A system comprising: a transformer comprising a valve controlled port for use when accessing oil contained inside the transformer; a bi-directional oil-flow adapter that is attached to the valve-controlled port of the transformer, the bi-directional oil-flow adapter comprising: an oil outlet port configured to output an oil sample acquired from the transformer via the valve-controlled port and the bi-directional oil-flow adapter; a first conduit contained inside the bi-directional oil-flow adapter, the first conduit having a first cross-sectional area that is selected to provide a first oil flow velocity to the oil sample when flowing from the valve-controlled port and through the bi-directional oil-flow adapter to the oil outlet port; an oil inlet port configured to accept an inflow of a volume of oil into the bi-directional oil-flow adapter; and a second conduit contained inside the bi-directional oil-flow adapter, the second conduit having a second cross-sectional area that is smaller than the first cross-sectional area, the second cross-sectional area selected to provide a second oil flow velocity to the volume of oil when flowing from the oil inlet port and through the bi-directional oil-flow adapter into the valve-controlled port, the second oil flow velocity being higher than the first oil flow velocity; a dissolved gas analyzer coupled to the oil outlet port of the bi-directional oil-flow adapter, the dissolved gas analyzer being operable to analyze the oil sample for evaluating at least one gas content of the oil sample; a purge tank configured to store the volume of oil; and a pump that is operable to pump the volume of oil from the purge tank and into the oil inlet port of the bi-directional oil-flow adapter. a transformer comprising a valve controlled port for use when accessing oil contained inside the transformer; a bi-directional oil-flow adapter that is attached to the valve-controlled port of the transformer, the bi-directional oil-flow adapter comprising: an oil outlet port configured to output an oil sample acquired from the transformer via the valve-controlled port and the bi-directional oil-flow adapter; a first conduit contained inside the bi-directional oil-flow adapter, the first conduit having a first cross-sectional area that is selected to provide a first oil flow velocity to the oil sample when flowing from the valve-controlled port and through the bi-directional oil-flow adapter to the oil outlet port; an oil inlet port configured to accept an inflow of a volume of oil into the bi-directional oil-flow adapter; and a second conduit contained inside the bi-directional oil-flow adapter, the second conduit having a second cross-sectional area that is smaller than the first cross-sectional area, the second cross-sectional area selected to provide a second oil flow velocity to the volume of oil when flowing from the oil inlet port and through the bi-directional oil-flow adapter into the valve-controlled port, the second oil flow velocity being higher than the first oil flow velocity; an oil outlet port configured to output an oil sample acquired from the transformer via the valve-controlled port and the bi-directional oil-flow adapter; a first conduit contained inside the bi-directional oil-flow adapter, the first conduit having a first cross-sectional area that is selected to provide a first oil flow velocity to the oil sample when flowing from the valve-controlled port and through the bi-directional oil-flow adapter to the oil outlet port; an oil inlet port configured to accept an inflow of a volume of oil into the bi-directional oil-flow adapter; and a second conduit contained inside the bi-directional oil-flow adapter, the second conduit having a second cross-sectional area that is smaller than the first cross-sectional area, the second cross-sectional area selected to provide a second oil flow velocity to the volume of oil when flowing from the oil inlet port and through the bi-directional oil-flow adapter into the valve-controlled port, the second oil flow velocity being higher than the first oil flow velocity; a dissolved gas analyzer coupled to the oil outlet port of the bi-directional oil-flow adapter, the dissolved gas analyzer being operable to analyze the oil sample for evaluating at least one gas content of the oil sample; a purge tank configured to store the volume of oil; and a pump that is operable to pump the volume of oil from the purge tank and into the oil inlet port of the bi-directional oil-flow adapter.