Abstract: Esters of formula: HS—X—COOR in which X denotes a C1-C4 alkylene radical and R a C1-C18 alkyl radical, are prepared by reaction of a hydrosulphide with the corresponding halocarboxylic ester: Y—X—COOR where Y denotes a chlorine or bromine atom. The reaction is performed under a hydrogen sulphide pressure of at least 10 bars absolute, and preferably in an anhydrous or substantially anhydrous alcoholic medium.

Abstract: Process for the preparation of a carboxyalkylthiosuccinic acid of formula ##STR1## in which n=1 to 3 and R.dbd.H or CH.sub.3, a mercapto ester of formula HS--(CH.sub.2).sub.n --COOR' in which R' is a C.sub.1 to C.sub.4 alkyl radical, is reacted, in aqueous medium and without a catalyst, with maleic acid, citraconic acid or their anhydride. The invention is more particularly directed towards the preparation of carboxyethylthiosuccinic acid (CETSA).

Abstract: Esters of formula:HS--X--COORin which X denotes a C.sub.1 -C.sub.4 alkylene radical and R a C.sub.1 -C.sub.18 alkyl radical, are prepared by reaction of a hydrosulphide with the corresponding halocarboxylic ester:Y--X--COORwhere Y denotes a chlorine or bromine atom. The reaction is performed under a hydrogen sulphide pressure of at least 10 bars absolute, and preferably in an anhydrous or substantially anhydrous alcoholic medium.

Abstract: The invention relates to production of esters of mercaptocarboxylic acids and alcohols forming an azeotrope with water.The esterification is carried out continuously in the presence of an excess of alcohol and the water formed is removed by entraining azeotropically under vacuum at a temperature such that the residual water concentration in the reaction mixture remains constantly below 0.5% by weight.The process according to the invention applies more particularly to the synthesis of octyl esters of thioglycolic acid.

Abstract: The housing comprises an actuating lever (8) articulated about a transversal spindle (13), and a mechanism (16), controlled by the lever, capable of driving, in opposite direction, two rods (17, 18); each rod is provided, at its end farthest away from the housing, with a bolt, in order to bring about a locking at an upper point and a lower point, respectively. The actuating lever (8) comprises a unilateral thrust organ (19) capable of co-operating with one or two complementary abutments (21, 22) provided for on a driving organ (23) of the mechanism (16), whereby the lever (8) may be tilted from one position into another, to co-operate with the appropriate complementary abutment (21, 22), in order to selectively allow the fitting onto a "right-hand" or "left-hand" door.

Abstract: The antipanic lock comprises at least a bolt and an actuating rod pivotingly connected to a door by a unit formed by at least two housings fixed onto the door and two levers (2) integral, towards their one end, with the actuating rod and pivotingly mounted, at their other end, into an associated housing (4); said lock comprises a torsion spring (10), in a first dihedron corresponding to a first direction of opening of the door, the actuating rod and the levers (2) towards a neutral position, one of the levers being a control lever co-operating with members in order to actuate the bolt.

Abstract: The invention relates to an electrical connector for transmitting electrical signals between the outside and the inside of a well having a well head (20) terminated by a valve assembly (10). The connector comprises at least two inductively coupled electrical coils (1A, 1B; 5A, 5B) whose respective winding axes are aligned with the axis (zz') of the well head. The coils are integrated in the fluid connector interconnecting the valve assembly and the well head, with one of the coils being releasably fixed to the valve assembly (10) while the other coil is releasably fixed to the well head (20).

Abstract: Safety-drum antipanic lock comprising a bolt (3, 103), an actuating rod pivotingly connected to the door, at each of its ends, by means of a unit formed by a housing (1, 101) fixed onto said door and a lever (2, 102) pivotingly mounted, in said housing (1, 101), at least one lever (2, 102) being an actuating lever cooperating with components of its housing (1, 101) to actuate the bolt (3, 103). The housing (1, 101) of the actuating lever (2, 102) is associated with at least a safety-drum (19, 20; 120) driving a bit (21, 23; 151) co-operating with actuating means for said housing to actuate the bolt (3, 103). Said housing (1, 101) of the actuating lever (2, 102) comprises at least two different operating means (14, 15a, 15b; 114) capable of separately co-operating each with a drum (19, 20; 120) to actuate said bolt (3, 103).

Abstract: The invention relates to a hydraulic method and apparatus for the remote hydraulic control of a device connected to a hydraulic fluid source by means of at least one flexible line filled with hydraulic fluid.Hydraulic energy is accumulated in the flexible line by increasing the pressure of the hydraulic fluid in the line so that the line increases in volume. The pressure is maintained in the line so that the hydraulic energy thus accumulated by the expansive deformation of the line may be used rapidly to control the device.The invention finds particular application in the control of an underwater valve in the petroleum industry.

Abstract: A method and article for horticultural protection of plant growths during the maturation thereof whereby the volume exchange of oxygen, carbon dioxide, and moisture is controlled in accordance with the demands thereof during maturation.