摘要:
The invention relates to soluble homo- or copolyimides of formula I ##STR1## wherein Y is hydrogen or the substituents Y, together with the linking N atom, are a divalent radical of of formulae IIa to IIc ##STR2## and X is the radical of of an aromatic amine after removal of the amino end groups, and n is an integer from 5 to 150.The compounds of the invention are readily soluble in organic solvents and are suitable tougheners for epoxy, bismaleimide and triazine resin systems.
摘要:
Compositions comprisingA) compounds of formula I ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are identical or different and each is hydrogen or methyl, and X is a divalent organic radical comprising from 2 to 60 carbon atoms,B) compounds of formula II, III or IV ##STR2## wherein each of R.sub.11, R.sub.12 and R.sub.13, independently of the others, is a hydrogen atom or a C.sub.3 -C.sub.10 alkenyl group, at least one of the radicals R.sub.11 to R.sub.13 being an alkenyl group, ##STR3## wherein Q is a direct bond, methylene, 2,2-propylidene, --CO--, --O--, --S--, --SO-- or --SO.sub.2 -- and each of R.sub.14, R.sub.15, R.sub.16 and R.sub.17, independently of the others, is a hydrogen atom or a C.sub.3 -C.sub.10 alkenyl group, at least one of the radicals R.sub.14 to R.sub.17 being an alkenyl group, or ##STR4## wherein each of R.sub.18, R.sub.19, R.sub.20, R.sub.21, R.sub.22 and R.sub.23, independently of the others, is a hydrogen atom, C.sub.1 -C.sub.4 alkyl or C.sub.3 -C.sub.10 alkenyl, at least one of the radicals R.sub.18 to R.sub.23 being an alkenyl group, and a is a number from 0 to 10, andC) compounds of formula V ##STR5## wherein R.sub.24 and R.sub.25 are identical or different and each is hydrogen or C.sub.1 -C.sub.10 alkyl, or of formula VI ##STR6## wherein R.sub.26 and R.sub.27 are identical or different and each is hydrogen or C.sub.1 -C.sub.8 alkyl, and Y is a direct bond, methylene, 2,2-propylidene, --O--, --S--, --SO--, --SO.sub.2 -- or --CO--, are distinguished by good storage stability, favourable processing behaviour and high glass transition temperatures.
摘要:
Compositions comprisingA) compounds of formula I ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are identical or different and each is hydrogen or methyl, and X is a divalent organic radical comprising from 2 to 60 carbon atoms, andB) compounds of formula II ##STR2## wherein R.sub.5 and R.sub.6 are identical or different and each, independently of the other, is C.sub.1 -C.sub.8 alkyl, and Y is hydrogen or an allyl radical, are distinguished by a favorable processing behaviour and high glass transition temperatures.
摘要:
In a hydraulic control device (S) comprising a double-acting hydraulic consumer (V) which is actuable by pressure via two working conduits (4, 5) and secured in at least one working direction by a load holding valve (H) which is hydraulically openable and closable in a controlled way, further comprising a control pressure conduit (12) which is connected to a control connection of the load holding valve and selectively actuable, as well as a damping throttle (13) arranged in control pressure conduit (12), there is provided a valve (15, 15', 15", 15'", 15.sup.IV) which during the controlled closing movement of load holding valve (H, 6) is automatically responsive to a delay of the controlled closing movement which is caused by the instantaneous viscosity of the pressure medium and/or a too tight setting of damping throttle (13) and is critical as to the after-running of hydraulic consumer (V) under a load (F), with the valve switching in such a case to passage and bypassing damping throttle (13). The valve offsets the effect of a pressure medium which is too cold, and/or a setting of the damping throttle that is too tight for an intended damping action with respect to a controlled closing of the load holding valve, and it ensures the rapid closing of the load holding valve as is required for stopping and holding the load, in particular during a safety shut-off operation.
摘要:
In the case of a hydraulic control device for an oscillating load moving system comprising a double-acting hydroconsumer (V), which is adapted to be selectively connected to a pressure source (P) or to a reservoir (T) via two separate main lines (9, 10) and a control valve (C), and further comprising a load supporting valve (H), which is arranged in at least one main line (10) between the control valve (C) and the hydroconsumer (V) and which is adapted to be opened from the other main line (9) via a pilot line (16), a damping device (X), which consists of a bypass line (23) and an interference throttle aperture (D2), is connected to the pilot line (16) of the load supporting valve (H). The pilot line (16) has provided therein a throttle aperture (D1) which is smaller than the interference throttle aperture (D2).
摘要:
An electromagnetically operable valve, comprising a coil and an electromat containing an armature, the armature of which impinges an actuating member connected to or forming an active member of the valve in operating connection and a lever mechanism arranged between the armature and the valve member for the step-up or step-down transmission of the stroke.In valves of this kind known from prior art a considerable expense in construction is incurred for the accommodation of the lever mechanism which offsets the savings with respect to the costs and the constructive area in long-stroke magnets; this is avoided by a novel construction incorporating the lever mechanism into the electromagnet and between the armature and the actuating member.
摘要:
The invention relates to a two-position switching valve having hydraulic f-holding properties and comprising a closure piston disposed in a flow path for displacement between an open position and a closure position for controlling a pressure between a maximum value and a minimum value, and operatively coupled to a control piston mounted for displacement in a housing. In known switching valves of this type, a creeping approach of respective switching points is scarcely avoidable under certain operating conditions. In accordance with the invention, a reliable switching function is achieved by forming the housing bore as a continuous stepped bore for slidably guiding therein a stepped piston consisting of a closure piston, a control piston, and a piston portion and by providing alternately openable and closable flow connections therein permitting an annular space between the closure piston and the piston portion to communicate with an annular chamber adjacent the control piston in the closure position of the closure piston, and the annular chamber to be pressure-relieved in the open position of the closure piston. These provisions result in the generation of a servo force for abrupt switch-over operation of the valve.
摘要:
The invention relates to a hydraulic control valve comprising a housing w a housing bore (2) formed therein, a control piston (3) being guided in said housing bore for sliding displacement between a neutral position (n) for zero-pressure through-flow and at least one control position (I, II), and further comprising a pressure inlet (6) opening in said housing bore (2), a through-passage (8) in said control piston (3), and a discharge outlet (7) communicating with said pressure inlet via said through-passage in the zero-pressure through-flow position. In a control valve of this type, particularly if employed in a high pressure hydraulic system, displacement of the control piston from a control position to the neutral position is hampered by unsatisfactory pressure compensation. In accordance with the invention, this undesirable effect is avoided by forming substantialy diametrally opposite said discharge outlet (7) a relief area (9, 9', 16, 17, 18, F26) compensating at least the effective area of said discharge outlet and being of substantially the same size as the discharge outlet and subjected to the same pressure as the latter. For ensuring effortless displacement of the control piston of an upstream control valve from its neutral position in a battery-type arrangement of a plurality of control valves even if a downstream control valve is in its control position, there is further provided an area (33) compensating the effective area of the relief area (9, 9', 16, 17, 18, F26) said compensating area communicating with return pressure at least in the neutral position (N).
摘要:
A pressure oil or hydraulic fluid pump is provided wherein a container holding a supply of the liquid to be pumped also contains the fluid pump assembly and houses an electric motor driving the pump assembly. The container is filled or partially filled with the liquid and has the stator of the electric motor supported in it so that the liquid flows directly around and through the motor while the pump is operating.
摘要:
A seated valve comprising a housing and a valve seat, a cylinder bushing for an actuation and a closure element provided in a bore of said housing, said closure element being adjustable in relation to said valve seat by means of the actuator, said closure element being a full sphere having a concentric waist portion the diameter of which being larger than the diameter of said valve seat but smaller than the inner guiding diameter of said cylinder bushing, which guiding diameter of said cylinder bushing being smaller than the diameter of said full sphere, such that said closure element can be inserted into or removed from said cylinder bushing from the out side of said housing.