Description:-Please see the attached .pdf file- , Claims:We claim:
1. A steam trap comprising:
an inlet (205) for receiving a flow of steam and condensate;
a collection chamber (206, 706) coupled to the inlet (205) so as to receive the steam and condensate (250) and defining a collection volume (204) in which the steam and condensate are separated from one another by gravity,
a valve (202) provided in a wall of the collection chamber (206, 706),
a first sensor for determining the temperature of the steam at the inlet,
a second sensor for determining the temperature of the condensate (250) in the collection volume (204),
a controller (230) coupled to the first and second sensors and the valve (202), the controller (230) being configured to control the opening and closing of the valve (202) so as maintain a difference in the temperature of the steam at the inlet (205) and the temperature of the condensate (250) in the collection volume (204) determined using the first and second sensors at a predefined subcool value setpoint, wherein the subcool value is the temperature difference between the upstream gaseous phase temperature and the temperature of the condensate (250) in the collection volume (204), characterized in that
the controller (230) is configured to determine the quantity of condensate (250) discharged from the collection volume (204) using a flow rate calculation for a choked flow of vaporizing liquid.
2. The steam trap as claimed in claim 1, wherein the controller (230) determines the quantity of condensate (250) discharged from the collection volume (204) using the formula m =
or a formula derived therefrom.
3. The steam trap as claimed in claim 2, wherein the valve (202) is a solenoid valve which has an open position and a closed position, wherein the controller (230) controls a duty time of the solenoid valve to maintain the difference in temperature at the subcool value setpoint.
4. The steam trap as claimed in claim 3, wherein the value of FLP used in the calculation of the quantity of condensate (250) is based on the duty cycle and the predefined subcool value, wherein the duty cycle is the proportion of time that the valve (202) is open.
5. The steam trap as claimed in claim 4, wherein the value of FLP used in the calculation of the quantity of condensate (250) is based on the ratio of the duty cycle (DC) to the subcool value (SC).
6. The steam trap as claimed in claim 5, wherein FLP is calculated using the formula where A and B are constants.
7. The steam trap as claimed in claim 6, wherein the constants A and B are set at different values for different pressure bands.
8. The steam trap as claimed in any of claims 1-7, wherein the first sensor is a pressure sensor and wherein the temperature of the steam at the inlet is derived based on a saturated steam table.
9. The steam trap as claimed in any of claims 1 to 7, wherein the first sensor is a temperature sensor.
10. The steam trap as claimed in any of claims 1-9, wherein the controller (230) is a PID controller.
11. The steam trap as claimed in any of claims 1-10, wherein the controller (230) has a user interface through which a user is able to set the subcool value setpoint.
12. The steam trap as claimed in any of claims 1-11, wherein the controller (230) is configured to determine and output a user notification confirming the presence of one or more of the following conditions:
the steam trap is cold if the temperature of the steam at the inlet (205) and the temperature of the condensate (250) in the collection volume (204) are determined to be below a predetermined value for a predetermined period,
the valve (202) has failed open if the temperature of the steam at the inlet (205) and the temperature of the condensate (250) in the collection volume (204) both exceed a predetermined value for a predetermined period and are equal to one another,
the valve (202) has failed shut if the temperature of the steam at the inlet (205) and the temperature of the condensate (250) in the collection volume (204) are both below a predetermined value for a predetermined period and are equal to one another,
the first sensor has failed if the output of the first sensor is open circuit,
the second sensor has failed if the output of the second sensor is open circuit,
and
the steam trap has flooded if the difference in temperature between the steam at the inlet (205) and the condensate (250) in the collection volume (204) exceeds a maximum subcool value for a predetermined period.
13. The steam trap as claimed in any of claims 1-12, wherein an exterior surface of the collection chamber (206) is provided with cooling fins.

Dated this the 01st day of January 2024.


JYOTISIKHA DEKA
[IN/PA-3700]
of SUBRAMANIAM & ASSOCIATES
Attorneys for the applicants