US2689706A - Pilot controlled flush valve - Google Patents

Description

PILOT CONTROLLED FLUSH VALVE Filed Aug. 23, 1950 CARL O. CARLSQN BY fixture F Ian I Patented Sept. 21, 1954 UNITED STATES PATENT OFFICE 2,689,706 PILOT CONTROLLED FLUSH VALVE Carl Oscar Carlson, Oakland, Calif. Application August 23, 1950, Serial No. 181,007

1 Claim. 1

This invention relates to a valve for a system for flushing toilets of the type which deliver flushing Water from pressure accumulators.

It is one of the principal objects to provide a valve for a system whereof satisfactory operation can be expected with low hydraulic supply pressures and fluid conduits of smaller diameters than prior systems have been capable of employing. This objective is realized in part by the use of a new valve system herein particularly described. I have found that in systems heretofore used, large supply pipes have been necessary to conduct the flushing liquid to the accumulator and to the flushing valve, and that by the use of the valve of my invention these supply pipes can be much reduced in diameter.

It is another object to provide a flushing valve Wherewith the amount of flushing fluid released at each operation may be varied through relatively wide limits; for example, from a quart to five gallons of liquid.

It is an additional object to provide a relatively silent flushing valve.

It is a further object to provide in a flushing valve for a system having provision for storing a charge of flushing fluid adjacent the point of use in a storage tank and for permitting the development of a gaseous pressure head over the liquid charge during a period between flushings, for operation at relatively low values of hydraulic pressure at the source. Thus it is possible with applicants invention to utilize a source of low water pressure to operate this type of valve and extends the benefits of the valve to residential water systems where low pressure prevails. I have found that flushing valves in systems of this type heretofore used are so constructed that relatively high values of pressure are required at the valve in order to effect satisfactory flushing operation. The attainment of this objective hinges in part on the removal of obstructions to fluid flow from the storage tank to the fixture being flushed while flushing occurs, and in part on the construction of the flushing valve in a manner so that it operates without such obstructions as have heretofore been found essential to the operation of such systems.

With the foregoing objects and advantages in view, reference is made to the following specifications and accompanying drawing for a full description of a preferred embodiment of the invention. In the drawing:

Fig. 1 is a diagrammatic illustration of a flushing system;

Fig. 2 is a vertical section through a flushing valve;

ing from tank I2 through valve I 4 and thence to the fixture, which may be a conventional toilet.

The tank [2 is an air sealed metal vessel, usually cylindrical and of relatively small diameter and considerable vertical height, the long dimension being disposed vertically. The inlet and outlet for pipes it and [6 are placed at the bottom of vessel [2. With valve l4 closed, fluid is forced into tank I! and compresses air therein above the fluid level. When valve I4 is opened, the compressed air in tank I2 drives the liquid out through the large short pipes l8 and. 16 to the fixture. In systems of this general character as heretofore known, it has been necessary to employ a pipe I!) of relatively large diameter in order to insure the proper operation of the usual valves employed at M, even though the tank itself tends to reduce the diameter of the pipe needed. According to this invention, the cross section of pipe Ill is much reduced over those used at this point in the past. Furthermore, in systems of this general character as heretofore known, the pressure applied to drive fluid through pipe H) has been required to be relatively high in order to insure the proper operation of the valve [4. According to this invention, the pressure existing in the supply pipe I0 may be relatively low as compared to other systems.

Although the flushing system is, as: a whole,

improved by using lower pressures which result in system economies and reduced pipe sizes, these modifications are permitted through the employment of the valve l4 specifically illustrated in Figs. 2, 3, and 4. I

The valve I4 includes the body 29 which may be described to include a cylinder portion 22, the head of which is closed by a sealing cap 24 threaded thereon; a valve chamber 25 subioining the cylinder portion 22 to which chamber there is provided an inlet fitting 28 for the connection therewith of pipe It; and a portion 36 subjoining the valve chamber wherein there is disposed valve tripping elements to be described, and through which portion 30 the flushing liquid is discharged to pipe [8, suitable connection being provided with pipe I 8 as by threads 32.

At the bottom of valve chamber 26 and below inlet 28 there is provided a valve seat 34 centered preferably on the axis of cylinder 22 and of a diameter somewhat smaller than the diameter of cylinder 22. A piston 35, which is preferably cup shaped to provide an upwardly disposed piston skirt 38 having an axial length approximately one-half the cylinder length, is fitted for snug sliding in cylinder 22 and carries integral therewith a main tubular valve stem iii to the lower end of which there is rigidly attached a main flushing valve .2 for engagement against valve seat 34. The construction and arrangement are such that valve 42 is moved to a retracted position where it ofiers little or no obstruction to the passage of flushing fluid through chamber 28.

A pilot valve comprising a stem 44 having a trip lever engaged end at, cruciform guide lugs 48 slidably received in tube to and providing a fluidpassage between the stem and the tube, and valve 58, normally seats by its own weight on valve seat 52 formed at the junction of the inside tube as with the piston cup bottom formed by piston head 35.

The piston head 36 is provided with an adjustable valved passage device 54 by which liquid is allowed to pass from the valve chamber 28 to the cylinder part above the piston at an adjustable rate. The cap 2 is removed for the purpose of effecting this adjustment. Normally, however, the cap zdform's an air seal with the cylinder. A tripping lever 56 connected to a shaft 58 journalled in the valve body 20 drives arm 59 disposed in outlet passage 30 to engage the foot of the'pilot valve stem 44. A suitable adjustable spring structure 60 serves to bias the lever 59 to the position of Fig. 2, out of contact relation with the pilot valve stem.

Fig. 2 illustrates the position of the parts of the valve prior to flushing. Full static pressure from source I is transmitted through the bypass d into the cylinder 22 above piston 36, holding valve 59 against its seat and therefore forming a downward force by piston 36 which is proportional to the static pressure and the cross sectional area of cylinder 22. This force is transmitted through tubular stem ii! to valve i2 and eiTects closure of valve 42 on seat it. Under these conditions the charge of flushing liquid in chamber 22 has accumulated to the height permitted by the air trapped in tank I2.

Upon moving lever 55 counterclockwise in Fig. 2, the stem ts is moved upwardly causing valve 5!! to unseat and remove the downward seating thrust on valve d2 caused by piston 35 by allowing the escape of some liquid from above the piston 36. The action is enhanced by the impact with which lever 55 may be activated, whereby valve 59 is impelled well above its seat 3 5. The pressure tank i2 is nowactive on the top of valve 42 and the exposed bottom of head 35. Since head 35 is larger than the valve 42 the resultant thrust is upward and valve d2 is impelled up to the Fig. 3 position. The passage by bleeder 54 is so minute that it has no substantial eilect in retarding this movement.

The movement to Fig. 3 position is almost instantaneous, being facilitated by the large pilot valve passage through stem ii which allows the liquid above piston 36 to be driven out at high velocity as the piston 36 moves up under the impact of pressure from tanl: l2. The pressure in chamber 2% under the stem 5 3 tends to hold valve 59 well above its seat until the pressure in chamber 26 drops due to discharge of the liquid from the tank. The energy of the air stored in tank 12 accelerates the fluid which also engages under valve .2 and temporarily assists to hold it in Fig. 3 position. At the Fig. 2 position, as the pressure in chamber 26 falls away, valve 59 is moved by gravity and the pull of fluid on foot it into closed position. Thus the valve 50 closes while the piston 36 is still near the upper position of Fig. 3, and causes the sealing of the chamber 22 except for bleeder 54. In this way the chamber 22 becomes somewhat vacuous due to the downward pull of gravity and fluid flow pull on the moving parts. It is this vacuous condition which pre vents the valve parts from being greatly accelerated to the Fig. 2 position, and which allows the valve to close gradually and without noise productive impact. The rate of lowering is governed by adjusting the opening in bleeder 54, which also results in governing the amount of fluid that escapes from'tank l2 before the valves reclose. As soon as the valve 52 reaches its seat the pressure above it builds up both in chamber 26 and chamber 22 so as to give maximum thrust on the valve.

As a specific example of the construction emloyed, the pipe Hi may be as small as one quarter inch in diameter but it has been chosen as onehalf inch. In most instances of prior devices of this general nature, the pipe diameter is of the order of one and one-half inches, and the pressure accumulator is not employed. The pipes l6 and 98 are one inch pipes. The accumulator I2 is constructed of standard two inch pipe and is about four feet long for the maximum desired amount of flushing water, and may be mounted in a wall out of sight. The height of the accumulator i2 is independent of the water supply pressure, but the accumulator may be wholly omitted if both high pressur and the large supply pipe are used. The water supply pressure may range as low as one and one-half pounds per square inch when the accumulator and my valve assembly M are used. The supply pipe it] enters from below the level of inlet 28, as shown. The valve seat 3% is of the order of one inch in diameter and the internal diameter of tube 66' is about three-eighths of an inch, its passage being large for the expulsion with great rapidity of the water from the head chamber 22 over the piston. This rapid activity insures that the valve 4s takes the elevated position of Fig. 3 instantly upon unseating the pilot valve 58, the motion of which reseats the pilot valve as shown. With these approximate physical constants, the ilushing system will operate on pressure ranges as indicated and will flush successfully as little as a quarter of a gallon of water, the amount of water flushed being dependent on the setting of the bleeder valve 54. Part of the flushing liquid comes from the accumulator and part from the supply pipe, the ratio depending upon the relative sizes of these and the time allowed for flushing by the bleeder valve. It is believed that the efficient flushing action is largely due to the freeing of the valve chamber and passage 33 of obstructions while the flushing takes place to a degree sufficient to the result, this being attained in part by the removal of the flushing valve to a point above the inlet to the valve chamber, and in part to the relatively small resistance to flow offered by the tappet 46 and the pilot release lever 59 as compared to other devices of this general nature, and in further part to the delayed fall of the valve into the valve chamber toward its seat.

My flushing system provides, in addition, for a vacuum break at the discharge side of valve M. The main function of this device is to prevent syphoning of the fluid in the fixture back into the water system and resultant pollution of drinking water. Such action might occur frequently where several flush valves are located along the same supply line l9 because when one valve opens the draft may open adjacent valves l4.

To prevent such syphon action I provide the body 20 adjacent chamber 30 with a vent passage 62 joining with an interior passage 64 disposed with its axis vertical and opening toward the pipe 18. A tube 65 having a small diameter portion 68 has threaded to the bottom end thereof a cap 12 provided with an orifice M. A series of wire screens 16 of fine mesh are stacked in the path of flow from orifice 14 to chamber 19 and serve to both restrict flow and to strain 01'1" solids. This device fits within the adjacent connected pipe end. Tube 56 provides enlarged reservoir portion m.

The action of this syphon preventer is that should valve 42 open due to vacuum in line I 9, air

is sucked through inlet 62 freely into space 30 and past valve 42, thus preventing flow from the fixture below space 39. When the valve 42 is operated in flushing the associated fixture, the orifice 14 and screens restrict the liquid flow to a minute amount which is deposited in reservoir and from which it later drains through the orifice and to the fixture. The passage 68 serves to restrict discharge from 62 by damping the flow of air displaced by water entering reservoir 70.

I claim:

A flush valve comprising a cylindrical body having a substantially uniform bore from end to end, one end being closed with a cap and the other end forming an outlet, said bore having a valve seat near its outlet end of slightly smaller diameter than said bore, an inlet for said bore of substantially the same diameter as said bore and positioned adjacent to the seat on the cap side thereof, a cup-shaped piston slidably mounted in the cap end of said bore and having a restricted orifice through its bottom connecting the inside of said piston with the bore adjacent the inlet, said piston also having a depending tubular stem of smaller outside diameter than either said piston or said seat and of a length substantially equal to the diameter of said inlet, a valve disc on the free end of said stem of slightly smaller diameter than said piston but larger than said tubular stem and coacting with said seat, the length of said bore beyond said inlet and the length of said piston being so dimensioned that the valve disc is moved out of the line of flow of fluid from the inlet when the valve disc is fully opened, a pilot valve coacting with the piston end of said tubular stem to control flow of fluid from within said cup-shaped piston to said outlet and having a pin extending through said stem and seat when the valve disc is seated, an enlarged head on the free end of said pin and an operator supported by said body adjacent the outlet for engaging said head to open said pilot valve.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 822,116 Grantland May 29, 1906 913,097 Brown Feb. 23, 1909 1,390,851 Winckler Sept. 13, 1921 1,540,267 Langston June 2, 1925 1,728,577 Schossow Sept. 17, 1929 1,755,993 Kelley Apr. 22, 1930 1,898,337 Brooks Feb. 21, 1933 2,079,329 Moseley May 4, 1937 2,215,133 Prosser Sept. 17, 940

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