US1957825A - Boiler feed and low water cut-off - Google Patents

Description

May 8, 1934- c. N, FLAGG BOILER FEED AND LOW WATER CUT-OFF Filed June 30, 1932 ATTOR 0 a Y I mN W8 l 1H h C H R in L ME w MUM .n v. z w MEI! w Q 5 W5 1 4/0 1 I 8 .v 2 I w n Qw .C 1 -11 (\m -I 2 Z 3 O i- Patented May 8, 1934 1,957,825 BOILER FEED AND LOW WATER CUT-OFF Charles N. Flagg, Meriden, Conn.

Application June 30, 1932, Serial No. SZilJO't 10 Claims.

This invention relates to steam boilers, and more particularly to an apparatus for controlling the water feed and also for independently shutting oil the supply of heat in case of water failure.

A further object is to provide an apparatus of the above nature including a float chamber communicating with a boiler and a bell-crank lever located outside said chamber and having one arm thereof extending into a flexible tube sealed within the chamber and located in alinement with the float lever.

A further object is to provide a device of. this nature which will be simple in construction, inexpensive to manufacture, easy to install and manipulate, compact, and very eflicient and durable in use. 1

With these and other objects in view there has been illustrated on the accompanying drawing, one form in which the invention may be con veniently embodied in practice.

In the drawing:

Fig. 1 represents a front elevation of a boiler feed and low water cut-off apparatus embodying the invention, certain parts being broken away to show the interior construction.

Fig. 21s a diagrammatic view showing the invention installed upon a steam boiler. I

Fig. 3 is a fragmentary longitudinal sectional view of the flexible tube surrounding the inner arm of the switch operating bell-crank lever.

In previous devices for this purpose, the low water cut-ofi mechanism was either in direct contact with the float arm at all times, or sealed within a bellows, the deflection of which required the use of an exceptionally large ball float to operatethe mechanism. In the present invention the above and other disadvantages have been eliminated.

Referring now to the drawing in which like reference numerals denote corresponding parts throughout the several views, the numeral 10 in-= dicates generally a boiler feed and low water cut-off apparatus adapted to be attached to a boiler 11 at substantially the same height as a gauge glass 12 for indicating the level of the water within the boiler.

The boiler feed mechanism 10 consists generally of three units; a float chamber 13, a water feed valve 14, and a float controlled switch-operating mechanism 15.

The float chamber 13 is provided with a pair of upper and lower tapped bosses 16 and 1'7 within which may be fltted the pipes 18 and 19 for con= necting the float chamber to the boiler 11. By means of this construction, the water level in said float chamber 13 will always be responsive to that in the boiler.

The end of the float chamber 13 is provided with a detachable flanged cover member 20. Located within the chamber 13 is a ball float 21 which is adapted to be buoyed up by the water within said chamber 13. The ball 21 is secured to the end of a swinging float' lever 22 pivoted by means of a horizontal rod 23 to the upper end of a hollow valve casing 2% forming an integral part of the main valve 14 and extending upwardly into the float chamber 13.

The feed valve 14 is connected to any suitable water supply by means of a lower horizontal intake pipe 25 and is provided with a vertical bottom outlet pipe 26 leading to the boiler 11, as shown in Fig. 2.

In order to open and close the feed valve 14 -when the level of the water in the boiler rises and falls within predetermined limits, the valve casing 24 is provided with a tubular release chamber 27 leading into the feed valve 14, and having a restricted valve seat 28 at its upper end. The valve seat 28 is adapted to be closed by means of a small pilot valve plug 29 having a cam follower roll 30 attached to its upper end. The follower roll 30 is fitted within an arcuate cam slot 30a formed within the lower end of the float lever 22. For the purpose of shutting off the supply of heat to the boiler, such as a motor operated oil burner 31 controlled by the switch operating mechanism 15, in case the water should fail to be supplied to the boiler for any reason, provision is made of a'bell-crank lever 32 adapted to be raised for opening the switch when the float falls to the danger point below the feed control limits. The lower end oi" the float lever 22 is provided with an offset arm 33 which may have a friction roller 34 pivoted to its outer extremity.

The float chamber 13 is provided with an integral rearwardly offset conical housing 35 having a pair of tapered parallel lugs 36 on its outer end. A fulcrum shaft 37 is suspended between the ends of the lugs 35 for pivotally supporting said bell-crank lever 32 therebetween. One arm 38 of the bell-crank lever 3'? is made straight and is surrounded by a flexible convoluted tube 39 sealed into the outer end of the threaded hollow plug 40, as by soldering, having an end opening 41 through which passes crank lever 32.

The plug 40 is adapted to be tightly screwed into a tapped hole 4011 provided in the end of the conical housing 35. The inner end of the tube 39 is similarly secured to one end of a flanged the arm 38 of the bellcap 42 slidably fitted over the inner end of the arm 38. As shown in Fig. l, the cap 42 is located above and spaced from the roller 34 of the float lever 22- but is adapted to be engaged by said roller to swing the arm 38 upwardly when the water level in the boiler drops below the danger line;

As most clearly shown in Fig. 3, the adjacent convolutions 01' the tube 39are adapted to lie in contact with each other so that, while the tube will offer no resistance to the free lateral swinging of the arm 38 of the bell-crank lever, the tube will be longitudinally incompressible at any pressure to which the apparatus is likely to be subjected. The tube will, therefore, exert no pressure upon the fulcrum of said lever. This feature constitutes an important advantage over previous devices where the pressure in the boiler increased the friction on the operating parts and tended to render the operation sluggish and unreliable.

The bell-crank lever 32 is also provided with a curved arm 43 located outside the conical housing 35 and the extremity of said curved arm has an abutment head 44 adapted to engage against a flanged head 45 forming the lower end of a vertical plunger rod 46. The rod 46 extends upwardly into the switch box 15a and is adapted to actuate the electric switch mechanism contained therein.

The switch box 15a is supported upon a bracket 47 secured to the float housing 13 by means of screws 48. The curved arm 43 of the bell-crank lever 32 and its cooperating mechanism is enclosed within a dust-excluding guard member 49. The switch box 15a is electrically connected to the motor operated oil burner 31 or other fuel supply mechanism by means of a pair of electrical conductors 50 and 51. Current is adapted to be supplied from any suitable source by means of a pair of wires 52 and 53, the wires 51 and 52 being suitably connected to the switch contacts located within, said switch box 15a.

Operation In operation, when the float ball 21 falls within the chamber- 13, the pilot valve plug 29 will be lifted from the restricted valve seat-28. This action will permit a small amount of water to escape from the release chamber 27, and by an interior diaphragm operated mechanism not shown, will cause the feed valve 14 to open and admit water into the boiler. When the water level in the boiler has again risen to the desired point, the rising of the float 21 will close the release valve and shut off the supply of water to the boiler 11.

If, however, the water supply should fail or the feed valve should not operate, causing the water level in the boiler and float chamber 13 to drop to the danger point, the friction roller 34 carried on the end of the float lever 22 will rise and strike the cap 42, thus swinging the bellcrank 32 in a clockwise direction. This action will force the plunger rod 46 upwardly against the compression spring 54, thereby opening the switch 15a, and thus shuttingoif the supply of heat to the boiler.

It will be understood that the water level control apparatus is operated by the float lever 22 entirely independently from the operation of the low water cut-off mechanism.

It is to be further understood that by arranging the arm 38 of the bell-crank'lever out of contact with the float lever under normal conditions, no resistance will be offered to the free operation oi chamber, a flexible tube encasing said other arm the float 21 except under the abnormal conditions when the water level has fallen to the danger point. I

It will be further noted that when such an emergency arises, the float lever 22 will be located at the position of greatest leverage, and the full Power of said float 21 will be applied for operating the switch.

While there has been disclosed in this specification one form in which the invention may be embodied, it is to be understood that this form is shown for the purpose of illustration only, and that the invention is not to be limited to the specific disclosure but may be modified and embodied in various other forms without departing from its spirit. In short, the invention includes all the modifications and embodiments coming within the scope of the following claims.

Having thus fully described the invention, what is claimed as new, and for which it is desired to secure Letters Patent, is:

1. In a boiler feed apparatus, a float chamber connected to a boiler, a float in said chamber, a pivoted lever connected to said float, means for controlling the supply of heat to said boiler, said means having'a movable operating member, a lever having one arm engaging said member, the other arm of said lever extending within said i-ll and forming a water tight seal, said tube having a slidable head on its inner end, said head being in alinement with said float lever, whereby the falling of said float below the danger level will actuate said means to cut oil. the supply of heat to the boiler. l 2. In a boiler feed apparatus, a float chamber connected to a boiler, a float in said chamber, a pivoted lever connected to said float, means for controlling the supply of heat to said boiler, said means having a movable operating member, a l lever having one arm engaging said member, the other arm of said lever extending within said, chamber, a laterally flexible tube encasing said other arm and forming a water tight seal, said tube having a flanged cap for slidably receiving 1 the end of said other arm, said cap being in alinement with said float lever whereby the falling of said float below the danger level will actuate said means to cut ofi the supply of heat to the boiler.

3. In a combination boiler level control and 1 low water cut-off apparatus, a float chamber having a float operated lever housed therein, a water level controlling float-operated valve located in said chamber and connected to said float lever, a fuel shut-off lever pivoted outside of said chamber and having an arm extending into said chamber into alinement with said float-operated lever but normally out of contact therewith, said arm being adapted to be engaged by said floatoperated lever when the water level falls below a predetermined danger line, a sealing bellows closed at its inner end surrounding said arm and extending into said chamber.

4. In. a combination boiler level control and low water cut-off apparatus, a float chamber having a float operated lever housed therein, a water level controlling float-operated valve located in said chamber and connected to said float lever, fuel shut-oil lever pivoted outside of said chamher and having a sealed arm extending into said chamber into alinement with said float-operated lever but normally out of contact therewith, said arm being adapted to be engaged by said floatoperated lever when the water level falls below extending into said chamber and being closed at arm comprising a laterally flexible longitudinally incompressible tube closed at its inner end surrounding said arm and extending into said chamber.

5. In a combination boiler level control and low water cut-off apparatus, a float chamber having a float operatedlever housed therein, a water level controlling float-operated valve located in said chamber and connected to said float lever, a fuel shut-off lever pivoted outside of said chamber and having a sealed arm extending into said chamber into alinement with said float-operated lever but normally out of contact therewith, said arm being adapted to be engaged by said float-operated lever 'when the water level falls below a predetermined danger line, the seal for said arm comprising a laterally flexible metal tube extending into said chamber and being closed at its inner end.

6. In a cfimbination boiler level control and low water cut-01f apparatus, a float chamber having a float operated le.er housed therein, a

water level controlling float-operated valve located in said chamber and connected to said float lever, a fuel shut-off lever pivoted outside of said chamber and having a sealed arm extending into said chamber into alinement with said floatoperated lever but normally out of contact therewith, said arm being adapted to be engaged by said float-operated lever when the water level falls below a predetermined danger line, the seal for said arm comprising a longitudinally incompressible laterally flexible metal tube extending into said chamber and being closed at its inner end.

'7. In a combination boiler level control and low water cut-off apparatus, a float chamber having a float operated lever housed therein, a water level controlling float-operated valve located in said chamber and connected to said float lever, a fuel shut-off lever pivoted outside of said chamber and having a sealed arm extending into said chamber into alinement with said floatoperated lever but normally out of contact therewith, said arm being adapted to be engaged by said float-operated lever when the water level.

falls below a predetermined danger line, the seal for said arm comprising a longitudinally incompressible corrugated laterally flexible metal tube its inner end.

8. In a boiler feed apparatus, a chamber connected to aboiler, a float-operated lever in said chamber for controlling the feed of water to said boiler to normally maintain the water level in the boiler between predetermined limits, a fuel cutoff bell-crank lever pivoted outside of said chamber and having one arm extending into said chamber through an opening into alinement with said float operated lever, means for sealing said opening surrounding said arm and extending into said chamber, said arm being normally out of contact with said float-operated lever but adapted to be engaged thereby when the water level falls below the danger line in case of failure of the water supply or feed apparatus.

9. In a boiler feed apparatus, a float chamber connected to a boiler, a float-operated lever pivotally mounted in said chamber, a feed valve mechanism operated by the falling of'said float below a predetermined limit to control the water level in'said boiler, means for heating said boiler, a bell-crank lever for controlling said means, said bell-crank lever being pivoted outside said chamber and having one arm extending into said chamber, a tubular bellows closed at its inner end surrounding said arm, and means to cause the float-operated lever to strike said arm when the water level falls below said predetermined limit to shut oif said boiler heating means. i

10. In a boiler feed apparatus, a float chamber connected to a boiler, a float-operated lever pivotally mounted in said chamber, a feed valve mechanism operated by the falling of said float below a predetermined limit to control the water level in said boiler, means for heating said boiler, a bell-crank lever for controlling said means, said lever having one arm extending into said chamber, a laterally flexible longitudinally incompressible metal tube closed at its inner end surrounding said arm, and means to cause the floatoperated lever to strike said arm when the water level falls below said predetermined limit to shut off said boiler heating means, the operation of said bell-crank lever being unaffected by the

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