Nov. 12, 1946. v. v. BLASUTTA 2,411,020 FLUID CQMPRESSING APPARATUS Filed Oct. 27, 1943 2 Sheets-Sheet l 28 21) 33 33 ' _ INVENTOR Vi 010;Y V. Blusu?u ATTORNEY Nov. 12, 1946. v. v. BLASUTTA 2,411,020 FLUI‘D COMPRESSING APPARATUS Filed 001;. 27,}943 Fla. 2 Sheets-Sheet 2 2 . 4%‘742,1/?) I mvzmog viacYfor V. Blusu?u ' A'ITORNEY Z,ll,0f20 Patented Nov. 12, 719246 at s S ‘ 1 -st 2,411,020 FLUID COMPRESSING APPARATUS Victor V. Blasutta, Golum'bus, Ohio, assignor to The Denison Engineering Company, Columbus, Ohio, a corporation of Ohio Application October 27, 1943, Serial No. 507,862 7 Claims. 1 This invention relates to pumping, compressing and similar mechanical equipment in which cyl-. inders containing movable pistons are employed. In some equipment of-this general type, cyl (Cl. 309-4) - 2 chine shown in Fig. 1, the plane of the section ‘being indicated by the line 2-2 of Fig. 1; Fig. 3 is anenlarged detail sectional view of a portion of a piston in a cylinder showing the sealing ring as it appears when no pressures are inders and pistons are employed to create high applied to the opposite ends; and di?erentials in pressure, ‘for example, in certain Fig. 4 is a similar view showing the sealing ring hydraulic equipment, a piston is moved by a liquid as it appears when pressure di?erentials exist on under pressure to compress air for testing and opposite ends thereof. , other purposes. In such instances, the liquid, Although the present invention is applicable 10 usually oil, seeps past the piston and becomes to any type of pump or engine employing a pis entrained in the compressed air causing faulty ton, the same has been illustrated as applied to operation of some of the associated equipment. an air compressor. ' An object of this invention resides in the pro Referring more particularly to the drawings, vision of a piston so constructed as to prevent the 15 the numeral 20 designates the air compressing seepage of ?uid from one end thereof to the cylinder of a spark plug testing machine 2| which other. includes the compressing cylinder 20 in which Another object of the invention resides in the piston v22 is disposed for longitudinal reciprocat provision of a piston in which compressible seal ing movement. The lower end of the cylinder 20 ing rings may be employed, the construction of has a conduit 23 communicating therewith, the the piston providing for maintaining pressure dif conduit extending from a suitable source of hy ferentials on opposite ends of each of the sealing draulic ?uid under pressure. Normally, the pis rings during the movement of the piston and to ton 22 occupies the lower end of the cylinder 20 "utilize the differential in pressure to force the and the upper portion thereof is ?lled with air. rings into tight engagement with the adjacent 25 When hydraulic ?uid is forced into the cylinder walls of the cylinder and piston. 20 through the conduit 23, the piston is caused A further object resides in the provision of a to move upwardly and compress air in the upper piston having spaced ring-receiving grooves and a end of the cylinder 20. This compressed air is passage extending from one end of the piston to conducted by a pipe 24 to a chamber 25 where the outside surface of the piston between the 30 it is employed to raise the pressure in the cham ber 25 in which the electrodes of a spark plug or grooves, check valve means being arranged in plugs are positioned for test purposes. The pres the passage to permit ?ow in one direction only , sure is built up in this manner to simulate ac through the passage. tual working conditions in the testing operation. _ It is also an object of the invention to provide a piston having a plurality of spaced ring-receiv 35 To insure an accurate test, the electrodes must be clean and free from any foreign matter, ing grooves for the reception of sealing and wip therefore, to prevent the entrance of dirt, mois ing rings and valved passage ‘means. extending ture or other undesirable substances, the air inlet from one end of the piston to the outer surface tube 26 is provided with a‘?lter 21 and a drier thereof between adjacent rings to permit ?uid which has escaped to the space between the rings, 40 28, these members being of any well known and satisfactory type. After the entering air has to return to the proper section of the chamber be passed through the ?lter 21 and drier 28, it ?ows tween strokes of the piston and thus decrease the through a check valve 3| disposed in the inlet possibility of the ?uid escaping to the wrong end tube 26 adjacent the cylinder 20. The valve 3| of the piston. » Further objects and advantages of the present 45 may be of any conventional construction and is employed to prevent the air from escaping back invention will be apparent from the following through the tube 26 during the compression stroke description, reference being had to the accom of the piston 22. As the compressed air ?ows panying drawings wherein a preferred form of from the cylinder 20 to the testing chamber 25, embodiment of the invention is clearly shown. 60 it is further cleaned by passing through another In the drawings: ?lter 32 disposed in the pipe 24. This ?lter is Fig. 1 is a diagrammatic view of a spark plug of such type that it will remove hydraulic ?uid testing machine embodying the present inven tion; as well as other materials from the air to pre vent fouling of the spark plugs being tested. Fig. 2 is a detail vertical sectional view taken through the air compressing cylinder of the ma 55 To reduce the possibiltiy of hydraulic ?uid be 3 2,411,020": 4 coming mixed with the air, the piston 22 has been constructed in accordance with the present invention. In this instance, the piston has been lect between the rings. It is essential for the proper operations 01' the sealing rings that pres sure di?'erentials exist on opposite sides thereof. made of a plastic composition and has been It is, therefore, necessary to relieve the ?uid formed to include a plurality 01' longitudinally 5 which has entered the space between the rings, spaced circumferential grooves 38. These grooves otherwise the pressure will build up until it sub are formed for the reception of resilient sealing stantially equals the pressure on the bottom of rings 34, preferably ‘of a rubber composition, the piston. Due to the presence or the passages which have a substantially circular cross section. 31 and 38 and the fact that the ?uid which has The grooves 33 are of a width su?lcient to pro 10 seeped past the rings is under pressure this ?uid vide a limited degree 01' clearance above or below will ?ow out of the spaces between the rings when the rings when the piston is operatively positioned ' the ?uid pressure below the piston is reduced to in the cylinder whereby proper sealing action permit the piston to return to its normal position, will result when pressure differentials exist on opposite ends of the rings 34. _ l5 ?cient to force valve 42 away from its seat against thepressureoi’the?uidinthepassagesbelngsuf As shown in Fig. 3, the rings 34 are slightly compressed by the cylinder and piston walls when the force exerted by the light spring 43. In the form 01' the invention illustrated, the piston is provided with four rings. The two in the piston and rings are under no pressure. When fluid under pressure is applied to one end of the termediate rings serve as wipers to remove ex piston, however, some or the ?uid ?ows between 20 cess oil from the cylinder walls and return it to the adjacent piston and cylinder walls and into the groove 33 where it acts upon the end ofv the: ring 34 and forces it into ?rm engagement with“ one side wall of the groove 33. Due to this forcible engagement, the sides of the ring 34 will be ex 25 panded into ?uid tight engagement with the cyl inder and piston wall, as shown in Fig. 4 to pre the body of the hydraulic ?uid beneath the pis ton. It is obvious that more rings could be em ployed if desired or that the wiping rings-could be omitted without seriously a?'ecting the op eration of the device. , While the form of embodiment of the present invention as herein disclosed constitutes a pre vent ?uid from passing the piston. Due to faulty ferred Iorm,~it is to be understood that other construction, prolonged periods of operation, wear forms might be adopted, all coming within the and other causes, leakage sometimes develops 30 scope of the claims which follow. and ?uid escapes to the space between adjacent I claim: ' rings. The pressure of this ?uid builds up until ,1. Fluid compressing apparatus comprising, in it is equal on opposite ends of the rings at which combination, a cylinder; a piston movable in said time the rings will not seal properly. ‘ 'Ihe con cylinder, said piston having three annular grooves struction about to be described has been adopted 35 in the outer side wall thereof; sealing means in to vent the space between the rings and avoid the outermost grooves engaging the interior- wall the‘ accumulation of ?uid therein. of the cylinder; wiping means in the intermediate Between adjacent grooves 33, the exterior wall groove engaging the interior wall of the cylinder; of the piston is relieved as at 35 to provide an said piston forming passages extending to the nular spaces 36 between the piston and cylinder 40 side wall between adjacent grooves and forming a walls. Laterally extending branch passages 3‘! common passage connected with the ?rst men connect the spaces 36 with a trunk passage 38 tioned passages and leading to one end of the which extends into the piston 22 from the lower cylinder; and valve means in the common passage. end. Below the lowermost branch passage 31, the 2. Fluid compressing apparatus comprising, in trunk passage 3' is provided with a valve seat 4! 45 combination, a cylinder; a piston movable in said with which a ball valve 42 is normally adapted to cylinder, said piston having a plurality of an engage, a compression spring 43 being employed nular grooves in the outer side wall thereof; seal to urge the ball 42 toward the seat 4|. The ing means in the outermost grooves and engaging spring 43 is disposed within the counterbored the inner wall of said cylinder; wiping means in portion 44 of a plug 45 which is threaded into the 50 an intermediate groove for engaging the inner lower end or the passage 38. An opening 48 wall of said cylinder; said piston having pas extends through the lower end of the plug 45 to sages extending to the side wall between adjacent permit communication between the space in the grooves and a common passage connected with cylinder 20 below the piston and the passage 38. the ?rst-mentioned passages and leading to one Accidental removal of the plug 45 is precluded 55 end of the cylinder; and valvemeans in the com by a set screw 41 which is threaded into the side mon passage between the end of the piston and' ' of the piston as at 48. This set screw 4'! serves the point of connection of the ?rst passage there to press a relatively soft slug 5| against the with. threads of the plug 45 and thus prevent rotation 3. A piston comprising, in combination, a cylin thereof as well as injury to its threads. The set 60 drical body having one end for compressing a ?uid screw" is prevented from backing out of the ‘ piston and scoring the cylinder wall by a plug 52 formed from the same plastic material as the piston and inserted in the outer end of the hole for the set screw. When the hydraulic ?uid under pressure is in troduced into the cylinder 20 beneath the piston 22, the ?uid will engage the lowermost ring 34 and compress the same into sealing engagement with the walls of the cylinder and piston. The pressure of the ?uid on the bottom of the piston 22 causes it to move upward and compress the air in the cylinder above the piston. During these compressing operations, the hydraulic ?uid has‘a tendency to seep past the ?rst ring and col and the other end for engagement by a motivating force, said body having longitudinally spaced an nular grooves formed in the outer side wall there- ' of; compressible sealing rings disposed in said 05 grooves: said body having passage means extend ing from the outer side wall between said rings to .the end formed for engagement by the motivating force ; and valve means in said passage for pre venting ?uid ?ow into said passage from said 10 last-mentioned end of said piston. 4. A piston comprising, in combination, a cylin drical body having one end for compressing a ?uid and the other end for engagement by a motivating force, said body having longitudinally spaced an 75 nular grooves formed in the outer side wall there 2,411,020 6 of ; endless rubber-like rings having circular cross sections disposed in said grooves, said body hav ing passage means extending from the outer side wall between said rings to the end formed for engagement by the motivating force; and valve means in said passage for preventing ?uid ?ow into said passage from said last-mentioned end of eii'ect the compression of another ?uid at the op ' posite end comprising a body having a plurality of grooves in the outer side wall thereof; compres sible sealing rings disposed in said grooves; pas sage means extending into said piston from the end'exposed to the ?uid pressure and terminating at the outer side wall between said rings; and, check valve means in said passage means, said valve means permitting ?uid ?ow only in the 5. Piston means in a cylinder formed for the reception ofv a substantially non-compressible 10 direction from between said rings to the end of the cylinder receiving the ?uid pressure. ?uid under pressure at one end to effect the com 7. A piston in a cylinder formed to receive a pression of another ?uid at the opposite end com motivating ?uid in one end to compress a ?uid in prising a body having a plurality of grooves in the said piston. ~ - the otherend comprising a body having spaced outer side wall thereof; compressible sealing rings disposed in said grooves; a passage extending 15 grooves in the outer side wall thereof; compres sible sealing rings disposed in said grooves; a into said body from the end exposed to the non. passage in said body extending from the end ex compressible ?uid;_ a branch passage extending posed to said motivating ?uid to the space be ‘from said ?rst-mentioned passage to the outer tween said grooves; and valve means for pre side wall between said grooves; and, a check valve in said ?rst passage to permit ?uid ?ow only 20 venting the ?ow of motivating ?uid into said pas sage from the end of the cylinder receiving the from between said grooves to the end of the cyl inder receiving said non-compressible ?uid.- g‘ ‘ same. 6. Piston means in ‘a cylinder formed for the reception 01’ a ?uid under pressure at one end to VICTOR V. BLASU'I'I‘A.