Constant gas injection valve

The utility model relates to a constant steam injection valve, and pertains to oil well steam injection tools. The oil well adopting fixed construction in steam injection has the shortcoming of incorrect open area adjustment. Therefore, the utility model includes an upper contact, a central body, a outer barrel, an adjustable valve, a spring, a gland, a sealing body, an adjustable ring, an adjustable screw, an automatic adjustor outer bushing and an automatic adjustor. The upper contact (1) is provided with a vapor lock (14) therein and is connected with the central body (2). The upper contact is connected with the gland (8) and the adjustable ring (11) outside in order. An automatically adjustor outer bushing (4) is positioned between the central body (2) and the outer barrel (3). The automatic adjustor (5) is arranged below the automatic adjustor outer bushing and is connected with the adjustable valve (6). Two ends of the spring (7) are blocked on the steps of the adjustable valve (6) and the central body (2). The sealing body (9) is positioned between the gland (8) and the adjustable ring (11). The outer barrel (3) is provided with through holes (13) distributed evenly. In work, the utility model could guarantee the consistency of the steam injection flow amount and the correctness of the steam injection unit amount, inject into the middle and low filter layers and improve the oil well output, with the advantages of simple structure and convenient usage.