1. A continuous process for the production of poly(trimethylene terephthalate) comprising the steps of:
(a) continuously producing poly(trimethylene terephthalate) oligomers comprising 1,3-trimethylene and terephthalate repeating units and having a degree of polymerization of from about 1.9 to about 3.5 by (i) ester exchange reaction of dimethyl terephthalate with excess 1,3-propanediol at an elevated temperature or (ii) direct esterification reaction of terephthalic acid with excess 1,3-propanediol at an elevated temperature;
(b) continuously precondensing the poly(trimethylene terephthalate) oligomers to form a poly(trimethylene terephthalate) prepolymer having an intrinsic viscosity of at least about 0.23 and gaseous by-products comprising volatilized by-product 1,3-propanediol; and
(c) continuously polymerizing the poly(trimethylene terephthalate) prepolymer to form higher molecular weight poly(trimethylene terephthalate) having an intrinsic viscosity of at least about 0.55 dlg and additional gaseous by-products comprising volatilized by-product 1,3-propanediol,
wherein:
(i) the gaseous by-products are condensed in at least one spray condenser to form condensed by-product 1,3-propanediol, which is then collected in at least one hotwell under conditions such that the temperature of the condensed by-product 1,3-propanediol entering the at least one hotwell is at about 50\xb0 C. or lower;
(ii) a portion of the condensed by-product 1,3-propanediol from the hotwell is cooled in at least one heat exchanger and then sprayed in the at least one spray condenser to condense the gaseous by-products; and
(iii) a portion of the condensed by-product 1,3-propanediol from the hotwell, without purification, is fed back into the ester exchange or direct esterification reactions at one or more locations where the temperature is about 150\xb0 C. or higher.
2. The process of claim 1, wherein the condensed by-product 1,3-propanediol entering the at least one hotwell is at about 30\xb0 C. to about 45\xb0 C.
3. The process of claim 1, wherein the additional gaseous by-products are condensed in at least one spray condenser to form at least one stream of condensed by-product 1,3-propanediol which is then collected in at least one hotwell and cooled under conditions such that the temperature of the condensed additional by-product 1,3-propanediol entering the at least one hotwell is about 50\xb0 C. or lower; and (ii) a portion of the condensed additional by-product 1,3-propanediol from the hotwell is cooled in at least one heat exchanger and then sprayed in the at least one spray condenser to condense the gaseous by-products.
4. The process of claim 3, wherein the condensed by-product 1,3-propanediol from the additional gaseous by-products entering the at least one hotwell is at about 35\xb0 C. to about 45\xb0 C.
5. The process of claim 3, wherein a portion of the condensed additional by-product 1,3-propanediol from the hotwell, without purification, is fed back into the ester exchange or direct esterification reactions at one or more locations where the temperature is about 150\xb0 C. or higher.
6. The process of claim 1, wherein the condensed by-product 1,3-propanediol comprises 1,3-propanediol and solid by-product comprising a mixture of trimethylene terephthalate cyclic dimer and poly(trimethylene terephthalate) oligomers.
7. The process of claim 1, wherein (i) the gaseous by-products and the additional gaseous by-products are condensed in at least one spray condenser for the precondensing stage (b) to form a condensed by-product 1,3-propanediol, and at least one spray condenser for the polycondensation stage (c) to form a condensed additional by-product 1,3-propanediol, which is then collected in at least one hotwell under conditions such that the temperature of the condensed by-product 1,3-propanediol and the condensed additional by-product 1,3-propanediol entering the at least one hotwell is about 50\xb0 C. or lower; (ii) wherein a portion of the condensed by-product 1,3-propanediol and the condensed additional by-product 1,3-propanediol is cooled in at least two heat exchangers and then sprayed in the at least two spray condensers to condense the gaseous by-products and additional gaseous by-products; and (iii) a portion of the condensed by-product 1,3-propanediol and the condensed additional by-product 1,3-propanediol from the hotwell, without purification, is fed back into the ester exchange or direct esterification reactions at one or more locations where the temperature is about 150\xb0 C. or higher.
8. The process of claim 1, wherein a direct esterification reaction is used in step (a).
9. The process of claim 1, wherein an ester exchange reaction is used in step (a).
10. The process of claim 3, wherein a direct esterification reaction is used in step (a).
11. The process of claim 3, wherein an ester exchange reaction is used in step (a).
12. The process of claim 5, wherein a direct esterification reaction is used in step (a).
13. The process of claim 5, wherein an ester exchange reaction is used in step (a).
14. The process of claim 7, wherein a direct esterification reaction is used in step (a).
15. The process of claim 7, wherein an ester exchange reaction is used in step (a).
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
We claim:
1. A pressure sensor module for use in conjunction with an electropneumatic brake, the pressure sensor module comprising:
a casing having an upper casing and a lower casing cooperatively formed to mate with one another to form a generally sealed interior chamber there between;
at least one ear on a lateral edge of the casing, the at least one ear including an aperture formed therein to receive a fastener in order to fasten the pressure sensor module onto a manifold;
a plurality of pneumatic input ports on a first face of the casing;
a plurality of transducers inside the casing and in communication with its own port;
a common electrical connector on a second face of the casing; and,
each of the transducers being connected, interior the casing, to the common electrical connector.
2. The pressure sensor module as in claim 1, further comprising a retainer adjacent the ear to retain a fastener passing through the apertures in the aperture prior to fastening the pressure sensor module to the manifold.
3. The pressure sensor module as in claim 2, wherein the retained fastener is an Allen screw.
4. The pressure sensor module as in claim 3, further comprising a washer positioned between the fastener and the aperture.
5. The pressure sensor module as in claim 1, further comprising a latch on one of the upper or lower housing, and a catch on another of the upper or lower housing, the latch and the catch cooperatively configured to engage one another and hold the upper and lower casings together.
6. The pressure sensor module as in claim 1, further comprising a raised wall positioned at each respective pneumatic input port, each raised wall extending from an inner surface of the lower casing.
7. A pressure sensor module for use in conjunction with an electropneumatic brake, the pressure sensor module comprising:
a casing;
a printed circuit board positioned within the casing;
a gasket positioned between the casing and the printed circuit board;
a plurality of pneumatic input ports on a first face of the casing;
a plurality of transducers mounted on the printed circuit board inside the casing and in communication with its own port;
a common electrical connector on a second face of the casing; and,
each of the transducers being connected, interior the casing, to the common electrical connector.
8. The pressure sensor module as in claim 7, wherein the transducers are in electric communication with the electric connector mounted on the printed circuit board.
9. The pressure sensor module as in claim 3, further comprising a plurality of internal o-rings, each internal o-ring positioned adjacent a respective pneumatic input port on an face of the lower housing.
10. The pressure sensor module as in claim 7, further comprising raised walls extending inwardly from each of the pneumatic input ports.
11. The pressure sensor module as in claim 10, further comprising a gasket positioned inside the casing, the gasket having holes formed to receive the raised walls, which retain the gasket in place.
12. The pressure sensor module as in claim 7, wherein the casing includes a lower casing and an upper casing;
the lower casing having a protuberance protruding outwardly from a lateral edge of the lower casing; and
the gasket includes a retaining finger cooperatively configured with the protuberance, such that as the casings are closed, the protuberance and the retaining finger will align with one another, thereby wedging the retaining finger between the protuberance on the lower casing and an ear extending from the upper casing.
13. The pressure sensor module as in claim 12, wherein the retaining finger extends into the aperture within the ears to engage a fastener passing there though thereby retaining the fastener in the aperture.