This standard outlines the specifications for wooden separators utilized in lead-acid storage batteries, including those used in automotive and other applications. It details suitable timber species, permissible dimensional variances, treatment procedures to improve performance, and restrictions on manganese and iron content to ensure electrical and mechanical effectiveness. It serves as a critical guideline for manufacturers and engineers to ensure high-quality separators compatible with battery systems.
Overview
This standard outlines the specifications for wooden separators utilized in lead-acid storage batteries, including those used in automotive and other applications. It details suitable timber species, permissible dimensional variances, treatment procedures to improve performance, and restrictions on manganese and iron content to ensure electrical and mechanical effectiveness. It serves as a critical guideline for manufacturers and engineers to ensure high-quality separators compatible with battery systems.
Audience
Contents
Structure
This section defines the application range of wooden separators in lead-acid batteries, excluding contractual terms. It references IS 707-1958 for terminology not explicitly stated here. It also specifies dimensional tolerances for width, height, and thickness, measured by two defined methods depending on accuracy and equipment availability, and confirms the use of metric units.
Clarifies terms aligned with IS 707-1958 and lists acceptable timber species, including both indigenous and imported types, with botanical and trade names. It reiterates dimensional tolerances and emphasizes the adoption of the metric system for all measurements.
Identifies the specific timber varieties approved for separator fabrication, highlighting both local and imported woods. Details dimensional tolerance limits and sets maximum electrical resistance limits for different thicknesses used in vehicles and train lighting applications.
Describes manufacturing requirements including veneer color uniformity and moisture conditions. Specifies treatment by boiling in 2% caustic soda solution for several hours with fresh batches each time, followed by cold water washing. Covers testing method options for quality control.
Lists permissible size deviations for width, height, and thickness of separators in their finished, treated green state. Notes that untreated or dry separators' dimensions must be mutually agreed upon and that storage conditions should maintain moisture. Emphasizes dimension control for proper battery assembly.
Specifies maximum electrical resistance values for separators of various thicknesses. Details an AC bridge circuit measurement method involving oscillators and transformers to accurately determine resistance, including accounting for reactive components and ensuring physical squareness.
Sets a maximum manganese content threshold and provides a detailed chemical analysis method involving sample preparation, reagent addition, and colorimetric comparison with a standard manganese solution. Outlines preparation of the standard solution and interpretation of test results based on color intensity.
Defines acceptable iron content by comparing sample color intensity against a calibrated standard iron solution prepared with ferrous ammonium sulphate and sulfuric acid. Describes the colorimetric testing procedure and specifies that in case of disputes, the method in Appendix A prevails.
Details inspection techniques including holding the separator against light and applying slight bending to detect defects such as cracks or splits. Links visual inspection criteria to compliance with iron content and electrical resistance standards.
Specifies packing separators in air-tight containers in batches of 100 to prevent moisture loss. Requires clear marking with manufacturer identification and optionally the ISI certification mark. Includes inspection steps to verify physical integrity before shipment.
Elaborates on the use of an AC bridge circuit setup with a coupling transformer, oscillator, and amplifier for resistance measurement. Describes measuring resistance with and without a hole in the separator and calculating the difference, while ensuring accuracy by filtering harmonics and verifying separator geometry.
Outlines a stepwise chemical testing method involving sample drying, ignition, acid digestion, reagent addition, and colorimetric comparison against a prepared standard manganese sulphate solution. Specifies conditions for sample preparation, solution concentration, and interpretation of results.
Describes preparation of a standard iron solution with ferrous ammonium sulphate and sulfuric acid, titration with potassium permanganate, and colorimetric comparison with test samples. Specifies permissible iron levels and directs use of Appendix A method to resolve disputes.
Frequently Asked
The standard approves several timber species for battery separators, including indigenous types like Fir (Abies pindrow), Deodar (Cedrus deodara), Cypress (Cupressus torulosa), Champ (Michelia champaca), and Spruce (Picea smithiana). It also permits imported timbers such as Port Orford cedar (Chamcoyparis lawsoniana) and Oregon pine or Douglas fir (Pseudotsuga taxifolia). These species are selected to ensure the separators' durability, electrical insulation, and chemical resistance.
Dimensional tolerances apply to finished, treated separators in a green condition with moisture content above 25%. The width may have a tolerance of +0.75 mm and -0.00 mm, height +0.00 mm and -0.75 mm, and thickness ±0.05 mm. For dry or untreated separators, dimensions for ribs and webs must be mutually agreed by the purchaser and manufacturer. Proper dimensional control ensures correct fit and function in batteries.
Separators must be boiled in a 2% caustic soda solution for 3 to 5 hours using fresh solution batches to remove resins and impurities, followed by thorough washing in cold water. Additionally, an anti-fungal treatment involves dipping or spraying with a 1% aqueous emulsion of rosha grass oil and thymol mixed in a 2:1 volume ratio. These treatments enhance electrical resistance and prevent fungal growth during storage.
The manganese content must not exceed 1.5 mg per 100 grams of oven-dry separator material, while the iron content limit is 0.06 grams (60 mg) per 100 grams of oven-dry separator. Iron content is verified by comparing sample color intensity against a standard iron solution color. These limits ensure chemical properties that support separator durability and performance.
Electrical resistance is measured using an AC bridge circuit setup with a coupling transformer, a 1000 c/s oscillator, and an amplifier with harmonic filtering. The resistance of the battery cell is measured first with the separator intact and then with a similar separator containing a hole aligned with the baffle hole. The difference in resistance values, normalized per square centimeter of separator face, represents the separator's electrical resistance. Maximum allowable resistances depend on separator thickness and application.
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