JPS6240045B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sludge collector having parallel chains to which transversely arranged flights are attached.

When non-metallic chains are applied to sludge collection, their low specific gravity is a problem. Traditionally, dense but buoyant red woods such as American cedar are used with cast chains. However, the non-metallic chain with wooden flights had a low overall specific gravity, which caused the assembly to float and not work properly without weights.
In addition to weighting, another problem is that wood absorbs significant amounts of water when immersed in water for long periods of time. for example,
Red wood absorbs up to 40% of its original weight in water. When periodic cleaning of the sludge treatment tank is required, the moist flights and added weights exert significant tension on the chain and sprockets, accelerating wear.

It is therefore an object of the present invention to provide a chain link and flight mechanism for a sludge collector that has sufficient specific gravity to minimize reversal effects and sufficient stiffness to minimize flight curvature.

To achieve this object, the present invention provides: 1. A large number of chain cables each having the following (a) and (b): (a) a tank for the waste liquid to be treated; (b) (1) a hole each extending in the axial direction; and a body having at least a tensile force coupled to a pair of spaced apart side arms having an opening extending outwardly from the aperture and coaxial with the aperture in the adjacent link body. Strength
8500psi (approximately 597Kg/cm ² ), creep value
(2) a number of links consisting of a material that is 2.0% or less under 2000 psi (140 Kg/cm ² ) for 10 years;
18000psi (approximately 1265Kg/cm ² ), the deflection coefficient is
1000000psi (approximately 70323Kg/cm ² ) or more, creep value below 2000psi (approximately 140Kg/cm ² ) for one year
(3) a number of pins made of a glass fiber reinforced polymeric material having a dimensional change due to moisture absorption of not more than 0.5% and substantially the same as the link material; (3) while the pins are fitted into the holes in said body; , structural means cooperating with both the link and the pin to releasably lock the pin against longitudinal movement, and at least two non-metallic chains coupled to the chain string; , each constructed of a fiber-reinforced polymer having sufficient stiffness to minimize flexing under operation, such that the upper end surface is below the liquid surface line when conveyed across the liquid surface contained within the processing tank. a sludge consisting of a number of laterally spaced parallel flights extending upward and having an overall specific gravity, together with the chain, sufficiently greater than 1 to prevent retrograde effects caused by the buoyancy of the liquid; The present invention provides a chain link and flight mechanism for a collector aircraft.

Before going into the explanation along with the drawings, I would like to add some additional information about the progress that led to the present invention.As mentioned above, in sludge collectors that are constantly exposed to active substances and mixtures present in waste liquid, conventional cast iron chains do not deteriorate. I have a problem that cannot be avoided. Replacing or replacing the chain as it deteriorates requires considerable time, which is completely contrary to the desired intent of minimal maintenance. A problem that often arises in connection with routine maintenance of sludge collectors is the weight of the wooden flights. As previously mentioned, the initial buoyancy force is offset by the addition of weights so that each flight is properly driven to the surface of the liquid and to the bottom of the collection tank. However, wooden flights gradually absorb large amounts of moisture. Added weight due to water absorption will inevitably accelerate chain deterioration, especially when the tank is empty, as there is no buoyancy on the weight of the flight, and this deterioration will be severe enough to require frequent replacement of abrasive sliding materials on the flights. A need arises.

To solve this problem, the applicant has invented a sludge collector that uses a non-metallic chain and fiber-reinforced polymer flights. Patent application filed on the same day: “Non-metallic conveyance chain” (JP-A-Sho)
54-35977) discloses in detail a non-metallic chain suitable for use in a sludge collector. However, in order to solve the above-mentioned problems, an appropriate combination of the above-mentioned chain and fiber-reinforced polymer flights is required, and this combination constitutes the present invention, which will be described in detail below.

Sludge collectors are well-known devices used to remove suspended solids and sediment from wastewater. Such equipment forms part of the process necessary to return environmentally safe materials to nature, for recycling, or for consumption. Sludge collectors generally include an elongated rectangular tank made of concrete into which the wastewater to be treated is placed. A series of spaced apart flights are carried by an endless chain that extends along the liquid surface from one end of the tank, travels to the bottom of the tank, and slides along rails provided at the bottom of the tank. A series of abrasive glides provide protection and reduce wear and tear from friction. The sludge sediment is pushed by each flight toward a sump at the bottom of the tank, while floating material moves toward the other end of the tank.

The present invention will be explained below with reference to the drawings. FIG. 1 shows a typical sludge collector. As shown in the figure, the tank 20 has a sludge pump 2 at one end.
2, an inlet 22a extending to the bottom of the pump 22, and a number of steel rails 24 extending along the bottom parallel to the longitudinal sides. As best shown in Figure 3, the second group of steel rails 2
6 is attached along the side of the tank 20 near its upper end. A pair of endless chains 28 are mounted around a sprocket 30, which is mounted on a shaft bearing the side of the tank 20. Chain 28, driven by motor 21 and drive chain 21a, carries flights 32 spaced apart by fixtures 34. Flight 32 as shown
has substantially the width of tank 20. FIG. 2 is a diagram for explaining the flight 32 and the fixture 34.

FIG. 4 shows the links of the chain 28,
The chain 28 includes a pair of spaced apart side arms or bars 36, 38 extending from one end of the cylindrical body 40 and deviating outwardly from the body end. As shown, the middle portions of the side arms 36, 38 are thicker, and both sides of each side arm are curved to provide a long, wide sliding member. The loads occurring in the sludge collector during operation are distributed over a broadly defined area, resulting in a longer life for both the chain and sprocket.

The end surface 40a of the body portion 40 is flat, and the body portion 4
It protrudes from the cylindrical surface of 0 to become part of the flange 42. Hole 44 extends in the axial direction and communicates with each end surface 40a. The side arms 36, 38 have inner flat surfaces 36a, 38a having holes 46, 48 and extending to the ends.

The side arms 36, 38 have flat surfaces 36a, 38
The distance between the end surfaces 40a is somewhat smaller than the distance between the end surfaces 40a and directed inward. Therefore, some force is required to position the flat surfaces 36a, 38a onto the corresponding end surfaces 40a. The inward bias and correspondingly large planar surface of the side arms 36, 38 provides an effective sealing engagement against grit and abrasive materials, if desired.

Pin 50 is located within hole 44 and passes through holes 46, 48 in side arms 36, 38. As best shown in Figures 4-6, pin 50
consists of a head end 52, a cylindrical body 54, and a tip 56. A portion 54 of body 54 located within hole 44
a has a slightly larger diameter for the reason described below. The gap between the body 54 of the pin 50 and the inner wall of the hole 44 is also shown in FIG. 6, which is a side view of the pin 50, partially in section. For ease of understanding, the pin 50 is shown partially fitted into the hole in the link in FIG.

On opposite sides of the flat surfaces 36a, 38a are a pair of protrusions 43, 45, and holes 44, 46 also extend into these protrusions. The protrusion 45 has a non-circular recess 58 complementary to the shape of the pin head end 52. Once the pin is inserted into the hole, the head end 52 is restrained from rotation by the recess 58. Each protrusion has a flat end surface 43a, 45a extending around the hole, and serves as a mounting surface for a chain assembly/disassembly tool.

Before discussing the construction in further detail, it is pertinent to point out that one of the biggest drawbacks to cast iron chains is the labor required for their assembly and disassembly. As is the case when assembling a new chain, even more labor is required when the chain is corroded. For example, when a chain needs to be dismantled, maintenance personnel may burn the chain pin at the pin lock, heat and expand the link side arm at the pin head, and then use a drift pin or strong hammer to pull the pin out of the hole. Taking it out requires a lengthy disassembly of the entire assembly.

However, by using non-metallic materials throughout the applicant, the applicant can eliminate most of the above-mentioned steps, and furthermore, the locking mechanism that utilizes a single structure of the pin 50 and the side arm hole can reduce the assembly and disassembly time of the chain. We have found that it is possible to shorten the As shown in FIG. 4, the pin 50 has a tapered region 56a toward the tip 56 and a circumferential groove 59 that is slightly shorter than the tapered region. A wedge or finger 60 of complementary shape to the circumferential groove extends circumferentially around the end of one hole 46 in the side arm that receives the pin 50. As best seen in FIG. 5, the wedge 60 is chamfered 59a at its end where it first contacts the pin.
The tapered region 56a and chamfered portion 59 of the pin 50 are
However, when the pin is fitted into the hole 46 and the wedge 60
The fitting into the circumferential groove 59 can be easily performed. Removal of the pin 50 from the holes 46,48 requires considerably more force than when it is inserted into the holes 46,48. A snap lock mechanism allows pins 50 to be inserted into holes 44 and 46, 48.
The vertical movement of is removed.

As previously mentioned, the elasticity of polymeric materials is typically much greater than that of metallic materials, so flexing of the side arm during heavy load carrying becomes an issue that the user must consider. Not only is material fatigue an important factor, but often a large degree of bending can cause the pin to pop out of the hole. The deflection coefficient of metal is 30 times higher than that of plastic, so increasing the thickness of the side arm is not a solution. For example, to achieve the stiffness of a 6mm thick cast iron link, regular acetal resin would need to be 19mm thick. Composite materials may be one answer, but in this case cost and undesirable side effects must be taken into account.

In the process of applying a technique commonly referred to as "interference fitting" to non-metallic chains, the applicant happened to discover a method for reducing deflection (or the need to use thicker side arms for most common loads). I discovered it by chance. In cast iron chains, "interference fitting" is often used to prevent the pin from moving out of the hole due to vibration. Essentially, "interference fitting" is easily achieved by making the pin diameter somewhat larger than the hole in the body or link. Although the diameter dimensions are very close, it requires an extremely large force to move the pin once it is fitted vertically within the hole.

The cast iron link sidearms have virtually no flex, so there is no risk of the pins becoming dislodged. In most cases, the movement of the pin is due to vibration, and the cotter pin that passes through the pin is usually sufficient to prevent movement of the pin during heavy loads. As a result, the additional use of "interferometric fitting" methods is often considered superfluous.

However, the applicant has discovered that the overall effect of the pin composition (described below) and "interference fitting" can provide side stiffness comparable to that of cast iron chains, without the need for expensive lightweight composites or even thicker side arms. I found that giving to the arm. In particular, FIG. 5 shows a pin structure for providing this result.
As previously mentioned, the pin body 54 includes an area of increased diameter 54a near the head end 52. Hole 48, on the other hand, has a diameter somewhat smaller than the diameter of body portion 54a. Preferably, the diameter of hole 48 is no less than 1.0% smaller than the diameter of body portion 54a. The hole 46 and the body 54 fitted therein have a similar relationship. Hole 46 as shown
has a smaller diameter than hole 48 corresponding to the smaller radius portion of pin body 54 .

Apparently "interference fitting" is pin 50.
The curved length of the pin 50 is reduced by fixing it between the opening surfaces of the holes 46 and 48, that is, between the inner bearing surfaces 36a and 38a of the side arm. Otherwise, the load on the body resting on a pin loosely fitted within a link hole will cause the pin to bend over a longer distance. The outward deflection of the side arm increases accordingly.

Applicants have investigated various composite materials that can be used as links and have found that many prior art applications employ acetal polymers manufactured by DuPont and sold under the trade name "Delrin." I knew. Links made of this or similar materials have been found to be quite satisfactory provided that the various physical properties are held within certain limits. Tensile strength and deflection coefficient are clearly important points. For the high loads for which the chains of the present invention are designed, the chain material has a tensile strength of at least 8,500 psi (approximately 597 Kg/cm ² ) and a deflection coefficient of at least 370,000 psi (approximately 26,000 Kg/cm ² ). There is a need. Furthermore, when the chain is used underwater or in a high humidity environment, it is important to select a material that will not expand by more than 0.4% due to moisture absorption.

Another important factor is the creep value. Many composites expand irreversibly after a period of use. The creep value is the magnitude of this expansion or elongation, and is defined as the amount of deformation after a certain period of time under the action of a constant load. We have determined that it is important to select a material that has a creep value of about 2% or less under stress of 2000 psi (about 140 kg/cm ² ) for 10 years.

Unfortunately, pins made of materials such as the above-mentioned "Delrin" were unable to perform a sufficient function. Although the exact reasons are not complete, we believe that the following simple explanation is applicable and sufficient to appreciate the unexpected and complex nature of the combinations essential to non-metallic chains.
That is, when a non-metallic chain is placed under a load, the pins deform more or less depending on their composition. This deformation results in bending of the pin, which causes unexpected deflection of the side arm. Whenever the chain is under load, as occurs between the driving and driven sprockets, the pins will bend and the sidearms will warp as described above. Once it passes the drive sprocket, there is no load on the chain, so the pin and side arm loosen.
This repetition of deformation, flexing, and loosening accumulates as a slight but detrimental effect on the side arm, resulting in breakage after a certain period of time. This problem has not previously been encountered in the art since conventional non-metallic chains have been applied in the low load range. Furthermore, even though the chain was made of non-metallic material, pins made of steel or other alloys were used.

In search of compositions that could be used as pins, many other polymer materials were also studied. Initially, Applicants did not believe that polymeric materials mixed with glass or other materials could be used in chain drive systems. This is because it was well known that such materials have greater friction than composite materials that do not contain glass or the like, and are more likely to scratch or scratch. Links made from glass blends have been shown to experience significant wear when the link body engages the sprocket teeth. The sprocket was gouged by the glass material, which still had a rough surface, accelerating wear and further deterioration.

It was therefore quite fortunate for the applicant to discover that certain glass-laced polymeric materials work well enough. Pins made of such materials not only withstood heavy loads, but also suffered from less wear and tear and reduced side arm deflection.

Although other manufacturing methods are possible, manufacturing the links by mold casting has been the optimal method.
The mold inlet can be located at any convenient location, for example, one preferred location is along the longitudinal centerline of the inner surface of the link.

The material of choice is 612 nylon mixed with glass, but materials such as glass-mixed acetal, sold under the trade name "Celcon" by Celanese, can also be used. First, it is desirable that the material used as the pin has the same degree of dimensional expansion due to moisture absorption as the link material. The tensile strength and deflection coefficient of the pin must be greater than the link material. More specifically, tensile strength,
The deflection coefficient is 18000psi (approximately 1265Kg/
cm ² ) and 1,000,000 psi (approximately 70,323 Kg/cm ² ) or more. A value below this cannot provide the strength necessary to reduce the deflection of the side arm. The creep value must be less than the link material to maintain sidearm stiffness. It is thought that a value of 0.5% or less for one year under 2000psi (approximately 140Kg/cm ² ) is required.

Furthermore, non-metallic chains such as those mentioned above,
While suitable for use in environments unsuitable for cast iron chains, such as in sludge collector applications, this non-metallic chain can be used in combination with fiber-reinforced flights of specified properties and specific gravity. ,
Furthermore, it was found that the aptitude was significantly improved.
When combined with the traditionally used red wood flights, the chain is so light that such flights become impractical. Additional weight then has to be added to avoid the dual problems of flotation forces on the chain during operation and inefficient removal of submerged sludge material. However, this added weight creates additional problems caused by the water absorption properties of the flight material.

Merely replacing the wooden material with a material that does not absorb moisture is not a practical solution to the problem.
For example, it has been found that a certain degree of deflection coefficient is required to avoid deflection occurring in a plane perpendicular to the liquid surface, ie, along the length of the flight. In particular, the occurrence of flight deflection over the length normally required for sludge collectors, that is, 1000 cm or more, causes the upper end surface of the central part of the flight to travel below the liquid surface, resulting in cleaning and cleaning of suspended solids.
This results in failure of removal. For this reason, the flight is 1500000psi (approximately 105485Kg/cm ² )
It is extremely important to have a deflection coefficient greater than or equal to the above.

Various combinations of flight composition and construction have been validated to provide such deflection coefficients. For example, the flights themselves can be made from a fiber-reinforced polymer, such as glass fiber-reinforced polyester, available from Pultrusion, Inc. of the United States. Furthermore, as shown in Figure 7,
A particularly preferred structure is a fluted flight to provide greater stiffness, which would otherwise substantially increase the amount of material required when using the same material. If necessary, a block of the same material is inserted into the groove formed by the flights.
Otherwise, spacers are used between the flights 32 and the fixtures 34 as shown.

System balance is also important. In other words, the materials for both the flights and the chain are selected to give the combined overall specific gravity so that the additional weight is minimized. It has been found that the overall specific gravity is 2, particularly preferably in the range of about 1.6 to 2.4. In the case of the aforementioned Delrin chain, Zytel (trade name, glass mixed nylon manufactured by Dupont) pins and glass fiber reinforced polyester flights with a specific gravity of approximately 2, the weight on each sliding member is approximately 3.7 pounds (approximately 1.68
Kg). This was one-sixth of the cost using conventional cast iron chains and red wood flights. This weight is constant and smaller than conventional ones,
Moreover, since it absorbs almost no water, chain replacement costs are significantly reduced.

The fixture 34 shown in FIGS. 7 and 8 is of the fixed type and has two side plates 30a forming links of the chain 28.
It consists of The side plate 30a extends outwardly from the path of the chain, and the mounting plate 31 is preferably attached to the side plate 3.
It is formed integrally with 0a. The flights 32 are bolted to the mounting plate 31 by bolts 33.

The sliding material 35 is also bolted to the row of steps 32 by bolts 33. The second group of sliding members 39 is bolted to the rows by bolts 41. Other fixings and pivoting fittings can be used as needed. The material for the fixture can be any lightweight material such as urethane that can be molded for bolting.

[Brief explanation of the drawing]

Figure 1 is a side view showing the mechanism of the sludge collector;
Fig. 2 is a side view showing a part of the chain and attached flight, Fig. 3 is a plan view showing the chain, flight, and rail with some parts omitted, and Fig. 4 is a plan view of the chain that forms part of the present invention. Figure 5 is a sectional view along the body of the chain shown in Figure 4, Figure 6 is a side view including a partial cross section of the chain pin, and Figure 7 is an enlarged view of the fixture that fixes the flight to the chain. The side view, FIG. 8, is a plan view of the fixture shown in FIG. 20...Tank, 21...Motor, 22...Sludge pump, 24, 26...Rail, 28...
Chain, 30... Sprocket, 31... Mounting plate, 32... Flight, 33, 41... Bolt,
34... Mounting tool, 35, 39... Sliding material, 36,
38...Side arm, 40...Body part, 42...
...Flange, 43, 45...Protrusion, 44...Hole,
46, 48...hole, 50...pin, 52...head end, 54...body, 56...tip, 58...recess, 59...circumferential groove, 60...wedge.

Claims (1)

[Scope of Claims] 1 (a) A tank containing a waste liquid to be treated; (b) (1) each having a body portion with an axially extending hole, the body portion extending outwardly from the hole and adjacent to the tank; coupled to a pair of spaced apart side arms with openings coaxial with the holes in the link body and having a tensile strength of at least 8500 psi
(approx. 597Kg/cm ² ), creep value is 2000psi (approx.
140Kg/cm ² ) a number of links consisting of plastic material of not more than 2.0% in the last 10 years, (2) each configured to extend through said body and opening and having at least a tensile strength
18000psi (approximately 1265Kg/cm ² ), the deflection coefficient is
1000000psi (approx. 70323Kg/cm ² ) or more, creep value 0.5 in 1 year below 2000psi (approx. 140Kg/cm ² )
% or less and whose dimensional change due to moisture absorption is substantially the same as that of the link material; (3) while the pins are fitted into the holes in the body; at least two non-metallic chains having structural means cooperating with both said links and pins to releasably lock said pins against longitudinal movement; and (c) attached to said chains. The width of the tank is substantially the same as that of the above tank, and the deflection coefficient is
A sludge collection comprising: a large number of spaced apart and parallel flights made of a fiber-reinforced polymer of 1500000 psi (approximately 105485 Kg/cm ² ) or more and having an overall specific gravity of 1.6 to 2.4 together with the chain; Aircraft chain link and flight mechanism.