US1610694A

US1610694A - Liquid column for producing static stresses

Info

Publication number: US1610694A
Application number: US7782A
Authority: US
Inventors: Elmer T Mccarthy
Original assignee: D H Skeen & Co
Current assignee: D H Skeen & Co
Priority date: 1925-02-09
Filing date: 1925-02-09
Publication date: 1926-12-14
Anticipated expiration: 1943-12-14

Description

Dec. 14,1926. 1,610,694

E. T. MCCARTHY LIQUID COLUMN FORTRODUGING STATIC STRESSES Filed Feb. 9, 1925 4 Sheets-Sheet 1 1 'ra 50mm Dec. 14, 192e. 1,610,694

E. T. MccARTHY LIQUID COLUMN FDR PRODUCING STATIC STRESSES Filed Feb. 9, 1925 4 sheets-sheet 2 Dec. 14,19ze. l f 1 .11,610,694

` E. T. MGCARTHY A LIQUID COLUMN FOR PRODUGING STATIC STRESSES Filed Feb. 9 1925 4 Shee'cs-Sheet'r- Dec. 14 1926. 1,610,694

^ E. T. MCCARTHY LIQUID COLUMN Fon RODUQING1 STATIC sTREssEs Filed Feb. 9, 1925 4 Sheets-Sheet 4 7%655 E #man Mm` @y Patented Dec. 1.4, v1926.

UNITED STATES PATENT oFElcE.

ELMER T. MOCARTHY, 0F EVANSTON, ILLINOIS, AS-SIGN OR TOD. H. SKEEN & COMPANY, 0F CHICAGO, ILLINOIS, A COPARTNERSHIP COMPOSED OF DAWSON H. SKEEN, OF CHICAGO, ILLINOIS, AND ELMER T. MCCARTHY, OF EVANSTON, ILLINOIS.

LIQUID COLUMN FOR PRODUCING STATIC STRESSES.

. Application vfiled February This -invention relates to liquid columns for producing sta-tic stresses, particularly designed and adapted for producing difit'erential pressures and relates particularly to the production of such static stress by means of mercury columns.

A particular application for which ay static column of my invention is especially adapted is for use in connection with automatic valve control ymeans adapted for regulating the flow of fiuid under produce differential pressures.

Among specific applications for which my improved static column is especially -de-` signed and adapted, are the following:`

On pressure regulators f'or steam driven feed vpumps for boilers;

n pressure regulators for boiler feed pumps driven by motive force other than.

steam from the boiler to which the water is fed.

On constant pressure regulators or reducing valves; and

On back pressure regulators or relief valves.

Principal objects of thev invention are Toprevent loss and leakage of mercury in static mercury columns; v

To provide automatic fluid pressure regulators of' the general type specified, so constructed and arranged that the static column applied to the motive means for operating the valve control means may beinStalled at any elevation relative to the motive means; and

To provide means, ated ,and automatic means, for varying the effective height of the\static column t'o compensate for variations in pressure due to vfriction or other causes.

Broadly stated, a static column of mercury or other liquid embodying my invention comprises upper and lower pots, a tube which connects said pots and which communicates with said pots, respectively, substantially at the designed minimum levels therein of the mercuryor other liquid forming said static column, each of said pots being proportioned to hold somewhat more than all of the mercury or other liquid forming such static column, and a pipe adapted for connecting one of said pots above the designed pressure in order to both manually oper# maximum level therein of 'the' 9, 1925. Serial No. 7,782.

'liquid forming said static column, with a More specifically, a static column embodylng my invention comprises a mercury leg consisting of upper and lower pots, a tube which connects said pots and which communicates with said pots, respectively, substantially at the designed minimum levels therein of the mercury forming said static column, 4each of said pots bein proportioned to hold somewhat more t an all of the mercury in said column, and a water leg which communicates with the upper pot of the mercury leg above the 'designed maximum mercury level therein adapted for connecting said upper pot with an expansible chamber providing motive means for the' movable control member of a Huid pressure regulating valve, and a pipe which communicated with the lower pot of the mercury column above the designed maximum mercury level therein adapted for connecting said pot with a source of supply of Huid under pressure. Obviously, with this construction, the mercury j is confined to the mercury pots and the tube which connect said pots, thus reducing the number of joints at which leakage of mercury can occur, reducing and practically preventing loss of mercury. Y

With the described construction, also, it is obvious that the static column may be installed at any desired elevation relative to the expansible chamber forming the motive means.

As the invention relates to manually operated means for varying v the effective height ot the static ucolumn, I .effect the object of the invention by means of a by-pass which connects the Water leg of the static column with the pressure pipel which communicates with the 'lower mercury pot, a valve*preferably a needle valve-Twhich controls said by-pass, and a vent valve applied to said water leg, conveniently to the section of said by-pass between the control valve therein and the water leg of the static column Any desired variation may be provided for by properly proportioning the height of the pots forming the mercury column, and ,the use of a corresponding quantity of mercury.

The desirability of thus varyin the e`ective height of the mercury co umn and thereby the static pressure produced is to compensate for varying pressure losses due to friction in the system, to which said static column,is applied, at varying rates of ow therein,

As m invention relates to means for automatical y producing variatons in the effective height of the static mercury column, I attain the objects of the invention by forming the tube which connects the upper and lower mercury pots of the mercury leg of said static column with an enlarged lower port-ion which communicates with the lower mercury pot adjacent to its lower end and the height of which corresponds to any contemplated variation in the height o f the mercury column to compensate for frictlon losses; means for forming passageways within the enlarged lower portion of said tube which extend substantially from end to end thereof and are of such small bore that water or other liquid'of less specific gravity than mercury, will not rise through the mercury contained in said tubes and the aggregate cross sectional area lof" which is relatively much less than that of the upper pot, the relation being such that variations in the level of the mercury in the upper pot will produce much greater variationsin the level of the lower end of said static column, thereby producing corresponding variatons in the effective height of said static. column. In accordance with my invention, automatic control of the effective height of the mer-y cury column contemplates that the lower end of the mercury column shall at all times be within and above the lower end of the enlarged lower portion of the tube connecting the upper and lower pots of the mercury leg.

My invention also comprises the various other features, combinations of features and details of construction hereinafter described and claimed. f

In the accompanying drawings, in which my invention 1s fully illustrated and in which I have shown different applications of my improved static column,

Figure 1 is a, vertical sectional view of a static column embodying my invent-ion and improvements shown as appl'ed in use toa pressure regulator for a steam driven `feed water pump for boilers.

Figure 2 is a view substantially similar to Fig. 1, showing a static column of my invention comprising means, both manuall operated and automatic, for varying the e fective height of the static column.

Figure 3 is an enlarged longitudinal sectional view in a plane ninety degrees to the line 3-3 of Fig. 2.

Figure 4 is a transverse sectional view on the line 4 4 of Fig.

Figures 5, 6 and 7 are views similar to Fig. 4, illustrating modifications.

Figure 8 is a view substantially similar to Fig. 1, showing my improved static column applied in use-to a feed water pump for boilers driven by power other than steam from the boiler to which the Water is fed.

Figure 9 is a'view substantially similar columnembodying my invention and improvements, which will be separately de scribed. l

Referring now particularly to Figs. 1 and 11 of the drawings, in which I have shown my improved static column as applied to a differential pressure regulator for steam driven feed pumps for boilers, A designates as a whole, a control valve of the balanced type, comprising a casing 1, provided with steam admission and' discharge openings 2 and 3 adapted to be connected into the steam line 4 for supplying steam from a steam boiler 5 to a steam driven pump 6 (Fig. 11), for supplying feed water to said boiler.

My invention contemplates the use of any suitable or desired form of control valve, of which different kinds suitable for the purpose may be purchased commercially, and said valve need not, therefore, be described in detail.

The valve casing 1 forms part of a pres sure regulator which also comprises a diaphragm casing 7 which communicates with said valve casing 1 by means of a trunk 8, said diaphragm casing vbeing divided by a diaphragm 9 into

separate compartments

10 and 11, whereby the surface of the diaphragm 9, exposed in the 4compartment 10 of the diaphragm casing, will be subjected substantially to thc full steam pressure of the boiler. In the operation of the device, the trunk 8 will become filled with water of condensation and, in practice, said trunk'will be made of such length that the water in the lOl) llo

- is connected with the'boiler en f trunk 8 adjacent tothe diaphragm 9 will be of 'such low temperature that said diaphra m will not be injuriously affected there The valve plug or piston12 is connected by a rod or stem 13 with the diaphragm 9, whereby iexure of said diaphragm by eX- cess pressure on one sideor the other thereof, will operate to impart movement to said valve plug or piston to open or close the same, as the case may be. shown,y the relation is such that 'lexure of the diaphragm 9 due to an unbalanced excess steam pressurel inthe compartment 10 of the diaphragm casing, will impart movement to the movable valve member, specifically the plug or piston 12, Ito open the valve, while liexure of said diaphragm due to an unbalanced excess pressure in the compartment 11 of said diaphragm casin will impart movement to said movable va ve member to close the same. In the type of pressure regulator shown, the compartment 11 ofthe diaphragm casing has pipe connection with theA pump discharge line through a static liquid column. shown, said liquid column, which embodies my invention and improvements, comprises a mercury leg and a water leg, which communicate with each other at their upper ends. The mercuryA leg'of said static column comprises closed upper-and lower pots 14 and l5 and a tube 16, which connects said pots, and which communicates with said pots, respectively, adjacent to their lower ends and which define the minimum mercury levels therein, each of said pots being proportioned to hold somewhat more than all of the mercury contained in the apparatus.

The water leg of said static column consists of a pipe 17, oneend of which com-V municates directly with. the compartment 11 of the diaphragm casing, and the opposite...end of which communicates with the upper pot 14 of the mercury leg above the designed maximum mercury level therein.

The discharge opening from the pump 6 5V by a pipe 18, Fig. 11, with which thelower pot 15 of the mercury leg is connected above the de; signed maximum mercury level therein, by a pipe 19.

With the described construction it is obvious that when vthe valve A 'is fully open, a maximum quantity of steam will be det livered to the pump-and said pump will be driven' at maximum speed, the' relation bring such that when the pump is`running at approximately full speed, the ressure in the eed water pipe 18 will be sufcient to overcome the water frictionin the pipe, raise the column of water from the pump to the boiler inlet, and provide a sufficient excess of feed water pressure over` boiler pressure to insure the delivery of a contemplated diaphragm column, water will be forced into the lower pot 15 through the pipe 19, which will, in turn, force mercury from the lower pot 15 into'the tube 16 and from said tubeinto the upper pot 14, forcing water from said upper pot into'the water leg 17, and from the water leg 17 into the compartment 11 of the casing, thus iexing the diaphragm 9 in a direction to close the valve A, reducing the speed of the boiler feed pump and the feed water pressure, and maintaining, at all times, a constant excess of feed waterpressure over steam pressure at the pump, corresponding to the effective head of the mercury column, which may be figured at each, two inches in height of said mercury column.

- It is found in practice that due to the high pressure in the pipe 17 and its connections, it isy diliicult to prevent leakage of water at the joints therein.

With a static column constructed asde- !scribed, it is obvious that any leakage which may occur in said pipe 17 will at once be replaced from the pot 14, thus maintaining said water leg and the compartment 11 full of water at all times. Also, in case the leakage continues until a quantity of water substantially equal in volume to the quantity of mercury inthe lower pot 15- above the lower end of the tube 16, has escaped, the mercury in said lower pot 15 will be forced upwards through the tube 16thus permitting water contained in saidpot to enter the open lower end of said tube 16 which, due 'to its less specific gravity, will rise through the merciury in said tube to the pot '14, thus at all times compensating for any water leakage 1n the water leg. Also, by so proportioning the size of the posts 14 and l15 that each will contain somewhat more than all ofthe mercury in the apparatus, it is obvious that no mercury will be delivered from the upper pot 14 into the water leg 17, or the compartment-11 of the diaphragm casing 7 thus effectually preventing mercury from passing from the upper pot 14 into the water leg, reducing' the quantity of mercury in the mercury leg and preventing deteriorationpf the pipe 17 the mercury.

With the desired construction,y also, it is approximately one pound for' and its fittings by the action ofv ion obvious that said column maybe installed in any desired position relative to the diaphragm casing 7, a usual arrangement being one 1n which the lower mercury pot will be substantially at the levelof said diaphragm casing, thus obviating the work and expense of constructing a pit or well for said mercury column as is necessary, for example, with static columnsof the type shown in U. S. Letters Patent No. 1,452,223, dated October 12, 1921.

When the pump is shut off, the weight of the mercury column acting on the diaphragm 9, will operate to m'aintainthe valve A fully open.

YMy invention, also, contemplates means for varying the effective -hea'd of the vstatic column, to compensate for variations in pressure due to friction or other causes, both manually operated and automatic means being provided for this purpose. Such means are shown in Figs. 2 to 7, inclusive, of the drawings and'will now'be described.

To effect the object of the invention as it relates `to providing manually operated means for varying the effective height'of the static column, 1 effect said object by means of a by-pass which-'connects the water leg 17 of the static column with the pipe 19 which connects the lower pot 15 with the feed water pump 6, said pipe being controlled by a valve-'preferably a needle valve-and said water leg being provided with a vent valve, which may conveniently be installed in the by-pass between the con-- trol valve therein and the water leg of the static column. Said vent valve, also, will preferabl be, a needle valve.

With t e construction specified, it is ob# vious that the effective height of the mercury vcolumn may be increased by venting the water leg to permit the discharge of water therefrom, whereupon the water pressure in the'pipe 19 and the lower mercury ot will operate to force mercury from sai lower pot upwards in the tube 16 into the upper pot 14, thus increasing the distance between the mercury levels in the two ots and correspondingly increasing. the e ective height. of the mercury column, in the manner desired, the rise of the`mercury level ,in the upper pot operating to force water therefrom into the Water leg 17 to replace that discharged from said water leg.

On the'other hand, when it is desired to reduce the effective height of themercury column, this may be effected by opening the valve which controls. the by-pass connecting the lower mercury pot with the water leg 17, thus establishing communication between said lower pot and saidwater leg, balancing the water pressure on opposite ends of the mercury column and permittingpmercuryto flow by ravity from the upper mercury pot into the ower mercury pot, water to replace the mercury which passes out of said upper ot being replaced by water which passes rom the pipe 19 into the pipe 17 fthus forcing water from said pipe 17 into said upper the drawings in which. 7 designates the diaphragm casing; -8 the trunk which connects said diaphragm casing with the casing vof the control vvalve in the steam line; 14

and 15 the upper and lower mercury pots; 16 the tube connecting said pots; 17 the water leg connecting the upper mercury pot with the diaphragm casing; 19 the pipe con necting the lower mercury pot with the feed water pipe; 20 the by-pass connecting the pipe 19 with the water leg 17'; 21 a needle va ve which Controls said by-pass; and 22 a valve in said by-pass between the needle valve 21 and the water leg adapted for discharging water from the water leg.

With the described construction it is obvious that, within defined limits, variations in the effective head of the mercury column may be obtained by properly (proportioning the depth of the pots 14 an 15 and the quantity of mercury contained therein.

The foregoing description of means for Varying the effective height of the mercury column manually, assumes that the lower mercury pot shall be partially filled with mercury outside of the tube 16 and to a level above the lowerend thereof, and attention is calle-d to the fact that' changes in the mercury levels in the upper and lower pots, to

produce changes in the effective height of the mercury column are in opposite directions-rising in one pot and falling in the other. Under certain conditions, however, variations in the effective height of the mercury column are produced by differential changes in the levels of the upper and lower ends of the mercury leg in the same direcf tion, as hereinafter explained.

As the invention rel'ates to providing automatic means for varying the effective height of the static column, I effect the object of the invention in the following manner, as shown in Figs. 2 to 7 of the drawings:

The tube 16 which connects the upper and lower mercury pots, comprises an enlarged lower portion 23, the length of which corresponds to any contemplated or desired variatlon in the effective height of the mercury column to compensate for varying pressure losses due to friction in thesteam and feed water lines, or other causes. i The enlarged lower portion 23 of said tube 16 is provided with passageways 24 which extend'entirely through the same from end to end, said passageways being of such small size that water or other liquid of less specific gravity than mercury will not rise through the mercury contained in saidv passageways and the aggregate cross sectional area of lac f greater variations in the level of the lowersa id passageways being relatively much less than that of the upper pot, the relation being such that variations in the level of the mercury in the upper pot cause-d by movement of the diaphragm 9 will produce much end of said static column, thereby producing corresponding variations in the efectiv'e height of said static column in a direction to produce a greater effective height of the column and consequently greater differential pressure, when the diaphragm moves in la direction to increase the valve opening and thereby increases the flow of steam and Water the s stem controlled by the pump regulator, andY vice versa. Also, the cross sectional area of said passageways may be made to vary at different levels so that the differential pressure will vary according to anyl desired law at different rates of How of the fluids controlled by thevalve A.

The passageways 24 may be lformed in any desired-manner, as for example 1.-By round tubes 25 .which are packed in the enlarged lower portion 23 of the tube 16', said passageways 24 being formed in part bythe bores of said tubes and in part by the spaces between adjacentl tubes, as shown in Fig. 4;

2,'-By square tubes 26 which are packed into the enlarged lower portion 23- of the tube 16 so as to entirely lill the same, said passageways being formed by the bores of said tubes, as shown in Fig.'5;

3 By tubes 27 of any desired shape, as shown round tubes, which are secured in the enlarged lower portion 23 of the tube 16' by cement or the like, which entirely closesv the spaces between adjacent'tubes, the lpassageways 24 being formed by the bores oflsaid tubes, as shown in Fig. 6 of the drawings;or

4.---By rods 28, preferably round rods, which are packed into the enlarged lower portion 23 of the tube 16 so as to ll the same, the passageways 24 being formed'em tirely by the spaces defined by said rods, as shown in Fig. 7. Y

In accordance with my invention automatic control of the e'ective height of the mercury column contemplates that the lower end of said column shall at all times be within and between the ends of the passageways 24, the length of which correspond to a desired maximum variation in the effective height of the mercury leg, the length of said passageways varyingvin any glven case .with the ratio of the aggregate cross sectional areas of the passageways 24 and the upper mercury pot. A desired ratio in most ap plication of the aggregate c ross sectional areas of said passageways 24 to that of the lupper mercury pot is approximately 1 to 10. With this relation it is obvious that a variation of one inch in the mercury level in the -justing the level of upper pot will produce a variation of ten inches 1n the level of the lower end of the mercury column in the same direction, or of nine inches in the effective height of said mercury column.

Automatic control ofdthe effective height lof the mercury leg is based upon the discovery that wlth passageways 24 of suiiciently small size-say not exceeding the area of the bore of a tube 'TLG of an inch in inside diameter-water contained inV the lower end of the enlarged lower portion 23- willl not rise through mer-- lower ends with the lower pot 15', so that liquid willv -be free to enter said passageways-.either water from the lower pot or.

mercury from the upper'pot.

Regulating apparatus embodying my invention designed for use ,under conditions where there 1s a conslderable-pressure loss Adue to friction preferablyy embodies both,

manually controlled and automaticmeans for varying the effective heightof the static column, the manual control being provided primarily for the purpose of initially ad-y the lower end of the mercury column and the automatic control to compensate for variat-ions inpressure due to varying friction losses or other causes.

My invention, however, also contemplates the separate use of said manually operated and automaticcontrol means, if desired.

ressure regulating apparatus embodying astatic mercury column embodying my invention and improvementsand equipped with my improved means for automatically varying the effective height of the mercury column to compensate for variations in ressure due tov varying friction losses-either separately or in association with manually operated means for varying the effective height of the mercury column-presents conditions hereinbefore referred to, in which variations in the effective heil ht of the mercury column are produced y differential changes in the levels of the upper and lower ends of the mercury column in the same direction. i

Attention is called to the fact, also, that while the discharge of water from the water leg 17'v will always raise .the mercury level in the upper pot, it will produce aproportionate change in the mercury level in the lower pot, but in the opposite direction, where said lower pot is partially iilled with mercury outside of thetube 16', thus increasing the effective height of the mercury column; or a differential variation in the level of the lower end, of the mercury column in the same direction, if the lower end the lower end of the tube 16', or will increase the effective height of the mercury column, if the level of its lower end is within and above -the lower end of said passageways 24.

Attention is called to the further fact, also, that in a pressure regulator embodying my improved static column, constructed and arranged for automatically varying the ef.

fective height of the mercury co umn to compensate for variatlons 1n pressure due to varying friction, as shown in Figs. 2 to 7 of the drawings, leakage in the water leg 17 will not be replaced automatically, for the reason, as previously explained,'that the passageways 24 in the enlarged lower portion 23 of the tube 16 are of such small size that water will not rise through mercury contained therein. Obviously. therefore, to replace leakage in the water leg, it will be necessary to provide means for forcing water into said water leg, as the by-pass 20 and the valve 21 which controls said by-pass.

In Fig. 8 of the drawings I have shown my improved static column as applied in use to a feed water pump for boilers, driven by motive force other than steam from the boiler to which the water is fed, usually an electrically driven pump.

l In this application of my improved static column, the regulator which controls the delivery of water to the boiler is connected into the feed water pipe instead of into the steam pipe, the desired differential between feed water pressure and boiler pressure being obtained and maintained by means of my improved static column applied to augment the boiler pressure, and control of the quantity of water delivered Yto the boiler being effected by throttling the water pipe by means of the control valve-the combined steam pressure\ and mercury column head tending to open the control valve and the feed water pressure tending to close said valve.

Withthis construction it is obvious that, as the steam pressure falls, or the feed water pressure rises, the excess of the water pressure will flex the diaphragm in a direction -tending to close the control valve, thus 'throttling the feed water ipe and reducing the pressure of water admitted to the boiler.

On the other hand when the steam pressure' rises or the feed water pressure falls, thev excess steam ressure will flex the diaphragm in a valve in the feed :water pipe, thus increasing the water pressure and maintaining the derection to open the control sired excess yof feed water pressure above steam pressure. y l i In this application of my improved static column, the direction of flow in the feed water pipe will be reversed from the direction of flow in Figs. 1 and 2, the relation being such that the diaphragm will be exposed to the feed water pressure after it has passed through said valve-that isgafter 'instead of before it has been throttled, as is the case with the steam pressure in the application shown in Figs. 1 and 2.

Describing the application vof my improved static column with reference to Fig. 8, A2 designates the control valve, 82 the trunk which communicates therewith, 72

ythe'diaphragm casing, 92 the diaphragm, 122

the movable, valve member, 132 the valve stem, 142, 152 the upper and lower mercury pots, 162 the tube connecting said pots, 29 a pipe which connects the lower mercury pot with the compartment 112`of the diaphragm casing and 3() a pipe connecting the upper mercury pot with the source of steam supply.

VVatei 1to replace leakage from the diaphragm casing and pipe 29, or lower pot 152 is adapted to be supplied by means of a valve controlled pipe connection 31, which connects the high pressurev side of the feed water pipe or other source of supply of water under pressure, with the pipe 29.

As showing a slightly different form and application of my improved mercury column, I have in Fig. 9 o the drawings shown said column as applied in use to a regulator -for producing a constant pressure reduction.

In this embodiment, one side of the diaphragm is subjected to the fluid pressure in the discharge or low pressure side of the valve, the opposite side of said diaphragm being subjected to the pressure of a mercury column corresponding in height to a desired constant low pressure on the discharge side'of said control valve.

As thus applied, the mercury column consists of upper and lower mercury pots connected by a tube which communicates with said pots, respectively, ,adjacent to the designed minimum mercury levels therein, or adjacent to their lowerl ends, the lower pot beingr connected with ,the compartment of the diaphragm casing remote from the control valveby a pipe which communicates with said pot above the designed maximum mercury level therein, said Ipipe, the compartment of the diaphragm casing with which it communicates, and the lower mercury ot above the mercury level therein being lled 'with liquid through which the pressure of the mercury column is transmitted to the diaphragm.

In this application also, the top of the upper mercury pot usually is vopen and is a apted to be closed by a. removable cover lll which is provided with a vent lnaintaining pot.

Describing this application of my improved mercury column with particular reference to Fig. 9 of the drawings, A3 designates the control valve, 13 the valve casing, 23 the admission or variable high pressure side of the casing, 33 the discharge or constant low pressure side of the valve casing, 73 the diaphragm casing, 83 the trunk which connects said diaphragm casing with the discharge or low pressure side of the valve casopening for atmospherlc pressure 1n sa1d ing, 93 the diaphragm which divides the diaphragm casing into separate compartments 103 and 113, 123 the movable valve member, 133 the valve stem connecting the said movable valve member with the diaphragm 93, 143 and 153 the upper and lower mercury pots, 163 the tube which connects said pots, and 32 the pipe which connects the lower mercury pot above the designed maximum mercury level therein with the compartment 113 of the diaphragm casing. v

As stated, also, the top of the upper mercury pot is preferably open and is adapted to be closed by a removable cover 33 to exclude dirt, said cover being provided with a vent opening 34 adaptedto maintain atmospheric pressure in said mercury pot under all operating conditions.

As explained in connection with the device illustrating other applications of my improved mercury column, each mercury pot 143 and 153 is proportioned to hold somewhatmore than all of the mercury in the apparatus, thus effectually preventing mercury from passing from the mercury pot into the pipe which connects it with the dia.- phragm casing.

lith the described construction, it is obvious that the pressure at the discharge or low pressure side of the controlvalve casing will tend to flex the diaphragm 93 in a direction to close the valve A3, while the pressure on the said diaphragm due to the pressure of the static mercury column will tend to flex said diaphragm in a direction to open the valve.

Thus, when there is no pressure above atmosphere in the valve casing, the pressure of the mercury column will maintain the valve fully open, in which position it will remain until a fluid pressure is produced in the discharge or. low pressure side of the valve casing in excess of the pressure of the Ymercury column, whereupon the diaphragm 93 will be flexed to close the valve. suchclosing movement continuing until the valve is throttled to such an extent that the pressure at the discharge side of the valve will be equal tothe pressure of mercury. Any increase at the fluid discharge or low pressure side of the valve will operate to flex the diaphragm slightly to redischarge side of the static columny duce the fluid flow until a balance of the pressures on opposite sides of the diaphragm is reached. On t-he other hand any decrease in the fluid pressure at the discharge or low pressure side of the valve casing will permit flexure of the diaphragm under the pressure of the mercury column to open the valve slightly, thus increasing the fluid flow through the valve and increasing the pres sure at the discharge or low pressure side of the valve casing until, as before, a balanceis reached on opposite sides of the diaphragmhthus, at all times, maintaining a substantially constant low pressure at the of the valve casing, vin the manner desired.

lVater to replace leakage in the compartment 113 of the diaphragm casing, the pipe 32, the lower mercury pot 153 and their connections, can be supplied by a pipe 35 adapted for connecting the pipe 32 with a source of supply of water under pressure, not shown, greater than that of the mercury column.

Also, to provide for lowering the heights of the static column to reduce the pressure in the compartment 113 ofthe diaphragm casing to correspond to a desired constant low pressure at the discharge side of the control valve casing-should conditions require*said vstatic column preferably comprises means for discharging water from said static column. As shown, said means consists of a valve-preferably a needle valveindicated at 36, connected into the pipe 32 and adapted to discharge water therefrom, thereby lowering the effectiveheight of the static column, in the manner desired.

If desired, however, my invention contemplates the use of a closed upper mercury pot for the mercury column shown in Fig. 9, the mercury only partially filling said pot and the space above the mercury being lled with air or other elastic fluid under pressure, which will augment the pressure of mercury column and will permit the use of a relatively small quantity'of mercury. Said pot will be proportioned to provide a space above the mercury of such large size that variations in the pressure of the fluid contained therein, due to changes 'of the mercury level, in operation, will be negligible.

This modification is shown in Fig. 1() of the drawings, in which 144 designates the upper mercury pot and 164 the tube which connects it with the lower mercury pot, not shown, a; the mercury level and 37 the space abovethe mercury adapted to contain air or other elastic Huid under pressure. The pot 144 is proportioned of such large size that variations in the pressure of the elastic fluid contained therein due to contemplated changes of the mercury level in operation, will be negligible.

To provide for charging said pot with to provide a space 37 l fluid under pressure, it is equipped with a valve controlled fitting 38 adapted for making supply Connections thereto.

The pressure regulating means shown in Figs. 8 and 9 may readily be constructed to automatically vary the effective height of the mercury column to compensate for varying resisfances to the current flow, by substitut-ing for the tubes 162, 163 of the mercury columns shown in said Figs. 8 and 9, respectively, tubes having enlarged lower portions 23 provided with small passageways 23 as shown in Figs. 2 to 7, inclusive, and heretofore described.

In all pressure regulating apparatus which embody my improved static column, means are preferably provided for retarding flexureot' the diaphragm and opening or closing of the control valve under sudden variations of the fluid pressure in either compartment of the diaphragm casingor stated differently, for restoring the balance of pressure in the compartments of the diaphragm casing gradually under such sudden variation of fluid pressure.

In the ap aratus shown in Fig. 1, this is effected by t rottlingthe pipe 17; in Fig. 2, by throttling the pipe 19; in Fig. 8 by throttling the pipe 29; and in-Fig. 9 by throttling the pipe 32.

Convenient means for thus throttling said pipes consists of valves-preferably needle valves-con1iected into said pipes 17, 19', 29`

and 32, respectively, said valves being designated 39 in all of the different views.

My invention, however, contemplates any other means for throttling said pipes. If for any reason'desired, also, my invention contemplates throttling both of the pipes 17 and 19, Fig. 1; 17 and 19', Fig. 2; and the

pipes

29 and 30, Fig. 3.

,A particular advantage in throttling the

pipes

19, 19 and 30 in said Figs. 1, 2 and 3, respectively, is that, in case any part of the mercury column beyond the lower mercury pot should become ruptured or blow outfluid under pressure would be delivere thereto in such small quantities that it. would not blow the mercury out of the apparatus, as might happen if said pipes were not throttled and fluid under pressure in large volume were delivered to the ruptured'ap.- paratus.

While I have described my invention with particular reference to a static mercury column, I do not desire to limit `myself to the use of mercury and I therefore desireit to be understood that reference to a mercury column in the specification, merely exemplifies a static column in which any suitable liquid is employed to produce a desired differential stress.

Also, while I have described the invention with reference to ai flexible diaphragm,

I do not desire tol limit myself to the use of a diaphragm but to employ any other equiva ent motive means for operating the regulating valve'where the nature of the fluid used or mechanical condition may render the use of such other motive means desirable.

What I claim is j 1. In a fluid pressure regulator of the type specified,'thecombination of a source of supply of fluid under pressure, a pressure generator, a pipe line which connects said source of fluid supply with said pressure generator, a control valve connected into said pipe line comprising a movable control member, motive means comprising a movable member exposed on one side to the pres sure from said source of fluid supply and on its opposite side to the pressure of' said pressure generator less the pressure of a static liquid column comprising a mercury leg comprising closed upper and lower p'ots, and a tube which connects said pots and which communicates with said pots, respectively, adj'acentto their lower ends, each of said pots being proportioned to hold all of the 'mercury in the apparatus, and a water leg applied directly to said movable member and which communicates with the upper pot of the mercury column above the designed mercury level therein, and a pipe which connects the lower mercury pot above the designed mercury level therein with the pressure generator, and means which connects said movable motive member with the movable valve control member. i

2. In a fluid pressure regulator Eof the type specified, the combination of a source of supply of fluid under pressure, a pressure generator, a pipe line which connects said source of fluid supply with said pressure generator, a control valve connected into said pipe line comprising a movable control member, a diaphragm casing, a diaphragm which divides said casing into scparate compartments, a trunk which connects a compartment of said diaphragm casing with a chamber of the valve casing, and a static column applied to the chamber of said diaphragm casing other than that which.

communicates with the control valve casing, comprising a Water leg which communicates directly with said diaphra m casing, and a mercury leg comprising c osed upper and lower pots, and a tube which connects said pots, and which communicates therewith, respectively, adjacent to their lower ends, each of said pots being proportioned to hold all of the mercury in the apparatus, and the water leg of the static column communieating with the upper pot above the designedy mercury level therein, and a plpe which'connects the lower pot with the discharge line of the fluid pressure generator above the designed mercury level in said lower pot, and means which connects the diaphragm with the movable valve control member.

3. A fluid pressure regulator as specified in claim 1, which comprises means for throt tling a pipe forming part o'l the connection by which pressure from the pressure generator is transmitted to the motive member, to retard movement of said motive member due to changes of pressure. v 4. A liquid column for producing a static stress, comprising upper and lower pots, a tube which connects said pots, each of said pots being proportioned to hold all of the liquid forming the static column, and a pipe adapted for connecting one of said pots with a closed expansible ciamber.

5. A liquid column for producing a static stress as specilied`in claim 4, in which the upper pot has pipe connection with the closed expansible chamber.

6. vA liquid 'column for producing a static stress as specified in claim 4, in which pipes communicate withboth the upper andlower pots adapted for connecting said pots, re-

spectively, with a closed expansible chamber and with a source of supply of duidv under pressure.

7. A liquid column for producing a static stress as specified in claim 4, in which pipes communicate with both the upper and lower pots adapted for connecting said pots, re-

spectively, with a closed expansible chamber and with a source of supply of fluid under pressure the specific gravity of which is less than that of the liquid forming the static columnl 8. A liquid column for producing a static stress, comprising upper and lower pots, a

tube which connects said pots, each of said pots being proportioned to hold all of the liquid forming the static column, a pipe adapted for connecting one of said pots withv a closed expansible chamber, and means for varying the effective height of the static column.

' 9. A liquid column for producing a static stress, comprising upper and lower pots, a tube which connects said pots, each of said pots being proportioned to hold all of the liquid forming the static column, a pipe y adaptedfor connecting one of said pots with.

a closed expansible chamber, and means for automatically varying the effective height of the static column. r

10. A liquid column for producing a static stress, comprising upper and lower pots, a tube which connects said pots, each of said pots being proportioned to hold all of the li uid forming the static column, and a pipe adapted for connecting one of said pots with a closed expansible chamber, the tube connecting the Lipper and lower pots comprising a lower portion provided with passageways of such A`s mall size that liquid of less specific gravity than that which forms the 'static column proper will not rise through said pas ageways when they contain liquid formlng said static column, the aggregate cross- 4 sectional area of said passageways heilig less than'that of the upper pot and the lower end length and differential variations in the levels of opposite ends of said static column will be produced, thereby automatically varying the effective height thereof.

11. Avliquid column for producing a static stress as specified in claim l0, in which the means for varying the eilective height of the static column also comprises means adapted for discharging water from the pipe connecting a pot of said static column with said expansible chamber and for forcing liquid into the same.

12. A liquid column for producing a static stress, comprising upper and lower pots, a tube which connects sai-d pots, each of said pots being proportioned to hold all of the liquid forming the static column, pipesv which communicate withboth the upper and lower pots adapted for connecting said pots, respectively, with a closed expansible chamber and with a source of supply of fluid under' pressure, the tube connecting the upper and lower pots comprising a lower portion provided with passageways of such small size that liquid of less specific gravity than that which forms the static column will not .rise through said passageways when they contain liquid form-ing said static column, the aggregate cross-sectional area of said passageways being less than that of the upper pot and the lower. end ofthe liquid forming said static column terminating within and between the ends of' said passageways, whereby movement of the liquid forming the static column .proper will be in the same direction throughout its length and ldifferential variations in the levels of opposite ends of said static column will be produced, thereby automatically varying the efective height thereof, and a by-pass which connects the pipes which communicate, respectively, with the upper and lower pots of the mercury column, equipped with a discharge valve to atmosphere and with a valve adapted for admitting iuid under pressure directly from the pipe which communicates with the lower pot to the pipe which communicates with the upper pot.

ff 13. A liquid column for producing a static stress comprising upper and lower pots, a tube which connects said pots and which communicates with said pots, respectively, adjacent to their lower ends, each of said pots being proportioned to hold all of the liquid forming the static column, and a pipe adapted for connecting one of said pots above the designed maximum level therein of the liquid forming said static column with a closed expansible chamber.

14. A liquid column for producing a static stress as specified in claim 13, in which the upper pot is adapted to be connected with the expansible chamber. k

15.I A liquid column for producing a static stress as specified in claim 13, in which pipes communicate With both the upper and lower pots above the designed maximum levels therein of the liquid forming the static column proper, adapted for connecting said pots, respectively, with a closed expansible chamber and with a source of'iiuid under pressure.

16. A liquid column for producing' a static stress as specified in claim 18, in which pipes communicate with both the upper and lower pots above the designed maximum levels therein of the liquid forming the static column, adapted for connecting said pots,

respectively, with 'a closed expansible chamber and with a source of supply of fluid under pressure the specific gravity ofv which is less than that of the liquid `forming the static liquid column.

17. A liquid Column for producing a static stress as specified in claim 13, which com- -prises means for throttling the pipe which connects said mercury sible chamber.

18. A liquid column for producing a static stress as specified in claim 13, in which pipes communicate with both the upper and lower potsabovethe designed maximum levels therein of the liquid forming` the static column proper, adapted-for connecting said pots, respectively, with a closed expansiblc chamber and with a source of supply of fluid under pressure, and means for throttliugg; one of said pipes.

In Witness that I claim the foregoing :is my invention, I affix my signature this 2nd day of February, 1925.

EL JR T. MCCARTHY'.

pot and closed expau-