Tubular plate filling

The tubular positive plate uses rigid, porous fiber glass tubes covered with a perforated plastic foil as the active material retainer (Fig. 2). Dry lead oxide, PbO, and red lead, Pb O, are typically shaken into the tubes which are threaded over the grid spines. The open end is then sealed by a polyethylene bar. Patents describe a procedure for making a type of tube for the tubular positive plate (90) and a method for filling tubular plates of lead—acid batteries (91). Tubular positive plates are pickled by soaking in a sulfate solution and are then cured. Some proceed directiy to formation and do not requite the curing procedure. 

Tube filling. The tubular plates are filled, under pressure, with a slurry of 3BS or 4BS positive pastes diluted with water, or with a suspension obtained from leady oxide and red lead... 

Most often, high percentage (65 wt%) red lead and leady oxide blends are used for filling positive tubular plates for bofli traction and stationary batteries. 

Leady oxide manufacture is potentially very hazardous. It is therefore vital to take adequate measures to minimise, or even eliminate altogether, possible lead dust emissions out to the working environment and thus exposure of the personnel which would cause health problems. This is achieved by the use of a closed (isolated) leady oxide production equipment and transport pipes from the storage silos to the paste mixing unit. Special attention should be paid to file manufacture of tubular battery plates. Until recently, tubular plates were filled with a dry mixture of leady oxide and red lead powders. 

An overview of the general design and the properties of tubular plates is presented in Chapter 4.10. Here, we will discuss the process of filling tubular plates with lead oxides or suspension. 

Block scheme of the process of filling tubular plates with slurry obtained from paste. 

The production of tubular positive plates is in principle similar to that of pasted plates. A number of manufacturers use the same gray oxide as the basic filling substance. Sometimes the share or red lead or minium (Pb304) is increased above 25 or even to 100wt.%. The latter is more economic when the manufacturer runs his own minium plant then the expense of the chemical oxidation of lead oxide (PbO) to minium (Pb304) may be compensated by reduced formation cost. Furthermore, curing is not required, because of the high oxidation state, and the battery starts with full capacity when formed. 

Depending on the membrane shape (plate or tube) the reactor is different, but it is generally made of two chambers separated by the membrane. Figure 6 shows a reactor made of a tubular membrane and a conventional fixed-bed catalyst filling the inner part of the tube. In this example the reactant(s) is introduced into... 

A 1500-W tubular heater is wrapped around the reactor. The autoclave is placed inside a copper pipe, with Fiberfrax bulk fiber insulation packed between the copper pipe and the reactor. Four 1000-W quarter-circle ceramic heaters are placed around the copper pipe. The space between the copper pipe and the ceramic heaters is filled with aluminum balls for efficient and uniform heat transfer from the heaters to the copper pipe. The bottom of the copper vessel is closed with a copper plate. Beneath the copper plate, there are two heaters (a small one of 500 W and a larger one of 1000 W), which are tightly clamped to the bottom copper plate. The top of the copper pipe is similarly covered with another copper plate, and two slots are provided for the feed and product gas lines, coolant inlet and outlet lines, thermocouple extension wires, and the lead wires of the tubular heater. Two ring heaters (660 and 1000 W) are placed on the top copper plate. One thermocouple and a tape heater are placed on the shaft extension to minimize the heat loss through the shaft. No insulation is placed around the ceramic heaters to achieve better control of... 

The effect of hydration on the electrochemical activity of Pb02 has been investigated [33]. For the purpose, samples of charged PAM taken after the plate capacity tests, are ground to powder and filled into tubular electrodes at a density of 4.0 g cm . PAM obtained from 3BS and 4BS pastes, as well as chemical Pb02 (Merck), are used for these investigations. Other tubes are filled with the same PAM, but heated to 260 °C. The tubular electrodes are set to capacity tests. The obtained results are presented in Table 10.2. 

Most thermoplastics can be printed some thermosets. Handles flat, concave, or convex surfaces, including round or tubular shapes Can handle most thermoplastics. A big application area is bottles Handles flat, concave, or cylindrical surfaces Can handle special plating grades of ABS, PP, polysulfone, filled Noryl, filled polyesters, some nylons. 

Tubular positive plates are sometimes used in batteries for deep-discharge applications to reduce shedding of electro-active materials from the plate during cycling. The positive electrode has intercoimected porous tubes that are filled with positive lead paste. Lead rods in the centers of tubes are connected in parallel by a conductive lead bar at the top, and the bar is connected to the positive terminal. 

The negative current collector is a perforated nickel-plated steel pocket plate assembly. The tubes are produced from perforated nickel-plated strips that are wound to produce a tube. The tubular construction has one end crimped and the active material is poured into the open end in layers with nickel flakes. Alternatively, a machine automatically introduces the active material and tamps it into the pockets. After filling, the tubes/pockets are crimped and pressed into openings in the nickel-plated steel electrode frame. A similar process is used for the positive electrode. 

The static suspension method for preparing adsorption layer open tubular columns (ALOT) was suggested by Haiasz and Horvath [16, 17]. The columns prepared by this method have been successfully used for many separations. Haiasz and Horvath [16] filled stainless steel capillaries (50 m) with stable suspensions of many combinations of solid and liquid stationary phases, then closed the capillaries at one end and passed them through a furnace, where the solvent used to prepare the suspension evaporated through the open end. In this evaporation process the solid part of the suspension was retained on the capillary wall. This method was successfully used by Ettre and coworkers [18, 19] to produce efficient columns (a 45 m column has 57,000 theoretical plates). 

Paste that has been insufficiently cured is easily broken. The uncured paste is pale in color and soft. If the plate has been insufficiently cured, it can be rewetted and reheated to force the paste to cure. Another way is to dip the partially cured paste into dilute sulfuric acid, which is called pickling. The pickling curing process is also used for curing of powder-filled tubular positive plates. 

In Europe, and less commonly in the United States, many of the heavy-duty battery positive plates are made in porous tubular sheaths. The grid is cast or injection-molded of lead, with long-flnned spines attached to a header bar and a connection lug. Individual woven fiberglass plastic sheaths or a multitube gauntlet are placed on the spines. These plates are filled wifh powder or with a slurried paste until the tubes are full. A plastic cap plugs the open sheath ends and becomes the bottom of the plate (Fig. 23.15). 

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