1、Designation: D 2713 91 (Reapproved 2001)Designation: 395/98An American National StandardStandard Test Method forDryness of Propane (Valve Freeze Method)1This standard is issued under the fixed designation D 2713; the number immediately following the designation indicates the year oforiginal adoption
2、 or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the measurement of the drynessof propane-type produ
3、cts such as, but not limited to, commer-cial propane (see Specification D 1835).NOTE 1This test method is not applicable to propane-type productscontaining antifreeze agents. However, the relative freeze times of suchmaterials tested by this procedure may be an indication of the tendency ofthese pro
4、ducts to cause freezing in pressure reducing regulators.1.2 The values stated in SI units are to be regarded as thestandard. The values in parentheses are for information only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsib
5、ility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1265 Practice for Sampling Liquefied Petroleum (LP)Gases - Manual Method2D 1835 Specification f
6、or Liquefied Petroleum (LP) Gases23. Summary of Test Method3.1 A liquid-phase sample of the product to be tested isflowed through the propane water test valve to cool the valvebody. After cooling, the test valve is partially closed to a smallpreset flow rate and the time required for the valve to fr
7、eeze,and thus interrupt the normal flow, is recorded. The averageobserved time for several successive observations is recordedas the observed freeze time.4. Significance and Use4.1 This test is a functional test in which the water concen-tration in the product is related to product behavior characte
8、r-istics in a pressure-reducing system of special design to arriveat a measure of product acceptability in common use applica-tions. Experience has demonstrated that excessive water con-tent (dissolved water) will cause freeze-up difficulties inpressure reducing systems.5. Apparatus5.1 Propane Water
9、 Test Valve3A specially constructed andcalibrated valve manufactured solely for this test (Note 2). Thevalve has two open positions, a wide open position for flushing,and a small preset flow position for testing.NOTE 2The propane water test valve is a precision instrument and itshould be so treated.
10、 It should not be dropped, strained in any way, ordisassembled, except to clean the filter in accordance with the manufac-turers instructions. Valves suspected of being defective should bereturned to the manufacturer for inspection, reconditioning or recalibra-tion.5.2 Stop Watch.5.3 Sample Cylinder
11、, having a minimum capacity of 11.4 L(3 gal).5.4 Cloth, dry, clean.6. Sampling6.1 The sensitivity of moisture test measurements to uncon-trollable sampling errors is such as to warrant conducting allimportant tests at the propane supply source rather than onsamples taken from the bulk supply. Refere
12、e tests should beconducted on the bulk supply.6.2 If the test cannot be run by connecting the apparatusdirectly to the bulk propane supply, a sample can be taken intoa sample cylinder having a minimum capacity of 11.4 L. Insuch cases, the sample shall be taken strictly in accordancewith directions g
13、iven in Practice D 1265.7. Procedure7.1 Connect (Note 3) the propane water test valve to theliquid line of the bulk product source or to the liquid phaseconnection of the sample cylinder described in 6.2, so that thebody of the valve is horizontal and the outlet opening is aimedvertically upward. Th
14、e valve should be positioned so that the1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricantsand is the direct responsibility of SubcommitteeD02.Hon Liquified Petroleum Gas.Current edition approved March 15, 1991. Published July 1991. Originallypublish
15、ed as D 2713 68 T. Last previous edition D 2713 86.2Annual Book of ASTM Standards, Vol 05.01.3A list of suppliers of LP-Gas freeze valves is available from ASTM as aresearch report. Request D021423.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, U
16、nited States.internal surfaces of the outlet opening are clearly visible to theoperator. Open the main valve on the sample source (Note 4)and set the valve on the test apparatus in the purge position.Purge the sample line and the apparatus for 15 s. Close the testvalve for 2 or 3 s, open it for 2 or
17、 3 s, close it for 2 or 3 s, andcontinue this intermittent opening and closing until a uniformfrost cover has accumulated on the housing around the outlet ofthe test valve. Snap the valve closed to the test position andsimultaneously start the stop watch. Stop the watch at theinstant the liquid prop
18、ane ceases to flow through the valve(Note 4).NOTE 3Use only clean, dry pipe or metallic tubing for making thisconnection. Do not use rubber hose or plastic lined hose.7.2 Sample pressure, at the inlet to the test valve, must notbe more than 100 psi (690 kPa) above the vapor pressure of theproduct at
19、 the sample temperature. When sample sourcepressure is above this limit a liquid propane pressure regulatormust be used to hold the pressure, at the inlet to the test valve,within this limit.NOTE 4The instant liquid propane stops flowing through the valve,frost will form on the internal surfaces of
20、the valve outlet. The watchshould be stopped at this instant. The operator is forewarned of this instantof stoppage if he will watch the frost line climb and roll over the lip of thevalve outlet.7.3 Disregard the observed time for the initial freeze-off run.Quickly wipe the test valve outlet threads
21、 with a clean, drycloth. Open the test valve to the purge position for about 15 sto ensure the removal of ice from the preset opening. Repeatthe operations as described in the trial run until three succes-sive freeze-off times check each other to within6 2s.Forfreeze-off times of less than 1 min thi
22、s may require as many asseven or eight test runs. If the freeze-off time on threeconsecutive test runs is 3 min or greater, the test on the productcan be discontinued and the freeze-off time recorded as greaterthan 3 min. For freeze-off times shorter than 3 min record theaverage time for three conse
23、cutive determinations as thefreeze-time.NOTE 5Failure to purge the apparatus with the valve open to thepurge position for about 15 s between tests will give erroneous results.Purging assures that ice formed in the preset opening in the preceding testwill be removed.8. Report8.1 If the valve does not
24、 freeze off within 60 s, report theproduct as “pass.”9. Precision and Bias9.1 In the case of passfail data or results from otherqualitative tests, no generally accepted method for determiningprecision or bias is currently available.NOTE 6Data from a series of tests conducted in 1967 indicate thefoll
25、owing: At moisture levels of 14 and 26 ppm, all valves can be expectedto give freeze times over 3 min; at a moisture level of 49 ppm it can beexpected that none of the valves will give freeze times over 18 s; at amoisture level of 93 ppm it can be expected that none of the valves willgive freeze tim
26、es over 5 s.9.2 BiasThe procedure in Test Method D 2713 for mea-suring dryness of propane has no bias because the value ofdryness is defined only in terms of this test method.10. Keywords10.1 dryness; freeze valve; propane; waterThe American Society for Testing and Materials takes no position respec
27、ting the validity of any patent rights asserted in connectionwith any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any suchpatent rights, and the risk of infringement of such rights, are entirely their own responsibility.This sta
28、ndard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Headquart
29、ers. Your comments will receive careful consideration at a meeting of the responsibletechnical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make yourviews known to the ASTM Committee on Standards, at the address shown below.This standard
30、 is copyrighted by ASTM, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above address or at610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website (www.astm.org).D 27132
