US2702047A - Manostat - Google Patents

Description

Feb. 15, 1955 GlLMONT 2,702,047

MANOSTAT Filed Sept. 1, 1950 FIG. 1 VACUUM OPERATION 14 To System To Vacuum On Off Valve Top of Float IN V EN TOR.

United States. Patent O MAN 'OSYTAT Roger Gilinont, Brooklyn, N. Y., as'signor to The Emil GreinerCempany,New-Yorlc N: Y;-, a corporation of NeWYork Application. September 1, 1950; Serial No. 182,856 1 Claim. (Cl. 137-495).

The invention disclosed inthispatent application relates t'owhat' are. known as. thev Cartesian manostats, in which vacuum and pressure in a system are accurately controlled by the risingand falling movements of a gas bell floated with its: open lower end in a mercury seal and carrying at the top a closure cooperable with an orifice connected with asource of'pressu 're substantially as shown in, the Joseph. P. Bader Patent No. 2,436,350 dated February 17, 1948, and the Roger Gilmont Patent No. 2,482,167 dated September 20, 1949.

The primarypur-poseof thepresentinventionis toent I aBIe the manostat to, in etieet, memorize a particular vacuum at which it has been operating so that after the system has been shut down it will remember and return the system to the same pressure for which it was previously set. With this new facility the system may thus be shut down without disturbing a previous setting which may have been arrived at or determined only after extended study or experimentation.

The invention therefore preserves and retains what may have been extremely critical vacuum settings.

Further special objects of the invention are to provide a manostat of the character indicated which may be quickly applied and used in many diiferent control situations and which will operate efficiently in all those difierent uses.

Other important objects of the invention are to provide the manostat outlined in a simple, practical, rugged and inexpensive form of construction.

Other desirable objects and the novel features through which the purposes of the invention are attained are set forth or will appear in the course of the following specification.

The drawing accompanying and forming part of the specification illustrates a present practical embodiment of the invention and some of its many uses, but it will be appreciated that structure and operation may be further modified and changed, all within the true intent and broad scope of the invention as hereinafter defined and claimed.

Fig. 1 in the drawing is a vertical sectional view of one of the new manostats, with the valved by-pass connection between the float chamber and interior of the float shown in elevation;

Fig. 2 is a broken sectional detail illustrating a modified or reversely acting form of orifice.

In Fig. 1 the instrument is shown as comprising an upright tubular casing 7 closed and sealed at top and bottom by screw plugs 8 and 9, and providing a vertically extended chamber in which operates the tubular float 10, open at the lower end and dipping into the mercury seal 11, and closed at the upper end to eflect closure of the orifice nozzle 12.

The latter is shown as carried by a tubular screw stem 13 adjustable up and down in the top of the casing by the exposed knob 14 and adapted to be secured in adjusted relation by lock nut 15.

This orifice tube is in communication by ports 16, annular space 17 and port 18, with a screw stem 19 adapted to be connected with a vacuum or pressure source. This construction provides connection of the orifice tube with a desired vacuum or pressure source in all positions of vertical adjustment of the orifice in respect to the float.

The interior of the float chamber is arranged to be connected with the system to be controlled, by means of a second screw bushing 20 entered in the side of the top plug 8 into communication with a vertical bore 21 extending down through this plug to the float chamber.

This central pressure determining or pressure equalizing.

tube is shown as aving anoz'z'le formation 23 the top thereof directly opposite th Pressure. or vacuum supply nozzle 12, and. to provide eflie'ctive. closure and sealing of these two opposed nozzles, the floatiis shown as having rubber or other suitable sealing. discs 24"s'ecured by a gland nut 25 in the top of the sarneepposire. and operatingbetween the two nozzles. V

The float is guided straight up and ddwfi, 21's" ffiCtiOnfree as possible, over radial projections. 26' anClJZT on the upper and tower portions of thece'nti'al' tub e;

Accurate adjustment of the control pressure iS' attained in the presentinvent'ie by the provision ofa bypass-eonnection 28' extending in goos'e'iieckfdrm' from the lower screw bushing 29 in the'b'otton'l plug 9, which op-ensto the central tube 22, to the screw stein 20 at the top which normally is c'o'nnectedwith the system. r 1

. To enable connection of the stern ztl withthesysteni, with the bypass Z8"'interp'ofs'ed,f special fifting slits strewn coupled at" one's'ide at 3 1 with screw st'erii in endmvided at the opposite side with a screw hub 32 for direct connection with the system.

This coupling fitting or adapter 30 is shown as having a screw hub 33 in the lower side of the same to receive the end coupling 34 of the by-pass connection 28 or, in some instances, to receive a valve or the like, as indicated at 35, in which latter event the by-pass tubing is connected with the valve interposed at this point.

For vacuum operation as illustrated, the bushing 32 is connected to the system to be controlled and the bushing 19 is connected with a vacuum source of lower value than the partial vacuum to be maintained in the system.

The On-Oif valve 35 in by-pass 28 is opened to connect both sides of the manometer, that is, both float chamber and the interior of the float with the system and, with the float in lowered position, with the source of vacuum through the orifice nozzle 12. When the system is brought down to the desired degree of partial vacuum, as may be shown by a gage connected to the system, the On-Oif valve is closed. Finer adjustments of pressure may be made by turning the orifice tube up or down with respect to the valve seat 24 in the top of the float, the preferred setting for this purpose being one in which the sealing disc is at the point of contact with the orifice nozzle at the desired partial vacuum reading.

This partial vacuum will be accurately maintained so long as the system is in operation.

When the system is shut down the resulting increase in pressure in the float chamber will cause the float to snap closed against the central control nozzle 23, thereby trapping the amount of gas which maintained the control pressure, within the float.

Thereafter, upon starting up the system this trapped volume of control gas will bring the system directly to the control point.

The trapping of this control gas within the float under the pressure at which the system has been operating is assured by keeping the float always sealed under the maximum pressure conditions occurring in the float chamber, this being assured by reason of the fact that the annular space within the holder about the float is of greater capacity than the smaller annular space within the float about the stationary control tube 22 so that, as shown in Fig. l, the effect of greater pressure within the holder resulting from shut-down of the system will only be to close nozzle 23 without breaking the seal.

The barrel or casing 7 of the manostat may be of transparent plastic or other transparent material, this feature being of advantage in some cases where it may be desirable to see the relative position of the float and orifice tube or to observe operations of the float.

The reversely acting form of orifice illustrated in Fig. 2 may be used to restore pressure when the pressure in the system falls.

The construction shown upwardly opening check valve 42 seating on an O-ring 43 held by an overstanding washer 44 in the nozzle 45 which is screwed over the orifice tube 13 in place of the regular orifice nozzle 12.

The stem of the check valve 42 projects down beyond the-end of the nozzle far enough to be engaged by the top sealing disc of the float so as to be lifted thereby, and this nozzle is shown. as ported in the sides at 46 to freely admit gas into the orifice tube and hence into the system.

.When this valve form of orifice is used the coupling 19 is 'conected with a source of pressure which is higher than that to be maintained in the system.

The construction described provides a sensitive form of'pressure admission valve operable by the float, but it is contemplated that other forms of valves may be substituted for the same or other purposes.

" What is claimed is:

A manostat which will automatically retain the control pressure under which it has been operating after the system with which the manostat is connected has been shut down and will start operating under the same control pressure when the system is again started, and comprising a gas-tight holder containing a sealing liquid, an inverted tubular float open at the bottom and supported in the sealing liquid, a vacuum supplying orifice tube entered in the top of said holder and having an orifice at the lower end opposed to and engageable by the top of said float and thereby controlled by rising and lowering movements of the float, a stationary control tube extending from the for this purpose is a small,

' bottom of the holder centrally upwithin the float and terminating at the top in a nozzle opposed to the top of the float and closeable thereby in the lowering movements of the float, means for guiding said float in accurately centered relation about said stationary control tube and with the float spaced from the control tube and dipping in the sealing liquid, said float defining within it a relatively small annular space about the control tube and the holder defining a larger annular space about the float for holding a greater quantity of the sealing liquid about the float than that contained within the float whereby to maintain the float always sealed at the bottom under maximum pressure conditions within the holder, and means for effecting connection of said control tube and the interior ofv the holder with and disconnection from the system to be controlled and whereby upon shut-down of the system pressure within the holder greater than that within the float will force the float down to close the nozzle of the control tube, thereby to trap control pressure under which the system was operating within the float ready to resume control when the system is again started up.

Images