Hydronic, Zone-controlled Temperature Conditioning Systems

Abstract

Hydronic, temperature-control systems including either single or multiple line loops communicating with a source of circulating conditioned fluid for either providing upon demand and/or continuously circulating conditioned fluid, and in which thermostat-operated, solenoid-controlled valve-and-radiator assemblies include fail-safe means, plunger-dampening means, and/or lost-motion mounting for valve elements to afford proper seating; in which an expansion chamber is utilized to distribute fluid at increased pressure and reduced velocity for fluid distribution in a "bypass" system; and in which certain units are particularly adapted to facilitate maintenance and repair.

Description

This invention relates to temperature-control systems and more particularly to improved hydronic systems and control units for obtaining substantially regulated temperature in different zones.

Zone or room-by-room air-conditioning systems, are desirable for the following reasons:

1. Heat losses in any given room are extremely difficult to compute and are merely rough estimates; most heating and cooling systems are overdesigned to condition the temperature in the area most difficult to heat or cool;

2. Conditions vary from time-to-time, season-to-season, and room-to-room, for example:

A. room facing north or subject to cold winds;

B. sun shining on a room major portion of the day;

C. variations due to the number of people in a room;

D. number of lights in a room;

E. cooking heat in kitchen;

F. rooms next to or over a garage area;

G. heat from shower or bath;

H. electrical appliance generated heat, fireplace.

These different factors create a substantial demand variation taxing even the most carefully engineered system. Other factors effecting demand requirements are rugs, drapes, sofas, etc., when air circulation is affected; some rooms may be used only periodically; a nursery demands a higher temperature than an adult's room; room temperatures in rooms for people who are ill, old, etc., should preferably be maintained at a relatively high temperature, etc. It has generally been recognized that zonal control of room temperature is preferred and desirable.

A primary object of the present invention is to provide novel hydronic systems and control valves or units affording zonal control for conditioning a room temperature by radiation.

Another object of the present invention is to provide a novel temperature conditioning system which automatically maintains a uniform controlled temperature in selected areas by means of a novel thermostatic control valve which, in the event of power failure, continues to permit fluid flow in the system, to incorporate a "fail-safe" expedient therein.

A further object of the present invention is to provide a novel solenoid-controlled heat-exchanger and control valves for a hydronic, zonal control system.

A still further object of the present invention is to provide a novel temperature-control system of the character mentioned above in which the novel hydronic control valve includes a valve element having means affording easy valve operation in spite of pressure differential existing in the control valve.

And yet another object of the invention is to provide in a novel hydronic system in which the control valve includes a valve element having means for permitting fluid to bypass a heat-exchanger of the system. Other objects of the invention are to provide in a hydronic valve means eliminating valve chatter; means cushioning solenoid-operated control valves, and means for insuring proper seating of a valve element.

These, together with other and more specific objects and advantages, will become more apparent from a consideration of the following description when taken in conjunction with the accompanying drawing forming a part thereof in which:

FIG. 1 is a diagrammatic floor plan illustrating two typical installations affording room-by-room temperature control by demand flow of condition fluid and/or continuous flow of conditioned fluid and illustrating the thermostatic-controlled regulating valves of the systems;

FIG. 2 is a fragmentary wiring diagram illustrating generally the functioning of a thermostatic control in relation to a circulator or pump;

FIG. 3 is an enlarged, partially sectioned thermostatically controlled regulating valve and radiator conduit;

FIG. 4 is a view similar to FIG. 3 showing a modified valve element mounting;

FIGS. 5 and 5a show an embodiment similar to FIGS. 3 and 4 showing another modification;

FIG. 6 is a still further modification of the regulating valve;

FIGS. 7 and 7a are still further modifications;

FIGS. 8, 8a, and 8b show a still further modification;

FIG. 9 is another modification;

FIGS. 10 and 10a are another modification;

FIG. 11 is a view showing a radiator in which conditioning fluid continuously flows and the fluid volume divides;

FIG. 12 is a view illustrating a regulating valve used in a continuous flow system;

FIG. 13 is a view, similar to FIG. 12, showing another radiator element used in a continuous flow system; and

FIG. 13a is a section on line 13a--13a of FIG. 13.

Before referring to the drawings in detail, the systems to be described are hydronic and will function at relatively low pressures and circulation of a conditioned fluid will afford effective temperature or air conditioning.

Referring to FIG. 1, two conventional residential home installations are shown at A and B. These two installations would be found, for example, in a single-story dwelling such as a "ranch style" home, and a multistory dwelling conveniently described as a "split level" home. Obviously basement, garage or attic temperature conditioning can also be provided in correspondingly similar manners.

In FIG. 1 a furnace of any suitable character will include a boiler having fluid conditioning coils, burners, condensers, etc., these components being generally conventional and are not shown. The boiler includes an outlet pump P and inlet I. The pump outlet communicates through a Tee 10 to branch outlet conduits 12 and 14, respectively, leading to areas A or B.

Area A, for example, includes two separate "loops" or zones, one for conditioning the temperature in the "kitchen" and the other in combined "dining" area and "living" room.

The "kitchen" room is peripherally bounded by conduit 12 which is connected by Tee 16 to a conduit 18 to the inlet of a valve-and-radiator assembly 20. Assembly 20 has an outlet 22 connected by a Tee 24 to the inlet I and forming a complete circuit for one "loop." The other loop includes a valve-and-radiator assembly 26 connected by peripheral radiator conduits 28 and 30 and Ells 32 and 34 to a conduit 36 communicating with Tee 24.

Without describing specific details, in response to a temperature-responsive thermostat (not shown) operating either the valve-and-radiator assembly 20 or 26, simultaneously or independently, conditioned fluid will be circulated through one or both of the loops from the outlet pump P to the boiler inlet I.

Referring to area B, the conduit 14 is connected to a series of radiator-and-valve assemblies, 38, 40, 42, 44 and, the latter being connected by a conduit 46 and Tee 47 communicating with Tee 24 and boiler inlet I. The assemblies 38-46 are indicated as being utilized to condition the temperature of bedrooms and bathrooms as labeled. The assemblies 38-46, as will be described in detail, include a bypass conduit through which conditioned fluid continuously flows and solenoid-operated regulating valves, also to be described in detail, in which, according to predetermined temperature conditions sensed by a thermostat, will redirect fluid flow. Conditioned fluid will be directed to radiation conduits to provide a different supply of fluid to certain areas upon demand, i.e. bedroom, bathroom, etc., depending upon demand conditions.

In area A, for example, at an optimum location, an independent thermostat will be provided for the assemblies 20 and 26, respectively, whereby different temperatures are provided in these two zones, i.e. kitchen and combined dining area and living room. In area B each assembly 38-46 will include an independent thermostat. In this manner, if one bedroom is seldom used, i.e. guest room, it will not be conditioned more than to a minimum or maximum afforded by a bypass line of the respective assemblies.

The assemblies 38-46 are not shown in their operative attitude in FIG. 1 and B, but are illustrated diagrammatically as "lying on their sides;" however, in FIGS. 11-14 these units are shown in an operative attitude. Further, although radiation fins are shown on certain conduits all conduits can incorporate such fins, and bypass lines can be located beneath the floor of a room while the finned radiation line is above the floor. Additionally, suitable radiation housings may be provided for radiator conduits. Conventional "sweated" joints between conduits, Tees, etc., and/or threaded connections may be used. Additionally, materials used may comprise castings of bronze or iron, copper and/or equivalent materials.

Referring to FIG. 2, each of the designated rooms will have suitably located therein independent, thermostatic controls 47, 47', 47", etc. A boiler control relay 48 is connected to a conventional source of current and a motor 50 is operatively connected to pump P. Connected across the electrical conductors to motor 50 is a rectifier assembly 52 for supplying low-voltage direct current to the thermostatic control assemblies 47-47". Fuses are conveniently located in the circuits and rectified low-voltage direct current is directed from the rectifier 52 to a contact arm 54 of the control assemblies 47-47". The assemblies 47-47" include a thermal responsive contact 56 functioning to pivot between contacts 58 and 60. The contacts 58, when engaged by contact arm 54; see 47 and 47", indicate, for example, that the rooms or areas in which the thermostats are located demand additional heat, and a circuit is closed to the boiler relay 48 causing the motor 50 to operate pump P and hot water will be forced through the system. Although direct DC current is used in the disclosed system, alternating current AC can likewise be used.

The contacts 60 when engaged by contact arm 54 will be effective to direct current to a solenoid-operated regulator valve 62 including a field coil 64 and magnetically operated armature 66.

As will become apparent, operation of the armature 66 will result in operation of a respective valving element to afford regulation of the flow of conditioned fluid.

Referring to FIG. 3, a control valve-and-radiator conduit assembly is indicated generally at 62 and comprises the type used at 20 or 26 in area A of FIG. 1. A pipe or conduit 68 directs fluid flow into a chamber 70 of a casting 72 having a valve seat 74 surrounding an outlet 76. The casting 72 has suitably seated at 78 a second housing part 80 in which a finned radiation conduit 82 is connected. The housing part 80 has an internal stop 84 opposite the outlet 76, and a tubular extension 86 of the casting 72 extends axially from outlet 76. The extension 86 is sealed by a plug 88 and circumposed about extension 86 and plug 88 is a field coil or winding 90 which is connected by conductor 92 to the contact 60 of a thermostat. The coil 90 is suitably grounded at 94 and/or a separate ground line can be provided. An apertured, U-shaped mounting bracket 96 is received on extension 86 and plug 88, at opposite ends of the field coil 90, and a suitable lockwasher 98 is provided on the end of plug 88.

Reciprocally received in sleeve 86 is a plunger 100 which forms a cushioning chamber 102 with the adjacent end of plug 88 and which is loosely received in sleeve 86 to provide an axial passage 104 thereabout. The plunger 100 includes a reduced rod portion 106 shouldered to provide a seat upon which a valve 108 is secured by a lockwasher 110 or the equivalent. The valve 108 is preferably produced from "Teflon," for example, and rod 106 terminally engages stop 84 of housing post 80.

Noting the arrows directed from conduit 68 to conduit 82, they illustrate fluid flow which normally urges valve 108 off seat 74; thus providing a "fail-safe" expedient, i.e. when power is off in the field coil 90, fluid pressure urges the valve 108 off its seat 74. The chamber 102 will be filled with fluid, and thus energization of coil 90 will normally cause the valve 108 to engage seat 74; however, fluid in chamber 102 will prevent excessively rapid seating movement and valve chatter, i.e. fluid will bleed out of axial passage 104.

The valve, although shown installed horizontally at an L-connection between conduits 68 and 82, may be rotated 90.degree. whereby armature or plunger 100 reciprocates vertically. Thus in addition to fluid flow tending to force valve 108 off seat 74, gravity action on plunger 100 will also tend to unseat the plunger valve, or valve may be mounted in any position. Plunger 100 and plug 88 are preferably produced from a material becoming magnetized only when a magnetic field is generated in field coil 90. Frame or bracket 96 is also a material aiding to increase the effectiveness of the magnetic field generated by coil 90. Valve 108 is designed to engage seat 74 just before plunger 100 engages plug 88. The valve can be located wherever convenient in a given "loop" of a building or home.

Referring to FIG. 4, slight modifications are made with respect to FIG. 3. Sleeve 86' is produced as a separate element and projects into chamber 70, through an aperture 85 in the casting 72' and is suitably branched thereat. The plunger 100' forms a rear cushioning chamber 102' with plug 88' and housing part 80' has a stop 84'. The plunger 100' includes a spring-mounted valve element 108' in which a first spring 105 engages between sleeve 86' and the element 108' and a second spring 101 is interposed between valve element 108' and retainer 110' on the end of the plunger.

Spring 101 affords a lost-motion connection, i.e. after valve 108' seats on seat 74', the plunger 100' continues to move toward the left. Valve hum is materially reduced or eliminated by spring 101, and spring 105 operates to urge the valve off its seat in conjunction with fluid flow in the event of current failure.

In FIGS. 5 and 5a, a valve similar to that of FIG. 4 is disclosed. However, spring 105' is modified and includes some convolutions which are closer to each other than others; this expedient provides a variable ratio whereby the spring will tend to rapidly stiffen as it is compressed. Thus, when the coil 90 is energized, the magnetic force will be directly reflected in the compressive force stored in the compressed spring.

The fluid flow, in this embodiment is reversed as compared with FIGS. 3 and 4 and spring 105' is of sufficient strength to force the valve element 108 off seat 74' for maximum pressure to which the element 108 is subjected.

Additionally, tube 86" has a tapered mouth in which is received a correspondingly tapered partial seal 87 against which the spring 105' abuts. The bore 89 of partial plug 87 is of sufficient diameter to permit fluid flow from chamber 102' without excessively rapid movement of the plunger which might cause valve hum or piston hammer. The spring 105' is effective to urge valve 108 off seat 74' in spite of counterflow of fluid as indicated.

Referring to FIG. 6, the assembly shown includes a tapered valve seat 74" and the valve element 108" has a correspondingly beveled or tapered edge 109 which provides a force-fit in the tapered seat.

The various expedients such as springs, seals, etc., are clearly interchangeable in the different embodiments.

Referring to FIGS. 7 and 7a, a modified plunger and valve element are shown. The plunger or piston 100" includes a shoulder 110 formed by a reduced diameter stem 112 terminally engageable with stop 84. A valve element 114 is reciprocably supported on stem 112 and is engaged on opposite sides by washer elements 116 and 118, the latter being engaged by one end of a compression spring 120 circumposed about stem 112 and abutting retainer 122. The valve element 114 includes an internal recess or bore 124 opening toward washer element 116 and an O-ring seal 126 engages between the shaft stem 112 and bore 124.

The valve element 114 has relative angular movement with respect to stem 112 and lost motion is afforded by spring 120. When coil 90 is energized and piston is drawn to the left, if seat 74 and/or stem 112 are not in right angular relation the lost-motion mounting of valve 114 permits it to have flush engagement on seat 74, and spring 120 permits "over-travel" of plunger 100".

In FIGS. 8, 8a, and 8b, the assembly shows a vertically disposed sleeve 128 in which the terminal end is swaged or tapered at 130. The swaged portion 130 closely surrounds plunger 100"' which includes a flexible valve 114' similar to that of FIG. 7. In this embodiment, the fastener 122' comprises a nut element threaded on the terminal end of shaft 112' and permitting the adjustment of residual compressive spring pressure imposed by spring 120.

As seen in FIG. 8, the water level in the inlet conduit may fall, i.e. water does not completely fill the conduit. The lower end of tube 128, 130 will be immersed in the water, and even when valve 114' is "opened," water will still enter chamber 119, thus insuring a "cushion" when the plunger 100 moves upwardly, and "quiet" operation is insured.

Referring to FIG. 9, the valve assembly is similar to that of the previously disclosed and described embodiments, however, the piston 132 is modified. A cushioning chamber 102 is formed at the rear end of the plunger and the plunger reciprocates in sleeve 86'. Mounted on stem 134 is a valve element 136 retained thereon by fastener 138. The piston 132 includes an annular groove 140 receiving an O-ring 142 therein, and engaging the bore of sleeve 86'. The piston 132 has longitudinally therethrough a passage 144 opening at stop 84 and having a reduced diameter portion 146 opening into cushioning chamber 102.

By so choosing the plunger diameter, bore sizes, etc., the rate of movement of the plunger can be substantially controlled. Resistance to movement of plunger, i.e. damping movement, can be readily controlled in both directions of movement.

In FIG. 10 and 10a, a casting 148 is produced with opposed openings 150, 152 on opposite sides of a chamber 70'. The openings will communicate with conduits 68 and 82 as seen in FIG. 3. The plunger, valve seat and valve comprise a separate assembly or component 151 including a mounting flange 152 integral with a barrel 154 sealed at 156 with aperture 150, and flange 152 is sealed at 158, with respect to an opposing flange 160, by screws 162. A sleeve 164 is sealed in flange 152 and is terminably plugged at 166. The barrel 154 includes a terminal valve seat 168, and a plunger 170 reciprocates in sleeve 164. A valve element 172 is mounted on a stem portion of the plunger in engagement with a spring 174 positioned by retainer nut 176. Fluid enters barrel 154 through apertures 178 communicating with chamber 70'.

In a unit of the character shown in FIG. 10, replacement of the complete plunger valve seat, and valve is readily accomplished by merely removing screws 162.

In FIGS. 3-10, valve assemblies adaptable for use in a loop such as that shown at 20 or 26 in Area A of FIG. 1. These valve assemblies are generally described as "two-way" valves, in which fluid normally flows through the valve to the radiation conduit, until a room, zone, loop, etc., comes up or down to a temperature set on a control thermostat. Thereafter, the valve is "closed" and fluid no longer flows until a subsequent demand by thermostat operation due to changing temperature conditions.

In FIG. 11, there is illustrated a radiation line 180 connected through risers 182 and 184 to Tee connectors 186 and 188, respectively. The Tees 186 and 188 are connected by a coupling pipe 190 and inlet and outlet pipes 192 and 194, respectively. The Tee 186 has an expansion chamber 196 whereby fluid leaving line 192 decreases in velocity when entering chamber 196. The fluid pressure increases with velocity decrease and passes through pipes 182, 180, 184, whereby fins 198 cause heat exchange by convection. This type of radiation line is usable in a single-line loop as illustrated in FIG. 1, area A, this type line being found to be efficient since the cross-sectional area of the lines are not reduced in order to attain circulation through finned line 180.

Referring to FIG. 12, a "three-way" or "bypass" system valve assembly is indicated generally at 200. This arrangement is utilized in area B of FIG. 1 where temperature-conditioned fluid flows or is "bypassed" when no "demand" occurs at the various areas controlled by thermostat, i.e. at assemblies 38-46 fluid will continuously circulate. Additionally the solenoid controls coils, valves, etc., previously described are generally usable in the "bypass" assemblies of FIG. 1, area B.

In FIG. 12, fluid enters from conduit 201 to an expansion chamber 202 of a Tee casting which includes a lower body casting 203 similar to the valve shown in FIG. 3. An integral sleeve 204 has a solenoid coil 205 retained thereon and plug 206 by a bracket 207 and a retainer 208. The coil 205 is suitably grounded to either the casting 203 or a separate ground wire (not shown). A magnetically attractive plunger 210 having a valve element 212 retained on a stem portion by a retainer 215. The casting 203 has an integral chamber 216 communicating with an opening 217 surrounded by a valve seat 218 engageable by the valve element 212 and through which the piston or plunger 210 projects. A second casting 220 is seated at 221 and suitably secured about seat 218 including an internal stop 222 engaged by the terminal end of the piston stem, being normally urged toward the position shown in FIG. 12 by the direction of water flow and/or a compression spring 223 circumposed about the piston stem which is engaged between the casting at the entrance to sleeve 204 and the valve element 212.

The Tee portion 225 of the casting 203 has a pipe or conduit 227 of a calculated length, and casting 220 has an outlet 228 to which a radiating or finned conduit 229 is coupled.

The length of radiation conduit will be calculated in relation to the particular conditions of installation. A three-way casting 230 is connected at 231 and 232 to conduits 227 and 229 and an outlet portion 233. Suitably vent and drain plugs 234 and 235 are respectively secured in tapped bores of casting 230. As water enters chamber 202, the velocity decreases with a resulting increase in pressure. Water is urged through both conduits 227 and 229 the latter receiving water since valve 212 is off seat 218, until the coil 205 is energized. The return spring 223 is optional and can be eliminated, but is a safety factor to supplement fluid pressure to urge valve 212 off the valve seat 218. After heating and/or cooling conditions are met, the solenoid is energized and the valve element 214 prevents water from flowing through line 229 although a slight amount of leakage can occur, and is possibly preferred.

A slight leakage of fluid through conduit 229 tends to compensate for heat losses and/or gains in a particular area. Additionally, fluid flow through line 227, in the continuous flow circuit, will provide some radiation thus tending to maintain a controlled temperature constant.

The position of conduits 227, 229 can be reversed, and the radiating fins can be on one or both of the conduits. Additionally, conduit 213 may be totally or partially insulated depending upon whether a certain amount of residual radiation is desirable, for example.

In FIGS. 13 and 13a, a valve assembly 238 is similar in structure and function to that of FIG. 12. The distinctions are that inlet and outlet conduits are generally vertical, i.e. conduits 240 and 242 will project through the floor of a room. As seen in FIG. 13a, the casting 244 includes an expansion chamber 246 upstream or opposite the valve seat 248. In all other respects, the assembly of FIGS. 13 and 13a, functions in the same manner as unit 200.

Briefly, there has been disclosed two systems, i.e. a "two-way" or "demand" loop system per FIG. 1, area A (two loops), and a "three-way" or "continuous flow" system per FIG. 1, area B.

Each of the systems includes solenoid-operated control valves. These valves can incorporate the many disclosed interchangeable features.

Claims

What is claimed is:

1. In a temperature-conditioning system for different zones to have individual temperature control comprising, in combination, a plurality of zones, a unit for each of said zones, conduit means connecting said units, a source of pressurized treatment liquid connected in said system for circulating liquid through said system conduits, each of said units including an inlet and outlet port for receiving liquid therein and discharging liquid therefrom, a heat exchange conduit connected between said inlet and outlet ports, control valve means on certain of said units including valve means for optionally directing fluid to said heat exchange conduits, and temperature-responsive control means connected to each of said control valve means whereby certain of said units in a zone being controlled will function independently of another to cause treatment fluid to pass through said certain heat exchange conduit or be essentially bypassed to another unit in another zone, temperature-responsive control means comprising a solenoid, said valve means comprises an armature portion operatively associated with said solenoid, and thermostat means connected to said solenoid for controlling energization of said solenoid and orientation of said valve means, a valve seat interposed between said inlet and outlet ports, said valve seat being in axial alignment with said armature, said armature having a portion projecting through said valve seat, and a valve element on said armature and movable therewith for engagement on said valve seat in response to actuation of said solenoid, said solenoid including a liquid cushion means at the distal end of said armature opposite said valve element, said liquid cushion means comprising a tubular sleeve in direct communication with said system and in substantial axial alignment with said valve seat, said armature being reciprocably supported in said sleeve whereby liquid accumulates in said sleeve within said armature.

2. The temperature-conditioning system as set forth in claim 1 in which one of said units comprises a radiator for receiving temperature-conditioning fluid therethrough, said radiator comprising an inlet portion communicating with an expansion chamber; a pair of conduits connected to said expansion chamber; said conduits communicating with each other downstream of said expansion chamber; at least one of said pair of conduits comprising a radiation conduit and the other of said conduits comprising a bypass conduit.

3. The system as claimed in claim 1 in which the pressurized treatment fluid is directed toward said valve element upstream of said valve seat, and said biasing means normally urging said valve element off the valve seat in opposition to normal system pressure.

4. The system as claimed in claim 1 in which said valve element is reciprocably supported on said armature and has relative movement with respect to said armature in engagement with said valve element and normally urging the valve element toward said valve seat.

5. The system as claimed in claim 1 in which said sleeve includes a terminal-metering end converging axially to the outer surface of said armature.

6. The system as claimed in claim 1 in which said armature includes an axial bore extending from said opening at opposite ends of the armature.

7. The system as claimed in claim 1 in which said temperature-responsive control means comprises a separate replaceable assembly containing therein said solenoid, armature, valve seat and valve element, and a housing removably and sealingly receiving said replaceable assembly.

8. The system as claimed in claim 1 in which said armature and valve element are vertically disposed and the valve element is normally gravity-urged off said valve seat.

9. A temperature condition system as claimed in claim 1 in which said armature is vertically disposed and is normally urged off the valve seat due to the force of gravity in addition to normal fluid pressure.

10. The structure as claimed in claim 1 in which said valve element is disposed downstream of said valve seat whereby pressurized liquid flowing through the system normally urges the valve element off its cooperating valve seat.

11. The system as claimed in claim 10 including an abutment element downstream of and in spaced relation from said valve seat and in the path of travel of said armature for engagement by the terminal end thereof when the valve means is open and the solenoid is deenergized.

12. The system as claimed in claim 1 including an expansion chamber upstream of said valve seat for obtaining an increased pressure thereat as pressurized fluid flows through such system.

13. A system as claimed in claim 1 in which said valve element has limited universal movement on said armature for angularly conforming to discrepancies of said valve seat, said armature comprising a terminal undercut portion including a fastener on its distal end, said valve element comprising a disc circumposed about said undercut portion and having an interior recess containing a O-ring seal, and a spring element between said fastener on said distal end and said valve element for permitting said armature to have relative movement with respect to said valve seat after the valve element is seated.

14. In the system as claimed in claim 1 including conduit means in communication with said valve seat, whereby liquid flow through the valve seat is directed thereto, and auxiliary bypass conduit means connected upstream of said valve seat and communicating with said first-mentioned conduit means upstream thereof.

15. The temperature-conditioning system as claimed in claim 14 in which said conduit means includes an expansion chamber upstream of said valve seat whereby fluid pressure increases therein and is directed toward both said bypass line and said valve seat.

16. A system as claimed in claim 1 including a compression spring circumposed about said armature and extending axially between said tube and said valve element, said compression spring comprising a coil spring having graduated convolutions to provide a variable ratio as the same is compressed.

17. A system as claimed in claim 1 in which said tubular sleeve is disposed vertically and the lower end thereof is immersed in the body of liquid being controlled whereby the cushioning means is maintained filled with liquid to cushion reciprocation of said armature.