109 317359/2020/O/o PED/TMM/RDSO ISO: 9001-2015 Document No.: TM-52 Revision 01 Date Effective From:--/--/---- Document Title: Specification of Spirit Level (For use in Box type gauge cum level) SPECIFICATION OF SPIRIT LEVEL (For use in Box type gauge cum level) (No.TM-52 Dt.24.05.2000) First Revision, October-2020 Track Machines & Monitoring Directorate RESEARCH DESIGNS AND STANDARDS ORGANISATION Manak Nagar, Lucknow-226011 JRE/SSE/SSRE ARE/DTM/EDTM PEDTM Page 1 of 8 Prepared By: Checked By: Issued By 110 317359/2020/O/o PED/TMM/RDSO ISO: 9001-2015 Document No.: TM-52 Revision 01 Date Effective From:--/--/---- Document Title: Specification of Spirit Level (For use in Box type gauge cum level) 1.0 SCOPE: This specification covers the essential dimensional, functional and material characteristics with method of testing and accuracy of the spirit level. The spirit level is used to define a reference horizontal plane to compare the horizontality of the base of the spirit level with the plane containing the touching surfaces of the rail seatings of the gauge-cum-level. 1.1 Preference to make in India: compliance of the instruction contained in public procurement (preference to make in India) order -2017 “Make in India” shall be ensured or latest instructions issued on subject shall be ensured. 1.2 All the provisions contained in RDSO’s ISO procedures laid down in Document No. QO- D-8.1-11 dated 12.09.2018 (titled Vendor – Changes in approved status”), subsequent versions / amendments thereof shall be binding, and applicable on the successful manufacturers/suppliers in the contracts floated by Railways to maintain quality of products supplied to Railways. 20 REFERENCE DOCUMENTS: Following BIS/IS codes and references have been referred to in this specification. Updated copies of the same should be available in the works of the manufacturer/Suppliers. i. IS: 292-1983 Leaded Brass Ingots and Castings. ii. IS: 733-1983 Wrought aluminium and aluminium alloy bars, rods and sections for general engineering purpose. iii. IS: 737- 1986 Wrought aluminium and aluminium alloy shuts & springs for general engineering purpose. iv. IS: 1632- 1993 Optical instruments bubbles ( Ist revision) v. RDSO Drg. No. Spirit Level TM/2004 3.0 TERMINOLOGY: For the purpose of this specification following shall apply: 3.1 Bubble : The bubble is a device, which when fitted to an instrument can be used to define a reference horizontal plane as in leveling. It consists of a glass tube containing a filling liquid having low viscosity and which maintains its fluidity over a fairly wide range of temperature, thereby making its use possible at low temperature as well. 3.2 Bubble vial : A sealed glass tube suitably processed, partially filled with a liquid of low freezing point and low viscosity leaving an air-bell inside. 3.3 Air-bell : The small space, created inside the sealed tube due to its partial filling, which forms a bubble of mixed air and liquid vapour. 3.4 Bubble-Run : The travel of the `air-bell’ inside the tube corresponding to any angular tilt given to the bubble. JRE/SSE/SSRE ARE/DTM/EDTM PEDTM Page 2 of 8 Prepared By: Checked By: Issued By 111 317359/2020/O/o PED/TMM/RDSO ISO: 9001-2015 Document No.: TM-52 Revision 01 Date Effective From:--/--/---- Document Title: Specification of Spirit Level (For use in Box type gauge cum level) 3.5 Sensitivity : The sensitivity of a bubble is the angle of tilt which would cause its air-bell to move through one scale division. 3.6 Roll : The rotation of the bubble round an axis which is parallel to the axis of the bubble. 3.7 Effective Range : The internally processed surface of the bubble which responds correctly to the various functional requirements and is usually confined to the limits of the etched lines. 3.8 Consistency : The characteristics of the air- bell of the bubble each time to set itself to its original position throughout its effective range when such a setting is disturbed & restored. 3.9 Sluggishness : The incapability of the air-bell to exhibit corresponding deviations in its position as warranted by small changes in it. 4.0 SIZE & TYPE: The bubbles shall be of cylindrical type having outside diameter of 9.0 + 1 mm and length 70 + 1.0 mm . 5.0 Accuracy : The accuracy of the spirit level shall be from 0.05 mm/M to 0.1 mm/M at 270 C. 6.0 GENERAL REQUIREMENTS: 6.1 The glass vial shall be suitably housed in aluminium - alloy ( IS: 737-1986,Design HE 9 or HE 30) tubing in such a way that the housing shall protect primarily the vial from damage i.e there shall not be any physical contact of vial with the housing. The mounting of the vial with the housing shall be such as to permit slight longitudinal expansion ( Thermal ). 6.2 The metallic housing shall have a bubble opening of 50 mm x 8 mm. The metallic housing including the vial shall be encased in a square tubing having a transparent Perspex covering on the top. 6.3 All machined surfaces on the level shall be painted to have suitable protective finish. 6.4 The weight of the spirit level shall be within 150 gms (unpacked). 7.0 MATERIALS: 7.1 Housings of the vial : The main housing of the bubble shall be made from square tubing of Aluminium extrusion as per IS: 733 -83, Design-HE 9 or HE 30. The initial circular housing (Mounts ) of the vial shall be made of Aluminium alloy as per IS: 737-86 (Grade-1C). JRE/SSE/SSRE ARE/DTM/EDTM PEDTM Page 3 of 8 Prepared By: Checked By: Issued By 112 317359/2020/O/o PED/TMM/RDSO ISO: 9001-2015 Document No.: TM-52 Revision 01 Date Effective From:--/--/---- Document Title: Specification of Spirit Level (For use in Box type gauge cum level) 7.2 Mountings : Fixing of the vial with mount shall preferably be done by providing Teflon /adhesive tape at the ends of the vial. Both the ends of the mount shall be plugged with brass/ gunmetal plugs, suitably designed. 7.3 Vial : The glass tube used shall be well annealed, transparent, free from scratches, flaws and other defect and of 1.25 mm to 2.5 mm wall thickness. The composition of the glass shall be such that it is not reacted upon by the filling liquid. Borosilicate or soft soda glass tubes are suitable. 7.4 Filling liquid : Ethyl ether, industrial methylated spirit ( Grade -1), methyl alcohol, acetone, absolute alcohol or any other suitable liquid shall be used. The liquid shall be clear, shall not be discoloured and shall not cloud or noticeably change in fluidity with, age or at temperature as low as - 40 0 C. The liquid shall be chemically inert to the glass tube and the colouring material, if used. The liquid shall be free of water and impurities and shall not decompose under light and temperature. 7.5 Base Plate: The spirit level shall have two base plates as per drawing no. TM/2004 made of brass of grade LCB2 conforming to IS: 292-1983. The bottom of the base plate shall be machined so as to move smoothly over the ramps of gauge cum level. 8.0 FUNCTIONAL REQUIREMENTS: The spirit level shall have the following technical features: (i) Base length : 200 mm + 1 mm (ii) Base width : 20 mm + 0 - 1 (iii) Height : 25 + 1 mm (iv) Bubble opening : 50 mm x 8 mm (length x width) (v) Sensitivity : 2 Min. 30 Sec per 2 mm arc division of the vial (vi) Least count of graduation : 2 mm (vii) Weight (Without packing box) :150 gms. (approx). (viii) Effective length of bubble : 20 + 1 mm 8.1 The Perspex on the top of the spirit level shall be as transparent as glass and shall have enough mechanical strength to withstand breakage. Transparency shall be retained and shall not be frosted or hazy due to aging. 8.2 The dimension of the glass tube shall be so proportioned and the filling liquid inside the glass tube shall be so adjusted that both ends of the bubble may always be read against scale over a temperature range of 5 to 45 0 C and the air-bell shall retain an effective length for accurate measurements up to 70 0 C. 8.3 The bubble shall show displacement for at least a cross level difference of 1.0 mm. The design of the spirit level shall be such that necessary adjustment of the vial can subsequently be made in a simple way. JRE/SSE/SSRE ARE/DTM/EDTM PEDTM Page 4 of 8 Prepared By: Checked By: Issued By 113 317359/2020/O/o PED/TMM/RDSO ISO: 9001-2015 Document No.: TM-52 Revision 01 Date Effective From:--/--/---- Document Title: Specification of Spirit Level (For use in Box type gauge cum level) 8.4 The spirit level shall be durable and its functioning shall not be affected by aging up to its life span. 8.5 The spirit level shall have a suitable arrangement within the housing for adjusting the bubble vial portion. The arrangement mechanism shall be able to shift one end of the vial in vertical plan. 9.0 TESTING & CALIBRATION: 9.1 Requirements for Calibration : Calibration shall be made as per following requirements : (i) Adjustable Calibration test bench : The test bench shall have the facility for tilting the spirit level, being calibrated, from one end with an accuracy to match the bubble’s sensitivity.