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1、BRITISH STANDARD BS 7780-4: 1995 Specification for Rotary shaft lip type seals Part 4: Performance test procedures UDC 62-762.84:620.1004.15 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:25:15 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7780-4:1995 This B
2、ritish Standard, having been prepared under the direction of the Engineering Sector Board, was published under the authority of the Standards Board and comes into effect on 15 March 1995 BSI 03-1999 The following BSI references relate to the work on this standard: Committee reference MCE/11 Draft fo
3、r comment 93/715652 DC ISBN 0 580 23707 9 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Engineering Sector Board to Technical Committee MCE/11, upon which the following bodies were represented: British Compressed Air Society British Fl
4、uid Power Association British Hydromechanics Research Association British Industrial Truck Association British Rubber Manufacturers Association Ltd. Ministry of Defence Society of British Aerospace Companies Ltd. Society of Motor Manufacturers and Traders Ltd. Amendments issued since publication Amd
5、. No.DateComments Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:25:15 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7780-4:1995 BSI 03-1999i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2References1 3Pre-test procedure1 4Dynamic
6、 test1 5Dynamic low temperature test3 6Material testing of elastomeric components4 Annex A (informative) An example of a seal test report for the dynamic test6 Annex B (informative) An example of a seal test report for the dynamic low temperature test8 Annex C (informative) An example of a material
7、test report9 Figure 1 Typical example of dynamic test apparatus2 Figure 2 Typical example of low temperature test fixture3 Table 1 Standard shaft and housing dimensions1 Table 2 Recommended temperatures for compression set test4 Table 3 Test fluids for fluid immersion test4 Table 4 Temperature for d
8、ry heat ageing test5 List of referencesInside back cover Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:25:15 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7780-4:1995 ii BSI 03-1999 Foreword This Part of BS 7780 has been prepared under the direction of the
9、Engineering Sector Board and supersedes BS 1399 Specification for rotary shaft lip seals, Part 2:1970 Methods of performance rating, which has been withdrawn. The standard is one of a series which specify rotary shaft lip type seals. It is the fourth Part of a new standard which represents a complet
10、e revision and renumbering of BS 1399. This fourth Part adopts the dynamic performance requirements specified in ISO 6194-4:1988 Rotary shaft lip type seals Part 4: Performance test procedures, published by the International Organization for Standardization (ISO). Quality control requirements, forme
11、rly included in BS 1399-2:1970, and requirements for low temperature operation are also included. Other Parts of the new standard are: Part 1: Nominal dimensions and tolerances (implementing ISO 6194-1:1982); Part 2: Vocabulary (implementing ISO 6194-2:1991); Part 3: Storage, handling and installati
12、on (implementing ISO 6194-3:1988); Part 4: Identification of visual imperfections (implementing ISO 6194-5:1990). A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a Bri
13、tish Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 10, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendment
14、s incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:25:15 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7780-4:1995 BSI 03-19991 1 Scope This Part of BS 7780 specifies test r
15、equirements for rotary shaft lip type seals. The tests may be used for qualification purposes. Materials quality control, dynamic testing and supplementary low temperature testing requirements are also covered. 2 References 2.1 Normative references This Part of BS 7780 incorporates, by dated or unda
16、ted reference, provisions from other publications. These normative references are made at the appropriate places in the text and the cited publications are listed on the inside back cover. For dated references, only the edition cited applies: any subsequent amendments to or revisions of the cited pu
17、blication apply to this British Standard only when incorporated in the reference by amendment or revision. For undated references, the latest edition of the cited publication applies, together with any amendments. 2.2 Informative references This British Standard refers to other publications that pro
18、vide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but reference should be made to the latest editions. 3 Pre-test procedure 3.1 Inspect all seals submitted for testing for conformity to a relevant drawing o
19、r detailed specification declared by the seal manufacturer. 3.2 For seals with an elastomeric component, ensure that the seal manufacturer has stated the material batch number from which the seals have been made, together with the nominal density, nominal hardness, maximum compression set value and
20、maximum mass change after immersion in the test fluid. Where the seal is required for the low temperature stiffness test, ensure that the seal manufacturer has also stated the maximum modulus after test at the selected test temperature. Ensure that the batch of elastomer has been tested in accordanc
21、e with clause 6. 3.3 To facilitate accurate analysis of the test results, determine the following data concerning the physical characteristics of the seal and test apparatus before testing: a) lip diameter (without spring, measured not less than 24 h after removal of spring); b) lip diameter (with s
22、pring, immediately after fitting); c) outer case mean diameter and out-of-roundness; d) shaft diameter, material hardness and surface roughness; e) housing diameter, material and surface roughness; f) wiper lip diameter, where applicable (with and without primary lip spring fitted). 3.4 Ensure that
23、the specified shaft eccentricity and housing off-set of the test apparatus have been incorporated. 4 Dynamic test 4.1 Test apparatus The test apparatus shall be similar to the typical example shown in Figure 1 and shall consist of a suitable housing for retaining the test fluid and for positioning t
24、he test seals, as well as a rotating member having a spindle mounted horizontally on suitable bearings. The design of the housing for the seal shall be in accordance with the dimensions specified in BS 7780-1:1994. The housing and the rotating member shall be capable of reproducing the eccentricity
25、and off-set referred to in 3.4. Where it is not practicable to provide a test apparatus with the particular shaft and housing size relevant to the application, the test apparatus shall be selected from the standard sizes listed in Table 1. The size selected shall be that nearest to the application s
26、ize. Table 1 Standard shaft and housing dimensions The test apparatus shall also conform to the following additional requirements: a) the shaft shall be capable of cycling and/or maintaining the shaft speeds to within 3 %; b) the shaft shall be capable of maintaining the specified test eccentricity
27、under dynamic conditions to within 0.03 mm throughout each test; c) the test head shall be designed and constructed so as to maintain the housing bore alignment relative to the test shaft axis within 0.03 mm throughout the operating temperature range; Shaft diameterHousing diameterSeal width mmmmmm
28、20 40 60 90 200 35 55 80 120 230 7 8 8 12 15 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:25:15 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7780-4:1995 2 BSI 03-1999 d) the design of the test head support shall ensure minimum deformation and vibration; e
29、) the test head and heat transfer system shall be capable of maintaining the temperature of the test fluid within 3 C, and shall be vented to atmosphere; f) heat shall be applied in a manner that does not subject the test fluid to high localized temperatures which could cause fluid decomposition; g)
30、 the test shaft shall have a surface which is free of helical machine marks and shall comply with the requirements for shafts specified in BS 7780-1:1994; h) the test housing bore shall comply with the requirements specified in BS 7780-1:1994; i) the materials, surface finish and dimensions of the t
31、est shaft and test housing bore shall conform as closely as possible to the shaft and housing bore to be used in service; j) a minimum quantity of 0.75 l of test fluid shall be used; k) the level of the test fluid in the test head shall be 0.3d to 0.5d above the lowest point of the shaft diameter d;
32、 l) for seal housings with inboard bearings, the test housing shall be suitably relieved at the bearing supports to prevent excessive fluid pressure between the bearing and seals; m) means shall be provided for collecting and measuring the mass of any fluid leakage from the seals during the test. 4.
33、2 Installation 4.2.1 Thoroughly clean the test head of contaminants and extraneous matter. 4.2.2 Install the seal into the test head so that the cumulative eccentricities of the seal and the test head are known. 4.2.3 Ensure that the plane of the seal lip is perpendicular to the shaft axis, unless o
34、therwise specified. 4.2.4 Locate the test shaft in such a position that a clean unused area of its surface is in contact with the sealing element of the test seal. Figure 1 Typical example of dynamic test apparatus Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08
35、 11:25:15 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7780-4:1995 BSI 03-19993 4.3 Test conditions Apply test conditions which simulate the seal application operating conditions specified by the customer, i.e. normal operating temperature, normal operating shaft speed, maximum envisaged operating
36、temperature and maximum envisaged shaft speed. (See Annex A.) 4.4 Test procedure Submit six seals to ten cycles, each of 24 h duration, consisting of 14 h at normal operating temperature and speed, see Annex A, according to service conditions, and 6 h at the maximum envisaged operating temperature a
37、nd speed, followed by a 4 h shut-down when the test machine is allowed to cool to room temperature. If applicable, each alternate cycle shall be in the reverse direction of rotation. 4.5 Post-test measurements After completion of the test, determine the seal lip diameters, and where applicable, the
38、wiper lip diameters. 4.6 Recording Record all test data on a seal test report (an example of a seal test report for the dynamic test is shown in Annex A). 4.7 Acceptance criteria The total leakage from all six seals shall not be greater than 12 g and the leakage from any single seal shall not be gre
39、ater than 3 g. 5 Dynamic low temperature test 5.1 General This test is applicable to all rotary shaft lip type seals for which the minimum specified operating temperature is stated to be 10 C or lower. 5.2 Test fixture The test fixture shall be similar to the typical example shown in Figure 2. The t
40、est shaft and seal housing shall simulate the envisaged maximum eccentricities specified by the customer. The test shaft diameter, the test shaft surface roughness and seal housing dimensions shall also be those specified by the customer or as specified in BS 7780-1:1994. 5.3 Installation The requir
41、ements of 4.2.1, 4.2.2 and 4.2.3 shall be followed. 5.4 Test procedure Submit two seals to the following procedure. a) Soak the seal in test fluid for 70 h at normal operating temperature (see Annex B). b) Remove the seal from the test fluid and shake off the excess. Do not blot dry. c) Lubricate te
42、st shaft with a small quantity of the test fluid. d) Correctly locate the seal in the test fixture. Figure 2 Typical example of low temperature test fixture Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:25:15 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 77
43、80-4:1995 4 BSI 03-1999 e) Fill the test fixture with the test fluid to submerge the wetted side of the seal lip. f) Place the test fixture in a cold box and soak for 16 h at the minimum temperature specified by the customer (see Annex B). g) With the test fixture still in the cold box, rotate the s
44、haft 10 revolutions by hand at an approximate speed of 60 rpm, pausing once every 180. h) Remove test fixture from cold box and allow to stand at room temperature for a minimum period of 6 h. i) Remove seal from test fixture. 5.5 Post test measurements Inspect for leakage that may have occurred duri
45、ng the test and visually inspect seal lip, noting any cracks, tears, splits or any imperfections that may have appeared as a result of the test. 5.6 Recording Record all test data on a seal test report (an example of a seal test report for the dynamic low temperature test is shown at Annex B). 5.7 A
46、cceptance criteria There shall be no visible damage to lip and there shall be no leakage greater than that specified by the customer. 6 Material testing of elastomeric components 6.1 General Quality control tests shall be carried out on all batches of material from which the dynamic test seals are m
47、anufactured. In order to ensure that the material used for production seals does not vary significantly from that of the dynamic test seals, subsequent production batches shall also be tested. Tests shall be in accordance with clauses 6.2 to 6.7. 6.2 Density Each batch of material shall be tested in
48、 accordance with BS 903-A1:1980. The result shall be the specified nominal density (see 3.2) within a tolerance of 0.02 for all materials except silicone rubber which shall be within a tolerance of 0.04. 6.3 Hardness Each batch of material shall be tested in accordance with BS 903-A26:1969. The resu
49、lt shall be the specified nominal hardness (see 3.2) within a tolerance of 5 IRHD. 6.4 Compression set Each batch of material shall be tested in accordance with BS 903-A6:1992. The duration of test shall be 22 h and the temperature of the test for different elastomers shall be as given in Table 2. Table 2 Recommended temperatures for compression set test The result shall be not greater than the specified maximum value (see 3.2). 6.5 Fluid immersion Each batch of material shall be tested in accordance with BS 903-A16:1987. The durat