'•*■ ■yyi'y '■■.'■,•- I 



86 



The Weekly Florists^ Review* 



Mat 31, 1906. 



this pressure limit trouble is encoun- 

 tered in returning the water to the 

 boiler. 



It is, however, necessary to have a 

 temperature of 212 degrees in the heat- 

 ing coils under this system in order to 

 free the system from air, which must be 

 forced out against the atmosphere. Thia 

 temperature is often more than required, 

 but cannot be reduced without entirely 

 shutting off. 



One very strong point in favor of 

 steam heat is that in case of overheating, 

 or when artificial heat is not needed, the 

 system will cool down in a very short 

 time after steam is shut off. 



A Perfect System. 



From these analyses of hot water and 

 gravity steam there are good and bad 

 points to be found in each. "While water 

 can be used through a wide range of 

 temperature and is flexible to the ordi- 

 nary demands of outside temperature, it 

 is slow to respond to emergencies. Steam 

 will respond quickly to urgent demands, 

 but has no very wide range of tempera- 

 ture. 



A perfect system of heating, one that 

 will conform to the requirements of flexi- 

 bility and demand, and that will secure 

 practically a uniform temperature, must 

 necessarily combine the most important 

 points of these two systems and be free, 

 as far aa possible, from their objection- 

 able features. 



After making a study of heating sys- 

 tems for several years, I feel that 

 vacuum steam heating and automatic 

 heat regulation combine, as nearly as 

 possible the best elements of the two 

 systems above described. Through them 

 are secured the economy, flexibility and 

 quick action necessary to conform to 

 the demands and conditions of green- 

 house heating. 



The Vacuum System. 



As may be learned from any steam 

 table in a text-book, water will boil or 

 vaporize at 212 degrees at the sea level 

 and at atmospheric pressure, and at 98 

 degrees in a perfect vacuum. It follows 

 that if confined in a vacuum of any de- 

 gree water will boil at a corresponding 

 temperature. 



In the ordinary vacuum heating sys- 

 tem the steam, after condensation in an 

 ordinary radiator or coil, is discharged 

 as water from that coil through a 



vacuum valve that is supposed only to 

 allow the water of condensation and air 

 to escape. This discharge is into a par- 

 tial vacuum, as the entire return sys- 

 tem is under this partial vacuum which 

 is produced by a pump at the end of a 

 return line. 



In the compound system we conduct 

 the water of the condensation through a 

 secondary coil or radiator that contains 

 the same partial vacuum as the return 

 system, and so utilize the heat of this 

 vapor in giving out heat to this sec- 

 ondary coil. With this system it is not 

 necessary to carry any steam pressure 

 on the heating system, as, when the 

 weather is moderate, steam at one-half 

 pound to one pound below atmosphere 

 can be carried and a perfect circulation 

 secured at n correspondingly lower heat. 

 The vacuum pump always removes the 

 air and water, so that every square inch 

 of radiating surface is heating surface. 



The steam mains can be considerably 

 smaller than for gravity steam or for 

 hot water. The return pipes are very 

 much smaller than with either steam or 

 water systems. 



It is not necessary to carry return 

 pipes back under ground, as they can 

 as well be carried overhead. No air 

 valves are needed. 



In case of emergency steam at any 

 pressure up to twenty-five pounds (265 

 degrees) can be used and can be secured 

 on a moment's notice, as the boiler pres- 

 sure will be about that all of the time. 

 The pressure needed in the system regu- 

 lated by a reducing valve as required 

 usually is lees than one pound pressure 

 (212 degrees). The temperature of the 

 secondary coil is from 170 degrees to 

 195 degrees, according to the vacuum 

 carried. 



It ia not necessary to have any coil 

 either entirely free of steam or com- 

 pletely full, as the vacuum pump in keep- 

 ing the coils free of air and water, the 

 steam valve can be opened to admit only 

 sufScient steam to heat as much or little 

 of the coil as desired. 



Automatic Resulation. 



I have also an automatic heat regula- 

 tion that gives much closer and more 

 economical results than are possible by 

 hand regulation. Also, being on guard 

 all of the time, is always ready to 

 take care of any conditions that may 

 come up. Owing to the quick change 



secured by the steam in the radiating 

 surfaces, an approximately uniform tem- 

 perature is secured, according to the 

 temperature the thermostat is set at. 



The sun may break through the clouds 

 fifty times a day and give sufficient heat 

 for a few minutes that would result in 

 overheating if the artificial heat were 

 used at the same time. With the auto- 

 matic regulation this heat ia shut off 

 before any overheating takes place and 

 remains off as long as the outside tem- 

 perature ia maintaiueu. 



The thermostat keeps close watch of 

 the thermometer, and, when the proper 

 temperature is secured, immediately 

 closes the steam valves on the coils. 

 They lemain closed until the thermometer 

 shov o th3 temperature to be dropping, 

 when the valves are opened again. This 

 is constant and continues while the sys- 

 tem is in operation. 



A RHODE ISLAND PLANT. 



The accompanying illustration is re- 

 produced from a photograph of M. J. 

 Leach & Sons' greenhouse establishment 

 at Pawtucket, K. I. Located upon a 

 plot of ground over 100 acres in extent, 

 on the outskirts of the city and on a 

 direct line to Attleboro and Taunton, 

 it is indeed an ideal place — all that a 

 grower could possibly desire. 



Ten modern, good-sized greenhouses 

 of comparatively recent construction, 

 comprising about 40,000 feet of glass, 

 with everything else about the place in 

 the best of condition, are under the 

 direct care and management of M. J. and 

 Edward Leach. The store, at 20 Broad 

 street, is presided over by Herbert Leach. 



Although a general stock is grown for 

 their retail trade, roses and carnations 

 constitute their specialties. As a matter 

 of course, only the best varieties find 

 house room here — anything of question- 

 able behavior ia never given a second 

 chance. In the words of Mr. Leach, Sr., 

 < ' time is too short and room too valuable 

 to give to experiments." 



Mr. Leach is one of those progressive 

 growers, who, regardless of their own 

 wide experience, acquired during a 

 period of years at no small expense, are 

 ever ready to add to their store of 

 knowledge by exchanging {views with 

 their fellow-craftsmen along all lines 

 pertaining to floriculture. X. 



Eitablishment of M. J. Leach & Sons, Pawtucket, R. L 



