water therein from the cooling water within the jacket surrounding the motor cylinders does not boil. The upper end of the riser or stand pipe i l above the normal level of the water of the cooling system therein adjacent the cylinder head carries an adaptor fitting or nipple E'i interiorly threaded at both ends and having an intermediate vent hole it therethrough. The lower end of the nipple ll threads onto the upper end of the riser M as at it and an adaptor or ring nut 22 is threaded into the upper end of nipple i? as at 26 and has a wrench head 22 on its upper end interiorly threaded. to take a union plug or nut 23, the exterior threads of which engage or thread into the interiorly threaded upper end of adaptor or ring nut 22 as at 22.

A thermally controlled switch is provided between the riser id at nut 23 and the pump or engine control means or ignition circuit thereof to cut ofi or ground same and stop the motor should it become overheated such as from breaking of the fan belt or leakage of cooling water as heretofore pointed out. For this purpose a remote Bourdon tube or temperature responsive bulb 25 containing a gas or liquid such as methyl chloride or other expansible thermal fluid as in connection with my prior Patent No. 2,358,729, dated September 19, 1944, is carried by and extended down through the nut 23 preferably in insulated connection therewith, and depends through adaptor or ring nut ill and nipple ii below the vent ill to dip into the cooling water in the riser or stand pipe as at the normal running level thereof in and from the water jacket I! of the engine as indicated at in Figure In effect, a steam pocket or trap is provided around the tube or bulb 25 by closing the upper end of the pipe or housing around the tube formed by the riser i l, nipple ii and nut 726 closed by the nut or plug 23, except for the vent l8.

A conventional or other temperature indicating meter or indicator 25 is mounted on an insulation panel 2! bolted to and insulated from the engine or radiator 13 as seen in Figure 1. A pipe 28 rises from the nut or plug 23 around a terminal conduit or tube 29 extending from the tube 25 to the indicator 26 and may be coiled in 4 its length in connection with any excess capillary tubing as at 30 and taped if necessary to avoid chafing against any sharp metal surface. Terminal member or tubing 29 connects to the indicating meter or guage 25 through the casing thereof which may be metallic and grounded to the ignition circuit of the engine including a magneto 3| grounded at 32 through a conduitor Wire 33.

The indicator or guage 26, preferably of the liquid type, has its dial 34 calibrated or zoned to indicate the thermal condition of the circulating cooling liquid or water, such as Cold, Run" or Hot or merely the latter two, and in degrees of temperature in any standard scale, such as 90, 140, 170, and 212 or otherwise, indicating in this instance as shown, degrees Fahrenheit. A metallic pointer 35 is operatively connected or correlated to the remote thermal element 25 of the thermally controlled switch through tubing 2% to move over the dial from its pivot to indicate the temperature and is grounded through a conductor wire 36 as at 31. The pointer 35 forms a movable contact and is adapted to engage a contact 38 when the cooling medium or water is excessively hot or above 212 F. and may be of any suitable construction or type such as'in my prior patent above referred to in which the casing 3| has an opening in the wall thereof adjacent said pointer or Hot point of the dial above 212 F., to receive an internally and externally threaded sleeve 32 threaded through said opening and the contact 38 is adjustable by its head 40 for regulation of the temperature at which the switch closes by contact of the pointe1 therewith. The contact 38 may comprise a screw or threaded shank integral therewith and threaded through the sleeve constituting a binding post having a holding nut or nuts ll on the shank bearing against the outer end of the sleeve to connect a terminal 12 of a conductor wire 43 leading and connected at its opposite terminal 42 to the other side of the electrical power source or magneto 3i of the ignition circuit of the engine as seen in Figure 4 and to the positive lead or side of the ignition system circuit through conductor wire 44 with an interposed ignition or control switch 45.

While any thermal controlled switch may be employed and will work in connection with the control device on the motor as described the adjustable contact as described is preferred to give more minute and accurate control and to adapt it for different liquid or water cooled engines including especially the vapor cooling system with condensing radiator as described to operate at 212 F. at all times. A conventional safety switch arrangement will not operate with such a cooling system because failure of the latter due to a broken fan belt of the cooling fan of the radiator or condenser, or leakage of the cooling water will not raise the temperature above 212 F. as the engine continues to run with the cylinder wall getting hotter while the water jacket area and water in the riser I4 gets cooler with lack of vapors until the piston scores the cylinder walls and seizes causing irreparable damage, or possible warping or cracking.

With the present safety means or control device and switch the operation is simple, positive and reliable. During the ordinary running, when the temperature of the cooling medium or water is not excessive and the engine is not excessively hot, the water fills the riser I4 to the operating level of the engine jacket at 50-11 (Figure 2) and is far enough away from the engine or cylinder or head thereof and surrounded by cooler ambient atmospheres so that the water in the riser does not boil and in efiect serves or acts as a steam trap. Breaking of the fan belt causes the vapors to crowd in the radiator or condenser faster than it can condense them and the slight pressure thus caused forces the 212 water or higher steam or vapor temperature to seek escape through the vent I8 around the thermal element or Bourdon tube 25 causing the safety switch to close by movement of the pointer or movable contact 35 against the adjustable contact 38 by the escaping hot water and ground the pointer and ignition circuit of the engine or magneto thereof to cut oil the ignition system and cause stoppage of the engine thereby preventing any damage thereto. Should the water in the cooling system be lost as by leakage or otherwise dangerously below a safe or normal runnin level, the moment the level falls in the riser connection IS, the steam escapes through the riser vent It to expand the thermal fluid or methyl chloride in the element bulb or Bourdon tube 25, swings the pointer to engage contact 38 and close the switch to ground the magneto or ignition circuit at 31 to stop the engine. Filling of the jacket above the proper normal level will cause the excess water to be expelled through the riser vent. The device is simple, inexpensive as well as positive and reliable in operation as it can be depended upon to stop the engine operation to protect the same from damage. In addition, it can be expeditiously and economically installed and readily connected for efiective operation.

I do not mean to confine myself to the exact details of construction herein disclosed but claim all variations falling within the purview of the appended claims.

What I claim is:

1. In a safety means for engines having a closed vapor type cooling system and ignition means, a thermally controlled means for cutting off the ignition means when the engine is excessively hot, said means including a source of electrical power for the ignition means, a temperature indicatin guage, a switch forming a part of said guage having a movable pointer to indicate the temperature of the cooling liquid and connected to ground, a riser connected at its lower portion to the cooling liquid to receive the same at alevel corresponding to that in the cooling system and spaced from the engine and exposed externally to atmospheric air, said riser having a vent near the top, a Bourdon tube in the top of said riser and exposed to the liquid therein, the upper end of the riser being closed, and a conduit extending from the tube through the riser and connected to the guage to actuate the pointer to close the switch and ground the ignition circuit when the cooling liquid become overheated and tends to escape through the vent with steam and hot vapors therefrom around the Bourdon tube, to stop the engine.

2. In a safety means for internal combustion engines having a jacket for cooling liquid of a closed vapor type cooling system including a condenser for condensing vapors from the engine jacket, an ignition circuit for the engine including a grounded magneto, a temperature indicator for the cooling liquid including a dial calibrated to indicate running temperatures of the liquid, a grounded movable pointer coacting with said dial, an adjustable contact engageable by the pointer when the liquid temperature is above normal and connected in the ignition circuit, a stand pipe having its lower end connected to the jacket to receive the cooling liquid therefrom at normal running level and spaced from said jacket so as to be relatively cool, and a Bourdon tube in the pipe and dipping in the relatively cool liquid therein, a tubing leading from the Bourdon tube to actuate the pointer over the dial according to the temperature of the liquid, said pipe having a vent above the liquid and being closed elsewhere except where it connects to the jacket, whereby failure of said condenser to condense vapors at the rate at which the vapor is produced in the jacket will effect an increase in pressure in said cooling system to cause flow of heated coolant from the jacket to said standpipe to cause the expansible medium in the tube to actuate the pointer as a switch to engage the adjustable contact and close the ignition circuit therethrough to ground the same and stop the engine.

3. In combination with an internal combustion engine including a closed vapor coolin system having a liquid coolant receiving jacket disposed about the cylinders thereof, and a condens'ing radiator for condensing the coolant vapors and returning the condensed vapors to said jacket, and an ignition circuit for said engine including a grounded magneto; safety means comprising a vertically disposed riser spaced from said jacket, coupling means communicatin the lower end of said riser with said jacket substantially below the normal liquid coolant level therein whereby said liquid coolant will nornormally seek said level in said riser, a thermally responsive bulb positioned in the upper end of said riser and normally submerged in said liquid coolant, a vent opening in said riser above the normal liquid coolant level therein, normally open switch means interposed in an electrical conductor extending from said ignition circuit to ground and adapted to be actuated to closed position by said thermally responsive bulb, and means operatively connecting said bulb and said switch means whereby the liquid coolant in said riser will normally have a temperature lower than that of the liquid coolant in said jacket, and failure of said condenser to condense the coolant vapors at the rate at which the vapor is formed will effect an increase of pressure within the vapor cooling system causing a flow of the heated liquid coolant in the jacket into said riser thereby subjecting said temperature responsive bulb to increased temperatures for closing said switch means to thereby ground said ignition circuit and stop the engine.

FRANK W. MURPHY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 872,039 Adams Nov. 26, 1907 1,633,156 Antunes June 21, 1927 2,162,174 Jones June 13, 1939 2,231,845 Curran Feb. 11, 1941 2,445,625 Meinholdt July 20, 1948 2,450,630 Bourne, Jr Oct. 5, 1948

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