Exhibit 3.1

                      RESTATED CERTIFICATE OF INCORPORATION
                                       OF
                            FARR INTERNATIONAL, INC.

      The  undersigned,  Allan B. Foy and M. S. Farr,  certify that they are the
President  and  Secretary,   respectively,   of  Farr  International,   Inc.,  a
corporation  organized and existing under the laws of the State of Delaware (the
"Corporation"), and do hereby further certify as follows:
          1.  The name of the Corporation is Farr International, Inc.
          2. The original  Certificate of  Incorporation  of the Corporation was
      filed in the Office of the  Secretary of State of the State of Delaware on
      April 7, 1987.
          3. This  Restated  Certificate  of  Incorporation  was duly adopted by
      stockholder  written  consent in accordance with Sections 228, 242 and 245
      of the General Corporation Law of the State of Delaware.
          4.  The text of the Certificate of Incorporation of the Corporation
      as amended hereby is restated to read in its entirety, as follows:

                                    ARTICLE I

      The name of the Corporation is Farr Company.

                                   ARTICLE II

      The address of the  registered  office of the  Corporation in the State of
Delaware is 229 South  State  Street in the City of Dover,  County of Kent.  The
name of its  registered  agent at that  address  is  United  States  Corporation
Company.

                                   ARTICLE III

      The purpose of the  Corporation is to engage in any lawful act or activity
for which a  corporation  may now or hereafter  be  organized  under the General
Corporation Law of the State of Delaware as set forth in Title 8 of the Delaware
Code (the "GCL").

                                   ARTICLE IV

      The  total  number of shares of stock  which the  Corporation  shall  have
authority to issue is 5,000,000 shares of common stock, par value $.10 per share
(the "Common Stock").

                                    ARTICLE V

      The business and affairs of the  Corporation  shall be managed by or under
the  direction  of the  Board  of  Directors  consisting  of not  less  than six
directors  nor more than nine  directors,  the exact  number of  directors to be
determined  from time to time by  resolution  adopted by the Board of Directors.
The directors shall be divided into three classes,  designated Class I, Class II
and Class III.  Each  class  shall  consist,  as nearly as may be  possible,  of
one-third  of the total  number of  directors  constituting  the entire Board of
Directors. The term of the initial Class I directors shall terminate on the date
of the 1988 annual  meeting of  stockholders;  the term of the initial  Class II
directors   shall   terminate  on  the  date  of  the  1989  annual  meeting  of
stockholders; and the term of the initial Class III directors shall terminate on
the date of the 1990 annual meeting of  stockholders.  At each annual meeting of
stockholders  beginning in 1988, successors to the class of directors whose term
expires at that annual  meeting  shall be elected for a three-year  term. If the
number of directors is changed,  any increase or decrease  shall be  apportioned
among the classes so as to  maintain  the number of  directors  in each class as
nearly equal as possible,  and any additional  directors of any class elected to
fill a vacancy  resulting from an increase in such class shall hold office for a
term that shall coincide with the remaining  term of that class,  but in no case
will a decrease in the number of  directors  shorten  the term of any  incumbent
director.  A director shall hold office until the annual meeting for the year in
which his term expires and until his

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death,  resignation,  retirement,  disqualification  or removal from office. Any
vacancy  on the  Board of  Directors,  howsoever  resulting,  may be filled by a
majority of the directors  then in office,  even if less than a quorum,  or by a
sole  remaining  director.  Any  director  elected to fill a vacancy  shall hold
office for a term that shall  coincide  with the term of the class to which such
director shall have been elected.

                                   ARTICLE VI

      Any or all of the directors of the  Corporation may be removed from office
at any time, but only for cause and only by the affirmative  vote of the holders
of a majority of the outstanding shares of the Corporation then entitled to vote
generally in the election of directors,  considered for purposes of this Article
VI as one class.

                                   ARTICLE VII

      Elections  of directors  at an annual or special  meeting of  stockholders
shall be by written ballot unless the Bylaws of the Corporation  shall otherwise
provide.

                                  ARTICLE VIII

      Any  action  required  or  permitted  to be taken at any annual or special
meeting of stockholders  may be taken only upon the vote of the  stockholders at
an annual or special meeting duly noticed and called,  as provided in the Bylaws
of  the  Corporation,  and  may  not  be  taken  by a  written  consent  of  the
stockholders pursuant to the GCL.

                                   ARTICLE IX

      Special meetings of the stockholders of the Corporation for any purpose or
purposes  may be called at any time by the Board of  Directors,  the Chairman of
the Board of Directors or the President. Special meetings of the stockholders of
the Corporation may not be called by any other person or persons.

                                    ARTICLE X

      The  affirmative  vote of the  holders  of not less than 80 percent of the
outstanding shares of "Voting Stock" (as hereinafter defined) of the Corporation
shall  be  required  for  the  approval  or   authorization   of  any  "Business
Combination"  (as  hereinafter  defined) of the  Corporation  with any  "Related
Person" (as hereinafter defined);  provided, however, that the 80 percent voting
requirement shall not be applicable if:

          (1) The Board of  Directors of the  Corporation  by a vote of not less
      than 80 percent of the  directors  then holding  office (a) has  expressly
      approved in advance the  acquisition of the  outstanding  shares of Voting
      Stock of the  Corporation  that  caused  the  Related  Person  to become a
      Related Person or (b) has approved the Business  Combination  prior to the
      Related  Person  involved  in the  Business  Combination  having  become a
      Related Person;

          (2) The Business  Combination  is solely between the  Corporation  and
      another  corporation,  one hundred percent of the Voting Stock of which is
      owned directly or indirectly by the Corporation; or

          (3) The Business Combination is a merger or consolidation and the cash
      or fair market value of the property, securities or other consideration to
      be received per share by holders of Common Stock of the Corporation in the
      Business  Combination  is not less than the  highest per share price (with
      appropriate  adjustments for recapitalizations and for stock splits, stock
      dividends and like  distributions) paid by the Related Person in acquiring
      any of its holdings of the Corporation's Common Stock.

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      For the purposes of this Article:

          (i)  The term "Business Combination" shall mean  (a)  any  merger  or
      consolidation  of the  Corporation or a subsidiary  with or into a Related
      Person,  (b) any sale,  lease,  exchange,  transfer or other  disposition,
      including  without  limitation a mortgage or any other security device, of
      all or any  "Substantial  Part" (as  hereinafter  defined)  of the  assets
      either  of  the  Corporation  (including  without  limitation  any  voting
      securities of a subsidiary)  or of a subsidiary to a Related  Person,  (c)
      any  merger  or  consolidation  of a  Related  Person  with  or  into  the
      Corporation  or a  subsidiary  of the  Corporation,  (d) any sale,  lease,
      exchange,  transfer or other disposition of all or any Substantial Part of
      all or any  Substantial  Part of the  assets  of a  Related  Person to the
      Corporation  or a subsidiary of the  Corporation,  (e) the issuance of any
      securities   (other  than  by  way  of  pro  rata   distribution   to  all
      shareholders)  of the  Corporation or a subsidiary of the Corporation to a
      Related Person,  (f) the acquisition by the Corporation or a subsidiary of
      the  Corporation  of  any  securities  of  a  Related   Person,   (g)  any
      recapitalization that would have the effect of increasing the voting power
      of a Related Person and (h) any agreement,  contract or other  arrangement
      providing  for any of the  transactions  described in this  definition  of
      Business Combination.

          (ii) The term "Related  Person" shall mean and include any individual,
      corporation,  partnership  or other person or entity which,  together with
      its  "Affiliates"  and  "Associates"  (as defined on April 1, 1985 in Rule
      12b-2 under the Securities Exchange Act of 1934),  "Beneficially Owns" (as
      defined on April 1, 1985 in Rule 13d-3 under the  Securities  Exchange Act
      of 1934) in the  aggregate  10 percent or more of the  outstanding  Voting
      Stock  of  the  Corporation,   and  any  Affiliate  or  Associate  of  any
      individual, corporation, partnership or other person or entity.

          (iii) The term  "Substantial  Part" shall mean more than 10 percent of
      the book value of the total  assets of the  company in  question as of the
      end of  its  most  recent  fiscal  year  ending  prior  to  the  time  the
      determination is being made.

          (iv) Without limitation, any shares of Common Stock of the Corporation
      that  any  Related  Person  has  the  right  to  acquire  pursuant  to any
      agreement,  or upon exercise of conversion rights, warrants or options, or
      otherwise, shall be deemed beneficially owned by the Related Person.

          (v) For the purposes of  subparagraph  (3) of this  Article,  the term
      "other  consideration to be received" shall include,  without  limitation,
      Common  Stock  of  the   Corporation   retained  by  its  existing  public
      shareholders  in  the  event  of  a  Business  Combination  in  which  the
      Corporation is the surviving corporation.

          (vi) The term  "Voting  Stock"  shall mean all  outstanding  shares of
      capital stock of the Corporation or another  corporation  entitled to vote
      generally in the election of directors and each  reference to a proportion
      of shares of Voting  Stock  shall  refer to such  proportion  of the votes
      entitled to be cast by such shares.

                                   ARTICLE XI

      The  provisions set forth in this Article XI and in Articles VI, VIII, IX,
X and XIV herein may not be  repealed  or amended in any  respect,  unless  such
action is  approved by the  affirmative  vote of the holders of not less than 80
percent of the  outstanding  shares of Voting Stock (as defined in Article X) of
the Corporation.

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                                   ARTICLE XII

      The officers of the  Corporation  shall be chosen in such a manner,  shall
hold  their  offices  for such  terms  and shall  carry  out such  duties as are
determined  by the  Board of  Directors,  subject  to the  right of the Board of
Directors to remove any officer or officers at any time with or without cause.

                                  ARTICLE XIII

      A. The  Corporation  shall  indemnify  to the full  extent  authorized  or
permitted by law (as now or hereafter in effect) any person made,  or threatened
to be made, a defendant or witness to any action,  suit or  proceeding  (whether
civil or criminal or  otherwise)  by reason of the fact that he, his testator or
intestate,  is or was a director or officer of the  Corporation  or by reason of
the fact that such director or officer, at the request of the Corporation, is or
was serving any other corporation,  partnership, joint venture, employee benefit
plan or other enterprise, in any capacity. Nothing contained herein shall affect
any  rights to  indemnification  to which  employees  other  than  directors  or
officers  may be entitled by law. No  amendment  or repeal of this  Section A of
Article  XIII shall apply to or have any effect on any right to  indemnification
provided hereunder with respect to any acts or omissions occurring prior to such
amendment or repeal.

      B. No  director  of the  Corporation  shall be  personally  liable  to the
Corporation or its stockholders for monetary damages for any breach of fiduciary
duty by such a director as a director. Notwithstanding the foregoing sentence, a
director  shall be liable to the extent  provided by applicable  law (i) for any
breach of the director's duty of loyalty to the Corporation or its stockholders,
(ii) for acts or  omissions  not in good  faith  or  which  involve  intentional
misconduct or a knowing  violation of law,  (iii) pursuant to Section 174 of the
GCL, or (iv) for any  transaction  from which such director  derived an improper
personal  benefit.  No  amendment to or repeal of this Section B of this Article
XIII shall apply to or have any effect on the liability or alleged  liability of
any director of the  Corporation for or with respect to any acts or omissions of
such director occurring prior to such amendment or repeal.

      C.  In furtherance and not in limitation of the powers conferred by
statute:
          (i) the Corporation  may purchase and maintain  insurance on behalf of
      any person who is or was a  director,  officer,  employee  or agent of the
      Corporation,  or is  serving  at  the  request  of  the  Corporation  as a
      director, officer, employee or agent of another corporation,  partnership,
      joint venture,  trust,  employee benefit plan or other enterprise  against
      any  liability  asserted  against  him  and  incurred  by him in any  such
      capacity,  or  arising  out of his  status  as  such,  whether  or not the
      Corporation  would have the power to indemnify him against such  liability
      under the provisions of law; and

          (ii)  the  Corporation  may  create  a trust  fund,  grant a  security
      interest and/or use other means (including, without limitation, letters of
      credit, surety bonds and/or other similar arrangements),  as well as enter
      into contracts providing  indemnification to the full extent authorized or
      permitted by law and including as part thereof  provisions with respect to
      any or all of the  foregoing  to ensure the payment of such amounts as may
      become  necessary  to  effect  indemnification  as  provided  therein,  or
      elsewhere.

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                                   ARTICLE XIV

      In furtherance  and not in limitation of the powers  conferred by statute,
the Board of Directors is expressly authorized to adopt, repeal, alter, amend or
rescind  the  Bylaws  of  the  Corporation.  In  addition,  the  Bylaws  of  the
Corporation  may be adopted,  repealed,  altered,  amended,  or rescinded by the
affirmative  vote  of  sixty-six  and  two-thirds  percent  (66  2/3  %) of  the
outstanding stock of the Corporation entitled to vote thereon.

                                   ARTICLE XV

      The Corporation reserves the right to repeal, alter, amend, or rescind any
provision  contained in this Certificate of Incorporation,  in the manner now or
hereafter prescribed by statute, and all rights conferred on stockholders herein
are granted subject to this reservation.


      IN WITNESS WHEREOF, Farr International, Inc. has caused its corporate seal
to be hereunto affixed and this Restated Certificate of Incorporation to be
signed by Allan B. Foy, its President, and attested by M. Spencer Farr, its
Secretary, this 29th day of May, 1987.


                                    FARR INTERNATIONAL, INC.


                                    By  /s/  Allan B. Foy
                                        -----------------
                                             Allan B. Foy
                                              President



ATTEST:

By  /s/  M. S. Farr
    ---------------
         M. S. Farr
         Secretary








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