US2940593A - Automatic custody transfer of crude oil - Google Patents

Description

M. A. REMKE ETA'- AUTOMATIC CUSTODY TRANSFER OF CRUDE OIL June 14, 1960 9 Sheets-Sheet 1 Filed Aug. 18, 1958 )INVi 39H09 .LOOB

HBAIBDBH E K WM am W. MA M L. E. KUNTZ ATTORNEYS June 14, 1960 M, A, REMKE ETAL 2,940,593

AUTOMATIC CUSTODY TRANSFER OF CRUDE OIL Filed Aug 18. 1958 9 Sheets-Sheet 2 A7' TORNEVS June 14, 1960 M. A. REMKE ETAL AUTOMATIC CUSTODY TRANSFER 0F CRUDE OIL 9 Sheets-Sheet 3 Filed Aug. 18, 1958 ovm um@ um umm mm INVENTORS M, A. REMKE L. E. KUNTZ ATTORNEYS KOF-ZOE O...

June 14, 1960 M. A. REMKE EFA'- AUTOMATIC CUsToDY TRANSFER 0F CRUDE OIL 9 Sheets-Sheet 4 Filed Aug` 18, 1958 MAC.

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INVENTORS M A R E M K E bl., OP

L. E, KUNTZ ATTORNEYS June 14, 1960 M, A. REMKE EIAL 2,940,593

AUTOMATIC CUSTODY TRANSFER OF CRUDE OIL Filed Aug. 18, 1958 9 Sheets-Sheet 5 4| 4o H47 osclLLAToR UNIT MASTER UNIT PLATE i FILAME NT POWER I SUPPLY R LAY FOR osclLLA'roR f if \Jl4 I \4e i l Yl Y2 1 cI Hl 2 c2 H2 42 y l PROBE I laf N FIG. 4.

nsv Ac JR-m 23i N ci g Hl l L' C2i @L INVENTORS MAPEMKE LLKUNTZ WM YM A TTOR/VEYS June 14, 1960 M A, REMKE ErAL 2,940,593

AUTOMATIC cusTonY TRANSFER oF CRUDE: on.

Filed Aug. 18, 1958 9 Sheets-Sheet 6 INVENTORS MA. REMKE L.E. KUNTZ A T TORNEYS June 14, 1960 -M. A. REMKE ETAI- AUTOMATIC cUsToDY TRANSFER oF CRUDE: OIL

Filed Aug. 18, 1958 9 Sheets-Sheet 7 O E N O 2 '55g u [L E U Q (n 2 e l d n: 25 LLI ILD 2 E( LLI a E? C! l 5355, INvENToRs g MA. REMKE O LE. KUNTz 35 www 199% A T TOR/VE VS June 14, 1960 M, A, REMKE ETAL AUTOMATIC cUsToDY TRANSFER oF CRUDE on.

9 Sheets-Sheet 8 Filed Aug. 18. 195e uEDm KOZOE A T TORNEI/5 United States Patent O AUTOMATIC CUSTODY TRANSFER OF CRUDE OIL Filed Aug. 18, 1958, Ser. No. 755,851

9- Claims. (Cl. 210-84) This invention relates to the automatic transfer of liquids. In one aspect, it relates to automatic transfer of measured volumes of liquid of predetermined quality. In another aspect it relates to automatic transfer of measured volumes of crude Oil of predetermined quality as regards B.S. & W. (basic sediment and water) content.

This application is a continuation-in-part of our copending application, Serial No. 686,255, filed September 25, 1957, now abandoned.

The pumping, transporting, treating and storing of crude oil on the lease have been made automatic to various degrees in recent years. However, the measurements and handling required for the sale or custody transfer of crude oil have not changed to any great extent until quite recently.

The terms lease automatic custody transfer, lease automatic transfer, automatic transfer or automatic transfer' system as used throughout this specification and claims, are used synonymously `and interchangeably, and are intended to mean any system, process carried out thereby, or apparatus particularly adapted for use therein and comprise automatic means to inspect a liquid for the presence of a predetermined undesirable amount of at least one selected undesirable constituent, and automatic means to reject the liquid when said constituent content is above said amount, to meter accurately said liquid when said constituent content is below said amount and pass the inspected and metered liquid to a dispensing line, and subcombinations thereof, such as metering means, inspection means, treating means, pumping means, valving means and automatic control means particularly adapted for use therein, and processes carried out thereby. In the general system, if desired, there is also included automatic means to treat the liquid to remove the undesired constituent before said inspection, and/or automatic means to recycle said liquid when rejected to said treating means. Furthermore, the automatic means to reject contaminated liquid, that s, liquid containing more than the predetermined undesirable amount of the undesirable component, are provided to operate continuously except as interrupted by automatic operation of the system.

The term custody as used in conjunction with lease automatic custody transfer is intended to convey the meaning of the transfer of a liquid, for example, from one owner to another owner. For example, it refers to the transfer of crude oilfrom the producer to a purchaser.

In this specification we will describe our apparatus and process as applied to the automatic transfer of measured volumes of crude oil of predetermined quality as regards B.S. & W. merely as an example of our process and apparatus. It is realized that measured volumes of other 4, liquids of predetermined quality can be transferred by our apparatus according to the method disclosed herein, such as refined oils, natural gasoline, hydrocarbon products in process, finished hydrocarbon products, and such other hydrocarbon liquids as might be desired to be substantially continuously transferred.

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The sale of crude oil requires that temperature, volume, A.P.I. gravity and B.S. & W. content of the oil be known and recorded on a run ticket. In manually operated transfer systems, these measurements are usually made manually by a pumper who represents the crude oil producer and independently by a gauger who represents the crude oil pipe line purchasing company in case the oil is sold to a pipe line company for transportation. These men obtain samples of the oil from tanks through thief hatches. Tanks are gauged by reading the oil level to the nearest 1A inch on a gauge stick lowered through the hatch. Temperature is measured by lowering a specified typo 0f thermometer through the hatch into the oil, then removing the thermometer and quickly observing the temperature. A.P.l. gravity is measured by use of a hydrometer in a sample of the oil obtained by use of a special sample thief The purity of the oil as regards B S. & W. is determined by centrifuging a measured volume of the oil from the sample thief.

When these properties of the oil are determined manually, samples are taken through sample hatches and each time a sample hatch is opened vapors are lost.

One object of the present invention is to determine and record the temperature of the crude oil automatically and without loss of vapors through opened thief hatches:

Another object of this invention is to provide a system for metering crude oil and for transferring the metered oil to a point of disposal, the system being entirelyautomatic and free from errors inherent with manual operation.

Still another object of this invention is to provide a fully automatic and substantially continuous system for metering and transferring of quality crude oil with the system being operated without personal attention other than occasional maintenance and changing of recorder charts and the like.

Yet another object of this invention is to provide such a system which is foolproof and failure-proof so that neither the oil producer nor the pipe line company can be shorted by misbandling of the oil.

Still other objects and advantages of this invention will be realized upon reading the following specification and drawing, which describes and illustrates, respectively, preferred embodiments of our invention.

One advantage of our automatic transfer system is that there is less evaporation loss of the crude oil transferred than when manually transferred, which is a direct saving in volume as well as in quality of the oil because vaporization losses are always losses of the light ends. In one -instance, according to our invention, the custody transferred `crude oil had an A.P,'I. gravity 0.2 higher than the oil transferred by a manually operated transfer system. This 0.2 A.P.I. gravity represents 0.5 percent volume, or, in other words, 5 lbarrels crude oil saved per 1,000 barrels-crude oil transferred.

In the drawing, Figure 1 is a view, in perspective, of one embodiment of the automatic transfer system of our invention.

Figure 2 is aschematic view of a portion of the wiring diagram of our system.

Figure 2A is a schematic view of a second portion of the wiring diagram of our system and is a continuation ofthe diagram of Figure 2. 1

Figure 2B is a schematic view of a third portion of the wiring diagram of our system and is a continuation ofv the diagram of Figure 2A.

Figure 3 is a diagrammatic elevational view of a meter tank of Figure 1.

Figure 4 is a diagrammatic view illustrating one embodiment of electronic equipment used in the apparatus of Figures l, 2A and 2B.

Figure 5 is a diagrammatic view of an alternate embodiment of a portion of the apparatus of Figures 1, 2A and 2B.

Figure 6 is a schematic view of a portion of a wiring diagram of an improved Z-rneter tank automatic transfer Sylemf i l 'Figure 7 is a View, in perspective, of lan improved auto- .matic transfer system.

-;Figures 8er-and 8b illustrate a schematic view of a portion7off-wiring diagram for the improved system oiFigm s -Figure 9 illustrates a modification of a portion ofthe apparatus of Figure l.

-Considerably less steel is required for building our automatic custody transfer system than a manually op erable system :of the same capacity because'fewer tern- Apor'ary storage Itanks are required. This saving in steel ferring known volumes of hydrocarbon liquid of predetermined quality from a source to a point of disposal comprising, in combination, a treating lvessel for said hydrocarbon liquid, a surge vessel for receiving treated hydro carbon liquid, a meter vessel, tirst and second conduits communicating said treating vessel with said surge vessel, a rst pump in said second conduit, a third conduit communicating said surge vessel with said meter vessel, a'second pump in said third conduit, a four-th conduit communicating said meter vessel with a point of disposal, a monitor assembly for controlling quality of hydrocarbon liquid, said monitor assembly vcomprising amonitory for sensingv B.S. & W. content of the hydrocarbon liquid, means for passage of hydrocarbon liquid from said surge vessel to said monitor and return to said surge vessel, iirst and second motor valves in said second and third conduits, respectively,'a .first electrical circuit cornmunicating said monitorY with said first pump and with said first motor valve, a second electrical circuit communicating said monitor with said second pump and with said second motor valve, said monitor assembly being adapted to close said second motor valve and to close off electric current'to the motor of said second pump tostop same and to open said first motor valve and to close the circuit to the motor of said first pump to start sarne when said monitor senses a VB.S. 7 W. content in the .hydrocarbon liquid flowing therethrough higher than a predetermined B.S. & W. content.

Furthermore, our invention comprises a method for transferringa known volume of a hydrocarbon liquid having less than a predetermined concentration of B.S. & W. tofa pointof delivery, comprising the steps of receiving said liquid containing B.S. Vit W. in a receiving zone, treating said liquid in said receiving zone -to removesaid B.S. & W., withdrawing an aqueous phase from said receiving zone, passing liquid of reduced B.S. & W. conten'tl to aV surge zone, maintaining the B.S. & W. con-tent of-said liquid in said surge zone below a predetermined value by recycling liquid containing a greater B.S. & W. content than said 4predetermined content from said surge zone to said receiving zone, passing only liquid having a less B.S. & W. content than said predetermined content to va metering zone of predetermined volume until said Vmetering zone is completely full, then passing saidl liquid from said metering zone to said point of delivery.

While the terms probe and float, or liquid level oat, are used'in this specification and claimsv as liquid level sensing means, they are described herein merely as examples of suitable liquid level sensing means. Any other suitable type of liquid level' sensing meansy cari also be used in .the transfer system of our invention. Y

"In the operation of the transfer system of our invention, produced oil enters our system, from a sourcegnot sho'wmviapipe 11p. From this pipeV oil ows into a vertical pipe, commonly called a boot in Ywhich gas and water are allowed to separate from the oil. The separated gas -is discharged from boot 14 through an equalzis line 18 t0` a vent. Hare. or gathering System, not shown. Oil and water are discharged from the bottom of the boot into the bottom of a receiver tank 13a in which separation of oil and water is obtained. The separated water settles to the bottom of receiver tank 1321 and is drawn off through a pipe 12 to such disposal as may be desired. A water level is maintained in the receiver tank for some distance above the level of pipe 12, so that the oil entering 'fromthe hoot passes upwardly through 'a layer of, Water to. cleanse it @impurities and to reduce or break any emulsion present to the basic components of oil and water. If desired, heat is applied to the water section ofl the receiver to assistin breaking emulsion that may be present. `Clean, treated oil passes from the receiver tank through a pipel 20 into a surge tank 15. As illustrated in the drawing, there is a single surge tank, but it is to be understood that more than one surge tank is used, if needed.

As the oil enters surge tank 15 and the oil level begins to rise, a float actuated switch FS-k-6y operates to start a monitor pump 28 which circulates surge tank. oil throughr a pipe 21, a pipe 27 containingr a B.S. & W. monitor cell 29 and back to the surge tank.4 The monitor cell 29 is preferably a capacitance cell in which the liquid being measured is the dielectric. A capacitance cell suitable for use as herein disclosed isdescribed in a copending application, Serial No. 686,192, filed September 25, 195.7. -Itis preferable that the'capacitance` cell he calibrated in percent B.S. aW. so that if `theBS. &'. W. content of the crude oil circulating through thev monitor cell reaches a predetermined high limit, rsuch as 0.5v perJ cent, a motor valve V-3 opens and al circulating pump 25 starts. Oil having B.S. &'W. content of 01.5 percent and higher (bad oil) is then returned to the boot 14 for retreatment. The apparatus, described hereinafter, which operates to open valve V-3 and to start the circulating pump 25 in response to highB.S. & W. content oil passing through Ithe monitor, overrides all other operations so that detection of bad oil shuts down the transfer portion of the system. When oil containing less than 0.5 percent B.S. & W. is considered acceptable by the oil purchasing pipe line company, then such oil is hereinafter referred to as merchantable oil. The monitor 29 maintains valve V-3 .open and pump 25 operating until the oil has been sufficiently retreated and is merchantahle, at'which time V-.3 closes'and the circulating pump 25 is stopped. lf, however, the oil does not cleanaup, continued oil production lls the surge tank 15 to an einen gency high level indicated h-y the level of a probe LS. At this emergency high level, a signal will be given at a convenient location fornotiiication'of a pumper, or otherwise calling for. help. ln some instances, the actuation of J-.S closes valves to stopflow of lease oil to the treating system. As long as merchantable oil is passing through the monitor cell, the latter will .permit normal operation ofthe metering andV transfer system.

While the crude oil treating system herein described comprises a receiver tank 13a and boot 14, other suitable emulsion treating or dehydrationsystems in cornmon use commercially are, in some instances, used with our transfer system.

Continued passage of merchantable `oil through the monitor cell indicatesV that the surgek tank 15 contains merchantable oil. Filling continues to a'levcl identified by the level at which a probe J-7 is installed in the tank. When the oil vreaches the level of the probeV l7, a valve V.15 is opened and a transfer pump 26 starts and merchantable oil is .transferred from the surge tank through pipes 21, 22 and23a into a meter tank i6. yif the oil level in the surge tank falls to the Y,low level indicated by the float actuated switch FS.-6, this switch operates to stop the transfer pump 26. The pump remains inoperative until suchv timeV as the' merchantable oilk level' again reaches thelevel of probe'I-7.' VWhen probe I-7 is again wet, the transfer pumplv starts'. This'pump'continues' .tov transfer merchantable oil into Vthe meter tank 16 until oil wets a probe J13 at which time the wet probe causes valve V- to close, transfer pump 26 to stop and a one-minute delay period Ito start for venting of gas evolved from the oil through a gas equalizing line 18. At the end of this delay period a valve V-14 opens for drainage of oil from outside rim 16a in the dome portion 16b of the tank (Figure 3). When the oil level reaches that indicated by probe .l-14, i.e., when the oil level in the dome 16b is below rim 16a, a valve V-16 in pipe 31 opens, and a pipe line pump 33 starts. As valve V-16 opens and with a second meter tank 17 dry, a valve V-ZS opens and the transfer pump 26 starts thereby starting transfer of merchantable oil from surge tank 15 to the meter tank 17. The same cycle as regards filling of the meter tank 17 takes place as that which took place as meter .tank 16 was filling. Meter -tank 17 is thus provided with probes J-23, J-24 and L27, in locations corresponding to locations of probes I-13, I-14 and J-17 of tank 16,

After a suflicient length of time has elapsed for probe J-14 in the full meter tank 16 to become dry, by drainage of oil through a valve V14, the dry probe J-14 then causes valve V-14 to close, valve V-16 to open and the pipe line pump 33 to start. The pipe line pump continues pumping until probe I-17 becomes dry at which time valve V-16 closes and the pipe line pump is shut down. It is intended that the meter tank 17 be filled, and excess oil over the measured tank volume be drained oft through valve V-24 and this tank of oil prepared for delivery to the pipe line by the time the meter tank 16 is empty and valve V-16 closed. As probe J-17 in meter tank 16 becomes dry, valve V-24 can be closed and valve V-26 opened and the pipe line pump 33 will continue to run. In this manner there is substantially continuous transfer of oil to the pipe line until such time as the supply of merchantable'oil in the surge tank is depleted.

In Figure 2 is illustrated a portion of the electrical system employed in the practice of our invention, while Figures 2A and 2B illustrate detailed wiring and actuation of the various relays in operating the several valves and pumps in response to liquid levels in the vessels as sensed by probes, floats, and other sensing apparatus. The electrical system will be described lin conjunction with the functioning of each element of the system following the general operational outline as given hereinbefore.

vThis description will begin with the surge tank 15 of Figure 1 being empty, the control system of Figures 2, 2A and 2B being de-energized, all latching relays being in their unlatched position, all motor valves V-3, V-14, V-15, V16, V-24, V-ZS and V-26 being closed and the meter tanks 16 and 17 being empty. A complete normal cycle will be hereinafter outlined. following are toggle switches and are closed: the emergency shut down switch SW1, sequence interrupter switch SW2, pipe line pump stop switch SW-6 and monitor pump stop switch SW-10.

Closing a 3phase master switch MS energizes the primary winding of a 2 k.v.a. transformer 101 which is connected across lines L1 and l@ of the 3-phase 440-volt electrical power supply. The coil of a relay R-6, connected acrosslines L2 and L3, is also energized. This relay protects the motors from single phase operation by opening a contact R-6A thereby breaking contact between TD- lAand R-l when line L3 is open. If line L1 or L2 is open, the control circuit will be dead because there is no voltage across the primary coil of the transformer 101. A relay R-7 willbe energized to connect the recorder and time clock 'TC-1. (Figure 2) to the control voltage and disconnect it from a stand-by battery 102.

vAllmotor starters, including the pipe line pump starter, have 110 volt coils and are operated directly from the control system.v The chart drive motor inthe temperature and pressure recorder 37 (Figure 2) and the motor in the time clock-,TC-l are across the control transformer In Figure 2A the secondary winding ahead of a master control switch MCS. These motors will then run continuously on volts A C. or from the stand-by storage battery 102 which is connected automatically by operation of relay R-7 in case power from lines L1 and L2 fails. TC-l is a 24 hour clock which is preset to open a contact TC-IA at 7:45 am. and close it at 8: 15 am. This opening and closing of contact 'TC-1A allows completion of the run in progress and stops the pipe line pump as required by the pipe line company for taking their daily inventory.

Closing the master control switch MCS energizes the electronics of the water detecting monitor 29, the probe level control devices J7, I-S, J-13, I-14, I17, L23, J-24 and J-27 and the coil -of a time-delay relay TD-l. A latching relay LR-S is energized through a low contact .FS-6L of a float actuated switch FS-6 in the surge tank 15. Energized relay LR-8 then opens a contact LR8A. During the delay introduced by the time-delay relay TD1, the level control electronics and monitor electronics will bewarmed up to operating temperatures and all probe relay contacts will assume their operating positions, i.e., all L (low) contacts are closed and all H (high) contacts opened. Contact R6-A and the emergency shut down switch SW-1 are closed so that closing of a switch 'ID-1A energizes a. relay R-1 which then closes a contact R-lA to energize the meter tank control system. Since at the beginning of the operation the surge tank 15 is empty,

probe 1 8V (a capacitance probe) is dry, high contacts of probe J-8 are open, thus de-energizing an emergency pilot light on a panel board in a control house, and at a tele# phone P.B.X board at a convenient location. The 1 8 contact serves as a power failure signal at the telephone P.B.X board as well as emergency high.

'A time-delay relay TD-3 is operated by the monitor and is de-energized when Athe water content of .the crude oil passing through the monitor cell is within the allowl able limit. The time-delay of relay 'PD-3 is set at a predetermined time, as, for example, 30 seconds, until operating experience dictates otherwise. This delay is to delay operation of the bad oil (water content higher than 0.5 percent) sequence when transient drops of the water have caused the motor to read above 0.5 percent (above a predetermined set limit of water content). For the following description, it is assumed that the monitor cell, which also is a capacitance cell, is Ifilled with air, as on initial start up, or with merchantable oil. In either case the relay 'FD-3 is de-energized and the contacts controlled thereby are open or closed as illustrated in Figure 2B.

The next step is to start passage of crude oil from receiver tank 13a through pipe 20 into surge tank 15. When sufficient oil has entered the surge tank, the float of the float actuated switch FS-6 rises and the switch closes a contact FS-6H to close a circuit to start the pump 28 for circulation of oil from the surge tank through pipes 21,17 and the monitor cell and return to the surge tank. Closing of the circuit through the monitor .pump 28 closes contact MP-A. Since the high level contact FS-6H of the float switch FS-6 was closed, obviously the low level contact FS6L is open. Latching relay LR-8 remains latched with contact LR-SA remaining open. Oil is now being circulated from the bottom of the surge tank 15 through the monitor cell 2-9 and returned to the surge tank. Continued passage of oil from receiver tank 13a to the surge tank 15 raises the oil level, and finally the level reaches the (normal high) capacitance probe I-7 and at this time transfer of oil to meter tank 16 begins. The necessary circuits completed for transfer of oil from the surge tank to meter tank 16 are as follows: Probe I7 (in the surge tank) becomes wet, latching relay LR-8 tmlatches and contact LR-SA closes; latching relay LR-1 latches to open contact LR-lA and to close contact LR- 1B. When contact LR-IA opens, relay TD-4 energizes and contact TDMA opens and motor valve V-14 closes. The closing of contact LR-1B, just mentioned, opens geantes valve V-15, contact V-lS-A closes and the transfer pump 26,'start's thuspumping oil Vfrom 'the surgeY tank 15v to meter tank 16. YUponV closing contact V-15-A, Contact V,-`B opens and interlocks with valve V46 so' that oil cannot under any conditions leave the meter tank while oil is being admitted thereto. v`

` `It "is intended that oil is'to be transferred from the surge tank tof either meter tank at a slightly greater rate than the oil enters' the surge tank through pipe'ZO' from the receiver tank 13a. Upon continued passage of oil from the surge tank to 4meter tank 16,'the oil level in the surge tankfdr'ops below probe J J7 andthe high contact of probe Ill-"lopens with' no effect on the circuits set up by it through latching relays LR- and LR`-1.

Whilemeter vtank 16 is filling, probe J-17 is wet and its relay JR-1'7 opens switches JR-17-L1 and JR-17-L2 with no effect on the system. When meter tank 16 becomesfilled, the probe J14gbecomes wet, and the relay VIll-14 operates to open contact I R-14-L1 with no effect on the system. When thev contactJR-14-L1 is opened, contact JR-14-H1 is closed, also with no effect on the system. At the same time contact IR14H2 closes which operation latches latching relay LR-Z and contact LR-ZA is closed which operation merely prepares the circuit to V16. Contacts JR-lL-Hl and JR-24H1 are connected across Ithe contact LR-ASA to prevent incomplete operation of thesysteinin the event that the'lsurge jlevel dropsl the float on float operated switch FIS-6 when the level in the meter tank being filled is between J-'lli and AL13 or betweeen 1 24 andi-23, depending upon the meter tank being filled. For example, if meter tank16 is being filled and probe J-14 has just become wet as the surge tank became empty, the low contact 11S-6L of the oat switch FS-6 closes, latching relay LR-S latches contact LR-8A opens and the transfer pump 26 stops. I-f the level of oil in meter tank 16 should drop sufficiently for :any reason whatever .and probe J-14 should become `dry the circuit would be set up for running meter tankA 16 tothe pipe line but since probe I-13 had not beenreached by theoil, the operation would be incomplete. The rshunting contact JR-14-H1 will prevent the stopping of the transfer pump untilthe top probe J-.13 has 'been reached by oil even though the float switch has operated andcontact LR-.8A has opened. When the top probe I-.13 is reached by the oil, the transfer pump 26 willstop as .usual but .will not restart until the surge tank level reaches the level of the probe I-7. Meter .tank 16 will run tothepipe linev when .meter tank 17 is empty and both meter vtanks will be empty until the surge tank is filled to the Ynormal high level.

When meter tank 16 becomes full, oil to this tank is, of course, stopped and its passage started to meter tank 17. Thus,when probe J-13 in the top of meter tank 16 becomes ,.wet, the relay JR-13 of probe J-13 operatesto open switch JR-13L with no effect on the system other than protecting latching relay LR-l from cycling. Switch Ill-13H also closes and latching relay LR-l yunlatches and contact LR-1B opens which latter operation closes valve V-1-5, opens con-tact V-15-A which operation stops transfer pump 26 and closes contact V-lS-B which interlocks :with valve V-16. As contact LR-IB opens, contact LR-IA closes and time-delay relay 'TD-4 energizes, contact TD-4A closes thereby openingyalve V-14 after a one-minute time delay. As contact LR-1A closes, latchingirelay LR-6 latches and contactLR-GA opens thereby charging condenser Z-1 through the 22K resistor inseries with rectierX-l (Figure 2a). Latching relay LR-3 also latches and contact LR-SB closes thereby opening valve V- and closing contact V--ZS-Av with the .simultaneous starting vof the transfer pump 26, As contact LRf-SBcloses, contact LR-3A opens and de-energizes timer-delay relayv 'ID-5' which y opens switch TD-SA by yclosing vvalve V-24. Oil is' now vbeing `trans,- ferred to meter tank 17. On 4succeeding cycles one meter 'tank will still be running to pipe line when the 8 other has filled. The transfer pump 26 will stop and not restart untilone tank is completely empty.V and its pipe line valve has closed.

The topping-out of meter tank 16 involves wetting of probe J-13, then after the aforementioned one-minute time delay for gas-venting, valve V14. is opened thereby allowing oil from the dome 16b of tank 16 to drain through valve V-14 and pipe 19 to the. surge tank. Dur ingthe topping-out operation, probe J13 becomes. dry thereby causing relay JR-13 to open switch Ill-13H with no effect on the system. At the, same time. Contact JR-13L closes, also with no effect on the system. As probe J-14 becomes dry, in the topping-out of meter tank 16, the probe relay .IR-14 operates to open contact JR-14-H1 and to open contact IR14H2, both with no effect on the system. At the same time contact JR-`14L1 closes and valve Va-16 opens. At the time valve V.16 opens contact V-16A closes thereby causing the following operations to occur: valve V-16 relay VR--l` energizes thereby opening contact VR-16-A which interlocks with valve V-15; contact VR-16-B opens which interlocks with valve V-26; and contact VR-l-C closes thereby energizing time-delay relay TD-Z which closes contactTD-ZA and starts the pipe line pump 33.

A pressure switch 34 is provided in thepipe lineonthe dischargev side of pipe line pump 33 and is setto prevent starting of. the pipe linepump incase the pipe line pressure is higher than .a predetermined pressure. 4If desired, the pressure switch 34 isarranged to give a signal Whe/n apipe line pressure greater than the predetermined pressure is reached. i

When oil from the surge tank 15 starts `into meter tank 17, probe yL27 near the bottom thereof becomeswet with the result that probe relay JR-27 operatesy to open con- -tacts JR-27-L1 and JR-27-L2 with no effect on the system. When the oil level wets probe J-24 the proberelay iR-24 opens contact IR-24-L and closes contact JR-24-H1, with no effect on the system, and closes contact JR-24-H2 which latches latching rel-ay L11-4. As Y latching relay LR-4 latches, contact LR-4A closes with no effect other than to prepare a circuit to valve V-26. Topping out of meter'tank 17 involves wetting of probe L23 which, in turn, energizes probe relay JR-ZS thereby opening contact JR-23-L with no effect other than to prevent cyclingy of latching relay LR-3. Contact JReZS-H closeswith the result that latching relay LR-3 unlatches andv contact LR-3B opens thereby closing valve V-25. As valve V-ZS closes, contact V-25A opens and transfer pump 26 stops; also contact V-ZS-B closes with no effect on the system other than to prepare a circuit to valve V-26. As contact LR-3B opens, contact LR-3A closes thereby energizing time-delay relay TD-S and closing contact 'ID-5A and after a one-minute delay valve V-24 opens. As contact LR-3A closes, latching relay LR-7`latches and contact LR-7A opens thereby charging condenser Z-Z through a 22K resistor in series with rectifier X-Z. Simultaneous with latching of lfatching relay LR7 latching relay LR-l also latches thereby closing contact LR-lB with no effect on the system other than to prepare a circuit to valve V-IS, and'contact LR-lA opens thereby de-energizing time-delay relay 'ID-.4 and opening contact TD-4A which closes valve`V-14.

After =a time interval set by time-delay relay TD-S, oil drainsback to surge tankV 15 through valve V24 and meter tank 17 tops out. Thistopping-out of meter tank 17 involves probe J-23 becoming dry with the simul-V taneous opening of switch JR-23- H and closing of switch JR-23-L, bothrof which exert no effect on thesystern. When rsufiicient oil has drained through valve V-24 Yto thersurge tank from.: outside the upper metering rim (see rim 16a of Figurer3), probe 1 24 becomes dry thereby opening probe relay contact lIR--24-H1 and JR-Z4+H`2 with no effect on the system, and closing Vcontact JR24L which. also has no effect on the system,l other than preparing'the circuit vto valve vV-26. At this stage'of the 9 operation meter tank 17 is now topped out and will run to pipe line as soon as meter tank 16 is empty and valve V-16 closes. As soon as meter tank 16 is empty and ualve V-16 is closed, this meter tank immediately starts refilling. As meter tank 16 starts refilling, topped out meter tank 17 starts rimning to the pipe line, as follows: As the last of the oil leaves meter tank 16, probe J17 becomes dry thereby energizing probe relay .TR-17 to close switch JR-17-L1 which latter operation unlatches latching relay LR-6 thereby closing contact LR-6A and a run counter RC-l is pulsed. The run counter circuit is reset so no counts can register until tank 16 has refilled and emptied. As contact IR-17-L1 closes, contact JR-17-L2 also closes with the result that latching relay LR-Z unlatches and contact LR-ZA opens thereby closing valve V16y simultaneously with which closing contact V16A 'y opens, relay VR-16 de-energizes and contact VR-16-A closes after which valve 15 opens, contact V-15-A closes and transfer pump 26 starts, andvcontact V-15B opens interlocking with valve V-16. Meter tank 16 is now refilling. Contact VR-16C opens thereby de-energzing time-delay relay TD-Z and starts time-delay contact FD-2A` yto timing out. Contact VR-16-B also closes thereby opening valve V-26 and simultaneously closing .contact V-26-A, energizing relay VR-26 thereby opening contact VR-26A interlocking with valve V-25, and

opening contact VR-26-B Vinterlocking with valve V-16,

and closing contact VR-26-C thereby re-energizing 'time-delay relay TD-Z. Contact 'ID-2A remaining closed allows the pipe line pump 33 to continue .to run. Meter tank 17 is now running oil to the pipe line.

Meter tank 16 is now ready for refilling, the steps being as follows: Probe J-17 becomes wet andcontacts JR-17-L1 and JR-17-L2 open with no effect on the system. When the tank is substantially full and probe J-14 becomes wet, contact IR-14-L1 opens with no effect, and contact JR14H1 closes, also with no effect, -and contact IR-14-H2 closes with the simultaneous latching of latch relay LR-Z. Upon latching of this relay, contact LR-ZA closes with no effect on the system other than to prepare a circuit to valve V-16.

When meter tank 16 becomes full, probe J-13 becomesv wet and switch JR-13-L opens with no effect on the system other than a protection of latching relay LR-l from cycling. Contact IR-13-H closes with the simultaneous unlatching of latching relay LR-l, and opening of contact LR-1-B with the resulting closing of valve V-15. As valve V-15 closes, contact V-15-A opens and the transfer pump stops, contact V-15-B closes with no effect on the system other than to prepare a circuit to valve V-16. As contact LR-lB opens, contact LR-1A closes with the simultaneous energizing of time-delay relay TD4 and the closing of contact TD-4A with opening of valve V-14 after a one-minute time delay.

As contact LR-lA closes, latching relay LR-6 latches and contact LR-6A opens with charging of the condenser Z-1, latching relay LR-3 latches and contact LR-3B closes with no effect on the system other than to prepare a circuit to valve V-ZS, and contact LR-SA opens with the simultaneous de-energizing of time-delay relay TD-S and opening of contact TD-SA with the closing of valve V-24.

After a time interval set by time-delay relay TD4, oil ldrains back to the surge tank through Valve V-14 and meter tank 16 then tops out yas follows: Probe L13 becomes dry, contact IR-13-H opens and contact J R-13-L closes, these latter two operations having no effect onr the system. Probe J-14 then becomes dry with the simultaneous opening of contact JR-14-H1 and JR-14- H2 with no effect on the system and closing of contact JR14-L1 with no effect on the system other than to prepare the circuit to valve V-16. Meter tank 16 is now topped out and will run to pipe line when meter tank 17 is empty and valve V-26 is closed.

When meter tank 17 is empty, probe I-27 is dry and contact JR-27-L2 closes with the simultaneous uniatch ing of latching relay LR-7, contact LR-7A closes and run counter RC-1 is pulsed. The run counter circuit is reset so that no counts can be -registered until tank 17 'has refilled and emptied. As contact JR-27-L2 closes, contact JR-27-L1 also closes with the simultaneous unlatching of latching relay LR-4 and opening of contact LR-4A. Following this contact opening valve 26 closes `and contact V-26-A opens with the simultaneous de-energizing of valve relay VR-26, contact VR-l-A opens, valve V-25 opens, contact V-25-A closes and the transfer pump starts, contact V-ZS-B opens and interlocks with valve V26 so that V-26 cannot open until the tank has become completely filled and topped out. As contact V-26-A opens, contact VR-ZG-C also opens and time-delay relay 'TD-2 energizes with the simultaneous starting of the timing out period to open contact TD-ZA. Also contact VR-Z-B closes with the simultaneous opening of valve V-16 and closing of contact V-16-A. Valve relay VR-16 also energizes with the simultaneous opening of contact VR16A interlocking with valve V-15, and opening of contact VR-16B interlocking with valve V-26, and alsoclosing of contact VR-Z-C with the simultaneous reenergizing of time-delay relay TD-Z. Contact TD-ZA remaining closed allows the pipe line pump to continuey to run. Meter tank 16 is now running to the pipe line, and meter tank 17 is filling. Subsequent filling and emptying of the meter tanks follows the sequence as. hereinabove described.

Data for completion of a run ticket are taken once each day from the temperature-pressure recorder 37 of Figure 2, from run counters RC-l `and RC-Z of Figure 2A and from the composite oil sample stored in the sampling vessel 35 of- Figure l. The B.S. & W. content and A.P.I. gravity are determined manually from the composite oil sample. The pressure recorder serves as. a double check on the run counters and provides a permanent record of the filling and running of each tank.

The function of the pressure recorder is to record the static head of liquid in the meter tanks thus indicating each complete fill and dump of each meter tank. If partial dumps occur, the volume of oil transferred can be calculated from the static head pressure recorded. The pressure recorder thus gives a complete chronological record of the oil transferred into and out of the meter tanks. The pressure record being on the same chart with the temperature record serves to correlate the temperature of the oil with the time the oil started to pipe line.

In order that the system may be manually stopped, with an integral number of dumps recorded, switch SW-Z is opened. Opening switch SW-2 causes the transfer pump 26 to stop and allows the tank which is running to the pipe line to complete its emptying portion of the cycle. The counters and recorders are then read and the system returned to operation by the manual closing of the switch SW-Z.

The several motor valves of our system are normally closed, electrically operated valves. The motors of these valves require approximately -volt-amperes for a period of 25 seconds to open the valves completely. A solenoid pilot valve holds the main valve open against the action of the closing spring. Loss of power to the holding solenoid allows the valve to close, the time required for a closing being approximately five seconds. While the valves that we have used are as just described, it is realized that other suitable types of normally closed, electrically or pneumatically operated valves can be used.

While we have described the use and operation of capacitance probes such as J-7, J-8, etc., as liquid level sensing apparatus, it is realized that, if desired, suitable liquid level fioat control apparatus, such as float actuated switch assemblies similar to the float actuated switch FS-6, can be used. Figure 5 illustrates the alternative oat. switehassembly which, as stated herein, is .Sometimesusedy in `place offtheprobes- Float .45 in tank 4-7 operates a switch in .switch box46 to energize and deenergize relay lll-14 to open and close contacts as illustrated in FigureZA. Since upon closing the circuit to power leads 23 and N, the relay is immedately ready foroperation and power lead23. is beyond the time delay switchV TDfl.

A conduit. lisattached to .the uppermost part of each ofthe. two. meter tanks 16. and.1.7. and to thev surge tank 15 as welles. to the boot, 14. andreceiver 13a for gas pressure equalization purposes. In case, however, the oil contains a considerable amount ofvdissolved gas, the gas. which. weathers or. vaporizes from the oilduring its. lhandlingpasses through the gas, equalization -line to venting or to recovery, as desired. A pipe 32 leads from the bottom portion ofmeter. tank 17 topmotor valve tl-26 and thence to pipe 31 for-passageof oil to the pipe line pump 3.3.

Sampler vessel 35`r is provided, as illustrated in Figure i, for the. purposes of obtaining composite samples of thecrude oil being transferred. While temperature of each .metered volume of crude. oil is determined automatically, the B..S. & W. content and the A.P.I-. gravity are. determinedmanually, say once each day, from the composite.. sample. of crude oilfrom sampler vessel 35.

This sampler is otthecomposite sampler type `and takes a smallsample of oilpassingthrough pipel to the pipe line pumpeach time a meter tank of oilpasses to the pipe line pump. Any suitable sampling device can be. used, many are available commercially. A conduit 36 is connected with the upper portion of each of' the meter tanks and withtheV surgeftank 15 as. an emergencyoverflow pipe in case the meter tanks ever fill to a level above theuppermost probes.

.In the. metering Vtank 16 of Figure 3 is inserted a temperature probe 3,8 which is, if desired, a thermoconple, or other temperature sensing means suitable for obtaining crude oil temperaturesaccurately. This temperature sensing meansor probe. is operatively connected to temperature-pressure recorder 37, illustrated diagrammatically inFigure 2.

TheB. S. & W. content of the oil in the vtransfer line between the surge tank and theV transfer pump is continuously indicated on a meter relay in the monitor output circuit. This meter relay has movable. upper .and lower limit contacts. The upper contact makes it possible to set. thetolerable upperlimitot B. S. & W. content.` Ifthe instrument senses B. S. & W. content above the preset limit for 30 seconds or more, the transfer pump is stopped andthe circulating pump starts. Bad oil, that is, oil containing more. than a predetermined quantity of water, is recirculated through the treater until the monitor indicates that contamination is below the tolerable limit. Closing ofthe upper limit contact also energizes a signal Yat the telephone P.B.X board so that operatingand maintenance personnel can be informed that abnormal conditions exist.

The lower limit contact on the meter relay serves rto make the capacitant monitor itself fail-safe. The meter is calibrated. so that (zero) contaminationl of the oil reads 4 divisionson rthe scale. vThe meter will only reach the 'lower limit contact (set at O) when theV monitor cell output signal is lost, as it would be in the case of electronic trouble. y.

lt the transfer of oil from the surgetank to the meter tanks isY stopped, for any reason, the level in the surge tank. will rise above the normal .high level'indicated bythe elevation-of.. probe Jp-"7, andwactuate the emergency high. level control probed-8.- This control energizes a light on the panel ,in the control house 30 and also signals thetelephone P.B.X board. This same control is a safe highlevelcontrol, thatiis,.if.the level control itself fails, itwillrclosethe same contact` that` closes when it senses high level.. For this. reason the. high. level.controleV in thesurge tank. servesv also. as the power failuresignal.. j Thevv magnetic startersy for the monitor pump and the transfer. pump are interlocked so that the latter, that is, the transfer pump, cannot start unless the monitor pump is operating. This arrangement insures that no oil will transfer that has not been sampled by the monitor.

While themotor valves hereinbefore described in the operation of our automatic custody transfer system were.

described asr being electrically operated motor valves, it is. realized that the .use of electrically operated valves is not essential becausepneumatically operable diaphragm motorr valves can also be used. The relays which actuate. the. hereinabove described motor valves can, in a pneumatic system, operate a pilot which regulates the pneumatic pressure. to the diaphragm of. the diaphragm operated motor` valve. Diaphragm operated motor valves are, when desired, equipped with limit switches as well as are electrically operated valves.

The use of latching relays vin the meter tankv control system insures a proper continuation of uninterrupted operational cycles. Twoof these relays are used in a special circuit for operating .the run counters. Each tank must completely Yll and completely empty before the counterv will register.

The. limit switches on the fillvalve and the run valve oneach meter tank. are used for electrical interlocks .between the. valves. The ll valve and run valve on one tank cannot bothbe open at the same time. Also, thc

Vtwo runvalves on thetwo tanks. cannnot be open at the Sametime and neither. can the two fill valves on the.

two-meter tanks be open at the same time.

Thelatching relays, which control the transfer cycle,

are connected through a fuse Fv in such away that. malfunctioning of a level control will cause this fuse to blow.

Thus, if any meter tank level control fails, thenwithin one complete cycle of the metering system (i.e., trilling and dumping of both tanks) the contacts of the abnormal level control will cause one or more of the latching relays to oscillate on its own contactsthus causing fuse F to blow and dei-.energizing the transfer pump. and all latching relays. This particular feature makes the entire system practically fool-proof and self-protected in case of failure of any of the meter tank level controls.

While we have described our automatic transfer system as being a two-meter tank system7 it is realized by those skilled in the art that any number of meter tanks necessary can be used. It is merely necessary to increase correspondingly thenumber of apparatus parts fully disclosed relative to the two-meter tanks hereinabove described. Any number of tanks required can be intercontrolled and interregulated as well as the two tanksk of our inventori. In some cases it is desirable to employ two surge tanks in place of the single surge tank .as herein disclosed. In case two surge tanks are used, in some cases it may. be desired to have the surge tanks completely separated from one another or, if desired, the surge tanks can be interconnnected with each other so as to maintain the levelof liquid in both tanks thesarne.

In Figure 3 of thedrawing is illustrated, on an enlarged scale, a suitable metering tank for use according to our invention. The tank is fully described in a copending application, Serial No. 622,863, now Patent No. 2,893,595.. Briefly, tank 16, previously mentioned in the description of Figure l, is, in general, cylindrical in shape, and is provided witha truste-conical top and substantially aninverted conical bottom. The tank is supported by any suitable type of support desired. The.

bottom of thetank terminates substantitfiliyv as illustrated in Figure Y3, with the capacitance probe 1 17 disposed aty substantially the position shown. For tank volume purposes the bottom of the tank is considered as theY valve .V.-16 and the top as rim 16o. Thus the volume, preferably iribarrels4 of 42 gallons each is the volume between rim 16e and.- valve V-16. Meter vessels 1.6.and

, 13 17 'are considered for all volume vessels. Liquid which is admitted to the tank above the level indicated by rim 16a either overflows through the emergency overflow pipe 36 to `the surge tank 15 or is removed through valve V-14 in the drain pipe 19 to the surge tank 15. The'level controls identiiied in this gure as J-13 and J-14, as mentioned hereinabove, are in some instances capacitance probes, as described hereinabove, or, if desired, they are liquid level oat controls. In other words, any suitable type of level indicating or sensing apparatus is used in the practice of our invention. p

In the example described herein, when using capacitance probes as level sensing means, the probes J-8, J13

and J-23 are fail-safe-high probe units. When thesev probes are dry, that is, not immersed in oil, a vacuum tube oscillates and energizes the corresponding relay. For example, when probe J-13 is dry, the relay JR-13 is energized, and when this probe becomes wet with oily or when there is a circuit component failure, the relay becomes de-energized.

In the example herein described capacitance probes J-7, J-14, J-17, J-24 and J-27 are fail-safe-low probe units. When these probes are dry of oil, a vacuum tube oscillation is cut oit and the corresponding relay is de energized. For example, when probe J-14 is dry, relay JR-14 is deenergized and when this probe is wet with oil, the relay JR-14 becomes energized.

The fail-safe-high and fail-safe-low probes, with their electronic circuits, are available in commerce. As mentioned herein, oat switchesV are used, when desired, in`

place of the fail-safe-high and fail-safe-low capacitance probe assemblies.`

In Figure 4 is illustrated diagrammatically a wiring hookup for use with a capacitance probe. In this figure reference numeral 40 identities a master unit, that is, a master control unit -in which Y-l and Y-2 are terminals for connection with a power source, as leads 13 and N. Relay JR-14 is for operation of contacts as the relay is energized and de-energized. This relay corresponds to` relay JR-14 of Figure 2A and the connections L-1, C-I, H-1;` L-Z, C-Z and H-2 correspond to the L-l and L-Z low connections, the H1 and H-2` correspond to the high connections, and C-l and C-Z correspond to the common connections immediately below and operable with relay JR-14 of' Figure 2A. Reference numeral 41 identities the oscillator unit and reference numeral 42 the actual probe. the master unit 40L in order to provide warmup time for the electronicportionof this probe assembly.

The electrical leads at the bottom of Figure 2A connect with the leads of corresponding reference numerals of Figure 2B. Thus leads 23, A, 46a, 76a, 64a, 58a, 59a,

35a, 49a, 65a, 51a, 38a, 60a, 52a, 50a, 77a, 63a, 72a, 13,

53a, 24a, 52a and N correspond to the similarly numbered electrical leads at the top of Figure 2B.

Switches SW-l, SW-6, SW-- and SW-Z are manually operated switches.

Switch TC-lA of Figure 2A is operated by the sequence interrupter clock TC-l of Figure2.

Contact R-A of Figire 2A is disposed between contacts TD-lA and coil' R-l.

The arrowed connection identiiied in Figure 2A by the legend J-14 means thatthis connection is a. cable leading from relay JR-14 to the probe assembly i-14. The probe In Figure 2 the monitor hookup to power leads 13 and N is illustrated.

For standby operation of the temperature-pressure re practical purposes constant' Power source 13 and N -is used for' aan es assembly 48 illustrated in Figure 4 includes the capacitance probe itself identified by reference numeral 42 and In each of the corresponding corder 37 and the time clock TC-1, in case of failure of 75 spedisce' iiic R-7, Figure 2) enables the temperature-pressure recorder to operate continuously, even during time of a power failure, thereby recording any change in meter tank levels that might be caused by leaking inlet or outlet valves.

Figures 2, 2A and 2B, combined, illustrate the entire system. Leads 13, N and 23 of Figure 2 are provided with legends directed to Figure 2A and lead 7 is directed to Figure 2B. In a similar manner numerous wires identified by their reference numerals in Figure 2A are intended to lead to wires of the corresponding reference numerals in Figure 2B.

The small tank illustrated in Figure l and carrying the legend sump is installed as shown to provide a suf- Under certain specific conditions run counter RC-Z' can miss a count. This specific condition exists at a time when a power failure occurs when using a valve requin ing power for opening and power for closing and pipe line pressure is suiciently low that oil from the meter tank is running to the pipe line by gravity. Upon failure A of power whether the pipe line pump is used or not, oil

may then ilow by gravity, and when the discharging meter tank becomes empty, its counter will not be pulsed to record a count. A pipe line pump may be used to expedite transfer of meter tank oil to the pipe line even though pipe line pressure is suiciently low for gravity In Figure 9 is illustrated apparatus for passage of metered oil from the vessel having the legend sump to a pipe line with a pipe line pump and without a pipe line pump. In this iigure, gravity ow to pipe line is from the meter tanks of Figure 1 through pipe 31 or pipe 32 to the sump then through pipe 33b, with its valve open tovpipe line, the valve in the pipe provided with pump 33 being closed.

In Figure 6 is illustrated a wiring outlay in which the run counter will not miss a count when electric power goes oi during the time the meter tank is running by gravity to pipe line. Like reference numerals on Figure 6 and on Figures 2A and 2B refer to like apparatus parts. This Figure 6 shows a portion of Figure 2A with the required apparatus and wiring changes. In Figure 6 one side of switch LR-SA goes to the manually operable switch SW-Z while Athe other side is connected directly to lead 23. One connection of the coil of latching relay LR-7 is connected through a resistance to a switch RC-2XA, which, in turn, is connected directly with lead 23. The other two connections of the coil of relay LR-7 remain as shown in Figure 2A. Run counter RC2 is connected directly to lead N and to one contact of a normally open switch LR-7XA. The other contact ofV switch LR-7XA is connected to the switch attached to lead 38a, shown in Figure 2B. Rectifier X2 and the resistor in series therewith and condenser Z2 illustrated in Figure 2A are omitted.

One contact of normally open switch LR-6XA is con- 'nected to one side of run counter RC-l while the other contact of this switch leads directly to switch IR-17-L1. The rectifier X1 and the resistor in series therewith and condenser Z1, illustrated in Figure 2A, are omitted in the embodiment illustrated in Figure 6. The lead from the coil of latching relay LR6, which in Figure 2A led by way of the resistor to switch JR-17-L1, is disconnected from this switch and connected through the resistor to one contact of a switch RC-l-XA. The other l.contact of this switch RC-1-XA is connected directly 4'with lead 23.

. ln the operation. oftheeruletlirueut-illutrletliu Fig.-v ure 6, when mere-r rank 16 is. tolli, urobe.- l-..1...3i.s.fwet and probe relay 11i-13. (Figures Zd'eudll) eloseseontoet JR-.l-H which closingV completes a circuit through the. coil of latching relay LR-6 which latches. T henormally open switch LR-GXA is latched closed and thus `ppepares the circuit to the counter RC-L When meter tank 16 tops out, probe H3 becomes dry ond. probe. relay] R113 opens eonreer Iii-1.341 with no eiieet on the eireuit- Probe l-ld beeomes. dry und probe reloyIl-lfl-L closes thereby causing valve V- l to open so the meter tank 16 can. run to pipe. line (FiguresgZA and 1 Whenmeter tank 1 6 becomes empty, probe I-.17 becomesdry and probe relay .iR-17 actuates to close contact JR-l7-L1, which closing energizes a coil in run counter RC4. thereby recording a count and closing switch RC- IXA and unlatching relay L11-...6. Uponunlatching of relay LRn-6, switchLR- GXA opens.

When meter tank 17 is fullv and valve V116 at the bottom of meter tank 16 is closed, probe lf2- 3 isi'wet and probe relay Ill-23 closes-.contaciJR-gn-l-I vvvlnmich-closing` completes a circuit through the coil otlatchingrelay- L R -7 which latches. The normally open switch is latched closed and thus prepares elle .eireuii through. tileruu counter RC2-.2l When-metertenle-17-tous outfprobe J-Zs becomes dry and probe .relay lll-2t opensy eorrteet JR-23H with no eifeet ou the-.gire Trebel-24' loef cornes dry and probe relay 1li-244s closes thereby 4eensing valve Vaio to open `so meter tank 17 can .run to pipe line (Figures 2A ond 1.)- When nreter'tauk 1.7 beeoues eruuiy, Probe I-2i7 beeorrres dry and. probe .relay Y1R72?! actuates to close contact JR-.fM-Lzwhichciosing enerf ailes eeoil in run eounter .RC-whereby reeording e. `Count and. closing swiieh; EQ2-XA and unletehngrelay LR-7. Upon unlatching of relay LR-7, switch'vLR-XA opens.

rf. oil `is running rrorrreithermeter tanlsby enmity` to pipe. line when eleefrie power.. fails., the-.respeeriye run valve (V-16 or V.-26) which requires poyver iopopenf. ing and power for closing, remainsopen and the tank goes empty. Probe H7 goes dry during tire power outage, contact JR-17-L1 Will be closed when power isgrestored and the counter will be pulsed and, in turmwill close switeh RC4-XA to unlaten letehing relay Like. und continue the cycle.

It either meter tank, as, for example, metentank 1 6, hes. uo? eornpletely filled., and seine rnelturretion allows the oil to run outg o eouut will not oeeur beeeuse toet IRAs-H will not elose ondswitelr Lite-@XA will not be closed.

Power fluctuations cannot pulse counter RQ-pl, or RC4, because there is a complete circuit to the coil o f the counter only during the instant that the counter solenoid is energized. Once the solenoid plunger reaches -rthe top of its stroke, switchRCl-X or RC-L-Xir closes thereby unlatching the vrelay/I ,R-f -and causing switch LRgXA or L'R-XAvto open, i Y

Our automatic transfer -system has been-her ei nb efore described asbeing atvv'ofmeter tank sys't e niwithany nulllbef 0f metal' lilIlkS-llesaly belllgiueil- TM5-@lill ery number of. meter faults. iueludes. one roeier. tank. as 'vvell as systems containing tryqfthreeonevenmorej meter tanks.

.The .deserirtieu of e eue-meier.- onkosten.illusrreted in Figures 7. Se and 8b, y'rlrieh iellowswill. srertoyith the surge tank .lsfbeirrgerurrn ,rneeoutrolsysteru sleenergized, all latehing relays"infllelffuuletelled; ositiuuy.. a hydraulically operated motor valveXV-4 being c lo sed and a meter tank 101 empty. Many otthelpieces of equipment in this one-meter tanksystem are similar to corresponding pieces of the vtwo ta`1 1 k system described hereinbefore,u and like pieccsof appdlll are. identified by like reference characters,

In Figure? there are illustrated several improvements over the transfer system'illustrated'in Figurej 1. The

its;

.- operetetor 'regulating nested in. boot. 1.4, .settled in receiver. 13a, gas vented in pipe 181 dudu/eter Withdrawn. in pipe. 12 as enlnined reletiye- @Figure l Likewise, oil of reduced BSS.. & W. content is passed from receiver 13a through pipe 20 into surge reuk. 15 from .whiehoil is; circulated through PiPes;,.2.1"eud.-f.27 to.. and fromunonitor cell 29 in con-y rrol...lreu se.3.0 by ourngflr also. osfpreviously explained. A.. euiteble egiuleierrree.Y eell. for'. use in;Y this.. monitoring operatie l diselosed hereinheiore.

euduponigereese. et B-Sv &.W eontentnbove o pre to shut down transfer pump 26, stapt circulating pump 2.5v with ,eilrlseiugreeireuletedLto tire. booth until the nro ltouindiegt ll-ipereent or lessv B-S & W- When ther-.5.. QW lies. beeutloyvered to .o velue. below. die unner.liruitf-tl.reeeireu ...ug .narrati stops! oud transfer Porno. 26 ste.rts...,a1l -espongo to aerien. or .the rnouitor2 also erruleinedhereinbe. re- When transferring. uil to a pipe line, not shoyvn, us ing a pump,l as pump 33, the' oilresses .fron-.roule ltthrough o. Pire urrufided with punir 3.3.-. When tregsferriugoil to e Pire line by gravity flowtitireoilrgsses.troni reuk.r rtl4 through eine sse roerige.line-.rrotslrowus A low level float XL-l, a normal high or working leyeliloet Xue-enden Ae.ruergeney high level fleet XL-3 .diiow .inthe serge manner es probes .ES-6. .J 7 endl-S .et Figurel lt is .to lee noted that thl isnot a motor valve in a transfer pipe 102;

einel 1912 ediueeru .the meter reuk lill is en inverled-.U-.slrnpedripe .-with. e Siphon breaker. 106g This Siphon-. breaker. 1.06., Yeo.rnrnuuie.ete.s .with .vent pipe 1.8.- The .liorizontglporriouot the .LJ-shaped ripe is surrieiendy h ightha-t the pump 2Q must operate .to transfer oil from thesurge tank to the meter tank and that oil will not lluw by grevity treni the meter .tenis te the surge taule determined linntipes.;Orfnereeuti ure monitor iunetious.

-- and .the .Siphon breaker .is provided so that oil will not Siphon fromthe'meter tank to the surge tank. The meter reuk lill .eer-1, ifdesiredbe vsirnilerro meter tanks 16 and 1 7 or it canbe of other conguration, provided, of eonrse, that its volume can A be accurately determined.

When fill-ing the .meter tank, motor valve XV-4, which is any suitable hydraulic or pneumatic motor v alve which requires ,power for opening and power for closing, is closed. When a float XL-, in dome 111 of the meter tank, vbecomes Wet, pump 26. stops andoil above and outside a Weir 105 .drains through pipe 103 to the surge tank.

Upon drainage of oil `from 'outside of Weir l10S oat XL-6 becomes dry and then valve XV-4 opens and pipe line pump SS'starts. This pipe linepump is used for pipe line pressure requirements. In some cases, the oil passes through the. ypipe, line .by gravity iiow from the meter tank and in this case the pipe linefpumpy is not required.

...The rurpose .of the sump.. tenlgwhien is. .not a volume eoliuratedrenkes. isfrhe. meter reuk, is to Provide for continuous oii flow to pipe line while the meter tank is lling and toppingout. When,V for example,` themeter tank is a Z5-.barrel capacity tank, it is preferred that the sump tank befof vabout 1 5 barrels capacity. The drain The. monitor celly 2.?. eorrunu slyr iudigetesB-S. 64W' eontentofthe oil.

Vtacts XTDI-A close and then XLRZ-L energizes.

is intended that the oil level in the sump tank should ybe at least some short distance above the level of float XL-4 -by the time the next charge from the meter tank is ready for transfer to the pipe line. In this manner there is continuous gravity flow or pumping of oil to the pipe line. A vent line 110 is provided for passage of vapor to, and from the sump tank as required by its emptying and filling. When float XL-4 becomes dry, the pipe line pump stops.

In case a pipe line pump is not required, i.e., when there is gravity flow of oil from the sump tank to the pipe line, the circuit in Figure 8 carrying the legend pipe line circuit is not required.

On referring to Figures 8a and 8b, upon closing a twopole disconnect switch X-3, the primary coil of a. transformer X-4 which is connected across lines XL-l and XL-Z of a three-phase '440 volt power supply X-l, is energized. The coil of a relay XR-Z, connected across lines XL-Z and XL-3, is also energized. This relay protects the motors from single phase operation when disconnect switch X-Z is closed by opening a contactXR-ZA in the control circuit X423, XH and XN when line XL-3 is open. If line XL-l or XL-Z is open, the control circuits will be dead because there is no voltage across the control transformer. All motor starters have ll volt coils and are operated directly from the control system. The B.S. & W. monitor 29 is energized when the two-pole fused disconnect switch X-3` is closed. The monitor is preferably a capacitance cell as hereinbefore stated.

Upon closing a master control switch XSWZ, the system is energized for automatic operation and monitor pump 28 starts thereby circulating oil from the bottom of the surge tank 15 through the monitor 29 and back into the surge tank via pipes 21 and 27. Production is admitted from receiver 13a into the surge tank 15. When oil reaches a low level, float XL-1 becomes Wet and switch .XL-1A opens with no Veffect on the system. When pro- `turningon a transfer red light XRLZ, and normally closed Acontacts XLRl-Bto open thereby turning off a refill light XRL3. 'Ihe transfer pump 26 pumps .oil at a greater rate than the production; thus'the oil level in the surge tank 15 falls slowly. Float XL-Z then becomes dry and the latch coil XLR1-Lof latching relay XLR1 becomes Yde-energized with no effect on the system. Y v i The pipeline `sampler 35 is placed in the lposition shown in Figure 7 because sufcient crude oil pressure 1s available at the discharge of the transfer pump to assure proper sampling.

vwhi1e'n'1ertank 101 is suing, float xL-s iswet and switch lXL-SAopens with no effect on the system. When -the meter tankA becomes full, float XL-6 becomes wet and switch XL-6A closes, after which time-delay relay XTDl becomes energized and after a 30-second time delay ctis relay XLRZ latches, normally open contacts XLRZ-A close (no effect on system), normally closed contacts XLRZ-B open and transfer pump 26 stops. Simultaneously, with the stopping of the transfer pump, transfer pumpcontacts XTP-A open; then pipe line sampler is deenergized, and transfer red light XRLZ goes off. Simultaneous with opening of contacts XLR2B, normally open contacts XLRZ-C are closed which closing prepares cirycuit to a run counter )RQ' normally open contacts 18 mally closed contacts XR-A, closes normally open contacts XR-B and opens normally closed contacts XR6-B; all of these latter changes prepare a circuit to valve XV-4.

At the time float XL-6 becomes wet, switch XL-6B opens with no effect on the system. The meter tank tops out by oil draining back to the surge tank 15 until float XL- becomes dry. rIltis lioat is placed some little distance below the edge of weir 105. When the oil outside the weir drains down sufciently that the float becomes dry, switch XL-6A opens and as a result the coil of the time-delay relay XTDl becomes de-energized, contacts lXTDl-A open after which the latch coil of latching relay XLRZ is de-energized with no effect on the system. As switch XL6A opens, switch XL-6B closes and coil of relay XR4 becomes energized and normally Open contacts XR4-A close, followed by opening of valve XV-4 and pressure switch XPS-A opens (pressure switch on valve XV-4 that pressures up (opens) as thevalve approaches its open position and closes Aas the valve approaches its closed position). As pressure'switch XPS-A opens, pressure XPS-B closes (pressure switch on valve XV-4 that pressures up (opens) as valveapproaches its closed position and closes as the -valve approaches its open position). After XPS-B closes, coil of relay XRS is ener.- gized along with closing of contacts XRS-A, this latter loperation preparing a circuit for closing valve XV-4.

As the oil passes from meter tank 101 into sump tank 104 (and ultimately to the pipe line pump 33), the meter tank is considered empty at the time float XL-S becomes dry. As float XL-S becomes dry, switch XL-SA closes energizing time-delay relay XTDZ; after a preset delay (30 seconds) contact XTD2-A closes; then run counter solenoid energizes and makes one count. As the run counter solenoid is energized, run counter switch XRC-A closes and then latching relay XLRZ unlatches and contacts XLR2A open with no effect on the system; contacts XLR2-B close after which closing transfer pump 26 starts, contacts XTP-A close and pipe line sampler becomes energized, transfer pump red light XRL4 lights. Contacts XLRZ-C open, the run counter XRC solenoid de-energizes, run counter contacts or switch XRC-A open. Normally open contacts XLRZ-D open, coil of relay XR6 is de-energized, normally open contacts XR-A opens, normally closed contacts XR-A close, normallyvopen contacts XR6-B open and normally closed contacts XR6-B close, and finally valve XV -4 closes.

A preset counter XPC is provided for closing oi the system when a predetermined number of meter tank fulls of oil has been delivered to the pipe line, as determined by crude oil allowables.` v Y The sequence of steps including lling of the meter tank 101, topping out of the meter tank, running of oil from the meter tank to pipe line by way of the sump tank until the meter tank is empty (oil level below float XL-S) continues until such time as the low level float XL-l in the surge tank 15 becomes dry.

The system illustrated in Figures 7, 8a and 8b is .so arranged that the transfer cycle of oil from the surge tank 15 to the meter tank 101 ends and the meter tank refill cycle begins only after a complete previous filling of the metertank; that is, when oil in the surge tank is lowered to the level of float XL1.while the meter tank `is being filled, contact XL1A prepares the circuit to stop transfer of oil from the surge tank to the meter tank for refilling the surge tank but this operation does not occur until the meter tank filling has been completed. In this manner a part meter tank of oil is never left standing duri ing lling of the surge tank. To facilitate this type of tween float XL-I and the transfer pump connection.

When float XL-1 becomes dry, switch XL1A closes with no effect on the system. However, if the meter tank'is filling, it continues to ll, when float XL6 becomes wet contact XL-6A closes energizing XTDI which closes We claim: f-

1. A system for transferring known volumes of hydrocarbon liquid of predetermined quality lfrom a source to a point of disposal comprising, in combination, atreat# ing vessel for said hydrocarbon liquid, a surge vessel for receiving treated hydrocarbon liquid, a meter vessel of Iknown volume, first and second conduits communicating said treating vessel with said surge vessel, a first pump in said second conduit for transmitting liquid from said surge vessel to said treating vessel, a third conduit communicating said surge vessel with said meter vessel, a second pump in said third conduit, a fourth conduit communicating the bottom of said meter vessel with a point of disposal, `a monitor assembly for controlling quality of said hydrocarbon liquid, said monitor assembly comprising a monitor for sensing B S. `and W content of the hydrocarbon liquid, conduit means for passage of hydrocarbon liquid from said surge vessel to said monitor and return to said surge vessel, first and second motor valves in aid second and third conduits respectively, a first electrical circuit communicating said monitor'with said rst pump and with said rstkmotor valve, a second electrical circuit communicating said monitor with said -second pump and with said second motor valve, said monitor assembly being adapted to close said second motor valve and to close olf electric current to the motor of said second pump to stop same and to open said first motor valve and to close the circuit to the motor of said first pump to start same when said monitor senses a B. S. and W content in the hydrocarbon liquid flowing therethrough higher than a predetermined B. S. and W content.

2. In the system of claim 1, a third motor `valve and a third transfer pump in said fourth conduit, and an interlocking electrical relay circuit including said second motor valve and said third motor valve, said interlocking relay circuit being adapted to open said second motor valve only when said third motor valve is closed and to open said third motor valve only when said second motor valve is closed.

3. In the system of claim 2, a dome disposed fluidtight to the top portion of said meter tank, the top of said meter tank being open and extending into said dome, a first liquid level sensing means in said dome above the top of said meter tank, a second liquid level sensing means in said dome and outside said meter tank at a level below the top of said meter tank, a fifth conduit for draining liquid from said dome, a fourth motor valve in said fifth conduit, a fourth electrical circuit communicating said second liquid level sensing means with said third pump and said third motor valve, a fifth electrical circuit communicating said first liquid level sensing means with said second pump and with said second motor valve, said fifth electrical electrical circuit being adapted to close off electric current to said second pump to stop same and to close off said second motor valve upon sensing of level of liquid by said first liquid level sensing means, said fifth electrical circuit comprising a time delay relay, said time delay relay communicating with said fourth motor valve to open same after a predetermined time delay of said time delay relay thereby allowing drainage of hydrocarbon liquid from said dome, and said fourth electrical circuit being adapted to open said third motor valve and to start said third pump upon lowering of the liquid level below said second liquid level sensing means, a third liquid level sensing means in approximately the bottom of said meter tank, a sixth electrical circuit communicating said third liquid level sensing means with said third motor valve and with said third pump, said sixth electrical circuit being adapted to close said third motor valve and to stop said third pump upon drop of liquid level below said third liquid level sensing means.

4. A method for transferring a known volume of a hydrocarbon liquid having less than a predetermined con.- centration of B. S. and W. to a point of delivery, com- 22 prising the steps of receiving said liquid containing B. S. and W. in a receiving zone, treating said liquid in said receiving zone to remove at least a portion of said- B. S. and W., withdrawing an aqueous phase from said receiv-v ing zone, passing liquid of reduced B. S. and W. content to a surge zone, vmaintaining the B. S. and W content of said liquid inv said surge zoneV below a predetermined value by continuously withdrawing a stream of said liquid from said surge zone, passing 'this withdrawn stream through a B. S; and W.r sensing monitor and returning the stream to said surge zone, upon sensing a B. S. and W. content higher than the predetermined value recycling liquid from said surge zone to said receiving zone,

passing only liquid having a less B. S. and W content Y than said predetermined content from said surge zone to a metering zone of predetermined volume until said metering zone is completely full, then passing said liquid from said metering zone to said point of delivery.

5. A method for transferring known volumes of a hydrocarbon liquid having less than a predetermined concentration of B. S. and W in the form of an emulsion to a point of delivery, comprising the steps of receiving said liquid containing B. S. and W in the form of an emulsion into a receiving zone, treating said liquid in said receiving zone for breaking said emulsion whereby B. S. and W. settles to the bottom thereof as an aqueous phase thereby leaving a supernatant hydrocarbon liquid phase of reduced B. S. and W. content, withdrawing said aqueous phase from said receiving zone, passing said hydrocarbon liquid of reduced B. S. and W. content to a surge zone, maintaining the B. S. and W. content of said vliquid in said surge zone below a predetermined B. S. and

W. content by continuously withdrawing a stream of said liquid from said surge zone, passing this withdrawn stream through a B. S. and W. sensing monitor and returning the stream to said surge zone, upon sensing by said moni tor of 4a B. S. and W content higher than said predetermined B. S. and W. content recycling liquid from said surge zone into said receiving zone, passing only liquid of less than said predetermined B. S. and W. content into a first metering zone of predetermined volume until completely full, passing said liquid from said first metering zone to said point of delivery and simultaneously passing liquid from said surge zone into a second metering zone of predetermined volume, when said second zone is completely full of liquid yand said first zone is empty of liquid, passing liquid from said second metering zone to said point of delivery and simultaneously filling said first metering zone with said liquid from said surge zone.

6. A system for continuously transferring known volumes of hydrocarbon liquid from a source to a point of delivery comprising a first vessel, a second vessel of known volume, a first c onduit for passage of liquid from said first vessel to said second vessel, said first conduit including an inverted U-shaped tube, at least a portion of the inverted U-shaped tube being disposed at a higher elevation than the uppermost portion of said second vessel, a Siphon breaker in communication with the upper portion of said inverted U-shaped tube, a third vessel of volume of at least about half that of said second vessel for delivery of said liquid to said point of delivery, said third vessel being disposed below said second vessel, a second conduit communicating the bottom of said second vessel with said third vessel for gravity ow of liquid, said second conduit being adapted to pass liquid at a more rapid rate than said third vessel delivers liquid to said point of delivery, said first conduit being adapted to pass liquid at a sutiiciently rapid rate to fill said second vessel before a full third vessel of liquid passes from said third vessel to said point of delivery, means for monitoring impurity in said liquid from said first vessel, third and fourth conduits communicating said first vessel with said means for monitoring for passage of liquid from said first vessel to said means for monitoring and return to said first vessel, said means being adapted to terminate passage of liquid

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