UNIVERSITY OF ILLINOIS ENGINEERING EXPERIMENT STATION Circular Series No. 65 AN ELECTRIC RECORDING WATER METER JOHN K. TUTHILL Lale Professor of Electrical Engineering Published by the University of Illinois, Urbana
I. INTRODUCTION 1. Purpose of Circular 2. Acknowledgents CONTENTS II. ::VIETHODS OF :MEASURING LO COMOTIVE FEED WATER 3. Water Measureents 4. Gauge Sticks 5. Water Colun Gauges 6. Water Meters 7. Selsen Indicators III. ELECTRIC RECORDING w ATER METER. Principle of Operation 9. Advantages over Conventional Types 1. Construction 11. Calibration (a) Laboratory Facilities (b) Apparatus (c) Procedure 12. Deterination of Water Used IV. METER APPLICATIONS 5 5 5 6 6 6 6 7 7 12 14 14 15 16 1 25-11 -52-1947 UNIVERSITY OF ILUNO I S 3
1. Meter wi t h Hose Attached FIGURES 2. Contact-Making Device and Reducing Gear 3. Assebly of Meter Recorder 4. Details of Rotor Housing and Cover Plate 5. Rotor Details 6. Details of Rotor Recording Device 7. Layout of Calibration Equipent. Calibration Curve of Water :i\ieter 9. \Vater Meter Mounted on Locootive 1. Calibration of Water Meter TABLES 9 9 1 11 12 13 14 16 1 17 I. INTRODUCTION 1. Purpose of Circular This Circular presents inforation regarding the highly accurate water eter used for stea locootiye testing in connection with the UniHrsity of Illinois and Illinois Central R ailroad dynaoeter car. This eter is to be considered a piece of special testing equipent to be used in places where a conventional type of water eter would not be suitable, where dial readings are difficult or ipossible, and where continuous graphic records are desired. It is intended to give enough details of construction and operation so that siilar eters ay be built and calibrated in any well-equipped achine shop and hydraulic laboratory. The use of a hydraulic laboratory is suggested, since it is usually equipped with the necessary tanks and weighing scales and has eans provided for using t he water over and over again. However, a teporary arrangeent ay be assebled in accordance with the plan in Fig. 7. This eter \\ as originated, designed, and calibrated by the author, built by Mr. George H. Po\Yers, Senior Laboratory Mechanic of the Electrical Engineering Departent, and calibrated and tested in the University of Illinois Hydraulic Laboratory. 2. Acknowledgents The author is grateful to nuerous ebers of the University faculty and staff for aterial, help, and suggestions - chiefl y to Professor C. H. Casberg and ebers of his achine tool laboratory, for aking all castings; to Mr. George H. Powers, for patterns and achine work; to the D epartent of Theoretical and Applied Mechanics, of which Professor F. B. Seely was t he head, and to his associates, Professor Willia J. Putna and Professo r Wa llace :vr. Lansford, for their advice and suggestions on ethods of calibration. 4 5
Circ. 65. AN ELECTRIC RECORDING WATER METER 7 II. METHODS OF MEASURING LOCOMOTIVE FEED WATER 3. Water Measureents In any efficiency or coparative test of stea locootives the aount of water used is one of the iportant ites that ust be deterined. When aking tests in the past it has been the practice to calibrate the tank - that is, to deterine the nuber of gallons of water for each inch of tank height. This process is slow and usually inconyenient, coing at a tie when the locootive is being ade ready for testing and the test crew is busy \Yith details of the entire job. If either of the usual ethods described herein is used to easure \Yater, the task is dangerous, especially when observers ust clib on the water tender at night in story and wet weather. When a stop is ade to take on water, care ust be exercised to ake sure that none is added until the observers have taken the required easureents or gauge readings. If the test crew is short-h anded, the tie necessary to obtain the necessary data ay delay train oveent, for the readings taken on the water tender ust be written on the dynaoeter car recorder chart or in a log book and later transcribed on the recorder chart. 4. Gauge Sticks The siplest ethod of easuring the water in a locootive tender is to drop a painted pole, graduated in inches, to the botto of the tank at the filling hatch, noting the nuber of inches of water in the tank. This should be done at the beginning of a test, when the train stops, and when it starts again, and the aount of water calculated for the running and waiting period. If this ethod is to be satisfactory the tender should be standing on level track and the water surface should be allowed to level off before readings are ade. An average of the four readings \\ ill give the height of water in the tender, and fro previous easureents the \Yater used during any period of tie is readily calculated. Care should be taken to see that the valves are closed after each test and that the flexible connections are securely suspended when not in use. Four obsernrs should be available when \rnter readings are to be ade in order to ake the quickly and not delay the train. 6. Water Meters The first dynaoeter cars used for road testing of locootives were equipped with water eters of conventional design. HO\Yever, the water rates were low in those days, and except for the piping difficulties involved gave reasonably good results. Such eters ust be able to handle hot water and not be affected by live stea. 7. Selsen Indicators The University of Illinois dynaoeter car is equipped with d-c Selsen apparatus which gives a continuous indication of the height of water in the tender. Since the transitter is ounted in the center of the tank and subjected to the sae liitations as the single gauge stick, it has never been used to easure gallons of water. During a locootive road test the Selsen water indicator is valuable when a gauge is ounted in the locootive cab, in front of the engineer, so he ay know the aount of water in the tender at all ties. A duplicate gauge is ounted on the panel board of the dynaoeter car recording table. 5. Water Colun Gauges A ore accurate ethod of easuring locootive feed water is to put a pipe connection and valve in the four corners of the tender tank floor. A flexible hose is attached to the valve with a glass tube inserted in the open end. A graduated scale is either painted on or attached to the four corners of the tender. When a water reading is to be ade the valves are opened and the hose is lowered until water shows in the glass. The inches of water in the tender are easured by holding the tube in front of the graduated scale. 6
Circ. 65. AN ELECTRIC RECORD ING WATE R M ETER 9 111. ELECTRIC RECORDING WATER METER for the difference in the photographs and the detailed dra\\ ings. Several principal changes ha\ e been ade as bct" ecn the design described here and the ori ginal eters. One i::; the ain rotor bearing, which requires no lubrication and \\ hen properly pressed in position proyides a \Yatertight seal. Though a stand ard Oldsobile \Yater pup shaft and bearing. Principle of Operation The water eter described in t hi s Circul ar \YaS designed priaril y to easure locootive feed \rntcr, although there arc other diffi cul t situations \\ here it could be u e d to acl\'antage. It operates on t he principle of a "strea fto \Y eter," \\ here a rotor is placed directly in t he \\ ater strea and t urns in proportion to t he velocity of t he water. It operates equa ll y \\ ell for hot, \\ ar, or cold \\ ater ; hence it is especiall y desirable for locootiye use in the winter or wh en live stea ust be blown back through the injector. LiYe stea does not affect it. 9. Advantages over Conventional Types T o easure the water taken by a odern locootive would require a conventi onal eter of large diensions, perhaps too large to be connected in t he water hose between locootive and tender. Unless a syste for reote indication were provided, difficulty \rnuld be experienced in reading the eter during a road test. The electric recording eter is light, since it av be ade of aluinu alloy. It ay easily be placed in t he hose connection between locootive and tender " here t here is plenty of clearance for t he eters. The eters require little attention during a testing period. Figure 1 sho\ys the eter wi th connecting hose attached and t he cover OYer the recording echanis. Figure 2 is a vie"' of t he rotor reducing gear and t he contact-aking device. An electric circuit is energized by the closing of a icro-s\\ itch b? the four sall roll ers attached to a wheel \\ hose shaft is driven by the large gear wheel. If the rotor speed is high and the flow continuous, one or t wo of the sall roll ers ay be used t o give ore t ie between contacts and t he eter calibrated accordingly. 1. Construction This eter has been so designed that it can be built in t he average achine shop. The eters built and used by t he Illinois Central Railroad were the first of t heir type and should be considered as experiental equipent. Al though the principle of operation is t he sae, t he detailed drawings in Figs. 3-6 have been altered and siplified in order to facilitate the eter construction and ease of inspection and ain tenance. This will account Fi g. I. Meter with Hose Attached Fig. 2. Contact-Ma king Device and Re ducing Gear
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12 ILLJNOIS ENGINEERING EXPERIMENT STATION Circ. 65. AN ELECTRIC RECORDING WATER METER 13 Ko. 555747 has been specified for t his eter, alost any other ake of autoobile water-pup shaft could be substituted for it and allowances ade for a corresponding change in bearing housing and shaft diaeter. Alost any aterial cou ld be used for the ain eter housing. T he eters already built were ade of bronze because that etal \\ as available and there \\ as a desire to prcnnt rusting. Cast iron \YOtdd be sati,:factory for eters to be used on stea locootives. 11. Calibration The ost iportant feature in connection \Yith this type of \Yater eters is their calibration. If they arc ade exactly alike, only one eter need be calibrated. The two eters already built and in use were not constructed exactly alike, so a calibration had to be ade for each one. @.---- ''' \;;."' '.._.._..... I::'<:> ""i "'"' <.:> dji; rn.._ "". "' 11 r ti:,- '<l 1;-q; * 9//i7 II.:fl N Lw 1 Uf.J.-'tl "" <:::i --: L_ U J -+- 1" Solder 6/",,\. ' q,,,, 4 cl Coge Sheet Brcrss- 6 l?eq. Fig. 5. Rotor Details "' tl. <S'. 1::!S ':.L_ [] L,,-- -!'> ;::; ;<::..., "'. ' fr- -:...,. -4 7 - _,.) ''" fr [?.&;::;! 1.. i. ".L..;::"' "I "' ' j t! - l...,"oe: - '"' J ] id ±:1 1.. u ;::.. a "' c 'ti.. a u "' "' litl T. I,,, ' " " <:! I 11'f[ IQ-
14 ILLINOIS ENGINEERING EXPERIMENT STATION (a) Laboratory Facilities. Although not absolu tely necessary, it would be uch sipler to calibrate the eters in a hydraulic testing laboratory of any of the la rge r engineering colleges. An ideal setup \\"Ould ha, e a " ater tank - "A" in Fig. 7 - about the size of a locootive water tender and about as tall, 1 in. for exaple, with an outlet pipe of suffi cient size to connect a hose siilar to that used Tank A Contact Makinq Chronoeter c (9. ' Mt.1lfi-Pen Recorder R Water Meter M Valve D Valve Tank Platror Scale p Fig. 7. Layout of Calibration Equipent Pt/sh Bt/fton F between locootive and tender, to which is attached the water eter. The outlet fro the eter should contain a hand-operated valve and run to a second tank "B " ounted on a platfor weighing scale. (b) Apparatus. An Esterline-Angus or siilar ulti-pen recorder should be available for aking a peranent record of the eter calibration. The record chart should run at approxiately constant speed and at a paper rate sufficient to give a legible record. A contact-aking Circ. 65. AN ELECTRIC RECORDING WATER METER 15 chronoeter is necessary in order to hayc a tie record along with other data. Only three pens of the recorder need be used during the calibration to indicate the fo llo\yin g: (1) Tie in lh-, 1-, or 5-sec interrnls. (2) Revolutions of eter rotor, water record. (3) \Veight of water passing through eter. Figure 7 is a suggested scheatic diagra of the arrangeent and position of all t esting apparatus. ( c) Procedure. A suggested ethod of conducting the calibration " ould be to set up the apparatus as shown in Fig. 7. If the work is to be done in a hydraulic laboratory, all equipent will be ayailable and easy to asseble. If the eters are for railroad use and it is desired to calibrate the using railroad facilities, the sall aount of special equipent necessary could be borrowed or rented fro a nearby laboratory. In this case, Tank "A" could be a lo cornotiyc tender with provision for filling the tender with water. The hose connection will already be there and the eter ay be connected in the hose line with a valve "E" on the outlet side for regulating the flow of water. T ank "B" should be a large portable unit having a capacity of several hundred gallons of \Yater and capable of bein g placed on a portable platfor scale. A large valve "D " on tank "B" would perit it to be eptied after each test. With valve "D " closed, the recorder "R " is started, the battery switch "S" in the circuit of "C" is closed, a tare weight i,; placed on the scale "P,'' and valve "E" is fu lly opened. \Vhen the scale sho\ys a balance, push button "F" is closed, which energizes a pen agnet on recorder "R." This is t he start of the test. A 1-lb weight is placed on t he scale balance and when enough water has flowed into t he tank to again balance the scale, "F " is pushed again ; the distance between the two "F" arks represent 1 lb of water. Any other weight ay be placed on the scale balance, depending on the size of the tanks used. The process is continued until tank "B " is full; then valve "E" should be closed. The chart of recorder "R" will show three lines with offsets caused by the energizing of three electroagnets. Alongside the line with offsets ade by circuit "F,'' the distance between the representing 1 lb of water, will be the lines showing the contacts ade by eter "M " and t he t ie record in 2-, 1-, or 5-sec intervals, in accordance with the design of the contact-aking chronoeter. Fro these data ay be calculated the gallons of water per unit of tie for each contact or recording of the water eter. The sae recordings and calculations are
16 ILLINOIS ENGINEERING EXPERIMENT STATION Circ. 65. AN ELECTRIC RECORDING WATER METER 17 to be ade wi th different open in g of rnlye "E." (Figure 1 of Circular 52 shows the record of \rnter used.) A calibration graph for yarious \\ ater rates is ade,, ith seconds per contact as abscissa and gallons per contact as ordinate:::, as sho\yn in Fig.. Fro this graph, or an enl a rgeent of it, a calibration table siilar to T able 1 ay be prepared. 15 ' -..;: t:: (l 1., ::::: 5 - - _... _... i.,...- _... v...,,,... Seconds per Contact 2. 3. 4. 5. 6. 7.. 9. 1. 11. 12. 13. 14. 15. 16. 17. 1. 19. 2. Table 1 Calibration of Water Meler Gallons per Contact.9. 9 9.95 9. 27 9.5 9. 77 1. 5 1.35 1.665 11.3 11. 42 l l.2 12. 2 12. 1 13.35 13.93 14. 52 15. 14 15. 4 Electric counters operated by relays in the water eter circuit ay be used to give the nuber of contacts. The electri c counters are necessary, especially if the \Yater eter record is ade on a dynaoeter car chart which oves proportionally to the speed of the car, in order to know the nuber of contacts ade during layover periods. When easuring water during a locootive road test, there should be provided a pilot lap or signal in t he locootive cab to indicate to the engine crew when the eters are in operation so that when the injectors are shut off the electric circuit of t he water eter will not be in the "closed" position. For other than locootive installation, agnets and relays of electric circuits should be designed for continuous duty. 5 1 15 2 Seconds per Contact Fig.. Calibration Curve of Water Meter 12. Deterination of Water Used If the fl.ow of water is constant, as it usually is when the injectors are wide open and feeding water to a locootive boiler, or when boiler feed water pups (if they are used instead of inj ectors) are operating at a constant rate, the distance between offsets on the water record line will be unifor. The aount of water used during any desired period ay be found by deterining the tie in seconds between the offsets on t he water record line and finding fro the calibration curve or table the corresponding "gallons per contact." Multiplying the nuber of contacts by this constant will give the gallons of water used. However, if distances between offsets on the water record line are not equal, fairly accurate results have been obtained by calculating average seconds per contact for any period and finding gallons per contact for this value. i..._
IV. METER APPLICATIONS As has been stated (section ), this \rntcr eter is a special piece of equipent designed priarily to easure locootive boiler feed water under train operating conditions. The fact that a graphic recorder and tiing device arc necessary for its successful operation should liit its use to installations " here the conventional type eter would not be ;:afo:factory. Where a graphic record of " atcr or liquid flow is desired during a 24-hr cycle or any other period of tie, this eter could advantageously be applied. If the water rate is greater than approxiately 1, gal per hr, a larger eter should be constructed. Fig. 9. Water Meter Mounted on locootive 1