CA1176915A - Apparatus for reciprocating the feed ram in a furnace or the like - Google Patents
Apparatus for reciprocating the feed ram in a furnace or the likeInfo
- Publication number
- CA1176915A CA1176915A CA000386435A CA386435A CA1176915A CA 1176915 A CA1176915 A CA 1176915A CA 000386435 A CA000386435 A CA 000386435A CA 386435 A CA386435 A CA 386435A CA 1176915 A CA1176915 A CA 1176915A
- Authority
- CA
- Canada
- Prior art keywords
- shroud
- piston rod
- motor
- cylinder
- clearance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000012530 fluid Substances 0.000 claims description 15
- 239000000446 fuel Substances 0.000 claims description 12
- 230000033001 locomotion Effects 0.000 claims description 9
- 230000001681 protective effect Effects 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims 1
- 239000012535 impurity Substances 0.000 abstract description 3
- 239000000543 intermediate Substances 0.000 description 16
- 239000007788 liquid Substances 0.000 description 13
- 239000000126 substance Substances 0.000 description 10
- 238000005192 partition Methods 0.000 description 9
- 238000002485 combustion reaction Methods 0.000 description 8
- 239000000463 material Substances 0.000 description 8
- 230000035515 penetration Effects 0.000 description 7
- 239000007787 solid Substances 0.000 description 7
- 239000000356 contaminant Substances 0.000 description 5
- 230000002939 deleterious effect Effects 0.000 description 5
- 230000004044 response Effects 0.000 description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 4
- 229910052804 chromium Inorganic materials 0.000 description 4
- 239000011651 chromium Substances 0.000 description 4
- 230000006378 damage Effects 0.000 description 4
- 239000000428 dust Substances 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 239000003518 caustics Substances 0.000 description 3
- 235000002918 Fraxinus excelsior Nutrition 0.000 description 2
- 239000002956 ash Substances 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000012856 packing Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000000149 penetrating effect Effects 0.000 description 2
- 230000002028 premature Effects 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 238000010008 shearing Methods 0.000 description 2
- UYIFTLBWAOGQBI-BZDYCCQFSA-N Benzhormovarine Chemical compound C([C@@H]1[C@@H](C2=CC=3)CC[C@]4([C@H]1CC[C@@H]4O)C)CC2=CC=3OC(=O)C1=CC=CC=C1 UYIFTLBWAOGQBI-BZDYCCQFSA-N 0.000 description 1
- 241001052209 Cylinder Species 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000004200 deflagration Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- -1 excessive heat Substances 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 239000004449 solid propellant Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000010902 straw Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K3/00—Feeding or distributing of lump or pulverulent fuel to combustion apparatus
- F23K3/16—Over-feed arrangements
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Pistons, Piston Rings, And Cylinders (AREA)
- Actuator (AREA)
- Incineration Of Waste (AREA)
- Furnace Charging Or Discharging (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A horizontal fluid-operated motor wherein the foremost end of the horizontal piston rod is connected with the feed ram of an incinerator and with the front end portion of a hollow tubular shroud which spacedly surrounds the piston rod in each axial position of the latter and whose rear end portion permanently surrounds but is movable axially of the cylinder of the motor. The cylinder and the shroud define a narrow ring-shaped clearance which admits air into the interior of the shroud when the piston rod performs a forward stroke and which permits expulsion of air from the interior of the shroud when the piston rod performs a return stroke whereby the outflowing air entrains impurities which might have penetrated into the shroud. The shroud extends, without any or with minimal clearance, through the opening of a transverse wall at the front end of the cylinder.
A horizontal fluid-operated motor wherein the foremost end of the horizontal piston rod is connected with the feed ram of an incinerator and with the front end portion of a hollow tubular shroud which spacedly surrounds the piston rod in each axial position of the latter and whose rear end portion permanently surrounds but is movable axially of the cylinder of the motor. The cylinder and the shroud define a narrow ring-shaped clearance which admits air into the interior of the shroud when the piston rod performs a forward stroke and which permits expulsion of air from the interior of the shroud when the piston rod performs a return stroke whereby the outflowing air entrains impurities which might have penetrated into the shroud. The shroud extends, without any or with minimal clearance, through the opening of a transverse wall at the front end of the cylinder.
Description
11~7tj91S
The present invention relates to incinerators and other types of furnaces in general, and more particularly to improvements in fluid-operated motors (single-acting or double-acting cylinder and piston units) which can be utilized to transmit motion to reciprocatory fuel feeding means in such installations. Still more particularly, the invention relates to improvements in means for shielding or protecting the piston rods of fluid-operated motors against jamming, premature wear, extensive wear, con-taminants, excessive heat, corrosive substances and/or a combination of such undesirable influences.
United States Patent No. 3,559,823 granted February 2, 1971 to Ostrin discloses a ram feed for incinerators wherein a hydraulically operated ram advances batches of scrap material supplied by an upright hopper and tamped by a vertically reciprocable packing piston. The admission of scrap material into the path of the ram takes place when the latter is held in the retracted positlon, and the front end portion of the ram carries a shearing head which cooperates with a shearing edge on the outlet of the supply hopper to comminute coarser or larger pieces of scrap material prior to admission into the lncinerator. In order to protect the cylinder, the ram constitutes an elongated tube (i.e., it has a skirt) which slides within a rearward extension of the supply conduit that delivers scrap material to the incinerator proper when the ram performs a forward stroke. The tubular or cylindrical portion or skirt of the ram is very long so as to practically or completely confine the cylinder in the retracted position of the ram.
Such ram further offers a pronounced resistance to tilting and other stresses. The piston rod of the cylinder is attached to the inner side of the front end wall of the reciprocable ram, and the length of the ram suffices to reduce the likelihood of penetration of scrap material there-behind, i.e., scrap material which descends from the hopper (either by gravity or under the action of the aforementioned packing piston) is unlikely to reach the cylinder. A body of liquid is maintained in the lower part of the upwardly sloping supply conduit to establish a seal between the incinerator and the cylinder. In order to prevent the body of liquid ., -1- ~
11~76915 (normally water) from penetrating into the incinerator when the ram performs a forward stroke, the upper side of the ram has a longitudinally extending external groove which allows the displaced liquid to flow rearwardly by gravity, and such liquid is allowed to penetrate behind the ram, i.e., it can contact the cylinder of the hydraulic motor. Furthermore, the liquid (which contains numerous contaminants and often also contains highly corrosive substances) can reach and contact the piston rod so that the latter undergoes pronounced and rapid wear, especially if the nature of ingredients of the sealing liquid is such that they can readily attack the external layer (normally chromium) of the piston rod. The skirt of the ram surrounds the cylinder (and hence the piston rod) with substantial clearance 80 that the piston rod is likely to be contacted by large quantities of liquid which contains dirt, scraps of foodstuffs, particles of metal, glass or the like as well as other corrosive or otherwise aggressive substances which reduce the useful life of the piston rod.
German Offenlegungsschrift No. 28 21 767 published on November 22, 1979 discloses a modified incinerator wherein the liquid seal is omitted so that the piston rod of the hydraulic cylinder is less likely to be con-tinuously exposed to the corrosive and/or other deleterious influences of a contaminated liquid. The apparatus of this German publication is designed to feed straw into the furnace and uses a ram with a relatively long skirt which is dimensioned to surround the cylinder with a pronounced clearance so that it cannot prevent aggressive gases from penetrating into contact with and from attacking the external surface of the piston rod.
Each of the aforediscussed conventional incinerators exhibits the drawback that the piston rod of the (normally hydraulically operated) cylin-der is subject to pronounced corrosive and other influences so that its useful life is rather short. The likelihood of rapid corrosion is even more pronounced if the strokes of the piston rod are not constant, i.e., if the piston rod is held in partially retracted or partially extended position for relatively long intervals of time. Such situation can arise at the end of a shift. The exposed portion of the piston rod is then subject to unint~r-llt7tj9ls rupted attack by solid, gaseous and/or liquid contaminants so that its external surface (which, as a rule, is the external surface of a layer of chromium or a like metal) is destroyed, either entirely or in part, and the chromium layer begins to peel off the core or central portion of the piston rod. In many instances, the defects appear in the form of spots where the chromium layer begins to become separated from the layer therebelow, and --such spots rapidly merge into larger zones of defective external surface on the piston rod. The resulting and in part very sharp irregularities at the exterior of the piston rod cause rapid destruction of the seal through which the piston rod extends into the interior of its cylinder.
Another drawback of prolonged exposure of a portion of the piston rod to external influences is that the film of oil on the exposed external surface of the piston rod accumulates fragments of dust and/or other foreign matter which tend to cake, especially at elevated temperatures to which the piston rod is or may be subjected when the fluid-operated moto~ is used in a furnace or the like. The caked foreign matter at the exterior of the piston rod also contributes to or initiates and completes rapid destruction of the seal through which the piston rod extends into the interior of the cylinder.
When the fuel feeding unit of a furnace is actuated by a hydraulically or pneumatically operated motor in the form of a cylinder and piston unit, the length of the piston rod often exceeds the length of working or return strokes of the piston in the interior of the cylinder. This means that a portion of the piston rod is always exposed. If the piston rod is not retracted to the maximum permissible or possible extent, i.e., if the piston is not held in the rearmost position within the confines of its cylinder while the motor is idle for an extended period of time (such as over a weekend or even during a longer interval of time when the furnace is idle for any one of a number of reasons including a strike, the absence of combustible material, vacation period, extensive repair work and/or others), the seal surrounding the piston rod is highly likely to be destroyed in response to initial or repeated retraction of the piston rod when the motor is put to renewed use. Moreover, the provision of relatively large clear-i17~91S
ances between the skirt of the ram on the one hand and the piston rod and cylinder on the other hand renders it possible and quite likely that a combustible gaseous, solid and/or liquid substance in such clearance catches fire while the motor is idle so that the resulting heat causes total or practically total destruction of the piston rod, of the cylinder or both.
SUMMARY OF THE INVENTION
An object of the invention is to provide a novel and improved fluid-operated motor which can be used in or in connection with furnaces or the like and which is constructed and assembled in such a way that it is less likely to be rapidly and extensively affected by gaseous, liquid and/or solid contaminants, corrosive substances or the like, even after extensive periods of non-use.
The invention provides a fluid-operated motor, particularly for reclprocating the fuel feeding means of a furnace, comprising an elongated cylinder; a piston rod axially movable in said cylinder to perform working and return stroke6 and having a foremost end located externally of said cylinder in each axial position of said piston rod; and a hollow tubular protective shroud having an end portion sealingly secured to the foremost end of said piston rod and a second portion surrounding said cylinder and defining therewith a narrow clearance in each axial position of said piston rod.
The shroud should effectively shield the piston rod from dirt, dust, fuel and/or other undesirable influences, as well as effectively shield the piston rod and/or other parts of the motor from excessive heat. The useful life of the sealing means between the piston rod and the cylinder is a multiple of useful life of seals in heretofore known motors.
The motor can be used in existing incinerators and/or other types of furnaces as a superior substitute for heretofore known motors.
The narrow clearance between the second portion of the shroud and the cylinder admits air into the interior of the shroud while the piston rod performs a working stroke and permits air to escape from the interior of the shroud (together with dust and/or other foreign matter) in response to il~7691S
retraction of the piston rod into the cylinder. The latter may be of the single-acting or double-acting type.
If the rate of admission of air into the interior of the shroud by way of the aforementioned clearance does not suffice, or if such clearance is likely to be clogged from time to time, the motor can further comprise a conduit or other suitable means for admitting a gaseous fluid into the interior of the shroud intermediate the end portion and the second portion thereof. The fluid admitting means may comprise a nozzle which is disposed in the interior of the shroud and serves to spray or otherwise discharge gaseous fluid into the intermediate portion of the shroud, i.e., into the portion between the end portion and the second portion.
In order to prevent tilting or other undesirable changes in orientation of the shroud in response to reciprocation of the piston rod, the motor can be provided with means for guiding the shroud while the latter shares the axial movements of the piston rod. Such guiding means may com-prise one or more supporting rollers which contact the underside of the exterior of the intermediate portion of the shroud if the shroud and the picton rod are mounted for reciprocatory movement along a substantially horizontal path.
The motor can further comprise a transversely extending protective wall or partition which is disposed in the region of the foremost end of the cylinder (i.e., at that end of the cylinder beyond which the piston rod extends), and such partition is provided with an opening through which the intermediate portion of the shroud extends, either sealingly or with a minimal or small clearance.
If the foremost end of the piston rod is connected with a sub-stantially horizontal ram which has a top wall, the top section of the shroud is preferably located at the level of (i.e., exactly flush with) or slightly below the top wall of the ram.
As mentioned above, the second portion of the shroud can constitute the rear end portion of such part, and this second or rear end portion may constitute or comprise an end wall extending substantially radially of the cylinder and defining an opening which receives the cylinder with the aforementioned clearance. The motor can comprise one or more components (e.g., pipes which supply or evacuate gaseous or hydraulic fluid from the interior of the cylinder) which are adjacent to the external surface of the cylinder; the opening of the end wall of the shroud is then configurated in such a way that the aforementioned clearance can constitute a circumferential-ly complete clearance also extending around the pipe or pipes or analogous components at the exterior of the cylinder.
The intermediate portion of the shroud may have a polygonal cross-sectional outline, and the length of the shroud (namely, the length of the shroud between the end portion and the second portion thereof) preferably exceeds the maximum length of forward or return strokes of the piston rod.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved motor itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.
FIGURE 1 is a schematic fragmentary vertical sectional view of a furnace which can utilize the fluid-operated motor of the present invention;
FIGURE 2 is an enlarged fragmentary view of a detail of the furnace shown in FIGURE 1 and a longitudinal vertical sectional view of the improved motor whose piston rod is coupled to the fuel feeding ram of the furnace; and FIGURE 3 is a transverse vertical sectional view as seen in the direction of arrows from the line III-III of FIGURE 2.
FIGURE 1 shows a portion of a furnace having a chute or hopper 1 which feeds fuel in front of a reciprocable ram 3. When the ram 3 performs a forward stroke (in a direction to the right, as viewed in FIGURE 1), it pushes a supply of fuel (i.e., scrap material, coke, coal or a combination of two or more types of fuel) over a ledge 2 and onto the grate (not shown) of the combustion chamber 101.
` 117~915 The motor which reciprocates the ram 3 in the directions indicated by the double-headed arrow 3A of FIGURE 1 is illustrated in detail in FIGURES 2 and 3. This motor is assumed to be a double-acting hydraulic cylinder and piston unit having a substantially horizontal cylinder 4 secured to the frame F of the furnace by a horizontal pin 4a extending through a lug 4b at the rear end of the cylinder. The front end portion or foremost end 4c of the cylinder 4 has (but need not necessarily have) a somewhat larger diameter than the remainder or central portion of the cylinder and is spacedly surrounded by a radially extending wall or partition 14 forming part of the frame F and located behind the chute 1 of the furnace, i.e., to the left of the chute, as viewed in FIGURE 1 or 2.
The partition 14 has a polygonal opening 14a which is adjacent to a suitable seal 14b engaging the external surface of the intermediate portion 9a of a novel hollow tubular shroud 9 for the piston rod 5 and the cylinder 4 of the motor. The piston rod 5 extends forwardly beyond the foremost end 4c of the cyllnder 4 and its front end portion or foremost end 5a is sealingly connected to the front end portion 9b of the shroud 9. To this end, the front end portion 5a can be surrounded by a collar or sleeve 5b which is shrunk onto its external surface and is connected to the radially inwardly extending wall of the front end portion 9b by suitable fasteners 9c in the form of screws, bolts or the like. The connection between the foremost end 5a of the piston rod 5 and the front end portion 9b of the shroud 9 is such that the external surface of the piston rod within the confines of the shroud 9 is not likely to be contacted by particles of fuel or even by gaseous substances descending in the hopper 1 and intended for admission into the combustion chamber 101. The frort or foremost portion 5a of the piston rod 5 is further articulately connected with the ram 3 by a transverse shaft or stud 6 so that the ram 3 can turn, within limits, relative to the motor about an axis extending at right angles to the plane of FIGURE 2.
The lower end portion of the hopper 1 extends close to the top wall 3a of the ram 3, and such top wall is flush with or is located at a level only slightly above the top portion or section 9d of the intermediate portion il76915 9a of the shroud 9. As a matter of fact, and as shown in FIGU~E 2, the foremost part of the top section 9d can have a shallow recess 9e for the rear end of the top wall 3a of the ram 3. A stripping device 7 which is articulately connected to the frame F, as at 7a, slides along the top wall 3a of the ram 3 and/or top section 9d of the intermediate portion 9 to pre-vent penetration of solid fuel or the like into the interior of the frame F
(see the gap 8) when the piston rod 5 performs a return stroke (in a direc-tion to the left as viewed in FIGURE 2). Since the top wall 3a is flush or nearly flush with the top section 9d, these parts do not interfere with the operation of the stripping device 7 behind the gap 8, i.e., the device 7 can readily slide over such parts when the motor is in use.
The length of the forward or return stroke of the piston rod 5 is less than the length of the shroud 9, namely, less than the distance between the front end portion 9b and a second portion 9f which, in the illustrated embodiment, constitutes the rear end portion of the shroud 9. In accordance wlth a feature of the invention, the rear end portion 9f has a radially lnwardly extendlng end wall 17 formed with an opening 18 which is slightly larger than the maximum diameter of the cylinder 4 so that the parts 17 and 4 define a relatively narrow clearance 10 in the form of a substantially circular orifice (see also FIGURE 3). The end wall 17 permanently surrounds the cylinder 4, i.e., in each axial position of the piston rod 5, so that the piston rod is invariably shielded and protected by the shroud 9 irrespective of whether it is fully or partly retracted into the cylinder 4.
FIGURE 3 shows that the intermediate portion 9a of the shroud 9 haa a polygonal (substantially square) cross-sectional outline. However, it is equally possible to employ a shroud having a cylindrical or oval cross section.
When the piston rod 5 performs a forward stroke (in a direction to the right, as viewed in FIGURE 2), the clearance or orifice 10 performs the function of a suction port and allows air to penetrate into the space 11 within the intermediate portion 9a of the shroud 9. When the piston rod S
thereupon performs a return stroke, the clearance or orifice 10 allows for il~76915 escape of air from the interior of the portion 9a and such air entrains any solid impurities which might have found their way into the shroud during the preceding forward stroke. The cross-sectional area of the clearance 10 is sufficiently small and the speed of the piston rod 5 is sufficiently high to produce a pronounced pumping action in response to reciprocation of the piston rod between its end positions. In other words, the rate of air flow into and from the space 11 in the intermediate portion 9a of the shroud 9 is quite pronounced which is desirable on the aforediscussed ground (to expel any solid impurities which might have penetrated into the shroud 9 during a forward stroke of the piston rod S) as well as on the additional ground that the circulating (entering and exiting) streams of air cool the shroud 9, the piston rod 5 and the foremost end 4c of the cylinder 4. It has been found that the ~ust discussed dimensioning of the clearance 10 and selection of the speed of the piston rod 5 invariably prevent the deposition of substantial quantities of or any dust or other foreign matter on the exposed surface of the piston rod 5 when the motor is in use. The volume of the internal space 11 in the shroud 9 changes continuously when the piston rod 5 is in motion, and this entails the aforediscussed flow of air into and from the shroud.
However, if the rate of air flow into and from the space 11 via clearance 10 does not suffice, the apparatus can be equipped with means for admitting into the space air or another suitable gaseous fluid independently of air flow via clearance 10. In the embodiment of FIG~RE 2, the motor comprises a source 12a of compressed air which is connected with a conduit 12 via valve means 12b, and the conduit 12 extends into the space 11 by way of a cutout 18a which is provided in the end wall 17 and can be said to form part of the opening 18. The discharge end of the conduit 12 carries one or more nozzles 13 which inject compressed air into the space 11 when the valve means 12b is actuated to permit the flow of compressed gaseous fluid from the source 12a.
The source 12a may constitute the so-called underblast which serves to admit compressed oxygen-containing gas into the combustion chamber 101 below the grate or grates and whose pressure is often sufficiently high to ensure a highly satisfactory rate of admission of pressurized fluid into the space 11 769~5 of the shroud 9.
As explained above, the intermediate portion 9a of the shroud 9 is engaged by the seal 14b in the region of the opening 14a in the partition 14 so that the lower portion of the hopper 1 cannot receive air from the region surrounding the major part of the cylinder 4. This ensures that the burning of fuel in the chamber 101 can be controlled and regulated with a high degree of reliability. As shown in FIGURE 2, the rear end portion or second portion 9f including the wall 17 of the shroud 9 is located behind the partition 14, even when the piston rod 5 assumes its fully extended position. This prevents penetration of corrosive, extremely hot or otherwise deleterious gaseous fluids into the space around the cylinder 4 and/or into the clearance 10 because the seal 14b between the intermediate portion 9a of the shroud 9 and the partition 14 is active at all times. As a rule, gaseous fluids will tend to penetrate toward the area around the cylinder 4 and into the clearance 10 only in response to deflagration in the combustion chamber 101 of the furnace, i.e., when the pressure in the combustion chamber 101 temporarily rises and causes hot gaseous products of combustion to travel along the ledge 2 and into the gap 8 to find their way into the region of the clearance 10 only if the frame F exhibits unforeseen leaks.
The motor preferably further comprises means for guiding the shroud 9 during movement of the piston rod 5 between its two end positions.
Such guiding means comprises one or more idler rollers 15 or analogous rotary elements which are installed in the frame F and preferably support the intermediate portion 9a from below. FIGURE 3 shows that the motor can comprise two rows of guiding and supporting rollers 15 which engage the underside of the flat horizontal bottom panel or wall of the intermediate portion 9a. The purpose of the rollers 15 is to reduce the likelihood of jamming of the piston rod 5, e.g., when the piston rod tends to leave its position of axial alignment with the cylinder 4 because the ram 3 encounters a pronounced obstruction and great resistance to its forward or return move-ment and such obstruction tends to move the front end portion 5a of the piston rod up, down or sideways, as viewed in FIGURE 2.
il~7~915 FIG~RE 3 further shows that the motor comprises certain additional components, namely, two pipes 16, which supply fluid (e.g., oil) to or permit evacuation of such fluid from the chambers of the cylinder 4. The opening 18 in the end wall 17 of the shroud 9 is configurated in such a way that it has recesses or cutouts 18b for the pipes 16 in addition to the aforementioned cutout 18a for the conduit 12. That portion of the opening 18 which remains unoccupied constitutes the clearance 10; as shown in FIGURE
3, this clearance is a circumferentially complete orifice which surrounds the cylinder 4 as well as portions of the pipes 16 and of the conduit 12.
An important advantage of the improved motor is that the shroud 9 constitutes a highly satisfactory but simple and inexpensive means for shielding the external surface of the piston rod 5 against external influ-ences, such as solid, liquid and/or gaseous substances which can readily penetrate into the skirts of the aforediscussed rams in conventional furnaces. Thus, the second portion 9f surrounds the cylinder 4 with relatively small clearance 10 which is just sufficient to allow for entry of relatively clean air into the space 11 when the piston rod 5 performs a forward stroke but can adequately shield the piston rod from contaminants, i.e., from substances which are likely to leave the combustion chamber 101 or the hopper 1. The piston rod 5 is invariably shielded from sparks, hot ashes or the like. Moreover, the end portion 9f of the shroud 9 is located in a region (in the frame F) which is designed to prevent penetration of ashes, sparks, hot gases or the like into its interior so that the likelihood of penetration of such substances into the space 11 by way of the clearance 10 is very remote. However, even if the apparatus which is shown in FIGURES
The present invention relates to incinerators and other types of furnaces in general, and more particularly to improvements in fluid-operated motors (single-acting or double-acting cylinder and piston units) which can be utilized to transmit motion to reciprocatory fuel feeding means in such installations. Still more particularly, the invention relates to improvements in means for shielding or protecting the piston rods of fluid-operated motors against jamming, premature wear, extensive wear, con-taminants, excessive heat, corrosive substances and/or a combination of such undesirable influences.
United States Patent No. 3,559,823 granted February 2, 1971 to Ostrin discloses a ram feed for incinerators wherein a hydraulically operated ram advances batches of scrap material supplied by an upright hopper and tamped by a vertically reciprocable packing piston. The admission of scrap material into the path of the ram takes place when the latter is held in the retracted positlon, and the front end portion of the ram carries a shearing head which cooperates with a shearing edge on the outlet of the supply hopper to comminute coarser or larger pieces of scrap material prior to admission into the lncinerator. In order to protect the cylinder, the ram constitutes an elongated tube (i.e., it has a skirt) which slides within a rearward extension of the supply conduit that delivers scrap material to the incinerator proper when the ram performs a forward stroke. The tubular or cylindrical portion or skirt of the ram is very long so as to practically or completely confine the cylinder in the retracted position of the ram.
Such ram further offers a pronounced resistance to tilting and other stresses. The piston rod of the cylinder is attached to the inner side of the front end wall of the reciprocable ram, and the length of the ram suffices to reduce the likelihood of penetration of scrap material there-behind, i.e., scrap material which descends from the hopper (either by gravity or under the action of the aforementioned packing piston) is unlikely to reach the cylinder. A body of liquid is maintained in the lower part of the upwardly sloping supply conduit to establish a seal between the incinerator and the cylinder. In order to prevent the body of liquid ., -1- ~
11~76915 (normally water) from penetrating into the incinerator when the ram performs a forward stroke, the upper side of the ram has a longitudinally extending external groove which allows the displaced liquid to flow rearwardly by gravity, and such liquid is allowed to penetrate behind the ram, i.e., it can contact the cylinder of the hydraulic motor. Furthermore, the liquid (which contains numerous contaminants and often also contains highly corrosive substances) can reach and contact the piston rod so that the latter undergoes pronounced and rapid wear, especially if the nature of ingredients of the sealing liquid is such that they can readily attack the external layer (normally chromium) of the piston rod. The skirt of the ram surrounds the cylinder (and hence the piston rod) with substantial clearance 80 that the piston rod is likely to be contacted by large quantities of liquid which contains dirt, scraps of foodstuffs, particles of metal, glass or the like as well as other corrosive or otherwise aggressive substances which reduce the useful life of the piston rod.
German Offenlegungsschrift No. 28 21 767 published on November 22, 1979 discloses a modified incinerator wherein the liquid seal is omitted so that the piston rod of the hydraulic cylinder is less likely to be con-tinuously exposed to the corrosive and/or other deleterious influences of a contaminated liquid. The apparatus of this German publication is designed to feed straw into the furnace and uses a ram with a relatively long skirt which is dimensioned to surround the cylinder with a pronounced clearance so that it cannot prevent aggressive gases from penetrating into contact with and from attacking the external surface of the piston rod.
Each of the aforediscussed conventional incinerators exhibits the drawback that the piston rod of the (normally hydraulically operated) cylin-der is subject to pronounced corrosive and other influences so that its useful life is rather short. The likelihood of rapid corrosion is even more pronounced if the strokes of the piston rod are not constant, i.e., if the piston rod is held in partially retracted or partially extended position for relatively long intervals of time. Such situation can arise at the end of a shift. The exposed portion of the piston rod is then subject to unint~r-llt7tj9ls rupted attack by solid, gaseous and/or liquid contaminants so that its external surface (which, as a rule, is the external surface of a layer of chromium or a like metal) is destroyed, either entirely or in part, and the chromium layer begins to peel off the core or central portion of the piston rod. In many instances, the defects appear in the form of spots where the chromium layer begins to become separated from the layer therebelow, and --such spots rapidly merge into larger zones of defective external surface on the piston rod. The resulting and in part very sharp irregularities at the exterior of the piston rod cause rapid destruction of the seal through which the piston rod extends into the interior of its cylinder.
Another drawback of prolonged exposure of a portion of the piston rod to external influences is that the film of oil on the exposed external surface of the piston rod accumulates fragments of dust and/or other foreign matter which tend to cake, especially at elevated temperatures to which the piston rod is or may be subjected when the fluid-operated moto~ is used in a furnace or the like. The caked foreign matter at the exterior of the piston rod also contributes to or initiates and completes rapid destruction of the seal through which the piston rod extends into the interior of the cylinder.
When the fuel feeding unit of a furnace is actuated by a hydraulically or pneumatically operated motor in the form of a cylinder and piston unit, the length of the piston rod often exceeds the length of working or return strokes of the piston in the interior of the cylinder. This means that a portion of the piston rod is always exposed. If the piston rod is not retracted to the maximum permissible or possible extent, i.e., if the piston is not held in the rearmost position within the confines of its cylinder while the motor is idle for an extended period of time (such as over a weekend or even during a longer interval of time when the furnace is idle for any one of a number of reasons including a strike, the absence of combustible material, vacation period, extensive repair work and/or others), the seal surrounding the piston rod is highly likely to be destroyed in response to initial or repeated retraction of the piston rod when the motor is put to renewed use. Moreover, the provision of relatively large clear-i17~91S
ances between the skirt of the ram on the one hand and the piston rod and cylinder on the other hand renders it possible and quite likely that a combustible gaseous, solid and/or liquid substance in such clearance catches fire while the motor is idle so that the resulting heat causes total or practically total destruction of the piston rod, of the cylinder or both.
SUMMARY OF THE INVENTION
An object of the invention is to provide a novel and improved fluid-operated motor which can be used in or in connection with furnaces or the like and which is constructed and assembled in such a way that it is less likely to be rapidly and extensively affected by gaseous, liquid and/or solid contaminants, corrosive substances or the like, even after extensive periods of non-use.
The invention provides a fluid-operated motor, particularly for reclprocating the fuel feeding means of a furnace, comprising an elongated cylinder; a piston rod axially movable in said cylinder to perform working and return stroke6 and having a foremost end located externally of said cylinder in each axial position of said piston rod; and a hollow tubular protective shroud having an end portion sealingly secured to the foremost end of said piston rod and a second portion surrounding said cylinder and defining therewith a narrow clearance in each axial position of said piston rod.
The shroud should effectively shield the piston rod from dirt, dust, fuel and/or other undesirable influences, as well as effectively shield the piston rod and/or other parts of the motor from excessive heat. The useful life of the sealing means between the piston rod and the cylinder is a multiple of useful life of seals in heretofore known motors.
The motor can be used in existing incinerators and/or other types of furnaces as a superior substitute for heretofore known motors.
The narrow clearance between the second portion of the shroud and the cylinder admits air into the interior of the shroud while the piston rod performs a working stroke and permits air to escape from the interior of the shroud (together with dust and/or other foreign matter) in response to il~7691S
retraction of the piston rod into the cylinder. The latter may be of the single-acting or double-acting type.
If the rate of admission of air into the interior of the shroud by way of the aforementioned clearance does not suffice, or if such clearance is likely to be clogged from time to time, the motor can further comprise a conduit or other suitable means for admitting a gaseous fluid into the interior of the shroud intermediate the end portion and the second portion thereof. The fluid admitting means may comprise a nozzle which is disposed in the interior of the shroud and serves to spray or otherwise discharge gaseous fluid into the intermediate portion of the shroud, i.e., into the portion between the end portion and the second portion.
In order to prevent tilting or other undesirable changes in orientation of the shroud in response to reciprocation of the piston rod, the motor can be provided with means for guiding the shroud while the latter shares the axial movements of the piston rod. Such guiding means may com-prise one or more supporting rollers which contact the underside of the exterior of the intermediate portion of the shroud if the shroud and the picton rod are mounted for reciprocatory movement along a substantially horizontal path.
The motor can further comprise a transversely extending protective wall or partition which is disposed in the region of the foremost end of the cylinder (i.e., at that end of the cylinder beyond which the piston rod extends), and such partition is provided with an opening through which the intermediate portion of the shroud extends, either sealingly or with a minimal or small clearance.
If the foremost end of the piston rod is connected with a sub-stantially horizontal ram which has a top wall, the top section of the shroud is preferably located at the level of (i.e., exactly flush with) or slightly below the top wall of the ram.
As mentioned above, the second portion of the shroud can constitute the rear end portion of such part, and this second or rear end portion may constitute or comprise an end wall extending substantially radially of the cylinder and defining an opening which receives the cylinder with the aforementioned clearance. The motor can comprise one or more components (e.g., pipes which supply or evacuate gaseous or hydraulic fluid from the interior of the cylinder) which are adjacent to the external surface of the cylinder; the opening of the end wall of the shroud is then configurated in such a way that the aforementioned clearance can constitute a circumferential-ly complete clearance also extending around the pipe or pipes or analogous components at the exterior of the cylinder.
The intermediate portion of the shroud may have a polygonal cross-sectional outline, and the length of the shroud (namely, the length of the shroud between the end portion and the second portion thereof) preferably exceeds the maximum length of forward or return strokes of the piston rod.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved motor itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.
FIGURE 1 is a schematic fragmentary vertical sectional view of a furnace which can utilize the fluid-operated motor of the present invention;
FIGURE 2 is an enlarged fragmentary view of a detail of the furnace shown in FIGURE 1 and a longitudinal vertical sectional view of the improved motor whose piston rod is coupled to the fuel feeding ram of the furnace; and FIGURE 3 is a transverse vertical sectional view as seen in the direction of arrows from the line III-III of FIGURE 2.
FIGURE 1 shows a portion of a furnace having a chute or hopper 1 which feeds fuel in front of a reciprocable ram 3. When the ram 3 performs a forward stroke (in a direction to the right, as viewed in FIGURE 1), it pushes a supply of fuel (i.e., scrap material, coke, coal or a combination of two or more types of fuel) over a ledge 2 and onto the grate (not shown) of the combustion chamber 101.
` 117~915 The motor which reciprocates the ram 3 in the directions indicated by the double-headed arrow 3A of FIGURE 1 is illustrated in detail in FIGURES 2 and 3. This motor is assumed to be a double-acting hydraulic cylinder and piston unit having a substantially horizontal cylinder 4 secured to the frame F of the furnace by a horizontal pin 4a extending through a lug 4b at the rear end of the cylinder. The front end portion or foremost end 4c of the cylinder 4 has (but need not necessarily have) a somewhat larger diameter than the remainder or central portion of the cylinder and is spacedly surrounded by a radially extending wall or partition 14 forming part of the frame F and located behind the chute 1 of the furnace, i.e., to the left of the chute, as viewed in FIGURE 1 or 2.
The partition 14 has a polygonal opening 14a which is adjacent to a suitable seal 14b engaging the external surface of the intermediate portion 9a of a novel hollow tubular shroud 9 for the piston rod 5 and the cylinder 4 of the motor. The piston rod 5 extends forwardly beyond the foremost end 4c of the cyllnder 4 and its front end portion or foremost end 5a is sealingly connected to the front end portion 9b of the shroud 9. To this end, the front end portion 5a can be surrounded by a collar or sleeve 5b which is shrunk onto its external surface and is connected to the radially inwardly extending wall of the front end portion 9b by suitable fasteners 9c in the form of screws, bolts or the like. The connection between the foremost end 5a of the piston rod 5 and the front end portion 9b of the shroud 9 is such that the external surface of the piston rod within the confines of the shroud 9 is not likely to be contacted by particles of fuel or even by gaseous substances descending in the hopper 1 and intended for admission into the combustion chamber 101. The frort or foremost portion 5a of the piston rod 5 is further articulately connected with the ram 3 by a transverse shaft or stud 6 so that the ram 3 can turn, within limits, relative to the motor about an axis extending at right angles to the plane of FIGURE 2.
The lower end portion of the hopper 1 extends close to the top wall 3a of the ram 3, and such top wall is flush with or is located at a level only slightly above the top portion or section 9d of the intermediate portion il76915 9a of the shroud 9. As a matter of fact, and as shown in FIGU~E 2, the foremost part of the top section 9d can have a shallow recess 9e for the rear end of the top wall 3a of the ram 3. A stripping device 7 which is articulately connected to the frame F, as at 7a, slides along the top wall 3a of the ram 3 and/or top section 9d of the intermediate portion 9 to pre-vent penetration of solid fuel or the like into the interior of the frame F
(see the gap 8) when the piston rod 5 performs a return stroke (in a direc-tion to the left as viewed in FIGURE 2). Since the top wall 3a is flush or nearly flush with the top section 9d, these parts do not interfere with the operation of the stripping device 7 behind the gap 8, i.e., the device 7 can readily slide over such parts when the motor is in use.
The length of the forward or return stroke of the piston rod 5 is less than the length of the shroud 9, namely, less than the distance between the front end portion 9b and a second portion 9f which, in the illustrated embodiment, constitutes the rear end portion of the shroud 9. In accordance wlth a feature of the invention, the rear end portion 9f has a radially lnwardly extendlng end wall 17 formed with an opening 18 which is slightly larger than the maximum diameter of the cylinder 4 so that the parts 17 and 4 define a relatively narrow clearance 10 in the form of a substantially circular orifice (see also FIGURE 3). The end wall 17 permanently surrounds the cylinder 4, i.e., in each axial position of the piston rod 5, so that the piston rod is invariably shielded and protected by the shroud 9 irrespective of whether it is fully or partly retracted into the cylinder 4.
FIGURE 3 shows that the intermediate portion 9a of the shroud 9 haa a polygonal (substantially square) cross-sectional outline. However, it is equally possible to employ a shroud having a cylindrical or oval cross section.
When the piston rod 5 performs a forward stroke (in a direction to the right, as viewed in FIGURE 2), the clearance or orifice 10 performs the function of a suction port and allows air to penetrate into the space 11 within the intermediate portion 9a of the shroud 9. When the piston rod S
thereupon performs a return stroke, the clearance or orifice 10 allows for il~76915 escape of air from the interior of the portion 9a and such air entrains any solid impurities which might have found their way into the shroud during the preceding forward stroke. The cross-sectional area of the clearance 10 is sufficiently small and the speed of the piston rod 5 is sufficiently high to produce a pronounced pumping action in response to reciprocation of the piston rod between its end positions. In other words, the rate of air flow into and from the space 11 in the intermediate portion 9a of the shroud 9 is quite pronounced which is desirable on the aforediscussed ground (to expel any solid impurities which might have penetrated into the shroud 9 during a forward stroke of the piston rod S) as well as on the additional ground that the circulating (entering and exiting) streams of air cool the shroud 9, the piston rod 5 and the foremost end 4c of the cylinder 4. It has been found that the ~ust discussed dimensioning of the clearance 10 and selection of the speed of the piston rod 5 invariably prevent the deposition of substantial quantities of or any dust or other foreign matter on the exposed surface of the piston rod 5 when the motor is in use. The volume of the internal space 11 in the shroud 9 changes continuously when the piston rod 5 is in motion, and this entails the aforediscussed flow of air into and from the shroud.
However, if the rate of air flow into and from the space 11 via clearance 10 does not suffice, the apparatus can be equipped with means for admitting into the space air or another suitable gaseous fluid independently of air flow via clearance 10. In the embodiment of FIG~RE 2, the motor comprises a source 12a of compressed air which is connected with a conduit 12 via valve means 12b, and the conduit 12 extends into the space 11 by way of a cutout 18a which is provided in the end wall 17 and can be said to form part of the opening 18. The discharge end of the conduit 12 carries one or more nozzles 13 which inject compressed air into the space 11 when the valve means 12b is actuated to permit the flow of compressed gaseous fluid from the source 12a.
The source 12a may constitute the so-called underblast which serves to admit compressed oxygen-containing gas into the combustion chamber 101 below the grate or grates and whose pressure is often sufficiently high to ensure a highly satisfactory rate of admission of pressurized fluid into the space 11 769~5 of the shroud 9.
As explained above, the intermediate portion 9a of the shroud 9 is engaged by the seal 14b in the region of the opening 14a in the partition 14 so that the lower portion of the hopper 1 cannot receive air from the region surrounding the major part of the cylinder 4. This ensures that the burning of fuel in the chamber 101 can be controlled and regulated with a high degree of reliability. As shown in FIGURE 2, the rear end portion or second portion 9f including the wall 17 of the shroud 9 is located behind the partition 14, even when the piston rod 5 assumes its fully extended position. This prevents penetration of corrosive, extremely hot or otherwise deleterious gaseous fluids into the space around the cylinder 4 and/or into the clearance 10 because the seal 14b between the intermediate portion 9a of the shroud 9 and the partition 14 is active at all times. As a rule, gaseous fluids will tend to penetrate toward the area around the cylinder 4 and into the clearance 10 only in response to deflagration in the combustion chamber 101 of the furnace, i.e., when the pressure in the combustion chamber 101 temporarily rises and causes hot gaseous products of combustion to travel along the ledge 2 and into the gap 8 to find their way into the region of the clearance 10 only if the frame F exhibits unforeseen leaks.
The motor preferably further comprises means for guiding the shroud 9 during movement of the piston rod 5 between its two end positions.
Such guiding means comprises one or more idler rollers 15 or analogous rotary elements which are installed in the frame F and preferably support the intermediate portion 9a from below. FIGURE 3 shows that the motor can comprise two rows of guiding and supporting rollers 15 which engage the underside of the flat horizontal bottom panel or wall of the intermediate portion 9a. The purpose of the rollers 15 is to reduce the likelihood of jamming of the piston rod 5, e.g., when the piston rod tends to leave its position of axial alignment with the cylinder 4 because the ram 3 encounters a pronounced obstruction and great resistance to its forward or return move-ment and such obstruction tends to move the front end portion 5a of the piston rod up, down or sideways, as viewed in FIGURE 2.
il~7~915 FIG~RE 3 further shows that the motor comprises certain additional components, namely, two pipes 16, which supply fluid (e.g., oil) to or permit evacuation of such fluid from the chambers of the cylinder 4. The opening 18 in the end wall 17 of the shroud 9 is configurated in such a way that it has recesses or cutouts 18b for the pipes 16 in addition to the aforementioned cutout 18a for the conduit 12. That portion of the opening 18 which remains unoccupied constitutes the clearance 10; as shown in FIGURE
3, this clearance is a circumferentially complete orifice which surrounds the cylinder 4 as well as portions of the pipes 16 and of the conduit 12.
An important advantage of the improved motor is that the shroud 9 constitutes a highly satisfactory but simple and inexpensive means for shielding the external surface of the piston rod 5 against external influ-ences, such as solid, liquid and/or gaseous substances which can readily penetrate into the skirts of the aforediscussed rams in conventional furnaces. Thus, the second portion 9f surrounds the cylinder 4 with relatively small clearance 10 which is just sufficient to allow for entry of relatively clean air into the space 11 when the piston rod 5 performs a forward stroke but can adequately shield the piston rod from contaminants, i.e., from substances which are likely to leave the combustion chamber 101 or the hopper 1. The piston rod 5 is invariably shielded from sparks, hot ashes or the like. Moreover, the end portion 9f of the shroud 9 is located in a region (in the frame F) which is designed to prevent penetration of ashes, sparks, hot gases or the like into its interior so that the likelihood of penetration of such substances into the space 11 by way of the clearance 10 is very remote. However, even if the apparatus which is shown in FIGURES
2 and 3 would permit penetration of undesirable corrosive, too hot or con-taminating substances into the region of the clearance 10 (e.g., as a result of unforeseen malfunctioning of the furnace~ the clearance 10 is or can be sufficiently narrow to effectively prevent penetration of large or appreciable quantities of deleterious substances into contact with the external surface of the piston rod 5. The aforementioned design of the clearance 10 in the form of a substantially annular orifice also contributes 11~7~915 to prevention of contact between deleterious substances and the exterior of the piston rod 5, i.e., the orifice or clearance 10 causes a pronounced flow of fluid from the space 11 whenever the piston rod performs a return stroke so that any deleterious substances which happen to penetrate into the space 11 are expelled after a relatively short period of dwell in the interior of the shroud 9. Pronounced circulation in the space 11 prevents or reduces the likelihood of deposition of foreign matter on the external surface of the piston rod 5 and effects a highly pronounced conditioning (cooling) of the piston rod, of the shroud 9 and other parts in the region of the space 11. It is to be borne in mind that the clearance 10 admits air which fills the rear portion of the frame F, i.e., a space which is rather remote from the combustion chamber 101, so that air which flows into the space 11 when the piston rod 5 performs a forward stroke is invariably cooler than the air in the region of the ram 3. The conduit 12 and its nozzle 13 can further enhance the cooling and solid-expelling effect of air or another gas which is circulated in the space 11. The utilization of a nozzle 13 at the discharge end of the conduit 12 contributes to acceleration of compressed air whlch is supplied by the conduit 12. The source 12a need not necessarily supply air, i.e., this source can also supply another gaseous fluid such as an inert gas. This is especially desirable if the motor of the present inven-tion is operated in a highly aggressive atmosphere so that the admission of at least some inert gas into the space 11 can greatly reduce the likelihood of premature reduction of quality of the external surface of the piston rod 5.
The partition 14 constitutes a simple but effective barrier which prevents excessive heating of the region around the cylinder 4 and thus enables the clearance 10 to admit relatively cool air when the piston rod 5 performs a forward stroke. The provision of a seal 14b between the inter-mediate portion 9a of the shroud 9 and the partition 14 is not critical but desirable and advantageous.
The presence or absence, the distribution, the number and the dimensions of combined supporting and guiding means 15 for the shroud 9 will 1~7~9~5 depend on a variety of factors, namely, the overall dimensions of the improved motor, the length of strokes of the piston rod 5, the nature of fuel which is being conveyed by the ram 3, the likelihood of pronounced resistance to retention of the piston rod 5 in accurate axial alignment with the cylinder 4 and/or others. If the shroud 9 is relatively large and heavy, the combined guiding and supporting means 15 will preferably camprise several rows of rollers; however, a single raw of rollers will suffice in many instances, especially if the rollers are relatively long.
The placing of the top section 9d of the shroud 9 at the level of or slightly below the top wall 3a of the ram 3 is desirable for the afore-discussed reasons, i.e., these parts do not interfere with the function of the stripping device 7 because the latter can slide along the top section of the shroud if the piston rod 5 is moved or must move beyond the extended position of FIGURE 2. Were the top section of the shroud 9 located at a level above the top wall 3a of the ram 3, the device 7 could interfere with further rightward movement of the piston rod 5.
The improved motor can be used in incinerators, other types of furnaces and/or in any such installations where the piston rod is likely to be subjected to pronounced heating action, corrosive fluids or solids and/or other undesirable influences which are likely to entail rapid destruction or deterioration of quality of the external surface of the piston rod.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of our contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the appended claims.
The partition 14 constitutes a simple but effective barrier which prevents excessive heating of the region around the cylinder 4 and thus enables the clearance 10 to admit relatively cool air when the piston rod 5 performs a forward stroke. The provision of a seal 14b between the inter-mediate portion 9a of the shroud 9 and the partition 14 is not critical but desirable and advantageous.
The presence or absence, the distribution, the number and the dimensions of combined supporting and guiding means 15 for the shroud 9 will 1~7~9~5 depend on a variety of factors, namely, the overall dimensions of the improved motor, the length of strokes of the piston rod 5, the nature of fuel which is being conveyed by the ram 3, the likelihood of pronounced resistance to retention of the piston rod 5 in accurate axial alignment with the cylinder 4 and/or others. If the shroud 9 is relatively large and heavy, the combined guiding and supporting means 15 will preferably camprise several rows of rollers; however, a single raw of rollers will suffice in many instances, especially if the rollers are relatively long.
The placing of the top section 9d of the shroud 9 at the level of or slightly below the top wall 3a of the ram 3 is desirable for the afore-discussed reasons, i.e., these parts do not interfere with the function of the stripping device 7 because the latter can slide along the top section of the shroud if the piston rod 5 is moved or must move beyond the extended position of FIGURE 2. Were the top section of the shroud 9 located at a level above the top wall 3a of the ram 3, the device 7 could interfere with further rightward movement of the piston rod 5.
The improved motor can be used in incinerators, other types of furnaces and/or in any such installations where the piston rod is likely to be subjected to pronounced heating action, corrosive fluids or solids and/or other undesirable influences which are likely to entail rapid destruction or deterioration of quality of the external surface of the piston rod.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of our contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the appended claims.
Claims (17)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A fluid-operated motor, particularly for reciprocating the fuel feeding means of a furnace, comprising an elongated cylinder; a piston rod axially movable in said cylinder to perform working and return strokes and having a foremost end located externally of said cylinder in each axial position of said piston rod; and a hollow tubular protective shroud having an end portion sealingly secured to the foremost end of said piston rod and a second portion surrounding said cylinder and defining therewith a narrow clearance in each axial position of said piston rod.
2. The motor of claim 1, wherein said second portion constitutes a second end portion of said shroud.
3. The motor of claim 1, wherein said clearance is an annular orifice.
4. The motor of claim 1, further comprising means for admitting a gaseous fluid into the interior of said shroud intermediate said portions thereof.
5. The motor of claim 4, wherein said admitting means comprises a conduit having a fluid-discharging nozzle in the interior of said shroud.
6. The motor of claim 1, further comprising means for guiding said shroud while said shroud shares the axial movements of said piston rod.
7. The motor of claim 6, wherein said means for guiding comprises a plurality of supporting rollers contacting the exterior of said shroud intermediate said portions thereof.
8. The motor of claim 7, wherein said shroud is substantially horizontal and said rollers are disposed at a level below said shroud.
9. The motor of claim 1, wherein said cylinder has a front end portion beyond which said piston rod extends and further comprising a wall extending transversely of said shroud in the region of the front end portion of said cylinder, said wall having an opening and said shroud having an intermediate portion disposed between said end portion and said second portion thereof and extending through the opening of said wall.
10. The motor of claim 9, wherein said intermediate portion of said shroud at least substantially seals said opening in each axial position of said piston rod.
11. The motor of claim 1, wherein said piston rod is substantially horizontal and further comprising a ram receiving motion from and located in front of the foremost end of said piston rod, said ram having a top wall and said shroud having a top section located at least close to the level of said top wall.
12. The motor of claim 11, wherein the top section of said shroud is at least substantially flush with the top wall of said ram.
13. The motor of claim 11, wherein at least a part of the top section of said shroud is located slightly below said top wall.
14. The motor of claim 1, wherein said second portion of said shroud has an end wall extending substantially radially of said cylinder and defining an opening receiving the cylinder with said clearance.
15. The motor of claim 14, further comprising at least one component externally adjacent to said cylinder, said opening including a portion for such component.
16. The motor of claim 1, wherein said shroud includes an intermediate portion disposed between said end portion and said second portion of said shroud, said intermediate portion of said shroud having a polygonal cross-sectional outline.
17. The motor of claim 1, wherein the distance between said end por-tion and said second portion of said shroud at least slightly exceeds the maximum length of strokes of said piston rod.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19803036053 DE3036053A1 (en) | 1980-09-24 | 1980-09-24 | PROTECTIVE DEVICE FOR PISTON RODS OF WORK CYLINDERS, ESPECIALLY FOR COMBUSTION SYSTEMS |
| DEP3036053.3 | 1980-09-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1176915A true CA1176915A (en) | 1984-10-30 |
Family
ID=6112762
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000386435A Expired CA1176915A (en) | 1980-09-24 | 1981-09-23 | Apparatus for reciprocating the feed ram in a furnace or the like |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0048362A3 (en) |
| JP (1) | JPS57108587A (en) |
| BR (1) | BR8106084A (en) |
| CA (1) | CA1176915A (en) |
| DD (1) | DD200533A5 (en) |
| DE (1) | DE3036053A1 (en) |
| DK (1) | DK421181A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7594466B2 (en) | 2007-01-12 | 2009-09-29 | Rotobec Inc. | Actuator with a protective sleeve for a piston |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3803964C2 (en) * | 1988-02-10 | 2002-03-28 | Festo Ag & Co | guard |
| DE4010225A1 (en) * | 1990-03-30 | 1991-10-02 | Porsche Ag | PROTECTIVE DEVICE FOR A PISTON ROD OF A HYDRAULIC CYLINDER |
| ITRM20030438A1 (en) * | 2003-09-24 | 2005-03-25 | Jolly Drive S R L | PROTECTION DEVICE FROM MARINE VEGETATION |
| CN102536955A (en) * | 2011-12-30 | 2012-07-04 | 东北农业大学 | Bearing hydraulic cylinder with oppositely arranged two cylinder bodies and hinged structures at parts excluding end parts |
| CN110410380A (en) * | 2019-08-27 | 2019-11-05 | 杭州先力液压机械有限公司 | Water cooling charging accessory and its working method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1551906B2 (en) * | 1966-03-01 | 1976-05-06 | Martin, Johannes Josef, Dr.-Ing., 8000 München | FEEDING DEVICE FOR LARGE FIRES, IN PARTICULAR WASTE INCINERATION PLANTS |
| DE1601715A1 (en) * | 1968-03-09 | 1970-08-13 | Rolf Dohrendorf | Hydraulic equipment, in particular for driving construction machines |
| US3559823A (en) * | 1969-03-14 | 1971-02-02 | Albert Ostrin | Ram feed for incinerators |
-
1980
- 1980-09-24 DE DE19803036053 patent/DE3036053A1/en not_active Withdrawn
-
1981
- 1981-09-03 EP EP81106898A patent/EP0048362A3/en not_active Withdrawn
- 1981-09-22 DD DD23348481A patent/DD200533A5/en unknown
- 1981-09-22 JP JP14891081A patent/JPS57108587A/en active Pending
- 1981-09-23 DK DK421181A patent/DK421181A/en not_active Application Discontinuation
- 1981-09-23 CA CA000386435A patent/CA1176915A/en not_active Expired
- 1981-09-23 BR BR8106084A patent/BR8106084A/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7594466B2 (en) | 2007-01-12 | 2009-09-29 | Rotobec Inc. | Actuator with a protective sleeve for a piston |
Also Published As
| Publication number | Publication date |
|---|---|
| DD200533A5 (en) | 1983-05-11 |
| JPS57108587A (en) | 1982-07-06 |
| EP0048362A3 (en) | 1982-09-01 |
| EP0048362A2 (en) | 1982-03-31 |
| DE3036053A1 (en) | 1982-04-08 |
| DK421181A (en) | 1982-03-25 |
| BR8106084A (en) | 1982-06-08 |
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