HVAC/R system contaminant removal solvent having N-propanol and flame suppresion additives, and method for flushing HVAC systems using the solvent

Abstract

An aerosolized HVAC/R system solvent for decontaminating HVAC/R components and line sets The solvent contains 25-90 wt % propellant, and 10-75 wt % solvent mixture which is about 60-95 wt % trans-1,2,dichloroethylene, about 5-20 wt % n-propanol, and an inerting constituent providing a weight percent ratio of the inerting constituent to n-propanol of less than 1.5. The solvent is packaged in a container that is connected to the HVAC/R components or line sets to be decontaminated for supplying the solvent mixture under pressure to the HVAC/R components or line sets.

Claims

1. An aerosolized HVAC/R system solvent for decontaminating HVAC/R components and line sets, comprising 25-90 wt % propellant, and 10-75 wt % solvent mixture, the solvent mixture comprising: (i) about 60-95 wt % trans-1,2, dichloroethylene; (ii) about 5-20 wt % n-propanol; and (iii) an inerting constituent selected from the group consisting of hydrofluorocarbons, hydrofluoroethers, and mixtures thereof to provide a weight percent ratio of the inerting constituent to n-propanol of less than 1.5; and wherein the propellant is selected from the group consisting of isomers of R-1234 refrigerant.

2. An aerosolized HVAC/R system solvent for decontaminating HVAC/R components and line sets, comprising 25-90 wt % propellant, and 10-75 wt % solvent mixture, the solvent mixture comprising: (i) about 60-95 wt % trans-1,2, dichloroethylene; (ii) about 5-20 wt % n-propanol; and (iii) an inerting constituent selected from the group consisting of hydrofluorocarbons, hydrofluoroethers, and mixtures thereof to provide a weight percent ratio of the inerting constituent to n-propanol of less than or equal to 1.33.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The addition of n-propanol to a mixture of t-DCE and MFHs or t-DCE and HFC-365mfc/MFBE results in a solvent with a significantly larger capacity for moisture and acid removal than t-DCE alone, mixtures of t-DCE and MFHs, or mixtures of t-DCE and HFC-365mfc/MFBE. I have also discovered that increasing the flame-suppressing, propellant concentrations in aerosol formulas of t-DCE/MFHs/n-propanol and t-DCE/HFC-365mfc/MFBE/n-propanol beyond 20 wt % enables the use of higher concentrations of t-DCE and/or n-propanol in solution with MFHs and HFC-365mfc/MFBE while maintaining non-flammability by ASTM D-3065. My invention also now enables, via the inerting action of the propellant, the use of inerting solvents With better KR values that would otherwise suffer from flammability issues. The Vertrel? Sion? is given a range of 85-97 wt % t-DCE by the manufacturer, and I found the concentration to be approximately 93 wt % by GC-MS. The EnSolv? NEXT is given a range of 70-90 wt % t-DCE by the manufacturer, and I found the concentration to be approximately 90 wt % by GC-MS. My formulas, due to the use of propellant concentrations higher than 20 wt %. contain inerting solvent/property modification solvent wt % ratios of less than 1.5. As above noted, this enables a larger fraction of the solvent mixture to be occupied by productive cleaning components (e.g. t-DCE for oil removal, n-propanol for acid and moisture removal) and less of the liquid solvent being occupied by inerting flame suppressant solvents which do not contribute in a meaningful way to cleaning, Tables 1-3 show the different flushing solvents that went evaluated. The results for moisture removal are shown in Example 1.

(2) TABLE-US-00001 TABLE 1 Composition (wt %) Sample # 100 t-DCE 1 100 Diversitech Pro-Flush? 2 100 Nu-Calgon Rx-11 3 100 ACE Power Flush 4 100 Vertrel? Sion? 5 95 Vertrel? Sion?/5 n-propanol 6 90 Vertrel? Sion?/10 n-propanol 7 80 Vertrel? Sion?/20 n-propanol 8 100 EnSolv? NEXT 9 95 EnSolv? NEXT/5 n-propanol 10 90 EnSolv? NEXT/10 n-propanol 11 80 EnSolv? NEXT/20 n-propanol 12

(3) TABLE-US-00002 TABLE 2 Composition (wt %) Sample # 100 Vertrel? Sion? 5 95 Vertrel? Sion?/5 n-propanol 6 90 Vertrel? Sion?/10 n-propanol 7 80 Vertrel? Sion?/20 n-propanol 8

(4) TABLE-US-00003 TABLE 3 Composition (wt %) Sample # 100 EnSolv? NEXT 9 95 EnSolv? NEXT/5 n-propanol 10 90 EnSolv? NEXT/10 n-propanol 11 80 EnSolv? NEXT/20 n-propanol 12

Example 1

(5) 2.5 g of denied water was added to 25 g of solvent to determine the moisture absorption capacity. The sample was swirled and allowed to phase separate before drawing from the organic layer for moisture analysis. 0.1 ml of solvent was it into a Karl Fischer titrator to determine the amount of moisture absorbed.

(6) TABLE-US-00004 Sample # Moisture in Solvent (ppm) 1 400 2 4000 3 650 4 2200 5 460 6 1210 7 5600 8 17590 9 620 10 1160 11 6300 12 18550

(7) As can be seen in this example, the addition of the MFHs or HFC-365mfc/MFBE into the flushing mixture had little effect on moisture absorption; however, the addition of the 5-20% (by weight) n-propanol (Samples ##6-8 and 10-12) made an unexpected and dramatic increase in the moisture absorption capability of the cleaning mixture. The mixtures of either Vertrel? Sion? or EnSolv? NEXT with at least 10 wt % n-propanol are also superior to other line-set flushes on the market. Even with polar additives of acetone and butyl-acetate, Sample #2 is still significantly less effective than my formulas (Samples ##7-8 and 11-12) for removing moisture. Sample #4 discloses 1-11 wt % ethanol in their SDS, however, it is not as effective as n-propanol at about 10-20 wt % in my formulas.

(8) Strong acids are also important contributors to compressor failure in HVAC/R systems. Another unexpected result that I discovered was that the addition of the n-propanol dramatically increased the amount of acid absorbed when compared to the acid absorption of t-DCE alone, mixtures of t-DCE and MFHs or mixtures of t-DCE and HFC-365mfc/MFBE. Example 2 shows the results of my acid testing.

Example 2

(9) 86?l wt % HCl in water was added to 20 g of solvent. The samples listed above in Table 1 were swirled and allowed to phase separate if necessary. 5 mL of the organic layer was titrated with a Mettler Toledo DL 70 automatic titrator.

(10) TABLE-US-00005 Sample # HCl in Solvent (mg/L) 1 40 2 174 3 42 4 2000 5 91 6 1830 7 1863 8 2079 9 50 10 1380 11 1813 12 1929

(11) As can be seen in Example 2, the addition of the MFHs or HFC-365mfc/MFBE into the flushing mixture had a negligible impact on acid absorption; however, the addition of 2-20 wt % propanol made an unexpected and far more significant increase in the acid absorption capability of the resulting cleaning mixture. The mixtures of either Vertrel? Sion? or EnSolv? NEXT with at least 10 wt % propanol are also superior to or on-par with other line-set flushes on the market. Even with polar additives of acetone and butyl-acetate, Samples #2 is still significantly less effective than my formulas (Samples ##6-8 and 10-12) with n-propanol for removing acid. The ethanol in sample #4 is effective in removing acid, but is not as effective as propanol in removing moisture in my formulas. Commercially available flushes also have lower amounts of t-DCE than my samples.

(12) t-DCE has a dosed cup flash point of 6? C. This is highly flammable and unacceptable for use as a cleaning solvent in many applications including cleaning air conditioning and refrigeration components, since a brazing torch will most likely he used to connect these components. Adding approximately 3.5 wt % MFHs to t-DCE results in a formula with no measurable closed cup flash point according to U.S. Pat. No. 8,410,039. Safety Data Sheets for EnSolv? NEXT also indicate that the addition of HFC-365mfc/MFBE to t-DCE results in a solvent with no closed cup flash point, Since many alcohols are flammable, it was unexpected that ternary mixtures of t-DCE, MFHs, and, n-propanol would be non-flammable. For instance, n-propanol has a flash point of 22? C. However, I found that a ternary mixture of 77.2 wt % t-DCE, 2.8 wt % MFHs, and 20 wt % n-propanol was non-flammable with a substantially higher flash point of 45? C. Since the n-propanol provides an unexpected and dramatic increase in the acid and moisture removal of the ternary mixture of the cleaner, and due to its far lower cost (compared to the other ingredients), it makes a far superior line-set flushing formulation.

(13) One common method of flushing HVAC/R line sets is to use a pressurized solvent canister to administer solvent to the parts needing cleaning. I believe this is the preferred method since, by packaging the mixture in a pressurized can, the introduction of atmospheric air and all the moisture contained in ambient air, is avoided in as much as the value of a cleaner that absorbs moisture is reduced if the cleaner is already saturated with moisture from the air even before it is used. It is also understood that, for readily apparent reasons, the pressurizing propellant itself should be non-flammable, (e.g. R-134a) so as not to introduce flammability to the solvent during use. I have discovered that, in addition to being non-flammable itself, R-134a has the added advantage of providing flame suppression as a propellant for administering flushing solvents containing flammable additives. I have also found that up to approximately 20 wt % (of liquid solvent) n-propanol can be used in t-DCE/MFHs and t-DCE/HFC-365mfc/MFBE mixtures (with t-DCE at approximately 90 wt %, higher than what is used by competitors) when propelled by 20-30 wt % (of total aerosol mixture) R-134a and still remain non-flammable as determined by ASTM D3065-01. Example 3 describes these tests.

Example 3

(14) ASTM D3065-01 was followed. Briefly, a 2 in. flame was generated from a paraffin candle with a 1 in. diameter base. The aerosol dispenser was shaken, inverted, and placed 6 in. from the flame. The liquid solvent was dispensed for 4 seconds and the length of any flame projection was recorded. An aerosol causing the flame to extend 18 in. or longer is deemed flammable. This procedure uses an open/close threaded valve to dispense the aerosol instead of a more typical aerosol nozzle with binary on/off function. This ASTM test is still the most relevant for this application to evaluate flammability of flushing solvent aerosols.

(15) TABLE-US-00006 TABLE 4 Flame R-134a Vertrel? Sion? wt % n-propanol wt % Extension wt % (wt % w/o R-134a) (wt % w/o R-134a) (in.) 90 9 (90) 1 (10) 1 40 54 (90) 6 (10) 1 20 72 (90) 8 (10) 4 50 42.5 (85) 7.5 (15) 1 40 51 (85) 9 (15) 1 30 59.5 (85) 10.5 (15) 3 20 68 (85) 12 (15) 6 50 40 (80) 10 (20) 3 40 48 (80) 12 (20) >18

(16) TABLE-US-00007 TABLE 5 Flame R-1234ze Vertrel? Sion? wt % n-propanol wt % Extension wt % (wt % w/o R-1234ze) (wt % w/o R-1234ze) (in) 90 9 (90) 1 (10) 1 50 45 (90) 5 (10) 3 40 54 (90) 6 (10) 4 30 63 (90) 7 (10) >18

(17) TABLE-US-00008 TABLE 6 Flame R-134a EnSolv? NEXT wt % n-propanol wt % Extension wt % (wt % w/o R-134a) (wt % w/o R-134a) (in) 90 9 (90) 1 (10) 1 40 54 (90) 6 (10) 3 30 63 (90) 7 (10) 3 45 47 (85) 8 (15) 1 40 51 (85) 9 (15) 1 35 55 (85) 10 (15) >18 60 32 (80) 8 (20) 1 50 40 (80) 10 (20) 1 40 48 (80) 12 (20) 4

(18) TABLE-US-00009 TABLE 7 Flame R-1234ze EnSolv? NEXT wt % n-propanol wt % Extension wt % (wt % w/o R-1234ze) (wt % w/o R-1234ze) (in) 90 9 (90) 1 (10) 1 50 45 (90) 5 (10) 3 45 50 (90) 5 (10) 4 40 54 (90) 6 (10) >18

(19) As can be seen in this example, the addition of the R-134a to the formula suppresses flammability when dispensed in an aerosol. The flame generally extends further as the amount of propellant is decreased, however, the aerosol remains non-flammable by ASTM D3065-01 down to about 20-40 wt % propellant depending on the n-propanol concentration with Vertrel? Sion? and EnSolv? NEXT. Another key element of my discovery is that the aerosol formulation does not necessitate that the liquid solvent be azeotropic or near-azeotropic. U.S. Pat. Nos. 8,410,039, 6,951,835 and 5,478,492 all teach azeotropic or near-azeotropic compositions. I have discovered that the aerosol does not need to be azeotropic or near-azeotropic because the propellant suppresses flammability during administration of the cleaner even in the presence of up to 20 wt % flammable n-propanol. U.S. Pat. No. 6,852,684 only teaches using 20 wt % propellant for aerosol flammability testing, Furthermore, U.S. Pat. No. 6,852,684 only shows data up to about 13 wt % ethanol on a propellant-free basis. While oxygen-containing solvents are disclosed, the data presented is only for ethanol and methanol. Examples 1 and 2 clearly show that there is a significant benefit to acid and moisture removal using higher n-propanol concentrations. Additionally, U.S. Pat. No. 6,852,684 teaches only using t-DCE in the range of 55-75 wt % in the solvent due to the need for higher amounts of inerting agents needed to suppress flame when limited to only 20 wt % propellant, whereas I have found a formulation that allows significantly higher concentrations of t-DCE and/or n-propanol. Vertrel? Sion? and EnSolv? NEXT as tested included approximately 93 and 90 wt % t-DCE, respectively. My formulation results in wt % ratios of inerting solvent/n-propanol less than 1.5, as compared to a minimum ratio of 1.5 taught in U.S. Pat. No. 6,852,684 when using HFC inerting solvents or aerosol Power Flush by Atlantic Chemical & Equipment Company with a minimum ratio greater than 1.7.

(20) I have also found that R-1234ze and R-1234yf which are currently proposed environmentally-friendly non-flammable replacement propellants, as well as other isomers of R-1234 can be used instead of R-134a. Other compatible non-flammable environmentally-safer propellants are, of course, contemplated for use with the present invention as they become available.

(21) While I have shown and described a currently preferred embodiment in accordance with my invention, it should be understood that the same is susceptible of further changes and modifications without departing from the scope of my invention. I, therefore, do not intend to be limited to the details shown and described herein but intend to cover all such changes and modifications that are encompassed by the attached claims.