Apparatus for quantitative determination of total base or acid number of oil

• US 5,800,782 A
• Filed: 09/12/1996
• Issued: 09/01/1998
• Est. Priority Date: 11/18/1994
• Status: Expired due to Term

• Current Assignee: Dexsil Corporation
• Original Assignee: Dexsil Corporation
• Inventors: Finch, Stephen R., Hagstrom, Richard A., Lynn, Timothy D.
• Primary Examiner(s): Pyon, Harold Y.
• Application Number:
  US08/712,969
• Time in Patent Office: 719 Days
• Field of Search: 436/60, 436/61, 436/100, 436/101, 436/102, 422/58, 422/61, 422/75, 422/100, 422/101, 422/102, 604/241
• US Class Current: 422/75
• CPC Class Codes: G01N 31/16 using titration
• CPC Class Codes: G01N 31/221 for investigating pH value
• CPC Class Codes: G01N 33/2876 Total acid number
• CPC Class Codes: Y10T 436/15 Inorganic acid or base [e.g. , hcl, sulfuric acid, etc. ]
• CPC Class Codes: Y10T 436/153333 Halogen containing
• CPC Class Codes: Y10T 436/156666 Sulfur containing

Abstract

The total base number of an oil sample of measured volume is determined by solvating the oil sample, adding a predetermined amount of acidic species to the solvated sample to react the acidic species with any basic species contained in the oil sample, extracting the remaining acidic species into an extractant phase, separating the extractant phase from the oil sample, and measuring the acidic species content of the extractant phase to determine the quantity of basic species in the oil sample. The same technique may be used to determine the total acid number of an oil sample by adding a predetermined amount of basic species to the sample and measuring the basic species content of the extractant phase. Apparatus comprising a test kit for carrying out the method comprises a sampling syringe (10) for drawing a fixed volume of sample oil, a reaction container (22) containing premeasured quantities of acidic species and solvent in first and second frangible ampules (28, 30) and a titration container (32) containing a pH indicator in a third frangible ampule (38). A titration syringe (50) contains a basic solution for titrating the extractant and bears graduations (55) which are scaled and numbered to indicate the total base number of the sample, and a cap (56) for securing the titration syringe (50) to titration container (32).

Claims

1. An apparatus for determining the quantity of acidic or basic resident species present in an oil sample, the apparatus comprising:

(a) sampling means for drawing a predetermined quantity of oil as a sample and introducing the sample into a reaction container;

(b) a container system comprising;

(i) a reactant container containing a predetermined quantity of a reactant species comprising one of an acidic species and a basic species, for reacting with a basic or acidic resident species in the sample, if any;

(ii) an extractant container containing a predetermined quantity of an extractant in which the reactant species is soluble but which is immiscible with the sample, for extracting unreacted reactant species from the sample; and

(iii) at least one reaction container dimensioned for receiving the sample from the sampling means and for receiving the predetermined quantity of the reactant species, to allow the reactant species to be mixed with the sample, and for receiving the extractant to allow the extractant to be mixed with, and to separate from, the sample to extract the unreacted reactant species from the sample;

(c) pH measuring means for determining the pH of the extractant;

wherein the pH measuring means comprises;

(d) a titration syringe containing a titrant for the reactant species, for titrating a predetermined quantity of the extractant having unreacted reactant species therein; and

(e) an indicator container containing a titration end point indicator for indicating the end point of the titration of the extractant with the titrant;

wherein the at least one reaction container is dimensioned for further receiving the titrant and the end point indicator; and

wherein the titration syringe bears graduations that are scaled and labeled to indicate one of the total base number and total acid number of the sample at the end point of the titration of reactant species in such predetermined quantity of extractant after reaction of said predetermined quantity of the reactant species with a sample drawn with the sampling means and extraction of remaining reactant therefrom by the extractant.

2. The apparatus of claim 1 wherein at least one of the reactant container and the extractant container comprises a frangible ampule.

3. The apparatus of claim 1 further comprising a solvent container containing a premeasured quantity of a solvent for mixing with the sample to produce a solvent phase to which the reactant species is added.

4. The apparatus of claim 1 comprising a second reaction container for receiving and holding the extractant, the titrant and the titration end point indicator separate from the sample during the titration.