Document b51mdzGzgZr8K42p8d7GyrZNy

[| i1 : : .. PLANT-TESTED IDEAS r TO . .SOLVE 'PROBLEMS . OF 0ESIGN,N0PERATI0tr.AND;.MAINTENANCE1 - 4A Circuit diogram of photoelectric and hot-cathode tube, i A Circuit diagram of photoelectric end hot-colhode 1 1 m As long as light does not reach tube, no current flows I V When light beam fells on photo tube's coihode.currentft Aspirator mirror. The mirror reflects the beam toward another prism. When the beam leaves thia prism it is going in a direc tion opposite to that when it left the lamp. Most optical systems are not so complicated, but this one shows thot, by proper use of lenses, prisms and mirrors, a light beam can be deflected in any direction. RofreeNo*. Refraction bends the light beam. A good example is passage of a light beam through a water column, Fig. 4. Hero woter bends the beom to fall on the cathode of the photoelectric tube, which bolds a relay open to pre vent water flow into the boiler or other vessel. When the water In tho column drops below tbo light beam, Fig. 5, the beam atraightena and goea above tho tube's cathode. This condition permits the relay u> close and open the valve in the water line or start the teed pump to restore the water levels. Amount of light falling on a photo.eiectrle tube's cathode is also voried in its intensity. One of these applications U a photoelectric relay turning on lights when natural lighting Intensity goes below o fixed minimum and turns them off with the natural source above a pre determined level. A photoelectric pyrometer is respon sive to the radiant-heat energy from tho material in a furnace or kiln. Thia heal can thus be made the means of regulat ing the temperature of the materiel or other related factors in the furnace. Color changes in lights, another form tically the same, point B, Increiw of changing light, intensity, also operate anode volts beyond 20 causes j photoelectric systems. These era ap cally no increase in current flow it plied to control chemical processes in which color changes are critical. Flame Intensity. Flame-failure safe vacuum tube. In the gas-filledff however, current increases rapidljf at 90 v it is 54 microamperes,' poijj guards may be considered as operating A similar relation exists betwestj on flame intensity, even though the only in lumens reaching the cathode siw lime they are called upon to function is croampere flow through the tubix when the flame goes oul This is simi curves, Fig. 11, show this relstiou lar to obstructing the light to the photo about 90 anode volts. With 0-3-Jr electric lube. beamed to the cathode, current C A photoelectric scanning system is sot about 4 microamperes in the t up so light from tho flame is focused tube, point A, and 18 miefoampeflj through a lent on the tube's cathode, the gas-filled tube, point B. Fig. 6. As long as the flame bums, lumens, current flow is 8 microeoj^ photoelectric protective system holds for the vacuum tube, point C, a tho fuel valve open. If fuel supply to microamperes in Ihe gns-fiUed| the burner foils the flame goes out. Then point D. ,t the photoeleclrio system permits the Current flow in the gas-filled-i fuel valve to close and it will not open electric tube increases for tbafl again until operated manually. reason as in the hot-cathode tubejj Photo-electric Tube Current. Consider ' Power, pp 108-112). Electrons e some elementary circuits In which from the cathode collide with gaiJ photo-electrio tubes are used. Fig. 7 and knock one or more electros*j shows the symbol for a vacuum Fig. 8 them. As a result, number of (n> tho symbol for a gas-filled tube. Tho irons is greatly increased in t dot. Fig. 8, indicates gas as in hot- between cathode and anode. cathode tubes. As previously mentioned. Atoms that lose one or more e Ailing the tube with gas at low pressure become positively charged J_ increases the current Row, particularly ions neutralize most of the at elevated voltages, as shown by the pace charge effect that exists^ curves in Fig. 10. high-vacuum tube, and peta For example, with one lumen of light electrons to reseh the anode, flux on cathode of the photoelectric tube lion combined with a Urge in*1 and 20 v. applied to enode, current flow free electrons produces o large b&jj is about 11 microamperes, point A. in current flow through the tiun With a gas-filled tube results are prac (Continued on page 1#)| 104 (556) POWER Sepl**1' SIMPLE ASPIRATORS REDUCE CO. IN MAKEUP WATER [Because op the proximity of a paper plant using large quantities of chemi cals a Southern utility plant foond its porfaee-watsr supply contained about ^ to 80 ppm of CO Several methods if reducing this concentration were led,with varying success. Spraying the toning makeup water through a &la- pipe, drilled with 200 %-in. holes, gad-Uttle effect. Investigation of spray wtr* and troughs proved they were $6 Coitly. * Another method that was tested In troduced compressed air into the. water through a series of holes in a copper tube. Results wero good, reducing COi by 70%, but this setup required run ning the air compressors 24 hr a day. - The present method was then de vised, the design being based on a sueeesaful type of ejector chlorinator. Three ejectors or aspirators were built up of fittings and hooked up os shown in tho above sketches. The mokeup wa ter flowing through the supply line enters the vertical l-ln. pipe. The stream leaving this short section of pipe aapiratea air from the atmosphere through the open branch end of the tee. Tests have shown a reduction in CO, content of $0 to 60%. Further advan tages of this system ere (1) no atten tion required (2) no maintenance needs (3) zero operating cost. Mechanical agitation would be of added value. Dalton Wiute Atlanta, Go. proper Expansion Loop jHmlnatos Steam Leaks J'UNt is nrreo with e buried oil tank and two 500,000-gal oil- r*8 fcokB- To reduce oil viscosity, tanks are provided with oil VVh supplied from a 1%-ln. steam lank had a direct end connection l0 this steam line as !? *i ^ter the first lew * tli .Opera^on> {he tee connection im i l developed pronounced jij T4*46, leaks were re- St.1" h onlr . of . **k,e the same trouble arose < 1 MMm-.upplr [-,1 'roubla, rodeiign 0( the V ' "> talto proper c count of this movement. This was ac complished by the rearrangement shown at right, which called for- only a few extra lengths of pipe and two elbows. This loop has been operating for two years without trouble. * Jonh R Baowtr Baiua, Cuba . (Continued on page 106) 1948 (SS7) 103