Centrifugal separator and method of controlling intermittent discharge by monitoring flow through the separator

Patent metadata

Field	Value
Publication number	US-10086384-B2
Application number	US-201314387191-A
Country	US
Kind code	B2
Filing date	Mar 22, 2013
Priority date	Mar 27, 2012
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

The invention relates to a centrifugal separator having a separation space with a set of separation plates, an inlet configured to feed a fluid product to be separated into the separation space, the inlet and the separation space being connected in a pressure mediating manner, a first and a second outlet extending from the separation space for discharge of a two phases of the product. A discharge control system is configured to trigger the opening of the second outlet upon a trigger condition, wherein the discharge control system comprises a sensor arranged to determine the inlet pressure and/or the inlet flow of fluid product, and the trigger condtion is associated with a decrease in inlet flow in relation to inlet pressure, indicating an increasing flow resistance downstream of the inlet. The invention further relates to a discharge control system and a method of controlling the intermittent discharge of a centrifugal separator.

First claim

The invention claimed is:

1. A centrifugal separator comprising:
a frame;
a rotor arranged for rotation in the frame around a rotational axis and forming within itself a separation space;
an inlet configured to feed a fluid product to be separated into the separation space, wherein the separation space is connected to the inlet;
a first outlet extending from the radially inner portion of the separation space for discharge of a first phase of the product;
a second outlet extending from the radially outer portion of the separation space for intermittent discharge of a second phase of the product;
an inlet pressure sensor arranged to determine an inlet pressure of the fluid product provided to the separation space;
a closure for the second outlet having a closed position and an open position; and
a discharge control system configured to trigger the opening of the closure based on the inlet pressure measured by the inlet pressure sensor,
wherein the first phase of the product has a lower density than the second phase of the product.

2. The centrifugal separator according to claim 1 , wherein the discharge control system comprises an outlet pressure sensor arranged to determine the outlet pressure in the first outlet, and
wherein the inlet pressure is compared to the outlet pressure to calculate a pressure drop between the inlet and the first outlet to trigger the opening of the closure.

3. The centrifugal separator according to claim 1 , further comprising a pump connected to the first outlet,
wherein the inlet pressure is compared to the pressure contribution of the pump to the outlet pressure to trigger the opening of the closure.

4. The centrifugal separator according to claim 1 , wherein the inlet is a hermetic inlet.

5. The centrifugal separator according claim 1 , wherein the inlet comprises an inlet tube configured to be immersed in fluid product fed into the rotor during normal operation of the centrifugal separator.

6. The centrifugal separator according to claim 5 , wherein the inlet tube comprises a flange that extends outwardly in a radial direction such that the flange is immersed in fluid product fed into the rotor during normal operation.

7. The centrifugal separator according to claim 5 , wherein the rotor comprises a set of discs configured to accelerate fluid product being fed into the separation space.

8. The centrifugal separator according to claim 1 , wherein the trigger condition is a ratio between the amount of flow of fluid product fed into the centrifugal separator and the inlet pressure.

9. A centrifugal separator, the centrifugal separator comprising:
a frame;
a rotor arranged for rotation in the frame around a rotational axis and forming within itself a separation space, wherein a set of separation plates is arranged, extending from a radially outer portion of the separation space to a radially inner portion of the separation space;
an inlet configured to feed a fluid product to be separated into the separation space, wherein the centrifugal separator is configured such that the separation space is connected to the inlet;
a first outlet extending from the radially inner portion of the separation space for discharge of a first phase of the product;
a second outlet extending from the radially outer portion of the separation space for intermittent discharge of a second phase of the product;
a closure for the second outlet having a closed position and an open position; and
a sensor detecting a pressure at the inlet,
a discharge control system for opening the closure for the second outlet based on the detected pressure at the inlet of fluid product provided to the separation space.

10. A method for controlling the intermittent discharge of a centrifugal separator, said method comprising the steps of:
supplying a liquid through an inlet;
separating the liquid into a first phase and a second phase;
removing the first phase through a first outlet;
removing the second phase through a second outlet, the second outlet having a closure, the closure having a closed positon and an open position;
detecting a pressure in the inlet of the centrifugal separator;
determining the flow of fluid product fed into the inlet of the centrifugal separator;
detecting a trigger condition, the trigger condition being the detected pressure in the inlet of fluid product provided to the separation space or the flow of the liquid to the inlet;
opening of the second outlet to discharge the second phase of the product based on the trigger condition.

11. The method according to claim 10 , wherein the trigger condition is a ratio between the amount of flow of fluid product fed into the centrifugal separator and the square root of the inlet pressure falling below a threshold value.

12. The method according to claim 10 , wherein the trigger condition is a pressure at the inlet increasing more than a predetermined amount.

13. The method according to claim 10 , wherein the trigger condition is a flow rate at the inlet decreasing more than a predetermined amount.

14. The centrifugal separator according to claim 1 , wherein the closure is a slide movable in an axial direction of the rotor.

15. The centrifugal separator according to claim 9 , wherein the closure is a slide movable in an axial direction of the rotor.

16. The centrifugal separator according to claim 9 , wherein the trigger condition is the pressure at the inlet increasing more than a predetermined amount.

17. The centrifugal separator according to claim 9 , wherein the trigger condition is a flow rate at the inlet decreasing more than a predetermined amount.

18. The centrifugal separator according to claim 9 , wherein the trigger condition is a ratio between the amount of flow of fluid product fed into the centrifugal separator and the inlet pressure falling below a threshold value.

Assignees

• Alfa Laval Corp Ab

Inventors

• Thorwid Peter
• Isaksson Roland
• Moberg Hans
• Häggmark Carl
• Krook Göran

Classifications

• B04B13/00

  Control arrangements specially designed for centrifuges; Program control of centrifuges (control arrangements for feed, charge or discharge B04B11/00) · CPC title

• B04B1/14

  with periodical discharge · CPC title

• B04B11/04 Primary

  Periodical feeding or discharging; Control arrangements therefor · CPC title

• B04B1/08

  of conical shape · CPC title