Hydrocarbon Oxidizer System

Abstract

A pollution-free system for disposing of gasoline vapors at a tank truck loading station, in which a booster pump energized in response to pressure within a vapor saver tank which receives the truck tank vapors feeds the vapors from the vapor saver tank through a control valve to the supply line of the hydrocarbon oxidizer and in which means responsive to the temperature in the oxidizer operates the control valve to regulate the vapor flow to the oxidizer to maintain the temperature therein below a predetermined temperature and in which various safety devices are incorporated to ensure the safety of both the installation itself and of personnel working at the installation.

Description

BACKGROUND OF THE INVENTION

In the prior art at a station at which gasoline tank trucks are refilled with gasoline for distribution, as liquid gasoline is pumped into a truck tank the vapor therein is forced out and is fed past a check valve to a vapor saver tank. Attempts have been made in the prior art to recover liquid gasoline from the vapor by feeding the vapor from the saver tank to a condenser which liquefies the vapor. While the recovered liquid theoretically is good gasoline, it has been discovered as a practical matter that the liquid is not usable as gasoline. That is, the recovered liquid contains so much impurity, such as water, that it is practically not usable. As a result, it has been disposed of as waste. Not only is the recovered liquid in such a system not usable, but also the installation for condensing the vapor is extremely expensive, costing, at present day prices, in the range of a quarter of a million dollars.

We have invented a system for disposing of gasoline vapors at a tank truck filling station which overcomes the defects of systems of the prior art. Our system disposes of these vapors without polluting the atmosphere. Our system is safe. It is appreciably less expensive than are vapor condensing systems of the prior art.

SUMMARY OF THE INVENTION

One object of our invention is to provide a system for disposing of gasoline vapors at a tank truck filling station.

Another object of our invention is to provide a system for disposing of gasoline vapors at a tank truck filling station which overcomes the defects of systems of the prior art for treating such vapors.

Still another object of our invention is to provide a system for disposing of gasoline vapors at a tank truck filling station without polluting the atmosphere.

A further object of our invention is to provide a system for disposing of gasoline vapors at a tank truck filling station which is safe in operation.

Still another object of our invention is to provide a system for disposing of gasoline vapors at a tank truck filling station which is considerably less expensive than are vapor condensing plants of the prior art.

Other and further objects of our invention will appear in the following description.

In general, our invention contemplates the provision of a system for disposing of gasoline vapors at a tank truck filling station in which a booster pump, activated in response to pressure within a vapor saver tank, feeds the vapors to a hydrocarbon oxidizer through a valve which is controlled in response to temperature within the oxidizer to regulate the proportion of vapor to combustion air fed to the oxidizer and in which various safety devices are incorporated to ensure the safety both of the installation and of its operating personnel.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings which form part of the instant specification and which are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views:

FIG. 1 is a partially schematic elevation of our system for disposing of gasoline vapors at a tank truck loading station.

FIG. 2 is a partially schematic view of the piping arrangement of our system for disposing of gasoline vapors at a tank truck loading station.

FIG. 3 is a sectional view of an electric-to-pneumatic transducer forming a part of our system for disposing of gasoline vapors a tank truck loading station.

FIG. 4 is a schematic view of the electrical control circuit which we employ in our system for disposing of gasoline vapors at a tank truck loading station.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1 of the drawings, our system, indicated generally by the reference character 10, is adapted to be installed at a station at which gasoline tank trucks such, for example, as a truck having a tank 12, are to be refilled with gasoline for distribution. While we have illustrated only one tank truck in the drawings, it will readily be appreciated that there are facilities for handling a multiplicity of such trucks at the normal refilling station. At such a station, gasoline is fed into the tank 12 through a line 16 leading into the refill fixture 14 on the tank. At the same time, vapor from within the tank 12 is forced outwardly through a line 18 and past a check valve 19. A gate valve 20 is adapted to be opened to pass the vapor to a vapor saver tank 22 of a type known in the art. Further as is known in the art, the tank 22 includes a bladder 24 which expands much in the manner of a balloon as the vapor pressure builds up within the tank 22.

We provide the tank 22 with a switch 26 adapted to be operated by the bladder 24 when the pressure within the tank reaches a predetermined value to activate a booster pump 28 to feed vapor from the tank 22 through a line 30 leading to a piping rack, indicated generally by the reference character 32. In some instances it may be desirable to eliminate the tank 22 and to feed the vapor from the tank 12 directly to the booster pump 28. In such a case the vapor comes from the truck through line 18 and past a check valve 19 to a specially designed valve 21. The valve 21 is activated by a specially designed pressure switch 19A. As the valve 21 is activated the booster pump 28 is also activated to feed vapor through a line 30 leading to a piping rack, indicated generally by the reference character 32. The specially designed switch 19A is known to the art, is manufactured by The Foxboro Company, and is known as Model 43A Controller. The arrangement is such that it continuously detects the difference between an actual measurement and its desired value and converts this difference to an air signal between 3 pounds and 15 pounds per square inch. It is this air signal which operates the valve. The actual measurement, the desired measurement, and the output signal are indicated on a controller. The arrangement is such that an air supply passes through a regulator, then through a pneumatic controller, and then to the control valve. The valve 21 is also known to the art and is manufactured by Fisher Controls Company. By way of example and not by way of limitation, the valve is a rotary butterfly which can maintain bubble-tight shutoff. As the valve rotates to open position, it actuates a rotary switch (not shown) to make electrical contact to activate the booster 28. Vapor from the rack 32 is carried by a pipe 34 to the supply line of a hydrocarbon oxidizer indicated generally by the reference character 36, whereat the vapor is ignited and burns. We employ any suitable type of pilot fuel such, for example, as butane contained in a tank 38. A line 40 conducts pilot fuel from tank 38 to the rack 32. Another pipe 42 leads from the rack 32 to the pilot line of the oxidizer 36.

Oxidizer 36 includes a door 44 which affords access to the interior of the oxidizer. A combustion air fan 46 is adapted to be activated in a manner to be described hereinbelow to supply combustion air to the oxidizer 36. A pair of thermocouples 48 and 50 sense the temperature within the stack of the oxidizer for reasons which will be described in detail hereinbelow. Our system includes a control house indicated generally by the reference character 52, which houses the control panel (not shown) and associated equipment for the system.

We mount a purging fan 54 driven by a motor 56 on housing 52 to ensure that the interior of the housing is at all times free of combustible vapors. A horn 58 on top of the house 52 is energized each time the system starts up to warn personnel in the area.

More specifically, the booster 28 may be, for example, a three-quarter horse power turbine rated at 100 cubic feet per minute at eight ounces driven by a three quarter horse power explosion proof motor. The pressurizing or purge fan 54 may be any suitable type of blower driven by a one-third horse power explosion proof motor 56. The supply fan may, for example, have a capacity of 6,500 cubic feet per minute driven at 1,368 rpm by a five horse power motor which also should be explosion proof.

Referring now to FIG. 2, we have illustrated the piping and valve structure of our system. A shut-off valve 60 connects line 30 leading from the booster pump 28 to a pressure regulator indicated generally by the reference character 62 of any suitable type known to the art. A tee 64 in the line leading from the regulator 62 supplies gas to a low pressure switch 66 adapted to be closed when the pressure from the regulator 62 exceeds a predetermined low value. We connect the outlet from tee 64 to a motor-operated safety shut-off valve 68 adapted to be opened by a motor 70 to feed the main gas and to close a switch to be described hereinbelow when it is open. A test cock valve 72 is adapted to be operated to test the pressure being fed through valves 68. A second tee 74 supplies vapor from the outlet of valve 68 to the high pressure switch 76 adapted to be opened if the pressure in the line exceeds a predetermined value. A normally open vent valve 78 connected to the line leading from tee 74 closes upon energization of a solenoid 80.

A blocking valve 82 is adapted to be operated in response to energization of solenoid 84 to open the line leading from tee 74. Our system includes a butterfly valve adapted to be operated to control the flow of vapor through the line leading from valve 82. Valve 86 may be operated in response to movement of a segment 88 connected by a link 90 to a lever 92 adapted to be positioned by a rod 94 of a piston and cylinder assembly 96. In a manner to be described, pneumatic pressure is supplied to the assembly 96 through a three-way low-fire relief valve 97 operated by a solenoid 98 in a manner to be described hereinbelow. A tee 99 feeds main gas to a suitable gauge (not shown) in house 52. A second shut off cock valve 101 connects tee 99 to line 34. All of the piping and valve system just described is adapted to be supported on the rack 100 adjacent to the house 52.

Referring now to FIG. 3, our system includes a pneumatic to electric transducer, indicated generally by the reference character 102, for translating an electrical signal into a pneumatic pressure. Transducer 102 includes an electrical section indicated generally by the reference character 104, as well as a pneumatic section indicated generally by the reference character 106. A lever 108 pivoted on a fulcrum 109 is initially positioned by a zero-adjust spring 110. One end of the lever 108 carries a winding 112 disposed in the air gap 114 of a magnetic frame 116. The central leg of the frame 116 incorporates a permanent magnet 118. The arrangement is such as will be apparent from the description hereinbelow that the current flowing through the winding 112 determines the force with which the lever 108 is urged to pivot on fulcrum 109.

The pneumatic section 106 includes a housing 120 having a supply pressure inlet passage 122 leading to a supply pressure chamber 124. Supply pressure to passage 122 may be from any suitable source (not shown). A passage 126 connects chamber 124 to a vent chamber 128. A diaphragm 130 having an opening 132 is mounted in the upper end of chamber 124 and is mechanically connected to the end of lever 108 remote from the winding 112.

A small pilot valve stem 134 mounted for axial movement in passage 126 carries an upper valve 138 adapted to cooperate with the opening 132 and a lower valve 136 which cooperates with the lower end of passage 126.

Housing 120 includes a main chamber 140 connected to the supply chamber 124 by a passage 141. We mount a large diaphragm comprising an upper portion 142 and a lower portion 144 in chamber 140 to divide the chamber into sections. While the upper and lower diaphragm sections 142 and 144 are mounted for movement as a unit the space therebetween is connected to the atmosphere by a passage 146 in the wall of housing 120. The upper diaphragm includes an opening 148 which communicates with the space between the diaphragms. A load pressure passage 150 in housing 120 communicates with the passage 141. A booster valve stem 152 comprises an upper valve adapted to cooperate with the upper end of passage 141 and a lower valve 156 which cooperates with opening 148. An air loading pressure channel 158 provides communication between passage 126 and the space in chamber 140 below the lower diaphragm section 144.

In operation of the transducer 102, the magnetic force exerted by the lever by the interaction between the flux of magnetic 118 and the flux resulting from current through the coil, is normally balanced by a force exerted by the small diaphragm 130. When the input to the winding 112 changes the balance of forces acting on the opposite ends of the lever 108 is upset. As a result, the lever pivots slightly causing the diaphragm to move up or down which initiates a change in pilot air pressure to restore the balance of forces. When the small diaphragm 130 moves downwardly against the valve stem 134, pilot air pressure increases since additional air is admitted into the chamber 124 from the supply line 122. Pilot air pressure presses against the smaller diaphragm 130 and also against the lower section 144 of the large diaphragm. This pilot pressure is controlled by the pilot valve stem 134. Output pressure is controlled by the booster valve stem 152.

It will be seen that in the pilot system the magnetic force resulting from the electrical coil 112 is balanced by the force on the small diaphragm 130. In the booster system, air pressure against the lower section 144 of the large diaphragm is balanced against the output pressure on the upper section 142 of the diaphragm. If the force exerted by pilot pressure on diaphragm 130 is greater than the magnetic force, the small diaphragm moves away from valve 138 allowing some air to escape thus reducing pilot pressure until the forces are in balance. If the magnetic force is greater than the force on the small diaphragm, the pilot valve stem 134 is moved downwardly to admit air into chamber 128 to increase pilot pressure until the forces are again in balance. If, in the booster system, pilot pressure is greater than output pressure, the diaphragms 142 and 144 move stem 152 until the output pressure balances pilot pressure. If output pressure is greater than pilot pressure, the diaphragms 142 and 144 move away from the booster valve 156 to permit air to escape through the ventaport 146. In this manner, there is provided an output pressure P.sub.1 which is proportional to the current supplied to the winding 112.

Referring again to FIG. 2, pilot fuel from line 40 passes through a shut-off cock 160 to a pressure regulator 162 through a tee 164 adapted to connect the pressure to a gauge (not shown) and from the tee 164 to an on-off valve 166 controlled by a solenoid 168. From the valve 166 pilot fuel flows through the line 42 to the pilot burners of the oxidizer 36.

Referring now to FIG. 4, the control circuit which we employ in our system includes a three-phase supply feeding conductors 170, 172 and 174. The blower fan motor 56 designated as M1 in FIG. 4 is adapted to be coupled to the supply line upon closing of normally open relay switches 1R2 to 1R4. The supply air fan motor M2 which drives the fan 46 is adapted to be connected to the supply upon closing of contacts 3R2 to 4. Similarly, the motor M3 for driving the booster pump 28 is adapted to be connected to the supply on the closing of relay contacts 6R2 to 6R4.

A transformer 176 is adapted to couple two phases of the supply to a ganged switch S1 adapted to be actuated to supply control voltage to the control circuit conductors 178 and 180. A normally open push button switch S2 is adapted to be actuated to energize a winding 1R through a normally closed push button switch S3. When energized, winding 1R closes a contact 1R1 which bypasses switch S2 to provide a holding circuit for winding 1R through switch S3. At the same time, contacts 1R2 to 1R4 are closed to energize motor M1 to start the purging fan 54 to ensure that all fumes are blown out of the house 52. When the fan 54 has reached operating speed, an air flow switch S4 located at the outlet of blower 54 closes to apply power to a delay circuit 182 connected in series with switch S4 and a winding 2R between the upper terminal of winding 1R and conductor 180. Delay circuit 182 which may be of any suitable type known to the art, delays the energization of winding 2R until such time as it can be certain that all of the fumes have been exhausted from house 52. For example, the circuit 182 may provide a delay of approximately five minutes. When the delay circuit completes the circuit of winding 2R this winding first closes contacts 2R1 to energize a subsequent control circuit to be described hereinbelow.

After the purging of the house and upon closing of contacts 2R1, a lamp L1, located on the control board (not shown) within the house 52 indicates that the system is ready for operation. Next, the operator closes a normally open push button switch S5 to complete the circuit of the winding 3R through a normally closed push button switch S6. When energized winding 3R first closes contacts 3R1 to bypass switch S5 thus to provide its own holding circuit through switch S6. At the same time, contacts 3R2 to 3R4 close to connect the combustion air supply fan motor M2 to the power source. In addition, upon the energization of winding 3R, contacts 3R5 close to ready the remainder of the control circuit. As soon as the supply fan 46 is in operation an air flow switch S7 in the outlet of the fan 46 closes to complete the circuit of another lamp L2 to indicate that combustion air is flowing to the oxidizer 36.

When switch S7 closes, it also supplies power to the ignition control circuit 184 of our system enclosed in broken lines in FIG. 4. Circuit 184 may be of any suitable type known to the art which is capable of performing the functions to be described hereinbelow. A specific type of this circuit is made and sold by Protection Controls Inc. of Skokie, Ill., under the trade name "PROTECTOFIER." Application of power to the circuit 184 in the manner just described energized the primary winding 186 of a transformer having secondaries 188 and 190. We connect a cam switch CS1 normally occupying the position shown in the drawing, a normally closed relay switch 5R1, a resistor 192, secondary 190 a bimetallic element 194, a switch 196 operated by element 194 and a winding 4R in series between now-closed switch S7 and the conductor 180. As a result, upon application of power to circuit 184, winding 4R is energized. Upon energization of winding 4R, formerly open contacts 4R1 close to prepare a circuit which is complete through the thermostatic element 194 and secondary 190 when CS2 closes. At the same time, contact 4R2 and 4R3 close to complete the circuit of a timer cam motor TM through a normally closed switch 5R2.

When the timer motor begins to drive, it first moves switch CS1 from the position shown to an alternate position to complete the circuit of the timer motor and to bypass switches 4R2, 4R3 and 5R2. Switch 4R2, however, completes a holding circuit for winding 4R from the common terminal of element 194 and switch 196 through 4R2 to switch S7. At the end of a purge cycle, sufficient to clear the oxidizer 42 of vapors, such for example as a period of one minute, switch CS2 closes to complete a circuit across secondary winding 190 and including switch 5R1, resistor 192, element 194, switch 4R1 and CS2 to ensure that current is flowing through element 194.

Motor TM closes CS3 to energize pilot fuel supply valve solenoid 168 through normally closed contacts 5R3 and to apply power to a transformer 198 to actuate an ignition device 200. Ignition device 200 operates to ignite the pilot fuel. If the flame is properly established, the flame sensing device 202 completes a circuit for winding 5R across secondary 188. When winding 5R is thus energized, contacts 5R1 in the safety check circuit open. Contacts 5R2 in the timer motor starting circuit open to permit the motor to stop when it has returned to the zero position at which switch CS1 contacts the upper contact indicated in FIG. 4. When winding 5R is energized in the manner described, contacts 5R3 open to interrupt the ignition circuit and contacts 5R4 close to bypass the cam switch CS3 to hold the solenoid 168 energized. Finally, contacts 5R5 close to light lamp L3 to indicate that the pilot is lit. At the same time, control power is applied to the remainder of the circuit through contacts 5R5.

The bladder-responsive switch 26 in the vapor-saver tank 22 includes a pair of ganged normally open contacts S8A and S8B. When the vapor pressure within tank 22 reaches a predetermined level the bladder 24 operates switch 26 to close contacts S8a and S8b. Contact S8a, when closed, energizes a relay winding 6R to close a normally open switch 6R1 which starts the booster pump to feed vapors to the system. We connect switch 6R1 in series with the low pressure switch 66 indicated as S10 in FIG. 4 and a high pressure switch indicated as S9 in FIG. 4 in series with a lamp L4 between the control circuit conductors. With winding 6R energized and with switches S9 and S10 closed, lamp L4 lights to indicate that gas pressure is on. At the same time a high temperature limit switch 204 is activated. Switch 204 is under the control of a thermocouple 48. So long as the temperature being sensed by thermocouple 48 does not exceed that which has been set on a dial 206 or the like of the high temperature limit switch 204, the switch is closed to apply a signal to the winding 208 of the motor-operated shut-off valve 70 to close normally open contacts 210 to energize solenoids 84, 80 and 98 and to light a lamp L5 to indicate that the main gas pressure now is on. At the same time, a winding 7R is energized to open normally closed contacts 7R1.

Switch 26 also closes normally open contacts S8b to complete a circuit through contact 7R1 and normally closed contact 8R1 to the warning horn 58. It will be appreciated that winding 7R is not energized by the motor-operated relay until a short time after contacts S8b close so that the warning horn operates for a predetermined period of time before full gas pressure flows. If, as will be explained hereinbelow, relay winding 7R is not energized so that contact 7R1 failed to open and yet switch S8b closes, horn 58 continues to operate until the operator actuates a button S9 to energize a winding 8R to open contacts 8R1 to stop the horn and to close contact 8R2 to light a lamp L5 which indicates danger on the control board. While we may employ any suitable type of high temperature limit switch known to the art which accomplishes the function just described, one particular switch which we have employed is sold by Barber Coleman Inc. as model 72G Miniature Temperature Controller.

Our control circuit further includes a temperature controller 212 responsive to thermocouple 50 for producing a current which is a measure of the difference between the temperature sensed by thermocouple 50 and the temperature set on any suitable means, such for example as a dial 214 on controller 212. While we may employ any suitable device known to the art for producing an output current which is a measure of the difference between a set temperature and a sensed temperature, one type which we have employed is a Barber Coleman No. 537G indicating temperature controller.

We feed the output from controller 212 to the input of the transducer 102. One particular form of transducer which we have employed is a series PO2R transducer made by Barber Coleman Co. Industrial Instruments Division of Rockford, Ill.

As is pointed out hereinabove, it may be desirable to feed the vapor directly from the truck tank 12 to booster pump 28. In this operation the same sequence ensues, with the exception that the rotation of the valve 21 in response to the pressure switch 19A will energize the circuit by the rotation of the valve 21. This initiates the sequence instead of switch 26.

The operation of our system will be apparent from the description hereinabove. To summarize, to initiate operation of the system, and with the control line switch S1 closed, S2 is actuated to energize relay winding 1R to activate motor M1 to cause the purging fan 54 to blow the fumes out of the house 52. After a delay of about five minutes, winding 2R is energized to apply power to the remainder of the control circuit to light the lamp L1 to indicate that the house purging operation is complete. When that has been done, the operator actuates switch S5 to energize relay winding 3R to activate the supply fan guide motor M2 to cause combustion air to be fed into the oxidizer 36. In response to the flow of air, switch S7 closes to energize lamp L2 to indicate that the supply fan is in operation. At the same time, the circuit 184 is supplied with power. After a purging time of about one minute in operation of the fan 46 and under the control of timer motor TM, power is applied to the igniter 200 and the pilot supply valve solenoid 168 is energized. If ignition takes place properly, lamp L3 is lighted to indicate that the pilot is on. If ignition does not take place properly in the time of about fifteen seconds, switch 196 opens and must manually be reset before circuit 184 will again operate.

In response to the pressure of the vapors within the saver tank 22, switch 26 operates contacts S8a and S8b. Contact S8a completes the circuit of the booster pump to feed vapors in the system. Contact S8b completes the circuit of the horn 58 to warn personnel in the area that the system is in operation. When the pressure at tee 64 in the supply line is above a predetermined low value, switch S10 closes to apply power to the circuit 204. When that occurs, the winding 208 of the safety shut-off valve motor 70 is energized to open the valve. When the valve is fully opened, contacts 210 close to energize the blocking solenoid 84, the vent solenoid 80, and the low fire solenoid 98. Further the lamp L5 is lighted to indicate that the main gas pressure is on. At the same time, winding 7R is energized to interrupt the circuit of the warning horn 58.

While the system is in operation, and in response to the thermocouple 50, the circuit 212 puts out a signal which is a measure of the temperature within the oxidizer 36. As the temperature rises, the output current decreases so that the transducer 102 puts out a decreased load pressure to cause the assembly 96 to actuate valve 86 to reduce the amount of vapor being fed to the oxidizer 36. In this way, the ratio of vapors to combustion air is decreased. Conversely, when the temperature in the oxidizer drops, the valve 86 is opened further to increase the ratio of vapors to combustion air.

In the event that the temperature within the oxidizer 36 exceeds a predetermined high temperature, thermocouple 48 causes the circuit 204 to open the connection to the motor 70 so that the valve 68 closes. As that occurs, contacts 210 open to deenergize all of the solenoids 84, 80 and 98. If, at this time, switch S8b is closed, the circuit to horn 58 is complete so that the horn sounds. The operator actuates switch S9 to complete the circuit of winding 8R to turn the horn off and to light the lamp L5 to indicate trouble.

In operation of our system, when vapors are fed directly from the tank 12 of a tank truck, pressure of the vapors on pressure switch 19A will operate valve 21. This in turn is the equivalent of closing contacts S8a and S8b of FIG. 4, and the system will then function as described above in respect of the vapor saver tank 22.

It will be seen that we have accomplished the objects of our invention. We have provided a system for disposing of vapors either directly from a tank truck or those at a gasoline tank truck refilling station. Our system operates substantially without pollution. It incorporates features for ensuring the safety of personnel and of the installation itself. It is appreciably less expensive than are condensation installations of the type known in the prior art.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of our claims. It is further obvious that various changes may be made in details within the scope of our claims without departing from the spirit of our invention. It is, therefore, to be understood that our invention is not to be limited to the specific details shown and described.

Claims

Having thus described our invention, what we claim is:

1. A system for disposing of hydrocarbon vapors contained in a tank including in combination, an oxidizer, means for supplying combustion air to said oxidizer, means including a booster pump and a control valve for feeding vapors from said tank to said oxidizer, means for energizing said booster pump, and means responsive to the temperature within said oxidizer for operating said control valve.

2. A system as in claim 1 in which said means for energizing said booster pump comprises means responsive to the pressure of vapors within said tank.

3. A system as in claim 1 in which said feeding means comprises a normally closed blocking valve means for opening said valve, and means responsive to a predetermined high temperature in said oxidizer for disabling said opening means.

4. A system as in claim 1 in which said feeding means comprises a normally open relief valve, means for closing said relief valve, and means responsive to a predetermined high temperature in said oxidizer for deactivating said closing means.

5. A system as in claim 1 in which said feeding means comprises a normally closed blocking valve, a normally open relief valve, means for opening said blocking valve, means for closing said exhaust valve, and means responsive to a predetermined high temperature within said oxidizer for disabling said opening means and said closing means.

6. A system as in claim 1 in which said feeding means comprises a normally closed safety shut off valve, energizable means for opening said shut off valve, a normally open relief valve, energizable means for closing said relief valve, a normally closed blocking valve, energizable means for opening said blocking valve, means including a normally closed switch for energizing said motor, and means responsive to closing of said safety valve for energizing said shut off valve opening means and said exhuast valve opening means.

7. A system as in claim 6 in which said control valve is adapted to be positioned to determine the flow of vapors to said oxidizer and in which said temperature responsive means comprises pneumatic means for positioning said control valve, means for producing an electrical signal affording a measure of the temperature in said oxidizer, an electric to pneumatic converter for providing air at a pressure corresponding to the temperature in said oxidizer, a normally closed valve for feeding said air to said pneumatic means, energizable means for opening said air feeding valve, said means responsive to closing of said safety valve energizing said air feeding valve opening means.

8. A system as in claim 1 including a control house and a purging fan adapted to be activated to clear said house of fumes.

9. A system as in claim 8 in which said combustion air supply means includes a blower, means adapted to be enabled to initiate operation of said blower, means for activating said purging fan and means including delay means responsive to activation of said fan for enabling said blower operation activating means.

10. A system as in claim 1 including a supply of pilot fuel, means adapted to be enabled to supply pilot fuel from said supply to said oxidizer, means for igniting said pilot fuel fed to said oxidizer and means responsive to ignition of said pilot fuel for enabling said vapor pressure responsive means.

11. Apparatus for disposing of hydrocarbon vapors including in combination, a hydrocarbon oxidizer, a blower for supplying combustion air to said oxidizer, means adapted to be enabled to initiate operation of said blower, a supply of pilot fuel for said oxidizer means adapted to be energized to conduct pilot fuel from said supply to said oxidizer, means adapted to be energized to ignite pilot fuel fed to said oxidizer, means responsive to operation of said combustion air blower for energizing said fuel feeding means and said igniting means, a booster pump for feeding vapor to said oxidizer, means adapted to be enabled to operate said booster pump, means responsive to ignition of said pilot fuel for enabling said booster pump operating means, a control valve between said booster pump and said oxidizer and means responsive to the temperature within said oxidizer for operating said control valve.

12. Apparatus as in claim 11 including a control house, a purging fan for clearing vapors from said house, means for energizing said purging fan and means including delay means responsive to operation of said purging fan for enabling said blower operating means.

13. Apparatus as in claim 11 including a warning device and means responsive to operation of said booster pump for energizing said warning device.

14. Apparatus as in claim 11 including manually resettable means for disabling said pilot fuel feeding means and said igniting means upon failure of said fuel to ignite within a predetermined time after energization of said fuel feeding and igniting means.

15. Apparatus as in claim 11 including means responsive to a predetermined high temperature in said oxidizer for preventing the flow of fuel from said booster pump to said oxidizer.