CA1136734A - Step open zone valve - Google Patents
Step open zone valveInfo
- Publication number
- CA1136734A CA1136734A CA000332386A CA332386A CA1136734A CA 1136734 A CA1136734 A CA 1136734A CA 000332386 A CA000332386 A CA 000332386A CA 332386 A CA332386 A CA 332386A CA 1136734 A CA1136734 A CA 1136734A
- Authority
- CA
- Canada
- Prior art keywords
- switch
- motor
- diode
- output shaft
- responsive
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000000543 intermediate Substances 0.000 claims description 26
- 239000012530 fluid Substances 0.000 claims 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 25
- 238000010438 heat treatment Methods 0.000 description 7
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D23/00—Control of temperature
- G05D23/19—Control of temperature characterised by the use of electric means
- G05D23/275—Control of temperature characterised by the use of electric means with sensing element expanding, contracting, or fusing in response to changes of temperature
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Electrically Driven Valve-Operating Means (AREA)
Abstract
ABSTRACT
A control system for positioning the output shaft of a motor is disclosed having a motor for positioning the output shaft between first and second positions, the output shaft having an intermediate position between the first and second positions, a motor energizing circuit for energizing the motor to drive the output shaft from the first position towards the second position, a position responsive apparatus responsive to the intermediate position of the output shaft for stopping the output shaft at the intermediate position, a time delay circuit responsive to the output shaft reaching the intermediate position for driving the motor after the passage of a predetermined amount of time to position the motor at the second position, and a return mechanism for returning the output shaft to the first position when the motor is de-energized.
A control system for positioning the output shaft of a motor is disclosed having a motor for positioning the output shaft between first and second positions, the output shaft having an intermediate position between the first and second positions, a motor energizing circuit for energizing the motor to drive the output shaft from the first position towards the second position, a position responsive apparatus responsive to the intermediate position of the output shaft for stopping the output shaft at the intermediate position, a time delay circuit responsive to the output shaft reaching the intermediate position for driving the motor after the passage of a predetermined amount of time to position the motor at the second position, and a return mechanism for returning the output shaft to the first position when the motor is de-energized.
Description
~3~734 STEP OPEN ZONE VAL~7E
_ __~___ B~CKGF<OUND OF THE INVE~TION
_ ___ The present invention relates to a system for controlling the position of a motor and, more particularly, to a system for driving a valve partially open before opening the valve to its fullest extent after a predetermined time delay.
Hot water heating systems for private homesl apartment buildings and the like typically comprise a hot water boiler located in the basement of the building and connected to radiators located in the rooms of the building to be heated. The radiators are designed to be heated by the hot water to transfer the heat to the rooms. Each radi-ator may be controlled by a valve operating from a thermo-stat to allow the flow of hot water through the radiator on a call for heat. In such ~ystems, noise caused by the ther-mal expansion of the pipes and radiators carrying the hot water has been a known problem for ~uite some time.
One solution to this problem of noise has been to provide rubber mounting pads which fit around the pipes where they pass through the support joists of the building.
Thus, because of the flexture of these rubber pads, the rubbing of the hot water pipes as they expand and contract due to the circulation of hot water therethrough against the joists of the buildlng is minimiæèd. However, these rubber pads are expensive to install and are not entirely satisfac-tory in reducing noise caused by thermal expansion in hydronic heating systems. To help further reduce such noise, it has been suggested that if less than total water flow is initially permitted through the hydronic heating system for a predetermined period of time before total flow is allowed, noise due to thermal expansion of the pipes can ~ 3~73~
'~e ma~erialiy reduce~.
The present system, therefore, provides a motor positioning system whereby a valver on a call for heat, can be driven to a position intermediate its first and second positions before being driven to its second position after a predetermined time delay.
SUMMARY OF T~IE INVENTION
A control system for positioning the output shaft of a motor has a motor for positioning the output shaft between first and second positions, the output shaft having an intermediate position between the first and second positions, a motor energization circuit, which may be a con-dition responsive network, connected to the motor for energizing the motor to drive the output shaft from the first position towards the second positior., a position responsive mechanism connected to the motor and responsive to the intermediate position for stopping the output shaft at the intermediate position, a time delay apparatus connected to the motor and responsive to the intermediate position for driving the motor after the passage of a predetermined ~mount of time to position the output shaft at the second positionl and a return apparatus associated with the motor for returning the output shaft to the first position upon the de-energization of the motor.
BRIEF DESCRIPTI~ OF T~ RAW~NG5 These and other features and advantages will become apparent from a detailed consideration of the invention when taken in conjunction with the drawings in which:
Figure 1 is a schematic representation of the invention;
~3L3~ii73~
Figure 2 shows a variatiorl of t'ne water circulating system shown in Figure l; and, Figure 3 shows a variation of the circuit shown in Figure 1.
DET~ILED DESCRIPTION
__.
In Figure 1, radiator 11 is located in zone 10 and is connected to supply pipe 12 and return pipe 13. Return pipe 13 returns hot water circ~lating through radiator 11 ~o water heating apparatus 14 and is circulated by pump 15 which has an inlet connected to the outlet of water heater 14 and an outlet connected to valve 16. Valve 16 has valve chamber 17 within which is located a valve rnember in the form of ball 18 for seating against valve seat 19 to control the flow of water through valve 16 to its outlet port 20 from its inlet port 21. Outlet port 20 is connected to sup-ply line 12 for supplying hot water to radiator 11.
Valve member 18 is positioned within valve 16 by shaft 22 which forms an Olltput shaft from motor 23. Motor 23 is connected to output shaft 22 through gears 24. One terminal of motor 23 is connected directly to supply line L2 whereas the other terminal of motor 23 is connected to normally closed contact 25 o~ switch or microswitch 26 having operator 27 responsive to notch 28 of cam 29. Cam 29 is driven by output shaft 22 of the motor combination 23-24.
Switch 26 also has nortnally operl contact 30 and moveable contact 31. Normally closed contact 25 is connected to normally open contact 30 through the series combination of resistor 32 and diode 33. A bimetal time delay switch 34 comprising bimetal 35 connected to one side of resistor 32 and terminal 36 connected to the other side of diode 33 provides a time delay feature for shorting out the resistor 32, diode 33 combination after a predetermined time delay.
~.
Moveable contact 31 is connected to ON contact 37 of thermostat 38 located withln zone l0 for sensiny the tem-perature thereof. Thermostat 38 has OFF contact 39 which is left unconnected and moveable contact 40 connected to the other side of the supply source, line Ll. ON contact 37 of thermostat 38 is further connected to one side of pump 15 the other side of which is connected directly to line 1,2.
Finally, output shaft 22 has return spring 40 therearound for biasing valve member 18 against valve seat l9.
In operation, when thermostat 38 senses a call for heat, moveable contact 40 moves against ON contact 37 for energizing motor 23 through thermostat 38 and normally closed contact 25 of switch 26. Motor 23 will begin rotating output shaft 22 through gears 24 in the direction of the arrow to move valve member 18 away from valve seat l9. At the same time, pump lS is energized to begin circulating water through valve 16, port 20, line 12, radia-tor ll, return line 13 and water heater 14 back to the other side of pump 15. When cam 29 is rotated to the intermediate position of output shaft 22 between the first position where valve member 18 is against valve seat l9 and the second position where valve 16 is fully opened, a position which may represent, for example, a 25% flow rate through valve 16 to radiator ll, cam follower 27 senses notch 28 of cam 29 to operate moveable contact 31 o~ switch 26 against normally open contact 30. When switch 26 so operates, alternating current is no longer supplied to motor 23. Instead, direct current is supplied to motor 23 from line L2, through motor 23, resis~or 32, diode 33, norrnally open contact 30, moveable contact 31, thermostat 38, to line Ll. This direct current flowing through motor 23 will cause it to brake, stoppiny output shaft 22 in its interrnediate position. The ~3~734 curren~ through resistor 32 will also begin generating heat therefrom which, after a predeterrnined time delay, will cause bimetal 35 to warp against contact 36 for shorting out resistor 32 and diode 33 for again applying alternating cur-rent to motor 23. When ca~ follower 27 moves out of notch 28 of cam 29, moveable contact 31 will again operate against normally closed contact 25 of switch 26 for insuring that alternating current is maintained to motor 23 for driving output shaft 22 to its second position where valve 16 is fully opened. Thus, when output shaft 22 is in its interme-diate position, partial flow of water flows through pipes 12 and 13 and radiator ll and full flow will flow through this system when valve 16 and output shaft 22 are in their second position.
Figure 2 shows a variation on the system of Figure l. In Figure 2, zone 50 has a radiator 51 located therein.
Hot water is supplied to radiator 51 by pump 52 through inlet port 53 of valve 54, outlet port 55, supply line 56, radiator 51 and return line 57 to water heating apparatus 58 the output of which is connected to the input of pump 52.
Valve member 59 of valve 54 is controlled by the control system 60 which may be the same control system as shown in Figure 1 and is connected to thermostat 61 which may be sim-ilar to thèrmostat 38 shown in Figure 1. Connected to second output port 62 of valve 54 is a dornestic hot water heating tank 63 having a return line 64 conn~cted to return line 57. Pump 52 ma~y be continuously energized from an alternating current source for supplying water through valve 54 and, when valve member 58 is in its first position against valve port 55, to hot water heater 63 and back to water heating apparatus 58 through return lines 64 and 57.
When thermostat 61 senses a call for heat, control 60 dr.ives ~13~;~3~
valve member 59 to its intermediate position where partial flow is supplied to radiator 51 and the remaining water is supplied to hot water heater 63. After the predetermined time delay as established by bimetal switch 3~ shown in Fig-ure 1, valve member 59 Will be driven to its second position where it closes off port 62 for supplying full flow to radi-ator 51.
In Figure 3, which shows a variation of the cir-cuit disclosed in Figure 1, the direct current brake comprising diode 33 and resistor 32 is normally shorted by moveable contact 31 and stationary contact 25 of switch 26.
When thermostat 38 calls for heat, motor 23 is energized.
When cam 29 operates moveable contact 31 against s~ationary contact 30, direct current flowing through diode 33 and resistor 32 also flows through motor 23 braking it at this intermediary position. After an amount of time required for resistor 32 to heat bimetal 35, bimetal 35 will close against its contact 36 to again short out diodd 33 and resistor 32. Alternating current again flows through motor 23 driving it to its second position. As soon as motor 23 begins rotating cam 29, moveable contact 31 returns to its stationary contact 25 to maintain the short across the direct current braking circuit.
_ __~___ B~CKGF<OUND OF THE INVE~TION
_ ___ The present invention relates to a system for controlling the position of a motor and, more particularly, to a system for driving a valve partially open before opening the valve to its fullest extent after a predetermined time delay.
Hot water heating systems for private homesl apartment buildings and the like typically comprise a hot water boiler located in the basement of the building and connected to radiators located in the rooms of the building to be heated. The radiators are designed to be heated by the hot water to transfer the heat to the rooms. Each radi-ator may be controlled by a valve operating from a thermo-stat to allow the flow of hot water through the radiator on a call for heat. In such ~ystems, noise caused by the ther-mal expansion of the pipes and radiators carrying the hot water has been a known problem for ~uite some time.
One solution to this problem of noise has been to provide rubber mounting pads which fit around the pipes where they pass through the support joists of the building.
Thus, because of the flexture of these rubber pads, the rubbing of the hot water pipes as they expand and contract due to the circulation of hot water therethrough against the joists of the buildlng is minimiæèd. However, these rubber pads are expensive to install and are not entirely satisfac-tory in reducing noise caused by thermal expansion in hydronic heating systems. To help further reduce such noise, it has been suggested that if less than total water flow is initially permitted through the hydronic heating system for a predetermined period of time before total flow is allowed, noise due to thermal expansion of the pipes can ~ 3~73~
'~e ma~erialiy reduce~.
The present system, therefore, provides a motor positioning system whereby a valver on a call for heat, can be driven to a position intermediate its first and second positions before being driven to its second position after a predetermined time delay.
SUMMARY OF T~IE INVENTION
A control system for positioning the output shaft of a motor has a motor for positioning the output shaft between first and second positions, the output shaft having an intermediate position between the first and second positions, a motor energization circuit, which may be a con-dition responsive network, connected to the motor for energizing the motor to drive the output shaft from the first position towards the second positior., a position responsive mechanism connected to the motor and responsive to the intermediate position for stopping the output shaft at the intermediate position, a time delay apparatus connected to the motor and responsive to the intermediate position for driving the motor after the passage of a predetermined ~mount of time to position the output shaft at the second positionl and a return apparatus associated with the motor for returning the output shaft to the first position upon the de-energization of the motor.
BRIEF DESCRIPTI~ OF T~ RAW~NG5 These and other features and advantages will become apparent from a detailed consideration of the invention when taken in conjunction with the drawings in which:
Figure 1 is a schematic representation of the invention;
~3L3~ii73~
Figure 2 shows a variatiorl of t'ne water circulating system shown in Figure l; and, Figure 3 shows a variation of the circuit shown in Figure 1.
DET~ILED DESCRIPTION
__.
In Figure 1, radiator 11 is located in zone 10 and is connected to supply pipe 12 and return pipe 13. Return pipe 13 returns hot water circ~lating through radiator 11 ~o water heating apparatus 14 and is circulated by pump 15 which has an inlet connected to the outlet of water heater 14 and an outlet connected to valve 16. Valve 16 has valve chamber 17 within which is located a valve rnember in the form of ball 18 for seating against valve seat 19 to control the flow of water through valve 16 to its outlet port 20 from its inlet port 21. Outlet port 20 is connected to sup-ply line 12 for supplying hot water to radiator 11.
Valve member 18 is positioned within valve 16 by shaft 22 which forms an Olltput shaft from motor 23. Motor 23 is connected to output shaft 22 through gears 24. One terminal of motor 23 is connected directly to supply line L2 whereas the other terminal of motor 23 is connected to normally closed contact 25 o~ switch or microswitch 26 having operator 27 responsive to notch 28 of cam 29. Cam 29 is driven by output shaft 22 of the motor combination 23-24.
Switch 26 also has nortnally operl contact 30 and moveable contact 31. Normally closed contact 25 is connected to normally open contact 30 through the series combination of resistor 32 and diode 33. A bimetal time delay switch 34 comprising bimetal 35 connected to one side of resistor 32 and terminal 36 connected to the other side of diode 33 provides a time delay feature for shorting out the resistor 32, diode 33 combination after a predetermined time delay.
~.
Moveable contact 31 is connected to ON contact 37 of thermostat 38 located withln zone l0 for sensiny the tem-perature thereof. Thermostat 38 has OFF contact 39 which is left unconnected and moveable contact 40 connected to the other side of the supply source, line Ll. ON contact 37 of thermostat 38 is further connected to one side of pump 15 the other side of which is connected directly to line 1,2.
Finally, output shaft 22 has return spring 40 therearound for biasing valve member 18 against valve seat l9.
In operation, when thermostat 38 senses a call for heat, moveable contact 40 moves against ON contact 37 for energizing motor 23 through thermostat 38 and normally closed contact 25 of switch 26. Motor 23 will begin rotating output shaft 22 through gears 24 in the direction of the arrow to move valve member 18 away from valve seat l9. At the same time, pump lS is energized to begin circulating water through valve 16, port 20, line 12, radia-tor ll, return line 13 and water heater 14 back to the other side of pump 15. When cam 29 is rotated to the intermediate position of output shaft 22 between the first position where valve member 18 is against valve seat l9 and the second position where valve 16 is fully opened, a position which may represent, for example, a 25% flow rate through valve 16 to radiator ll, cam follower 27 senses notch 28 of cam 29 to operate moveable contact 31 o~ switch 26 against normally open contact 30. When switch 26 so operates, alternating current is no longer supplied to motor 23. Instead, direct current is supplied to motor 23 from line L2, through motor 23, resis~or 32, diode 33, norrnally open contact 30, moveable contact 31, thermostat 38, to line Ll. This direct current flowing through motor 23 will cause it to brake, stoppiny output shaft 22 in its interrnediate position. The ~3~734 curren~ through resistor 32 will also begin generating heat therefrom which, after a predeterrnined time delay, will cause bimetal 35 to warp against contact 36 for shorting out resistor 32 and diode 33 for again applying alternating cur-rent to motor 23. When ca~ follower 27 moves out of notch 28 of cam 29, moveable contact 31 will again operate against normally closed contact 25 of switch 26 for insuring that alternating current is maintained to motor 23 for driving output shaft 22 to its second position where valve 16 is fully opened. Thus, when output shaft 22 is in its interme-diate position, partial flow of water flows through pipes 12 and 13 and radiator ll and full flow will flow through this system when valve 16 and output shaft 22 are in their second position.
Figure 2 shows a variation on the system of Figure l. In Figure 2, zone 50 has a radiator 51 located therein.
Hot water is supplied to radiator 51 by pump 52 through inlet port 53 of valve 54, outlet port 55, supply line 56, radiator 51 and return line 57 to water heating apparatus 58 the output of which is connected to the input of pump 52.
Valve member 59 of valve 54 is controlled by the control system 60 which may be the same control system as shown in Figure 1 and is connected to thermostat 61 which may be sim-ilar to thèrmostat 38 shown in Figure 1. Connected to second output port 62 of valve 54 is a dornestic hot water heating tank 63 having a return line 64 conn~cted to return line 57. Pump 52 ma~y be continuously energized from an alternating current source for supplying water through valve 54 and, when valve member 58 is in its first position against valve port 55, to hot water heater 63 and back to water heating apparatus 58 through return lines 64 and 57.
When thermostat 61 senses a call for heat, control 60 dr.ives ~13~;~3~
valve member 59 to its intermediate position where partial flow is supplied to radiator 51 and the remaining water is supplied to hot water heater 63. After the predetermined time delay as established by bimetal switch 3~ shown in Fig-ure 1, valve member 59 Will be driven to its second position where it closes off port 62 for supplying full flow to radi-ator 51.
In Figure 3, which shows a variation of the cir-cuit disclosed in Figure 1, the direct current brake comprising diode 33 and resistor 32 is normally shorted by moveable contact 31 and stationary contact 25 of switch 26.
When thermostat 38 calls for heat, motor 23 is energized.
When cam 29 operates moveable contact 31 against s~ationary contact 30, direct current flowing through diode 33 and resistor 32 also flows through motor 23 braking it at this intermediary position. After an amount of time required for resistor 32 to heat bimetal 35, bimetal 35 will close against its contact 36 to again short out diodd 33 and resistor 32. Alternating current again flows through motor 23 driving it to its second position. As soon as motor 23 begins rotating cam 29, moveable contact 31 returns to its stationary contact 25 to maintain the short across the direct current braking circuit.
Claims (30)
1. A control system for positioning the output shaft of a motor comprising:
motor means for positioning an output shaft between first and second positions, said out-put shaft having an intermediate position between said first and second positions;
terminal means adapted to be connected to a source of supply;
motor energization means for connecting said motor means to said terminal means for energizing said motor means to drive said output shaft from said first position towards said second position;
position responsive means connected to said motor means and responsive to said intermediate position of said output shaft for stopping said output shaft at said intermediate position;
time delay means connected to said motor means and responsive to said intermediate position for driving said motor means after the passage of a predetermined amount of time to position said output shaft at said second position;
and, return means associated with said motor means for returning said output shaft to said first position upon the de-energization of said motor means.
motor means for positioning an output shaft between first and second positions, said out-put shaft having an intermediate position between said first and second positions;
terminal means adapted to be connected to a source of supply;
motor energization means for connecting said motor means to said terminal means for energizing said motor means to drive said output shaft from said first position towards said second position;
position responsive means connected to said motor means and responsive to said intermediate position of said output shaft for stopping said output shaft at said intermediate position;
time delay means connected to said motor means and responsive to said intermediate position for driving said motor means after the passage of a predetermined amount of time to position said output shaft at said second position;
and, return means associated with said motor means for returning said output shaft to said first position upon the de-energization of said motor means.
2. The system of claim 1 wherein said motor energiza-tion means comprises condition responsive means responsive to a condition for energizing said motor means to drive said output shaft from said first position towards said second position.
3. The system of claim 2 wherein said position respon-sive means comprises a cam attached to said output shaft and having a switch responsive to a switch operating means on said cam for operating said switch at said intermediate position.
4. The system of claim 3 wherein said position respon-sive means further comprises a DC brake connected to said motor means and to said switch for applying direct current to said motor means for stopping said output shaft in said intermediate position.
5. The system of claim 4 wherein said switch comprises first and second stationary contacts and a moveable contact, said DC brake comprises diode means having one side connected to said first stationary contact and a second side connected to said second stationary contact.
6. The system of claim 5 wherein said diode means comprises a resistor and a diode connected in series, and said time delay means comprises a bimetal operated switch connected in parallel with said series connected resistor and diode and operated by heat produced by said resistor.
7. The system of claim 6 wherein said condition responsive means comprises a thermostat having a moveable contact connected to said terminal means and an ON contact connected to said moveable contact of said switch.
8. The system of claim 1 wherein said position respon-sive means comprises a cam attached to said output shaft and having a switch responsive to a switch operating means on said cam for operating said switch at said intermediate position.
9. The system of claim 8 wherein said position respon-sive means further comprises a DC brake connected to said motor means and to said switch for applying direct current to said motor means for stopping said output shaft in said intermediate position.
10. The system of claim 9 wherein said switch comprises first and second stationary contacts and a moveable contact, said DC brake comprises diode means having one side connected to said first stationary contact and a second side connected to said second stationary contact.
11. The system of claim 10 wherein said diode means comprises a resistor and a diode connected in series, and said time delay means comprises a bimetal operated switch connected in parallel with said series connected resistor and diode and operated by heat produced by said resistor.
12. The system of claim 1 wherein said position respon-sive means comprises a DC brake connected to said motor means for applying direct current to said motor means for stopping said output shaft in said intermediate position.
13. The system of claim 12 wherein said position responsive means further comprises a switch having first and second stationary contacts and a moveable contact, said DC
brake comprises diode means having one side connected to said first stationary contact and a second side connected to said second stationary contact.
brake comprises diode means having one side connected to said first stationary contact and a second side connected to said second stationary contact.
14. The system of claim 13 wherein said diode means comprises a resistor and a diode connected in series, and said time delay means comprises a bimetal operated switch connected in parallel with said series connected resistor and diode and operated by heat produced by said resistor.
15. The system of claim 1 wherein said time delay means comprises a bimetal operated switch.
16. A valve positioning motor control system for positioning a valve member of the valve comprising:
a valve having an inlet for receiving a fluid and an outlet for supplying said fluid to a load, said valve having a valve member for controlling the flow of fluid between said inlet and said outlet;
motor means having an output shaft for positioning said valve member between said first and second positions, said valve member having an intermediate position between said first and second positions;
motor energization means connected to said motor means for energizing said motor means to drive said valve member from said first position towards said second position;
position responsive means connected to said motor means and responsive to said intermediate position of said valve member for stopping said valve member at said intermediate position;
time delay means connected to said motor means and responsive to said intermediate position for driving said motor means after the passage of a predetermined amount of time to position said valve member at said second position;
and, return means associated with said motor means for returning said valve member to said first position closing off said outlet port upon the de-energization of said motor means.
a valve having an inlet for receiving a fluid and an outlet for supplying said fluid to a load, said valve having a valve member for controlling the flow of fluid between said inlet and said outlet;
motor means having an output shaft for positioning said valve member between said first and second positions, said valve member having an intermediate position between said first and second positions;
motor energization means connected to said motor means for energizing said motor means to drive said valve member from said first position towards said second position;
position responsive means connected to said motor means and responsive to said intermediate position of said valve member for stopping said valve member at said intermediate position;
time delay means connected to said motor means and responsive to said intermediate position for driving said motor means after the passage of a predetermined amount of time to position said valve member at said second position;
and, return means associated with said motor means for returning said valve member to said first position closing off said outlet port upon the de-energization of said motor means.
17. The system of claim 16 wherein said motor ener-gization means comprises condition responsive means respon-sive to a condition for energizing said motor means to drive said valve member from said first position towards said second position.
18. The system of claim 17 wherein said position responsive means comprises a cam attached to said output shaft and having a switch responsive to a switch operating means on said cam for operating said switch at said interme-diate position.
19. The system of claim 18 wherein said position responsive means further comprises a DC brake connected to said motor means and to said switch for applying direct cur-rent to said motor means for stopping said valve member in said intermediate position.
20. The system of claim 19 wherein said switch comprises first and second stationary contacts and a moveable contact, said DC brake comprises diode means having one side connected to said first stationary contact and a second side connected to said second stationary contact.
21. The system of claim 20 wherein said diode means comprises a resistor and a diode connected in series, and said time delay means comprises a bimetal operated switch connected in parallel with said series connected resistor and diode and operated by heat produced by said resistor.
22. The system of claim 21 wherein said condition responsive means comprises a thermostat having a moveable contact connected to said terminal means and an ON contact connected to said moveable contact of said switch.
23. The system of claim 16 wherein said position responsive means comprises a cam attached to said output shaft and having a switch responsive to a switch operating means on said cam for operating said switch at said interme-diate position.
24. The system of claim 23 wherein said position responsive means further comprises a DC brake connected to said motor means and to said switch for applying direct cur-rent to said motor means for stopping said valve member in said intermediate position.
25. The system of claim 24 wherein said switch comprises first and second stationary contacts and a moveable contact, said DC brake comprises diode means having one side connected to said first stationary contact and a second side connected to said second stationary contact.
26. The system of claim 25 wherein said diode means comprises a resistor and a diode connected in series, and said time delay means comprises a bimetal operated switch connected in parallel with said series connected resistor and diode and operated by heat produced by said resistor.
27. The system of claim 16 wherein said position responsive means comprises a DC brake connected to said motor means for applying direct current to said motor means for stopping said valve member in said intermediate position.
28. The system of claim 27 wherein said position responsive means further comprises a switch having first and second stationary contacts and a moveable contact, said DC
brake comprises diode means having one side connected to said first stationary contact and a second side connected to said second stationary contact.
brake comprises diode means having one side connected to said first stationary contact and a second side connected to said second stationary contact.
29. The system of claim 28 wherein said diode means comprises a resistor and a diode connected in series, and said time delay means comprises a bimetal operated switch connected in parallel with said series connected resistor and diode and operated by heat produced by said resistor.
30. The system of claim 16 wherein said time delay means comprises a bimetal operated switch.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000332386A CA1136734A (en) | 1979-07-23 | 1979-07-23 | Step open zone valve |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000332386A CA1136734A (en) | 1979-07-23 | 1979-07-23 | Step open zone valve |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1136734A true CA1136734A (en) | 1982-11-30 |
Family
ID=4114769
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000332386A Expired CA1136734A (en) | 1979-07-23 | 1979-07-23 | Step open zone valve |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1136734A (en) |
-
1979
- 1979-07-23 CA CA000332386A patent/CA1136734A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |